Sample records for erode native pollination
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Corridors restore animal-mediated pollination in fragmented tropical forest landscapes
Kormann, Urs; Scherber, Christoph; Tscharntke, Teja; Klein, Nadja; Larbig, Manuel; Valente, Jonathon J.; Hadley, Adam S.; Betts, Matthew G.
2016-01-01
Tropical biodiversity and associated ecosystem functions have become heavily eroded through habitat loss. Animal-mediated pollination is required in more than 94% of higher tropical plant species and 75% of the world's leading food crops, but it remains unclear if corridors avert deforestation-driven pollination breakdown in fragmented tropical landscapes. Here, we used manipulative resource experiments and field observations to show that corridors functionally connect neotropical forest fragments for forest-associated hummingbirds and increase pollen transfer. Further, corridors boosted forest-associated pollinator availability in fragments by 14.3 times compared with unconnected equivalents, increasing overall pollination success. Plants in patches without corridors showed pollination rates equal to bagged control flowers, indicating pollination failure in isolated fragments. This indicates, for the first time, that corridors benefit tropical forest ecosystems beyond boosting local species richness, by functionally connecting mutualistic network partners. We conclude that small-scale adjustments to landscape configuration safeguard native pollinators and associated pollination services in tropical forest landscapes. PMID:26817765
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An invasive plant alters pollinator-mediated phenotypic selection on a native congener.
Beans, Carolyn M; Roach, Deborah A
2015-01-01
• Recent studies suggest that invasive plants compete reproductively with native plants by reducing the quantity or quality of pollinator visits. Although these studies have revealed ecological consequences of pollinator-mediated competition between invasive and native plants, the evolutionary outcomes of these interactions remain largely unexplored.• We studied the ecological and evolutionary impact of pollinator-mediated competition with an invasive jewelweed, Impatiens glandulifera, on a co-occurring native congener, I. capensis. Using a pollinator choice experiment, a hand pollination experiment, and a selection analysis, we addressed the following questions: (1) Do native pollinators show preference for the invasive or native jewelweed, and do they move between the two species? (2) Does invasive jewelweed pollen inhibit seed production in the native plant? (3) Does the invasive jewelweed alter phenotypic selection on the native plant's floral traits?• The pollinator choice experiment showed that pollinators strongly preferred the invasive jewelweed. The hand pollination experiment demonstrated that invasive pollen inhibited seed production in the native plant. The selection analysis showed that the presence of the invasive jewelweed altered phenotypic selection on corolla height in the native plant.• Invasive plants have the potential to alter phenotypic selection on floral traits in native plant populations. If native plants can evolve in response to this altered selection pressure, the evolution of floral traits may play an important role in permitting long-term coexistence of native and invasive plants. © 2015 Botanical Society of America, Inc.
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Two invasive acacia species secure generalist pollinators in invaded communities
NASA Astrophysics Data System (ADS)
Montesinos, Daniel; Castro, Sílvia; Rodríguez-Echeverría, Susana
2016-07-01
Exotic entomophilous plants need to establish effective pollinator interactions in order to succeed after being introduced into a new community, particularly if they are obligatory outbreeders. By establishing these novel interactions in the new non-native range, invasive plants are hypothesised to drive changes in the composition and functioning of the native pollinator community, with potential impacts on the pollination biology of native co-flowering plants. We used two different sites in Portugal, each invaded by a different acacia species, to assess whether two native Australian trees, Acacia dealbata and Acacia longifolia, were able to recruit pollinators in Portugal, and whether the pollinator community visiting acacia trees differed from the pollinator communities interacting with native co-flowering plants. Our results indicate that in the invaded range of Portugal both acacia species were able to establish novel mutualistic interactions, predominantly with generalist pollinators. For each of the two studied sites, only two other co-occurring native plant species presented partially overlapping phenologies. We observed significant differences in pollinator richness and visitation rates among native and non-native plant species, although the study of β diversity indicated that only the native plant Lithodora fruticosa presented a differentiated set of pollinator species. Acacias experienced a large number of visits by numerous pollinator species, but massive acacia flowering resulted in flower visitation rates frequently lower than those of the native co-flowering species. We conclude that the establishment of mutualisms in Portugal likely contributes to the effective and profuse production of acacia seeds in Portugal. Despite the massive flowering of A. dealbata and A. longifolia, native plant species attained similar or higher visitation rates than acacias.
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Stubbs, C.J.; Drummond, F.; Ginsberg, H.
2007-01-01
Invasive plant species can have profound negative effects on natural communities by competively excluding native species. Berberis thunbergii (Japanese barberry), Frangula alnus (glossy or alder buckthorn) and Lythrum salicaria (purple loosestrife) are invasive species known to reduce native plant diversity and are thus of great concern to Acadia National Park. Pollinators visit them for nectar and pollen. The effects of invasive plant species on pollinator behavior were investigated by comparing pollinator visitation to co-flowering native and invasive species with visitation to native species growing alone. The effect of invasives on pollination of native plants was studied by comparing fruit set in patches of the native species growing near invasives with patches far from invasive species in Acadia National Park. The coflowering pairs were as follows: in the spring native Vaccinium angustifolium (lowbush blueberry) was paired with B. thunbergii; in early summer native Viburnum nudum (wild raisin) was paired with F. alnus ; in late summer native Spiraea alba (meadowsweet) was paired with L. salicaria. We investigated whether these invasives competed with native plants for pollinators in Acadia and thus negatively affected native plant reproduction. Our objectives were to determine: 1) the influence, if any, of each invasive on pollinator visitation to a co-flowering native species, 2) factors that might affect visitation, 3) invasive pollen transfer to native plants, and 4) whether invasives influence native plant reproduction (fruit set). Our findings indicate that at times the number of flower visitors to natives was lower or the species composition of visitors different when invasives were present, that invasives sometimes attracted more pollinators, that generally the invasives were more rewarding as far as nectar and pollen availability for pollinators, and that generally native plant fruit set and seed set was not significantly lowered in the presence of the invasive. In fact, in one year fruit set of S. alba was significantly greater in the presence of L. salicaria. The number of invasive pollen grains on native stigmas was extremely low; on average less than one grain per stigma. These fruit set and pollen deposition findings indicate that native plant reproduction was not adversely affected in the short term by these invasive species and that therefore competition between the native and invasive species for pollinators did not occur. Native bee populations monitored in 2004-2005 at sites with and without B. thunbergii and/or F. alnus indicated a greater abundance of native bees at sites with these invasives present. Native bees collected from the native and invasive plants were compared with historical records to assess whether invasive plants favor different bee species than those that formerly predominated on Mount Desert Island. This does not appear to be the case. Several species of bumble bees (Bombus spp.) as well as nine solitary bee species were found that were not documented by the Procter surveys of 1917-1940. Collecting of native bees was limited to the study plants, which may, in part, explain why some bee species documented in the Procter Surveys were not found in the present research. A field guide for identification of native bumble bees has been produced to help Park Natural Resource personnel monitor the status of native bee populations in Acadia. Other educational materials were also developed, aimed at educating Park visitors by exposing them to: 1) the role of native plants and their bee pollinators in terrestrial ecosystems; 2) the effects of invasive plants on native plant-pollinator mutualisms; 3) the need for conserving native bees and other pollinators; and 4) conservation strategies for protecting and enhancing native plant-pollinator mutualisms in the Park. Based on the present findings, Acadia Park Resource Management personnel should continue to closely
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Jakobsson, Anna; Padrón, Benigno
2014-01-01
Invasive plants may compete with native species for abiotic factors as light, space and nutrients, and have also been shown to affect native pollination interactions. Studies have mainly focused on how invasive plants affect pollinator behaviour, i.e. attraction of pollinators to or away from native flowers. However, when an invasive plant provides resources utilized by native pollinators this could increase pollinator population sizes and thereby pollination success in natives. Effects mediated through changes in pollinator population sizes have been largely ignored in previous studies, and the dominance of negative interactions suggested by meta-analyses may therefore be biased. We investigated the impact of the invasive Lupinus polyphyllus on pollination in the native Lotus corniculatus using a study design comparing invaded and uninvaded sites before and after the flowering period of the invasive. We monitored wild bee abundance in transects, and visit rate and seed production of potted Lotus plants. Bumblebee abundance increased 3.9 times in invaded sites during the study period, whereas it was unaltered in uninvaded sites. Total visit rate per Lotus plant increased 2.1 times in invaded sites and decreased 4.4 times in uninvaded sites. No corresponding change in seed production of Lotus was found. The increase in visit rate to Lotus was driven by an increase in solitary bee visitation, whereas mainly bumblebees were observed to visit the invasive Lupinus. The mechanism by which the invasive increases pollinator visit rates to Lotus could be increased availability of other flower resources for solitary bees when bumblebees forage on Lupinus.
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Contrasting effects of invasive plants in plant-pollinator networks.
Bartomeus, Ignasi; Vilà, Montserrat; Santamaría, Luís
2008-04-01
The structural organization of mutualism networks, typified by interspecific positive interactions, is important to maintain community diversity. However, there is little information available about the effect of introduced species on the structure of such networks. We compared uninvaded and invaded ecological communities, to examine how two species of invasive plants with large and showy flowers (Carpobrotus affine acinaciformis and Opuntia stricta) affect the structure of Mediterranean plant-pollinator networks. To attribute differences in pollination to the direct presence of the invasive species, areas were surveyed that contained similar native plant species cover, diversity and floral composition, with or without the invaders. Both invasive plant species received significantly more pollinator visits than any native species and invaders interacted strongly with pollinators. Overall, the pollinator community richness was similar in invaded and uninvaded plots, and only a few generalist pollinators visited invasive species exclusively. Invasive plants acted as pollination super generalists. The two species studied were visited by 43% and 31% of the total insect taxa in the community, respectively, suggesting they play a central role in the plant-pollinator networks. Carpobrotus and Opuntia had contrasting effects on pollinator visitation rates to native plants: Carpobrotus facilitated the visit of pollinators to native species, whereas Opuntia competed for pollinators with native species, increasing the nestedness of the plant-pollinator network. These results indicate that the introduction of a new species to a community can have important consequences for the structure of the plant-pollinator network.
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Lack of pollinators limits fruit production in commercial blueberry (Vaccinium corymbosum).
Benjamin, Faye E; Winfree, Rachael
2014-12-01
Modern agriculture relies on domesticated pollinators such as the honey bee (Apis mellifera L.), and to a lesser extent on native pollinators, for the production of animal-pollinated crops. There is growing concern that pollinator availability may not keep pace with increasing agricultural production. However, whether crop production is in fact pollen-limited at the field scale has rarely been studied. Here, we ask whether commercial highbush blueberry (Vaccinium corymbosum L.) production in New Jersey is limited by a lack of pollination even when growers provide honey bees at recommended densities. We studied two varieties of blueberry over 3 yr to determine whether blueberry crop production is pollen-limited and to measure the relative contributions of honey bees and native bees to blueberry pollination. We found two lines of evidence for pollen limitation. First, berries receiving supplemental hand-pollination were generally heavier than berries receiving ambient pollination. Second, mean berry mass increased significantly and nonasymptotically with honey bee flower visitation rate. While honey bees provided 86% of pollination and thus drove the findings reported above, native bees still contributed 14% of total pollination even in our conventionally managed, high-input agricultural system. Honey bees and native bees were also similarly efficient as pollinators on a per-visit basis. Overall, our study shows that pollination can be a limiting factor in commercial fruit production. Yields might increase with increased honey bee stocking rates and improved dispersal of hives within crop fields, and with habitat restoration to increase pollination provided by native bees.
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Rader, Romina; Reilly, James; Bartomeus, Ignasi; Winfree, Rachael
2013-10-01
If climate change affects pollinator-dependent crop production, this will have important implications for global food security because insect pollinators contribute to production for 75% of the leading global food crops. We investigate whether climate warming could result in indirect impacts upon crop pollination services via an overlooked mechanism, namely temperature-induced shifts in the diurnal activity patterns of pollinators. Using a large data set on bee pollination of watermelon crops, we predict how pollination services might change under various climate change scenarios. Our results show that under the most extreme IPCC scenario (A1F1), pollination services by managed honey bees are expected to decline by 14.5%, whereas pollination services provided by most native, wild taxa are predicted to increase, resulting in an estimated aggregate change in pollination services of +4.5% by 2099. We demonstrate the importance of native biodiversity in buffering the impacts of climate change, because crop pollination services would decline more steeply without the native, wild pollinators. More generally, our study provides an important example of how biodiversity can stabilize ecosystem services against environmental change. © 2013 John Wiley & Sons Ltd.
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Indirect interactions between invasive and native plants via pollinators
NASA Astrophysics Data System (ADS)
Kaiser-Bunbury, Christopher N.; Müller, Christine B.
2009-03-01
In generalised pollination systems, the presence of alien plant species may change the foraging behaviour of pollinators on native plant species, which could result in reduced reproductive success of native plant species. We tested this idea of indirect interactions on a small spatial and temporal scale in a field study in Mauritius, where the invasive strawberry guava, Psidium cattleianum, provides additional floral resources for insect pollinators. We predicted that the presence of flowering guava would indirectly and negatively affect the reproductive success of the endemic plant Bertiera zaluzania, which has similar flowers, by diverting shared pollinators. We removed P. cattleianum flowers within a 5-m radius from around half the B. zaluzania target plants (treatment) and left P. cattleianum flowers intact around the other half (control). By far, the most abundant and shared pollinator was the introduced honey bee, Apis mellifera, but its visitation rates to treatment and control plants were similar. Likewise, fruit and seed set and fruit size and weight of B. zaluzania were not influenced by the presence of P. cattleianum flowers. Although other studies have shown small-scale effects of alien plant species on neighbouring natives, we found no evidence for such negative indirect interactions in our system. The dominance of introduced, established A. mellifera indicates their replacement of native insect flower visitors and their function as pollinators of native plant species. However, the pollination effectiveness of A. mellifera in comparison to native pollinators is unknown.
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Minimal Effects of an Invasive Flowering Shrub on the Pollinator Community of Native Forbs
Chung, Y. Anny; Burkle, Laura A.; Knight, Tiffany M.
2014-01-01
Biological invasions can strongly influence species interactions such as pollination. Most of the documented effects of exotic plant species on plant-pollinator interactions have been observational studies using single pairs of native and exotic plants, and have focused on dominant exotic plant species. We know little about how exotic plants alter interactions in entire communities of plants and pollinators, especially at low to medium invader densities. In this study, we began to address these gaps by experimentally removing the flowers of a showy invasive shrub, Rosa multiflora, and evaluating its effects on the frequency, richness, and composition of bee visitors to co-flowering native plants. We found that while R. multiflora increased plot-level richness of bee visitors to co-flowering native plant species at some sites, its presence had no significant effects on bee visitation rate, visitor richness, bee community composition, or abundance overall. In addition, we found that compared to co-flowering natives, R. multiflora was a generalist plant that primarily received visits from generalist bee species shared with native plant species. Our results suggest that exotic plants such as R. multiflora may facilitate native plant pollination in a community context by attracting a more diverse assemblage of pollinators, but have limited and idiosyncratic effects on the resident plant-pollinator network in general. PMID:25343718
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Effects of non-native Melilotus albus on pollination and reproduction in two boreal shrubs.
Spellman, Katie V; Schneller, Laura C; Mulder, Christa P H; Carlson, Matthew L
2015-10-01
The establishment of abundantly flowered, highly rewarding non-native plant species is expected to have strong consequences for native plants through altered pollination services, particularly in boreal forest where the flowering season is short and the pollinator pool is small. In 18 boreal forest sites, we added flowering Melilotus albus to some sites and left some sites as controls in 2 different years to test if the invasive plant influences the pollination and reproductive success of two co-flowering ericaceous species: Vaccinium vitis-idaea and Rhododendron groenlandicum. We found that M. albus increased the pollinator diversity and tended to increase visitation rates to the focal native plant species compared to control sites. Melilotus albus facilitated greater seed production per berry in V. vitis-idaea when we added 120 plants compared to when we added 40 plants or in control sites. In R. groenlandicum, increasing numbers of M. albus inflorescences lowered conspecific pollen loads and percentage of flowers pollinated; however, no differences in fruit set were detected. The number of M. albus inflorescences had greater importance in explaining R. groenlandicum pollination compared to other environmental variables such as weather and number of native flowers, and had greater importance in lower quality black spruce sites than in mixed deciduous and white spruce sites for explaining the percentage of V. vitis-idaea flowers pollinated. Our data suggest that the identity of new pollinators attracted to the invaded sites, degree of shared pollinators between invasive and native species, and variation in resource limitation among sites are likely determining factors in the reproductive responses of boreal native plants in the presence of an invasive.
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Positive and Negative Impacts of Non-Native Bee Species around the World.
Russo, Laura
2016-11-28
Though they are relatively understudied, non-native bees are ubiquitous and have enormous potential economic and environmental impacts. These impacts may be positive or negative, and are often unquantified. In this manuscript, I review literature on the known distribution and environmental and economic impacts of 80 species of introduced bees. The potential negative impacts of non-native bees include competition with native bees for nesting sites or floral resources, pollination of invasive weeds, co-invasion with pathogens and parasites, genetic introgression, damage to buildings, affecting the pollination of native plant species, and changing the structure of native pollination networks. The potential positive impacts of non-native bees include agricultural pollination, availability for scientific research, rescue of native species, and resilience to human-mediated disturbance and climate change. Most non-native bee species are accidentally introduced and nest in stems, twigs, and cavities in wood. In terms of number of species, the best represented families are Megachilidae and Apidae, and the best represented genus is Megachile . The best studied genera are Apis and Bombus , and most of the species in these genera were deliberately introduced for agricultural pollination. Thus, we know little about the majority of non-native bees, accidentally introduced or spreading beyond their native ranges.
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Positive and Negative Impacts of Non-Native Bee Species around the World
Russo, Laura
2016-01-01
Though they are relatively understudied, non-native bees are ubiquitous and have enormous potential economic and environmental impacts. These impacts may be positive or negative, and are often unquantified. In this manuscript, I review literature on the known distribution and environmental and economic impacts of 80 species of introduced bees. The potential negative impacts of non-native bees include competition with native bees for nesting sites or floral resources, pollination of invasive weeds, co-invasion with pathogens and parasites, genetic introgression, damage to buildings, affecting the pollination of native plant species, and changing the structure of native pollination networks. The potential positive impacts of non-native bees include agricultural pollination, availability for scientific research, rescue of native species, and resilience to human-mediated disturbance and climate change. Most non-native bee species are accidentally introduced and nest in stems, twigs, and cavities in wood. In terms of number of species, the best represented families are Megachilidae and Apidae, and the best represented genus is Megachile. The best studied genera are Apis and Bombus, and most of the species in these genera were deliberately introduced for agricultural pollination. Thus, we know little about the majority of non-native bees, accidentally introduced or spreading beyond their native ranges. PMID:27916802
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Threatened pollination systems in native flora of the Ogasawara (Bonin) Islands.
Abe, Tetsuto
2006-08-01
Various alien species have been introduced to the Ogasawara Islands (Japan). A survey was made investigating whether the native pollination systems fit an 'island syndrome' (biasing the flora to dioecy, with subdued, inconspicuous flowers) and whether alien species have disrupted the native pollination network. Flower visitors and floral traits were determined in the field (12 islands) and from the literature. Associations among floral traits such as sexual expression, flower colour and flower shape were tested. Among the 269 native flowering plants, 74.7 % are hermaphroditic, 13.0 % are dioecious and 7.1 % are monoecious. Classification by flower colour revealed that 36.0 % were white, 21.6 % green and 13.8 % yellow. Woody species (trees and shrubs) comprised 36.5 % of the flora and were associated with dioecy and white flowers. Solitary, endemic small bees were the dominant flower visitors and visited 66.7 % of the observed species on satellite islands where the native pollination networks are preserved. In contrast to the situation on the satellite islands, introduced honeybees were the most dominant pollinator (visiting 60.1 % of observed species) on the two main islands, Chichi-jima and Haha-jima, and had spread to satellite islands near Chichi-jima Island. The island syndrome for pollination systems in the Ogasawara Islands was evident in a high percentage of dioecious species, the subdued colour of the native flora and solitary flower visitors on satellite islands. The shape and colour adaptations of several flowers suggested native pollination niches for long-proboscis moths and carpenter bees. However, the domination and expansion of introduced honeybees have the potential for disruption of the native pollination network in the two main, and several satellite, islands of the Ogasawara Islands.
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Rosemary L. Pendleton; Burton K. Pendleton; Deborah Finch
2011-01-01
Throughout the southwestern U.S., riparian gallery forests of cottonwood and willow are being invaded by woody exotics, primarily Russian olive and salt cedar. We wondered what effect this might have on native pollinator populations. Pollinators are indispensable contributors to biodiversity, ecosystem health, and human food production. Recent declines in pollinator...
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Gibbs, Jason; Elle, Elizabeth; Bobiwash, Kyle; Haapalainen, Tiia; Isaacs, Rufus
2016-01-01
Highbush blueberry yields are dependent on pollination by bees, and introduction of managed honey bees is the primary strategy used for pollination of this crop. Complementary pollination services are also provided by wild bees, yet highbush blueberry is increasingly grown in regions outside its native range where wild bee communities may be less adapted to the crop and growers may still be testing appropriate honey bee stocking densities. To contrast crop pollination in native and non-native production regions, we sampled commercial 'Bluecrop' blueberry fields in British Columbia and Michigan with grower-selected honey bee stocking rates (0-39.5 hives per ha) to compare bee visitors to blueberry flowers, pollination and yield deficits, and how those vary with local- and landscape-scale factors. Observed and Chao-1 estimated species richness, as well as Shannon diversity of wild bees visiting blueberries were significantly higher in Michigan where the crop is within its native range. The regional bee communities were also significantly different, with Michigan farms having greater dissimilarity than British Columbia. Blueberry fields in British Columbia had fewer visits by honey bees than those in Michigan, irrespective of stocking rate, and they also had lower berry weights and a significant pollination deficit. In British Columbia, pollination service increased with abundance of wild bumble bees, whereas in Michigan the abundance of honey bees was the primary predictor of pollination. The proportion of semi-natural habitat at local and landscape scales was positively correlated with wild bee abundance in both regions. Wild bee abundance declined significantly with distance from natural borders in Michigan, but not in British Columbia where large-bodied bumble bees dominated the wild bee community. Our results highlight the varying dependence of crop production on different types of bees and reveal that strategies for pollination improvement in the same crop can vary greatly across production regions.
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Gibbs, Jason; Elle, Elizabeth; Bobiwash, Kyle; Haapalainen, Tiia; Isaacs, Rufus
2016-01-01
Highbush blueberry yields are dependent on pollination by bees, and introduction of managed honey bees is the primary strategy used for pollination of this crop. Complementary pollination services are also provided by wild bees, yet highbush blueberry is increasingly grown in regions outside its native range where wild bee communities may be less adapted to the crop and growers may still be testing appropriate honey bee stocking densities. To contrast crop pollination in native and non-native production regions, we sampled commercial ‘Bluecrop’ blueberry fields in British Columbia and Michigan with grower-selected honey bee stocking rates (0–39.5 hives per ha) to compare bee visitors to blueberry flowers, pollination and yield deficits, and how those vary with local- and landscape-scale factors. Observed and Chao-1 estimated species richness, as well as Shannon diversity of wild bees visiting blueberries were significantly higher in Michigan where the crop is within its native range. The regional bee communities were also significantly different, with Michigan farms having greater dissimilarity than British Columbia. Blueberry fields in British Columbia had fewer visits by honey bees than those in Michigan, irrespective of stocking rate, and they also had lower berry weights and a significant pollination deficit. In British Columbia, pollination service increased with abundance of wild bumble bees, whereas in Michigan the abundance of honey bees was the primary predictor of pollination. The proportion of semi-natural habitat at local and landscape scales was positively correlated with wild bee abundance in both regions. Wild bee abundance declined significantly with distance from natural borders in Michigan, but not in British Columbia where large-bodied bumble bees dominated the wild bee community. Our results highlight the varying dependence of crop production on different types of bees and reveal that strategies for pollination improvement in the same crop can vary greatly across production regions. PMID:27391969
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Groff, Shannon C.; Loftin, Cynthia S.; Drummond, Frank; Bushmann, Sara; McGill, Brian J.
2016-01-01
Non-native honeybees historically have been managed for crop pollination, however, recent population declines draw attention to pollination services provided by native bees. We applied the InVEST Crop Pollination model, developed to predict native bee abundance from habitat resources, in Maine's wild blueberry crop landscape. We evaluated model performance with parameters informed by four approaches: 1) expert opinion; 2) sensitivity analysis; 3) sensitivity analysis informed model optimization; and, 4) simulated annealing (uninformed) model optimization. Uninformed optimization improved model performance by 29% compared to expert opinion-informed model, while sensitivity-analysis informed optimization improved model performance by 54%. This suggests that expert opinion may not result in the best parameter values for the InVEST model. The proportion of deciduous/mixed forest within 2000 m of a blueberry field also reliably predicted native bee abundance in blueberry fields, however, the InVEST model provides an efficient tool to estimate bee abundance beyond the field perimeter.
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The effects of crop intensification on the diversity of native pollinator communities
USDA-ARS?s Scientific Manuscript database
Recent increases in agricultural conversion are leading to a decline in native grasslands and natural resources critical for beneficial insects. However, little is known regarding how these regional changes are affecting pollinator diversity. Insect pollinators were collected at 12 locations in Broo...
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Threatened Pollination Systems in Native Flora of the Ogasawara (Bonin) Islands
ABE, TETSUTO
2006-01-01
• Background and Aims Various alien species have been introduced to the Ogasawara Islands (Japan). A survey was made investigating whether the native pollination systems fit an ‘island syndrome’ (biasing the flora to dioecy, with subdued, inconspicuous flowers) and whether alien species have disrupted the native pollination network. • Methods Flower visitors and floral traits were determined in the field (12 islands) and from the literature. Associations among floral traits such as sexual expression, flower colour and flower shape were tested. • Key Results Among the 269 native flowering plants, 74·7 % are hermaphroditic, 13·0 % are dioecious and 7·1 % are monoecious. Classification by flower colour revealed that 36·0 % were white, 21·6 % green and 13·8 % yellow. Woody species (trees and shrubs) comprised 36·5 % of the flora and were associated with dioecy and white flowers. Solitary, endemic small bees were the dominant flower visitors and visited 66·7 % of the observed species on satellite islands where the native pollination networks are preserved. In contrast to the situation on the satellite islands, introduced honeybees were the most dominant pollinator (visiting 60·1 % of observed species) on the two main islands, Chichi-jima and Haha-jima, and had spread to satellite islands near Chichi-jima Island. • Conclusions The island syndrome for pollination systems in the Ogasawara Islands was evident in a high percentage of dioecious species, the subdued colour of the native flora and solitary flower visitors on satellite islands. The shape and colour adaptations of several flowers suggested native pollination niches for long-proboscis moths and carpenter bees. However, the domination and expansion of introduced honeybees have the potential for disruption of the native pollination network in the two main, and several satellite, islands of the Ogasawara Islands. PMID:16790463
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Native plant development and deployment [Section VII
Jessica Wright; Kas Dumroese; Amy Symstad; Theresa Pitts-Singer; Jim Cane; Gary Krupnick; Peggy Olwell; Byron Love; Elizabeth Sellers; John Englert; Troy Wood
2015-01-01
Native plant materials are needed to create, enhance, or restore pollinator habitat. They provide critical foraging and breeding areas for wild and managed pollinator species, including transnational migratory species such as hummingbirds and monarch butterflies. Although many pollinators and plants are generalists, some have limited, obligate relationships (i.e., one...
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Species traits and network structure predict the success and impacts of pollinator invasions.
Valdovinos, Fernanda S; Berlow, Eric L; Moisset de Espanés, Pablo; Ramos-Jiliberto, Rodrigo; Vázquez, Diego P; Martinez, Neo D
2018-05-31
Species invasions constitute a major and poorly understood threat to plant-pollinator systems. General theory predicting which factors drive species invasion success and subsequent effects on native ecosystems is particularly lacking. We address this problem using a consumer-resource model of adaptive behavior and population dynamics to evaluate the invasion success of alien pollinators into plant-pollinator networks and their impact on native species. We introduce pollinator species with different foraging traits into network models with different levels of species richness, connectance, and nestedness. Among 31 factors tested, including network and alien properties, we find that aliens with high foraging efficiency are the most successful invaders. Networks exhibiting high alien-native diet overlap, fraction of alien-visited plant species, most-generalist plant connectivity, and number of specialist pollinator species are the most impacted by invaders. Our results mimic several disparate observations conducted in the field and potentially elucidate the mechanisms responsible for their variability.
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Resource diversity and landscape-level homogeneity drive native bee foraging.
Jha, Shalene; Kremen, Claire
2013-01-08
Given widespread declines in pollinator communities and increasing global reliance on pollinator-dependent crops, there is an acute need to develop a mechanistic understanding of native pollinator population and foraging biology. Using a population genetics approach, we determine the impact of habitat and floral resource distributions on nesting and foraging patterns of a critical native pollinator, Bombus vosnesenskii. Our findings demonstrate that native bee foraging is far more plastic and extensive than previously believed and does not follow a simple optimal foraging strategy. Rather, bumble bees forage further in pursuit of species-rich floral patches and in landscapes where patch-to-patch variation in floral resources is less, regardless of habitat composition. Thus, our results reveal extreme foraging plasticity and demonstrate that floral diversity, not density, drives bee foraging distance. Furthermore, we find a negative impact of paved habitat and a positive impact of natural woodland on bumble bee nesting densities. Overall, this study reveals that natural and human-altered landscapes can be managed for increased native bee nesting and extended foraging, dually enhancing biodiversity and the spatial extent of pollination services.
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Degradation of soil fertility can cancel pollination benefits in sunflower.
Tamburini, Giovanni; Berti, Antonio; Morari, Francesco; Marini, Lorenzo
2016-02-01
Pollination and soil fertility are important ecosystem services to agriculture but their relative roles and potential interactions are poorly understood. We explored the combined effects of pollination and soil fertility in sunflower using soils from a trial characterized by different long-term input management in order to recreate plausible levels of soil fertility. Pollinator exclusion was used as a proxy for a highly eroded pollination service. Pollination benefits to yield depended on soil fertility, i.e., insect pollination enhanced seed set and yield only under higher soil fertility indicating that limited nutrient availability may constrain pollination benefits. Our study provides evidence for interactions between above- and belowground ecosystem services, highlighting the crucial role of soil fertility in supporting agricultural production not only directly, but also indirectly through pollination. Management strategies aimed at enhancing pollination services might fail in increasing yield in landscapes characterized by high soil service degradation. Comprehensive knowledge about service interactions is therefore essential for the correct management of ecosystem services in agricultural landscapes.
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Robotic bees for crop pollination: Why drones cannot replace biodiversity.
Potts, Simon G; Neumann, Peter; Vaissière, Bernard; Vereecken, Nicolas J
2018-06-14
The notion that robotic crop pollination will solve the decline in pollinators has gained wide popularity recently (Fig. 1), and in March 2018 Walmart filed a patent for autonomous robot bees. However, w present six arguments showing that this is a technically and economically inviable 'solution' at present and poses substantial ecological and moral risks: (1) despite recent advances, robotic pollination is far from being able to replace bees to pollinate crops efficiently; (2) using robots is very unlikely to be economically viable; (3) there would be unacceptably high environmental costs; (4) wider ecosystems would be damaged; (5) it would erode the values of biodiversity; and, (6) relying on robotic pollination could actually lead to major food insecurity. Copyright © 2018 Elsevier B.V. All rights reserved.
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Bumble bee (Hymenoptera: Apidae) community structure on two sagebrush steppe sites in southern Idaho
Stephen P. Cook; Sara M. Birch; Frank W. Merickel; Carrie Caselton Lowe; Deborah Page-Dumroese
2011-01-01
Although sagebrush, Artemisia spp., does not require an insect pollinator, there are several native species of bumble bees, Bombus spp. (Hymenoptera: Apidae), that are present in sagebrush steppe ecosystems where they act as pollinators for various forbs and shrubs. These native pollinators contribute to plant productivity and reproduction. We captured 12 species of...
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Gross, Caroline L; Whitehead, Joshua D; Silveira de Souza, Camila; Mackay, David
2017-10-01
The extent of self-compatibility and reliance on pollinators for seed set are critical determinants of reproductive success in invasive plant species. Seed herbivores are commonly used as biocontrol agents but may also act as flower visitors, potentially resulting in pollination. However, such contrasting or potentially counterproductive interaction effects are rarely considered or evaluated for biological control programs. We investigated the breeding system and pollinators of Bitou Bush ( Chrysanthemoides monilifera ssp. rotundata ), an invasive species in Australia that has been the subject of biocontrol programs since 1987. We found the species to be obligate outcrossing in all six populations tested. From 150 video hours, we found 21 species of potential pollinators, including Mesoclanis polana , the Bitou Seedfly, native to South Africa and released in Australia as a biocontrol agent in 1996. Mesoclanis polana transferred pollen to stigmas and was the most common pollinator (52% of pollinator visits), followed by the syrphid fly Simosyrphus grandicornis (9%) and introduced honeybee, Apis mellifera (6.5%). Fruit-to-flower ratios ranged from 0.12 to 0.45 and were highest in the population with the greatest proportion of Mesoclanis polana visits. In an experimental trial, outside the naturalized range, the native bee Homalictus sphecodoides and the native syrphid Melangyna viridiceps were the primary pollinators, and fruit-to-flower ratios were 0.35, indicating that Bitou Bush would have ready pollinators if its range expanded inland. Synthesis . Invasive Bitou Bush requires pollinators, and this is effected by a range of generalist pollinators in eastern Australia including the Bitou Seedfly, introduced as a biocontrol agent, and the major pollinator detected in this study. Fruit-to-flower ratios were highest when the Bitou Seedfly was in high abundance. This study underscores the importance of evaluating the pollination biology of invasive species in their native ranges and prior to the introduction of biocontrol agents.
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Modeling changes in rill erodibility and critical shear stress on native surface roads
Randy B. Foltz; Hakjun Rhee; William J. Elliot
2008-01-01
This study investigated the effect of cumulative overland flow on rill erodibility and critical shear stress on native surface roads in central Idaho. Rill erodibility decreased exponentially with increasing cumulative overland flow depth; however, critical shear stress did not change. The study demonstrated that road erodibility on the studied road changes over the...
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Create a pollinator garden at your nursery: An emphasis on monarch butterflies
Thomas D. Landis; R. Kasten Dumroese; Matthew E. Horning
2014-01-01
We realize that this type of article is a departure for FNN readers but feel that it is important for forest, conservation, and native plant nurseries to be good environmental stewards. In addition, establishing a pollinator garden at your nursery can be good for business, too. Demonstrating the role and beauty of native plants and their pollinators, particulary in a...
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Kas Dumroese; Tara Luna
2016-01-01
The decline of insects that pollinate flowers is garnering more attention by land managers, policymakers, and the general public. Nursery managers who grow native trees, shrubs, and woody vines have a promising opportunity to showcase these species, marketing their contributions to pollinator health and other ecosystem services in urban and wild landscapes....
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Nectar minerals as regulators of flower visitation in stingless bees and nectar hoarding wasps.
Afik, Ohad; Delaplane, Keith S; Shafir, Sharoni; Moo-Valle, Humberto; Quezada-Euán, J Javier G
2014-05-01
Various nectar components have a repellent effect on flower visitors, and their adaptive advantages for the plant are not well understood. Persea americana (avocado) is an example of a plant that secretes nectar with repellent components. It was demonstrated that the mineral constituents of this nectar, mainly potassium and phosphate, are concentrated enough to repel honey bees, Apis mellifera, a pollinator often used for commercial avocado pollination. Honey bees, however, are not the natural pollinator of P. americana, a plant native to Central America. In order to understand the role of nectar minerals in plant-pollinator relationships, it is important to focus on the plant's interactions with its natural pollinators. Two species of stingless bees and one species of social wasp, all native to the Yucatan Peninsula, Mexico, part of the natural range of P. americana, were tested for their sensitivity to sugar solutions enriched with potassium and phosphate, and compared with the sensitivity of honey bees. In choice tests between control and mineral-enriched solutions, all three native species were indifferent for mineral concentrations lower than those naturally occurring in P. americana nectar. Repellence was expressed at concentrations near or exceeding natural concentrations. The threshold point at which native pollinators showed repellence to increasing levels of minerals was higher than that detected for honey bees. The results do not support the hypothesis that high mineral content is attractive for native Hymenopteran pollinators; nevertheless, nectar mineral composition may still have a role in regulating flower visitors through different levels of repellency.
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Competitive impacts of an invasive nectar thief on plant-pollinator mutualisms
Hanna, Cause; Foote, David; Kremen, Claire
2014-01-01
Plant–pollinator mutualisms are disrupted by a variety of competitive interactions between introduced and native floral visitors. The invasive western yellowjacket wasp, Vespula pensylvanica, is an aggressive nectar thief of the dominant endemic Hawaiian tree species, Metrosideros polymorpha. We conducted a large-scale, multiyear manipulative experiment to investigate the impacts of V. pensylvanica on the structure and behavior of the M. polymorpha pollinator community, including competitive mechanisms related to resource availability. Our results demonstrate that V. pensylvanica, through both superior exploitative and interference competition, influences resource partitioning and displaces native and nonnative M. polymorpha pollinators. Furthermore, the restructuring of the pollinator community due to V. pensylvanica competition and predation results in a significant decrease in the overall pollinator effectiveness and fruit set of M. polymorpha. This research highlights both the competitive mechanisms and contrasting effects of social insect invaders on plant–pollinator mutualisms and the role of competition in pollinator community structure.
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Goodell, Karen; Parker, Ingrid M
2017-01-01
Through competition for pollinators, invasive plants may suppress native flora. Community-level studies provide an integrative assessment of invasion impacts and insights into factors that influence the vulnerability of different native species. We investigated effects of the nonnative herb Lythrum salicaria on pollination of native species in 14 fens of the eastern United States. We compared visitors per flower for 122 native plant species in invaded and uninvaded fens and incorporated a landscape-scale experiment, removing L. salicaria flowers from three of the invaded fens. Total flower densities were more than three times higher in invaded than uninvaded or removal sites when L. salicaria was blooming. Despite an increase in number of visitors with number of flowers per area, visitors per native flower declined with increasing numbers of flowers. Therefore, L. salicaria invasion depressed visitation to native flowers. In removal sites, visitation to native flowers was similar to uninvaded sites, confirming the observational results and also suggesting that invasion had not generated a persistent build-up of visitor populations. To study species-level impacts, we examined effects of invasion on visitors per flower for the 36 plant species flowering in both invaded and uninvaded fens. On average, the effect of invasion represented about a 20% reduction in visits per flower. We measured the influence of plant traits on vulnerability to L. salicaria invasion using meta-analysis. Bilaterally symmetrical flowers experienced stronger impacts on visitation, and similarity in flower color to L. salicaria weakly intensified competition with the invader for visitors. Finally, we assessed the reproductive consequences of competition with the invader in a dominant flowering shrub, Dasiphora fruticosa. Despite the negative effect of invasion on pollinator visitation in this species, pollen limitation of seed production was not stronger in invaded than in uninvaded sites, suggesting little impact of competition for pollinators on its population demography. Negative effects on pollination of native plants by this copiously flowering invader appeared to be mediated by increases in total flower density that were not matched by increases in pollinator density. The strength of impact was modulated across native species by their floral traits and reproductive ecology. © 2016 The Authors. Ecology, published by Wiley Periodicals, Inc., on behalf of the Ecological Society of America.
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Palladini, Jennifer D; Maron, John L
2013-08-01
Invasive plants have the potential to reduce native plant abundance through both direct and indirect interactions. Direct interactions, such as competition for soil resources, and indirect interactions, such as competition for shared pollinators, have been shown to influence native plant performance; however, we know much less about how these interactions influence native plant abundance in the field. While direct competitive interactions are often assumed to drive declines in native abundance, an evaluation of their influence relative to indirect mechanisms is needed to more fully understand invasive plant impacts. We quantified the direct effects of resource competition by the invasive perennial forb, Euphorbia esula (Euphorbiaceae), on the recruitment, subsequent performance, and ultimate adult abundance of the native annual, Clarkia pulchella (Onagraceae). We contrast these direct effects with those that indirectly resulted from competition for shared pollinators. Although E. esula dramatically reduced pollinator visitation to C. pulchella, plants were only weakly pollen-limited. Pollen supplementation increased the number of seeds per fruit from 41.28 to 46.38. Seed addition experiments revealed that the impacts of ameliorating pollen limitation only increased potential recruitment by 12.3 %. In contrast, seed addition experiments that ameliorated direct competition with E. esula resulted in an increase in potential future recruitment of 574 %. Our results show that, while the indirect effects of competition for pollinators can influence plant abundance, its effects are dwarfed by the magnitude of direct effects of competition for resources.
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Johnson, Anna L; Fetters, Andrea M; Ashman, Tia-Lynn
2017-09-01
Urban centers are important foci for plant biodiversity and yet widespread planting of wildflower gardens in cities to sustain pollinator biodiversity is on the rise, without full consideration of potential ecological consequences. The impact of intentional wildflower plantings on remnant native plant diversity in urban and peri-urban settings has not received attention, although shared pollinators are likely to mediate several types of biotic interactions between human-introduced plants and remnant native ones. Additionally, if wildflower species escape gardens these indirect effects may be compounded with direct ones. We review the potential positive and negative impacts of wildflower gardens on urban native flowering plants, and we reveal substantial gaps in our knowledge. We present a roadmap for research to address whether wildflower gardens, while benefiting pollinators, could also hasten the extinction of native remnant plants in urban settings, or whether they could have other effects that enrich urban biodiversity. Goals of future wildflower mixes should consider the totality of potential interactions. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.
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Kovács-Hostyánszki, Anikó; Espíndola, Anahí; Vanbergen, Adam J; Settele, Josef; Kremen, Claire; Dicks, Lynn V
2017-05-01
Worldwide, human appropriation of ecosystems is disrupting plant-pollinator communities and pollination function through habitat conversion and landscape homogenisation. Conversion to agriculture is destroying and degrading semi-natural ecosystems while conventional land-use intensification (e.g. industrial management of large-scale monocultures with high chemical inputs) homogenises landscape structure and quality. Together, these anthropogenic processes reduce the connectivity of populations and erode floral and nesting resources to undermine pollinator abundance and diversity, and ultimately pollination services. Ecological intensification of agriculture represents a strategic alternative to ameliorate these drivers of pollinator decline while supporting sustainable food production, by promoting biodiversity beneficial to agricultural production through management practices such as intercropping, crop rotations, farm-level diversification and reduced agrochemical use. We critically evaluate its potential to address and reverse the land use and management trends currently degrading pollinator communities and potentially causing widespread pollination deficits. We find that many of the practices that constitute ecological intensification can contribute to mitigating the drivers of pollinator decline. Our findings support ecological intensification as a solution to pollinator declines, and we discuss ways to promote it in agricultural policy and practice. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.
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Plant-pollinator interactions in New Caledonia influenced by introduced honey bees.
Kato, Makoto; Kawakita, Atsushi
2004-11-01
The flora of New Caledonia is characterized by remarkably high species diversity, high endemicity, and an unusual abundance of archaic plant taxa. To investigate community-level pollination mutualism in this endemic ecosystem, we observed flower visitors on 99 plant species in 42 families of various types of vegetation. Among the 95 native plant species, the most dominant pollination system was melittophily (bee-pollinated, 46.3%), followed by phalaenophily (moth-pollinated, 20.0%), ornithophily (bird-pollinated, 11.6%), cantharophily (beetle-pollinated, 8.4%), myophily (fly-pollinated, 3.2%), chiropterophily (bat-pollinated, 3.2%), and anemophily (wind-pollinated, 3.2%). The prevalence of ornithophily by honeyeaters shows an ecological link to pollination mutualism in Australia. The relative dominance of phalaenophily is unique to New Caledonia, and is proposed to be related to the low diversity of the original bee fauna and the absence of long-tongued bees. Although some archaic plants maintain archaic plant-pollinator interactions, e.g., Zygogynum pollinated by micropterigid moths, or Hedycarya pollinated by thrips and staphylinid beetles, the most dominant organism observed on flowers was the introduced honey bee, Apis mellifera. The plant species now visited by honey bees are thought to have originally been pollinated by native solitary short-tongued bees. Our data suggest that the unique systems of pollination mutualism in New Caledonia are now endangered by the establishment of highly invasive honey bees.
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The long-tongued hawkmoth pollinator niche for native and invasive plants in Africa
Johnson, Steven D.; Raguso, Robert A.
2016-01-01
Background and Aims Unrelated organisms that share similar niches often exhibit patterns of convergent evolution in functional traits. Based on bimodal distributions of hawkmoth tongue lengths and tubular white flowers in Africa, this study hypothesized that long-tongued hawkmoths comprise a pollination niche (ecological opportunity) that is distinct from that of shorter-tongued hawkmoths. Methods Field observations, light trapping, camera surveillance and pollen load analysis were used to identify pollinators of plant species with very long-tubed (>8 cm) flowers. The nectar properties and spectral reflectance of these flowers were also measured. The frequency distributions of proboscis length for all captured hawkmoths and floral tube length for a representative sample of night-blooming plant species were determined. The geographical distributions of both native and introduced plant species with very long floral tubes were mapped. Key Results The convolvulus hawkmoth Agrius convolvuli is identified as the most important pollinator of African plants with very long-tubed flowers. Plants pollinated by this hawkmoth species tend to have a very long (approx. 10 cm) and narrow flower tube or spur, white flowers and large volumes of dilute nectar. It is estimated that >70 grassland and savanna plant species in Africa belong to the Agrius pollination guild. In South Africa, at least 23 native species have very long floral tubes, and pollination by A. convolvuli or, rarely, by the closely related hawkmoth Coelonia fulvinotata, has been confirmed for 11 of these species. The guild is strikingly absent from the species-rich Cape floral region and now includes at least four non-native invasive species with long-tubed flowers that are pre-adapted for pollination by A. convolvuli. Conclusions This study highlights the value of a niche perspective on pollination, which provides a framework for making predictions about the ecological importance of keystone pollinators, and for understanding patterns of convergent evolution and the role of floral traits in plant colonization. PMID:26346719
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Montero-Castaño, Ana; Vilà, Montserrat
2015-01-01
Entomophilous non-native plants can directly affect the pollination and reproductive success of native plant species and also indirectly, by altering the composition and abundance of floral resources in the invaded community. Separating direct from indirect effects is critical for understanding the mechanisms underlying the impacts of non-native species on recipient communities. Our aims are: (a) to explore both the direct effect of the non-native Hedysarum coronarium and its indirect effect, mediated by the alteration of floral diversity, on the pollinator visitation rate and fructification of the native Leopoldia comosa and (b) to distinguish whether the effects of the non-native species were due to its floral display or to its vegetative interactions. We conducted field observations within a flower removal experimental setup (i.e. non-native species present, absent and with its inflorescences removed) at the neighbourhood scale. Our study illustrates the complexity of mechanisms involved in the impacts of non-native species on native species. Overall, Hedysarum increased pollinator visitation rates to Leopoldia target plants as a result of direct and indirect effects acting in the same direction. Due to its floral display, Hedysarum exerted a direct magnet effect attracting visits to native target plants, especially those made by the honeybee. Indirectly, Hedysarum also increased the visitation rate of native target plants. Due to the competition for resources mediated by its vegetative parts, it decreased floral diversity in the neighbourhoods, which was negatively related to the visitation rate to native target plants. Hedysarum overall also increased the fructification of Leopoldia target plants, even though such an increase was the result of other indirect effects compensating for the observed negative indirect effect mediated by the decrease of floral diversity.
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Montero-Castaño, Ana; Vilà, Montserrat
2015-01-01
Background Entomophilous non-native plants can directly affect the pollination and reproductive success of native plant species and also indirectly, by altering the composition and abundance of floral resources in the invaded community. Separating direct from indirect effects is critical for understanding the mechanisms underlying the impacts of non-native species on recipient communities. Objectives Our aims are: (a) to explore both the direct effect of the non-native Hedysarum coronarium and its indirect effect, mediated by the alteration of floral diversity, on the pollinator visitation rate and fructification of the native Leopoldia comosa and (b) to distinguish whether the effects of the non-native species were due to its floral display or to its vegetative interactions. Methods We conducted field observations within a flower removal experimental setup (i.e. non-native species present, absent and with its inflorescences removed) at the neighbourhood scale. Results Our study illustrates the complexity of mechanisms involved in the impacts of non-native species on native species. Overall, Hedysarum increased pollinator visitation rates to Leopoldia target plants as a result of direct and indirect effects acting in the same direction. Due to its floral display, Hedysarum exerted a direct magnet effect attracting visits to native target plants, especially those made by the honeybee. Indirectly, Hedysarum also increased the visitation rate of native target plants. Due to the competition for resources mediated by its vegetative parts, it decreased floral diversity in the neighbourhoods, which was negatively related to the visitation rate to native target plants. Hedysarum overall also increased the fructification of Leopoldia target plants, even though such an increase was the result of other indirect effects compensating for the observed negative indirect effect mediated by the decrease of floral diversity. PMID:26110630
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Thompson, Amibeth H; Knight, Tiffany M
2018-05-01
Both exotic and native plant species rely on insect pollinators for reproductive success, and yet few studies have evaluated whether and how exotic plant species receive services from native pollinators for successful reproduction in their introduced range. Plant species are expected to successfully reproduce in their exotic range if they have low reliance on animal pollinators or if they successfully integrate themselves into resident plant-pollinator networks. Here, we quantify the breeding system, network integration, and pollen limitation for ten focal exotic plant species in North America. Most exotic plant species relied on animal pollinators for reproduction, and these species varied in their network integration. However, plant reproduction was limited by pollen receipt for only one plant species. Our results demonstrate that even poorly integrated exotic plant species can still have high pollination service and high reproductive success. The comprehensive framework considered here provides a method to consider the contribution of plant breeding systems and the pollinator community to pollen limitation, and can be applied to future studies to provide a more synthetic understanding of the factors that determine reproductive success of exotic plant species.
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Bruckman, Daniela; Campbell, Diane R
2016-08-01
Effects of an exotic plant on pollination may change as the invasive increases in density. Quantity of pollinator visits to a native may increase, decrease, or change nonlinearly, while visit quality is likely to decrease with greater interspecific pollen movement. How visit quantity and quality contribute to the effect on reproductive success at each invasion stage has not been measured. We simulated four stages of invasion by Brassica nigra by manipulating the neighborhood of potted plants of the native Phacelia parryi in a field experiment. Stages were far from the invasion, near the invasion, intermixed with the invasive at low density, and intermixed at high density. We measured pollinator visitation, conspecific and invasive pollen deposition, and seed set for P. parryi at each stage. Native individuals near invasive plants and within areas of low invasive density showed greatest seed production, as expected from concurrent changes in conspecific and invasive pollen deposition. Those plants experienced facilitation of visits and received more conspecific pollen relative to plants farther from invasives. Native individuals within high invasive density also received frequent visits by many pollinators (although not honeybees), but the larger receipt of invasive pollen predicted interference with pollen tubes that matched patterns in seed set. Pollinator visitation was highest when exotic plants were nearby. Detrimental effects of heterospecific pollen deposition were highest at high exotic density. Our study quantified how reproduction benefits from near proximity to a showy invasive, but is still vulnerable when the invasive reaches high density. © 2016 Botanical Society of America.
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USDA-ARS?s Scientific Manuscript database
Recent reports of global declines in pollinator species imply an urgent need to assess native pollinator population sizes and density dependent benefits for linked plants. Here, we estimated effective population sizes (Ne) of four native bumblebee species, Bombus balteatus, B. flavifrons, B. bifariu...
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Ecology and economics of using native managed bees for almond pollination
USDA-ARS?s Scientific Manuscript database
Evidence of the efficacy of using managed native bees, rather than or concurrently with honey bees, in crop pollination is increasing. However, a broader ecological economic framework for evaluating the costs and benefits of using these bees has not been developed. We conducted a cost-benefit analy...
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The long-tongued hawkmoth pollinator niche for native and invasive plants in Africa.
Johnson, Steven D; Raguso, Robert A
2016-01-01
Unrelated organisms that share similar niches often exhibit patterns of convergent evolution in functional traits. Based on bimodal distributions of hawkmoth tongue lengths and tubular white flowers in Africa, this study hypothesized that long-tongued hawkmoths comprise a pollination niche (ecological opportunity) that is distinct from that of shorter-tongued hawkmoths. Field observations, light trapping, camera surveillance and pollen load analysis were used to identify pollinators of plant species with very long-tubed (>8 cm) flowers. The nectar properties and spectral reflectance of these flowers were also measured. The frequency distributions of proboscis length for all captured hawkmoths and floral tube length for a representative sample of night-blooming plant species were determined. The geographical distributions of both native and introduced plant species with very long floral tubes were mapped. The convolvulus hawkmoth Agrius convolvuli is identified as the most important pollinator of African plants with very long-tubed flowers. Plants pollinated by this hawkmoth species tend to have a very long (approx. 10 cm) and narrow flower tube or spur, white flowers and large volumes of dilute nectar. It is estimated that >70 grassland and savanna plant species in Africa belong to the Agrius pollination guild. In South Africa, at least 23 native species have very long floral tubes, and pollination by A. convolvuli or, rarely, by the closely related hawkmoth Coelonia fulvinotata, has been confirmed for 11 of these species. The guild is strikingly absent from the species-rich Cape floral region and now includes at least four non-native invasive species with long-tubed flowers that are pre-adapted for pollination by A. convolvuli. This study highlights the value of a niche perspective on pollination, which provides a framework for making predictions about the ecological importance of keystone pollinators, and for understanding patterns of convergent evolution and the role of floral traits in plant colonization. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Invasive species management restores a plant-pollinator mutualism in Hawaii
Hanna, Cause; Foote, David; Kremen, Claire
2013-01-01
1.The management and removal of invasive species may give rise to unanticipated changes in plant–pollinator mutualisms because they can alter the composition and functioning of plant–pollinator interactions in a variety of ways. To utilize a functional approach for invasive species management, we examined the restoration of plant–pollinator mutualisms following the large-scale removal of an invasive nectar thief and arthropod predator, Vespula pensylvanica. 2.We reduced V. pensylvanica populations in large plots managed over multiple years to examine the response of plant–pollinator mutualisms and the fruit production of a functionally important endemic Hawaiian tree species, Metrosideros polymorpha. To integrate knowledge of the invader's behaviour and the plant's mating system, we determined the efficacy of V. pensylvanica as a pollinator of M. polymorpha and quantified the dependence of M. polymorpha on animal pollination (e.g. level of self-compatibility and pollen limitation). 3.The reduction of V. pensylvanica in managed sites, when compared to unmanaged sites, resulted in a significant increase in the visitation rates of effective bee pollinators (e.g. introduced Apis mellifera and native Hylaeus spp.) and in the fruit production of M. polymorpha. 4.Apis mellifera, following the management of V. pensylvanica, appears to be acting as a substitute pollinator for M. polymorpha, replacing extinct or threatened bird and bee species in our study system. 5.Synthesis and applications. Fruit production of the native M. polymorpha was increased after management of the invasive pollinator predator V. pensylvanica; however, the main pollinators were no longer native but introduced. This research thus demonstrates the diverse impacts of introduced species on ecological function and the ambiguous role they play in restoration. We recommend incorporating ecological function and context into invasive species management as this approach may enable conservation managers to simultaneously minimize the negative and maximize the positive impacts (e.g. taxon substitution) of introduced species. Such novel restoration approaches are needed, especially in highly degraded ecosystems.
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Sandra J. DeBano; Samantha M. Roof; Mary M. Rowland; Lauren A. Smith
2016-01-01
Many federal, state, and tribal agencies, as well as nonprofit organizations, have recently increased efforts to understand how natural areas can be managed to enhance native pollinators and the ecosystem services they provide. However, managing this important group must be balanced with other services that natural areas provide including hunting, timber production,...
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An enigmatic Hawaiian moth is a missing link in the adaptive radiation of Schiedea.
Weller, Stephen G; Sakai, Ann K; Campbell, Diane R; Powers, John M; Peña, Sean R; Keir, Matthew J; Loomis, Alexander K; Heintzman, Scott M; Weisenberger, Lauren
2017-02-01
Shifts in pollination may drive adaptive diversification of reproductive systems within plant lineages. The monophyletic genus Schiedea is a Hawaiian lineage of 32 extant species, with spectacular diversity in reproductive systems. Biotic pollination is the presumed ancestral condition, but this key element of the life history and its role in shaping reproductive systems has remained undocumented. We observed floral visitors to two species of Schiedea and conducted field experiments to test pollinator effectiveness. We used choice tests to compare attraction of pollinators to species hypothesized to be biotically vs wind-pollinated. Pseudoschrankia brevipalpis (Erebidae), a recently described moth species known only from O'ahu, visited hermaphroditic Schiedea kaalae and S. hookeri and removed nectar from their unique tubular nectary extensions. Pseudoschrankia brevipalpis effectively pollinates S. kaalae; single visits to emasculated flowers resulted in pollen transfer. In choice tests, P. brevipalpis strongly preferred these hermaphroditic species over two subdioecious species capable of wind pollination. A shift from biotic to abiotic pollination is clearly implicated in the diversification of reproductive systems within Schiedea. Abundant pollination by a previously unknown native moth in experimental and restored populations suggests the potential for restoration to re-establish native plant-pollinator interactions critical for production of outcrossed individuals with high fitness. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.
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Howard, Aaron F; Barrows, Edward M
2014-06-23
Animals fertilize thousands of angiosperm species whose floral-display sizes can significantly influence pollinator behavior and plant reproductive success. Many studies have measured the interactions among pollinator behavior, floral-display size, and plant reproductive success, but few studies have been able to separate the effects of pollinator behavior and post-pollination processes on angiosperm sexual reproduction. In this study, we utilized the highly self-incompatible pollinium-pollination system of Asclepias syriaca (Common Milkweed) to quantify how insect visitors influenced male reproductive success measured as pollen removal, female reproductive success measured as pollen deposition, and self-pollination rate. We also determined how floral-display size impacts both visitor behavior and self-pollination rate. Four insect taxonomic orders visited A. syriaca: Coleoptera, Diptera, Hymenoptera, and Lepidoptera. We focused on three groups of visitor taxa within two orders (Hymenoptera and Lepidoptera) with sample sizes large enough for quantitative analysis: Apis mellifera (Western Honey Bee), Bombus spp. (bumble bees) and lepidopterans (butterflies and moths). Qualitatively, lepidopterans had the highest pollinator importance values, but the large variability in the lepidopteran data precluded meaningful interpretation of much of their behavior. The introduced A. mellifera was the most effective and most important diurnal pollinator with regard to both pollen removal and pollen deposition. However, when considering the self-incompatibility of A. syriaca, A. mellifera was not the most important pollinator because of its high self-pollination rate as compared to Bombus spp. Additionally, the rate of self-pollination increased more rapidly with the number of flowers per inflorescence in A. mellifera than in the native Bombus spp. Apis mellifera's high rate of self-pollination may have significant negative effects on both male and female reproductive successes in A. syriaca, causing different selection on floral-display size than native pollinators.
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USDA-ARS?s Scientific Manuscript database
Pollination efficacy of the oligolectic bee Ptilothrix bombiformis was measured as the number of pollen grains delivered to virgin Hibiscus stigmas. Such specialized bee foragers are often assumed to be highly efficient pollinators. Intriguingly, however, we discovered females fight over host blooms...
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Pollen loads and specificity of native pollinators of lowbush blueberry.
Moisan-Deserres, J; Girard, M; Chagnon, M; Fournier, V
2014-06-01
The reproduction of lowbush blueberry (Vaccinium angustifolium Aiton) is closely tied to insect pollination, owing to self-incompatibility. Many species are known to have greater pollination efficiency than the introduced Apis mellifera L., commonly used for commercial purposes. In this study, we measured the pollen loads of several antophilous insect species, mostly Apoidea and Syrphidae, present in four lowbush blueberry fields in Lac-St-Jean, Québec. To measure pollen loads and species specificity toward V. angustifolium, we net-collected 627 specimens of pollinators, retrieved their pollen loads, identified pollen taxa, and counted pollen grains. We found that the sizes of pollen loads were highly variable among species, ranging from a few hundred to more than 118,000 pollen grains per individual. Bombus and Andrena species in particular carried large amounts of Vaccinium pollen and thus may have greater pollination efficiency. Also, two species (Andrena bradleyi Viereck and Andrena carolina Viereck) showed nearly monolectic behavior toward lowbush blueberry. Finally, we identified alternative forage plants visited by native pollinators, notably species of Acer, Rubus, Ilex mucronata, Ledum groenlandicum, and Taraxacum. Protecting these flowering plants should be part of management practices to maintain healthy pollinator communities in a lowbush blueberry agroecosystem.
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Gemeda, Tolera Kumsa; Shao, Youquan; Wu, Wenqin; Yang, Huipeng; Huang, Jiaxing; Wu, Jie
2017-12-05
The foraging behavior of different bee species is a key factor influencing the pollination efficiency of different crops. Most pear species exhibit full self-incompatibility and thus depend entirely on cross-pollination. However, as little is known about the pear visitation preferences of native Apis cerana (Fabricius; Hymenoptera: Apidae) and adventive Apis mellifera (L.; Hymenoptera: Apidae) in China. A comparative analysis was performed to explore the pear-foraging differences of these species under the natural conditions of pear growing areas. The results show significant variability in the pollen-gathering tendency of these honey bees. Compared to A. mellifera, A. cerana begins foraging at an earlier time of day and gathers a larger amount of pollen in the morning. Based on pollen collection data, A. mellifera shows variable preferences: vigorously foraging on pear on the first day of observation but collecting pollen from non-target floral resources on other experimental days. Conversely, A. cerana persists in pear pollen collection, without shifting preference to other competitive flowers. Therefore, A. cerana outperforms adventive A. mellifera with regard to pear pollen collection under natural conditions, which may lead to increased pear pollination. This study supports arguments in favor of further multiplication and maintenance of A. cerana for pear and other native crop pollination. Moreover, it is essential to develop alternative pollination management techniques to utilize A. mellifera for pear pollination. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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USDA-ARS?s Scientific Manuscript database
Bumble bees (Bombus) are the primary pollinators of tomatoes grown in greenhouses and can significantly increase fruit weight compared to tomatoes that receive no supplemental pollination. Due to mounting concerns over the transportation of bumble bees outside of their native ranges, several specie...
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Sardiñas, Hillary S; Tom, Kathleen; Ponisio, Lauren Catherine; Rominger, Andrew; Kremen, Claire
2016-03-01
The delivery of ecosystem services by mobile organisms depends on the distribution of those organisms, which is, in turn, affected by resources at local and landscape scales. Pollinator-dependent crops rely on mobile animals like bees for crop production, and the spatial relationship between floral resources and nest location for these central-place foragers influences the delivery of pollination services. Current models that map pollination coverage in agricultural regions utilize landscape-level estimates of floral availability and nesting incidence inferred from expert opinion, rather than direct assessments. Foraging distance is often derived from proxies of bee body size, rather than direct measurements of foraging that account for behavioral responses to floral resource type and distribution. The lack of direct measurements of nesting incidence and foraging distances may lead to inaccurate mapping of pollination services. We examined the role of local-scale floral resource presence from hedgerow plantings on nest incidence of ground-nesting bees in field margins and within monoculture, conventionally managed sunflower fields in California's Central Valley. We tracked bee movement into fields using fluorescent powder. We then used these data to simulate the distribution of pollination services within a crop field. Contrary to expert opinion, we found that ground-nesting native bees nested both in fields and edges, though nesting rates declined with distance into field. Further, we detected no effect of field-margin floral enhancements on nesting. We found evidence of an exponential decay rate of bee movement into fields, indicating that foraging predominantly occurred in less than 1% of medium-sized bees' predicted typical foraging range. Although we found native bees nesting within agricultural fields, their restricted foraging movements likely centralize pollination near nest sites. Our data thus predict a heterogeneous distribution of pollination services within sunflower fields, with edges receiving higher coverage than field centers. To generate more accurate maps of services, we advocate directly measuring the autecology of ecosystem service providers, which vary by crop system, pollinator species, and region. Improving estimates of the factors affecting pollinator populations can increase the accuracy of pollination service maps and help clarify the influence of farming practices on wild bees occurring in agricultural landscapes.
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Makino, Takashi T.; Yokoyama, Jun
2015-01-01
When pollinators use flower color to locate food sources, a distinct color can serve as a reproductive barrier against co-flowering species. This anti-interference function of flower color may result in a community assembly of plant species displaying mutually different flower colors. However, such color dispersion is not ubiquitous, suggesting a variable selection across communities and existence of some opposing factors. We conducted a 30-week study in a plant community and measured the floral reflectances of 244 species. The reflectances were evaluated in insect color spaces (bees, swallowtails, and flies), and the dispersion was compared with random expectations. We found that co-existing colors were overdispersed for each analyzed pollinator type, and this overdispersion was statistically significant for bees. Furthermore, we showed that exclusion of 32 aliens from the analysis significantly increased the color dispersion of native flowers in every color space. This result indicated that aliens disturbed a native plant–pollinator network via similarly colored flowers. Our results demonstrate the masking effects of aliens in the detection of color dispersion of native flowers and that variations in pollinator vision yield different outcomes. Our results also support the hypothesis that co-flowering species are one of the drivers of color diversification and affect the community assembly. PMID:26650121
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USDA-ARS?s Scientific Manuscript database
Wild squash bees have all five traits ascribed to the most effective crop pollinators. They are abundant, competitive, efficient, faithful to a specific crop and fast. Shared pollinator surveys covering 2,700 ha of US squash and pumpkin (n = 50 farms) show strong parallels among Cucurbita’s bee gui...
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2014-01-01
Background Animals fertilize thousands of angiosperm species whose floral-display sizes can significantly influence pollinator behavior and plant reproductive success. Many studies have measured the interactions among pollinator behavior, floral-display size, and plant reproductive success, but few studies have been able to separate the effects of pollinator behavior and post-pollination processes on angiosperm sexual reproduction. In this study, we utilized the highly self-incompatible pollinium-pollination system of Asclepias syriaca (Common Milkweed) to quantify how insect visitors influenced male reproductive success measured as pollen removal, female reproductive success measured as pollen deposition, and self-pollination rate. We also determined how floral-display size impacts both visitor behavior and self-pollination rate. Results Four insect taxonomic orders visited A. syriaca: Coleoptera, Diptera, Hymenoptera, and Lepidoptera. We focused on three groups of visitor taxa within two orders (Hymenoptera and Lepidoptera) with sample sizes large enough for quantitative analysis: Apis mellifera (Western Honey Bee), Bombus spp. (bumble bees) and lepidopterans (butterflies and moths). Qualitatively, lepidopterans had the highest pollinator importance values, but the large variability in the lepidopteran data precluded meaningful interpretation of much of their behavior. The introduced A. mellifera was the most effective and most important diurnal pollinator with regard to both pollen removal and pollen deposition. However, when considering the self-incompatibility of A. syriaca, A. mellifera was not the most important pollinator because of its high self-pollination rate as compared to Bombus spp. Additionally, the rate of self-pollination increased more rapidly with the number of flowers per inflorescence in A. mellifera than in the native Bombus spp. Conclusions Apis mellifera’s high rate of self-pollination may have significant negative effects on both male and female reproductive successes in A. syriaca, causing different selection on floral-display size than native pollinators. PMID:24958132
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How scent and nectar influence floral antagonists and mutualists.
Kessler, Danny; Kallenbach, Mario; Diezel, Celia; Rothe, Eva; Murdock, Mark; Baldwin, Ian T
2015-07-01
Many plants attract and reward pollinators with floral scents and nectar, respectively, but these traits can also incur fitness costs as they also attract herbivores. This dilemma, common to most flowering plants, could be solved by not producing nectar and/or scent, thereby cheating pollinators. Both nectar and scent are highly variable in native populations of coyote tobacco, Nicotiana attenuata, with some producing no nectar at all, uncorrelated with the tobacco's main floral attractant, benzylacetone. By silencing benzylacetone biosynthesis and nectar production in all combinations by RNAi, we experimentally uncouple these floral rewards/attractrants and measure their costs/benefits in the plant's native habitat and experimental tents. Both scent and nectar increase outcrossing rates for three, separately tested, pollinators and both traits increase oviposition by a hawkmoth herbivore, with nectar being more influential than scent. These results underscore that it makes little sense to study floral traits as if they only mediated pollination services.
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Heidi Kratsch
2014-01-01
Pollinators, including bees, moths, beetles and butterflies, are critical to the production of nearly one?third of the world's food supply. Our pollinator populations are decreasing due to a combination of factors, including habitat loss and fragmentation, overuse of pesticides, malnutrition, disease and parasites. It is imperative that we, as responsible...
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Tomé, Hudson Vaner V; Barbosa, Wagner F; Martins, Gustavo F; Guedes, Raul Narciso C
2015-04-01
The risks imposed by novel insecticides, mainly bioinsecticides, are largely unknown despite their increased use and their perceived environmental safety, which is based on their natural origin. Furthermore, unlike honeybees, native pollinator species have received little attention. In the present study, the lethal and sublethal effects of the neonicotinoid imidacloprid and the bioinsecticide spinosad were assessed in the stingless bee species Meliponaquadrifasciata, an important native pollinator in the Neotropical region. The adult stingless bee workers exhibited high oral insecticide susceptibility, with LD50s of 23.54 and 12.07 ng a.i./bee for imidacloprid and spinosad, respectively. Imidacloprid also impaired worker respiration and overall group activity and flight, while spinosad significantly impaired only worker flight despite exhibiting higher oral toxicity to adult workers than imidacloprid. These findings indicate the hazardous nature not only of imidacloprid but also the bioinsecticide spinosad to adult workers of the native pollinator M. quadrifasciata. Therefore, bioinsecticides should not be exempted from risk assessment analysis due to their lethal and sublethal components. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Liu, Hong; Pemberton, Robert W
2009-03-01
Our understanding of the effects of introduced invasive pollinators on plants has been exclusively drawn from studies on introduced social bees. One might expect, however, that the impacts of introduced solitary bees, with much lower population densities and fewer foragers, would be small. Yet little is known about the potential effects of naturalized solitary bees on the environment. We took advantage of the recent naturalization of an orchid bee, Euglossa viridissima, in southern Florida to study the effects of this solitary bee on reproduction of Solanum torvum, an invasive shrub. Flowers of S. torvum require specialized buzz pollination. Through timed floral visitor watches and two pollination treatments (control and pollen supplementation) at three forest edge and three open area sites, we found that the fruit set of S. torvum was pollen limited at the open sites where the native bees dominate, but was not pollen limited at the forest sites where the invasive orchid bees dominate. The orchid bee's pollination efficiency was nearly double that of the native halictid bees, and was also slightly higher than that of the native carpenter bee. Experiments using small and large mesh cages (to deny or allow E. viridissima access, respectively) at one forest site indicated that when the orchid bee was excluded, the flowers set one-quarter as many fruit as when the bee was allowed access. The orchid bee was the most important pollinator of the weed at the forest sites, which could pose additional challenges to the management of this weed in the fragmented, endangered tropical hardwood forests in the region. This specialized invasive mutualism may promote populations of both the orchid bee and this noxious weed. Invasive solitary bees, particularly species that are specialized pollinators, appear to have more importance than has previously been recognized.
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Habitat management utilizing native wildflowers to foster pollinator abundance
USDA-ARS?s Scientific Manuscript database
Pollinators provide essential ecosystem services to agricultural crops, however their population has come under threat globally as a result of intensive agricultural practices and landscape simplification. Designing diverse heterogeneous agricultural landscapes to provide optimal resources serves as...
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Wilson, Michael E; Skinner, John A; Wszelaki, Annette L; Drummond, Frank
2016-04-01
This study investigated bee visitation on 10 agricultural crops grown on diverse small farms in Tennessee to determine the abundance of native bees and honey bees and the partitioning of visitation among crops. Summaries for each crop are used to generate mean proportions of bee visitation by categories of bees. This shows that native bee visits often occur as frequently, or in greater proportions than non-native honey bee visits. Visitation across multiple crops is then analyzed together with nonmetric multidimensional scaling to show how communities of bees that provide crop pollination change depending on the crop. Within squash and pumpkin plantings, continuous and discrete factors, such as "time of day" and "organic practices," further explain shifts in the community composition of flower visitors. Results from this study show that native bees frequently visit flowers on various crops, indicating that they are likely contributing to pollination services in addition to honey bees. Furthermore, the community of bees visiting flowers changes based on crop type, phenology, and spatial-temporal factors. Results suggest that developing pollinator conservation for farms that grow a wide variety of crops will likely require multiple conservation strategies. Farms that concentrate on a single crop may be able to tailor conservation practices toward the most important bees in their system and geographic locale. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Evaluation of native bees as pollinators of cucurbit crops under floating row covers.
Minter, Logan M; Bessin, Ricardo T
2014-10-01
Production of cucurbit crops presents growers with numerous challenges. Several severe pests and diseases can be managed through the use of rotation, trap cropping, mechanical barriers, such as row covers, and chemical applications. However, considerations must also be made for pollinating insects, as adequate pollination affects the quantity and quality of fruit. Insecticides may negatively affect pollinators; a concern enhanced in recent years due to losses in managed Apis melifera L. colonies. Row covers can be used in place of chemical control before pollination, but when removed, pests have access to fields along with the pollinators. If pollination services of native bees could be harnessed for use under continuous row covers, both concerns could be balanced for growers. The potential of two bee species which specialize on cucurbit flowers, Peponapis pruinosa Say and Xenoglossa strenua Cresson, were assessed under continuous row covers, employed over acorn squash. Experimental treatments included plots with either naturally or artificially introduced bees under row covers and control plots with row covers either permanently removed at crop flowering, or employed continuously with no added pollinating insects. Pests in plots with permanently removed row covers were managed using standard practices used in certified organic production. Marketable yields from plots inoculated with bees were indistinguishable from those produced under standard practices, indicating this system would provide adequate yields to growers without time and monetary inputs of insecticide applications. Additionally, application of this technique was investigated for muskmelon production and discussed along with considerations for farm management.
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Peter Bernhardt; Retha Meier; Nan Vance
2013-01-01
Brownâs peony, Paeonia brownie (Paeoniaceae), is one of only two peony species native to the Western Hemisphere, yet its pollination ecology and breeding system have never been documented. Using flowering individuals of an endemic colony in the Blue Mountains of Oregon, U.S., we investigated the peonyâs pollination system and floral function. We...
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NASA Astrophysics Data System (ADS)
Lo Verde, Gabriella; La Mantia, Tommaso
2011-09-01
The role of insects in pollination and consequently in fruit set and quality was assessed in two commercial orchards of the cactus pear, Opuntia ficus-indica (L.) Mill., in Agrigento Province, Sicily. In 1997, insects visiting flowers were sampled during May-June (the first bloom) and July (the second bloom, induced by the "scozzolatura" practise). More than 50 insect species belonging to 10 orders were collected in May-June, while only five species of Hymenoptera Apoidea were collected in July. The quality of fruits arising from the second bloom showed that Hymenoptera alone were able to guarantee effective pollination. To verify the role of insects in pollination in 1996 (during only the second bloom), and in 1997 and 2009 (during both blooms), 60 single flowers were marked during each bloom; 30 of them covered with paper sleeves (which prevented natural pollination), while the others were not covered. After withering, fruits produced by marked flowers were analyzed in laboratory: in all years and blooms, the total number of seeds, the number of developed seeds, and the weight and the percentage of pulp were significantly lower for covered flowers than for non-covered flowers. The results are consistent with the hypothesis that native insects effectively carry out the pollination of cactus pear flowers.
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Insect visitation and pollen deposition in an invaded prairie plant community
Larson, D.L.; Royer, R.A.; Royer, M.R.
2006-01-01
Invasive plants with large flowering displays have been shown to compete with native plants for pollinator services, often to the detriment of native plant fitness. In this study, we compare the pollinator communities and pollen deposited on stigmas of native plant species within and away from stands of the invasive alien plant, leafy spurge (Euphorbia esula) at a large natural area in North Dakota, USA. Specifically, we ask if infestation influences (1) visitation rates and taxonomic composition of visitors to native flowers, and (2) the amount of conspecific pollen, number of pollen species, and proportion of heterospecific pollen on stigmas of native plants. We observed visits to selected native species during May and June 2000 and 2001. Stigmas were collected from a subsample of the flowers within these plots, squashed, and the pollen identified and counted under a light microscope. Visitation varied between years and among species of native plants: infestation had mixed effects in 2000 but visitation, especially by halictids was always lower within infestations in 2001. Despite differences in visitation between years, we found significantly less conspecific pollen on stigmas from infested plots in six of eight cases; we never found significantly more conspecific pollen on stigmas from within infestations. Our results emphasize the temporal variability in plant-pollinator relations and the added complexity imposed by an invasive species that will always make prediction of effects difficult. Nonetheless, the consistently lower conspecific pollen counts on native stigmas within infestations, regardless of visitation, suggest the likelihood of negative effects. ?? 2005 Elsevier Ltd. All rights reserved.
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A guide to bumblebees of the Interior
USDA-ARS?s Scientific Manuscript database
Imports of pollinators are becoming problematic with high transportation and packaging costs, disease, and concerns regarding non-native species affecting native beneficial insects and habitat. Native bees, such as bumble bees, may be responsible for almost $3.07 billion of fruits and vegetables pro...
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Aging and body size in solitary bees
USDA-ARS?s Scientific Manuscript database
Solitary bees are important pollinators of crops and non-domestic plants. Osmia lignaria is a native, commercially-reared solitary bee used to maximize pollination in orchard crops. In solitary bees, adult body size is extremely variable depending on the nutritional resources available to the develo...
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How scent and nectar influence floral antagonists and mutualists
Kessler, Danny; Kallenbach, Mario; Diezel, Celia; Rothe, Eva; Murdock, Mark; Baldwin, Ian T
2015-01-01
Many plants attract and reward pollinators with floral scents and nectar, respectively, but these traits can also incur fitness costs as they also attract herbivores. This dilemma, common to most flowering plants, could be solved by not producing nectar and/or scent, thereby cheating pollinators. Both nectar and scent are highly variable in native populations of coyote tobacco, Nicotiana attenuata, with some producing no nectar at all, uncorrelated with the tobacco's main floral attractant, benzylacetone. By silencing benzylacetone biosynthesis and nectar production in all combinations by RNAi, we experimentally uncouple these floral rewards/attractrants and measure their costs/benefits in the plant's native habitat and experimental tents. Both scent and nectar increase outcrossing rates for three, separately tested, pollinators and both traits increase oviposition by a hawkmoth herbivore, with nectar being more influential than scent. These results underscore that it makes little sense to study floral traits as if they only mediated pollination services. DOI: http://dx.doi.org/10.7554/eLife.07641.001 PMID:26132861
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Native bees and plant pollination
Ginsberg, H.S.
2004-01-01
Bees are important pollinators, but evidence suggests that numbers of some species are declining. Decreases have been documented in the honey bee, Apis mellifera (which was introduced to North America), but there are no monitoring programs for the vast majority of native species, so we cannot be sure about the extent of this problem. Recent efforts to develop standardized protocols for bee sampling will help us collect the data needed to assess trends in bee populations. Unfortunately, diversity of bee life cycles and phenologies, and the large number of rare species, make it difficult to assess trends in bee faunas. Changes in bee populations can affect plant reproduction, which can influence plant population density and cover, thus potentially modifying horizontal and vertical structure of a community, microclimate near the ground, patterns of nitrogen deposition, etc. These potential effects of changes in pollination patterns have not been assessed in natural communities. Effects of management actions on bees and other pollinators should be considered in conservation planning.
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Cariveau, Daniel P; Williams, Neal M; Benjamin, Faye E; Winfree, Rachael
2013-07-01
More diverse biological communities may provide ecosystem services that are less variable over space or time. However, the mechanisms underlying this relationship are rarely investigated empirically in real-world ecosystems. Here, we investigate how a potentially important stabilising mechanism, response diversity, the differential response to environmental change among species, stabilises pollination services against land-use change. We measured crop pollination services provided by native bees across land-use gradients in three crop systems. We found that bee species responded differentially to increasing agricultural land cover in all three systems, demonstrating that response diversity occurs. Similarly, we found response diversity in pollination services in two of the systems. However, there was no evidence that response diversity, in general, stabilised ecosystem services. Our results suggest that either response diversity is not the primary stabilising mechanism in our system, or that new measures of response diversity are needed that better capture the stabilising effects it provides. © 2013 John Wiley & Sons Ltd/CNRS.
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The Effects of Crop Intensification on the Diversity of Native Pollinator Communities.
Mogren, Christina L; Rand, Tatyana A; Fausti, Scott W; Lundgren, Jonathan G
2016-08-01
Increases in agricultural conversion are leading to declines in native grasslands and natural resources critical for beneficial insects. However, little is known regarding how these changes affect pollinator diversity. Land use types were categorized within 300 m and 3 km radii of pollinator sampling locations in Brookings County, SD. Pollinator abundance and species richness were regressed on the proportion of the landscape dedicated to row crops, grass and pasture, forage crops, small grains, and aquatic habitats using variance components modeling. Row crops had a negative effect on bee abundance at 300 m, after fixed effects modeling accounted for outliers skewing this relationship. At 3 km, corn positively affected bee abundance and richness, while soybean acreage decreased species richness. The landscape matrix of outlying sites consisted of large monocultured areas with few alternative habitat types available, leading to inflated populations of Melissodes and Halictidae. Syrphids had a positive parabolic relationship between diversity and row crops, indicating potential for competitive exclusion from intermediate landscapes. Unlike other studies, landscape diversity within 300 m was not found to significantly benefit pollinator diversity. Within especially agriculturally developed areas of the region, high abundances of pollinators suggest selection for a few dominant species. There was no effect of forage crops or aquatic habitats on pollinator diversity, indicating that less highly managed areas still represent degraded habitat within the landscape. Incorporating pollinator-friendly crops at the farm level throughout the region is likely to enhance pollinator diversity by lessening the negative effects of large monocultures. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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USDA-ARS?s Scientific Manuscript database
Although persimmons are native (Diospyros virginiana) to the United States, commercial production consists almost exclusively of the Asian persimmon, Diospyros kaki. Cultivars within this species are classified by their astringency type; non-astringent, astringent, and pollination variant. In the U...
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The High Cost "of" Convenience: Satisfying Short-Term Needs Erodes Long-Term Learning
ERIC Educational Resources Information Center
Zimmerman, Dian P.
2015-01-01
Novel ways of thinking often come from the cross-pollination of language from other professions. The term "satisficing" is one such term and is a powerful construct that fuses two concepts, satisfy and suffice, together to explain something new. Satisficing describes the often-paradoxical results that plague decision making. Depending on…
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Pollination Services of Mango Flower Pollinators
Huda, A. Nurul; Salmah, M. R. Che; Hassan, A. Abu; Hamdan, A.; Razak, M. N. Abdul
2015-01-01
Measuring wild pollinator services in agricultural production is very important in the context of sustainable management. In this study, we estimated the contribution of native pollinators to mango fruit set production of two mango cultivars Mangifera indica (L). cv. ‘Sala’ and ‘Chok Anan’. Visitation rates of pollinators on mango flowers and number of pollen grains adhering to their bodies determined pollinator efficiency for reproductive success of the crop. Chok Anan failed to produce any fruit set in the absence of pollinators. In natural condition, we found that Sala produced 4.8% fruit set per hermaphrodite flower while Chok Anan produced 3.1% per flower. Hand pollination tremendously increased fruit set of naturally pollinated flower for Sala (>100%), but only 33% for Chok Anan. Pollinator contribution to mango fruit set was estimated at 53% of total fruit set production. Our results highlighted the importance of insect pollinations in mango production. Large size flies Eristalinus spp. and Chrysomya spp. were found to be effective pollen carriers and visited more mango flowers compared with other flower visitors. PMID:26246439
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Restoring arid western habitats: Native plants maximize wildlife conservation effectiveness
Kas Dumroese; Jeremy Pinto; Deborah M. Finch
2016-01-01
Greater sage-grouse (Centrocercus urophasianus) and monarch butterflies (Danaus plexippus) and other pollinating insects have garnered a lot of attention recently from federal and state wildlife officials. These two species and pollinators share dwindling sagebrush habitat in the western United States that is putting their populations at risk. Sagebrush...
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Global growth and stability of agricultural yield decrease with pollinator dependence
Garibaldi, Lucas A.; Aizen, Marcelo A.; Klein, Alexandra M.; Cunningham, Saul A.; Harder, Lawrence D.
2011-01-01
Human welfare depends on the amount and stability of agricultural production, as determined by crop yield and cultivated area. Yield increases asymptotically with the resources provided by farmers’ inputs and environmentally sensitive ecosystem services. Declining yield growth with increased inputs prompts conversion of more land to cultivation, but at the risk of eroding ecosystem services. To explore the interdependence of agricultural production and its stability on ecosystem services, we present and test a general graphical model, based on Jensen's inequality, of yield–resource relations and consider implications for land conversion. For the case of animal pollination as a resource influencing crop yield, this model predicts that incomplete and variable pollen delivery reduces yield mean and stability (inverse of variability) more for crops with greater dependence on pollinators. Data collected by the Food and Agriculture Organization of the United Nations during 1961–2008 support these predictions. Specifically, crops with greater pollinator dependence had lower mean and stability in relative yield and yield growth, despite global yield increases for most crops. Lower yield growth was compensated by increased land cultivation to enhance production of pollinator-dependent crops. Area stability also decreased with pollinator dependence, as it correlated positively with yield stability among crops. These results reveal that pollen limitation hinders yield growth of pollinator-dependent crops, decreasing temporal stability of global agricultural production, while promoting compensatory land conversion to agriculture. Although we examined crop pollination, our model applies to other ecosystem services for which the benefits to human welfare decelerate as the maximum is approached. PMID:21422295
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LeVan, Katherine E; Hung, Keng-Lou James; McCann, Kyle R; Ludka, John T; Holway, David A
2014-01-01
Mounting evidence indicates that trade-offs between plant defense and reproduction arise not only from resource allocation but also from interactions among mutualists. Indirect costs of plant defense by ants, for example, can outweigh benefits if ants deter pollinators. Plants can dissuade ants from occupying flowers, but such arrangements may break down when novel ant partners infiltrate mutualisms. Here, we examine how floral visitation by ants affects pollination services when the invasive Argentine ant (Linepithema humile) replaces a native ant species in a food-for-protection mutualism with the coast barrel cactus (Ferocactus viridescens), which, like certain other barrel cacti, produces extrafloral nectar. We compared the effects of floral visitation by the Argentine ant with those of the most prevalent native ant species (Crematogaster californica). Compared to C. californica, the Argentine ant was present in higher numbers in flowers. Cactus bees (Diadasia spp.), the key pollinators in this system, spent less time in flowers when cacti were occupied by the Argentine ant compared to when cacti were occupied by C. californica. Presumably as a consequence of decreased duration of floral visits by Diadasia, cacti occupied by L. humile set fewer seeds per fruit and produced fewer seeds overall compared to cacti occupied by C. californica. These data illustrate the importance of mutualist identity in cases where plants balance multiple mutualisms. Moreover, as habitats become increasingly infiltrated by introduced species, the loss of native mutualists and their replacement by non-native species may alter the shape of trade-offs between plant defense and reproduction.
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Brock, Marcus T
2009-08-01
Prezygotic reproductive barriers limit interspecific gene flow between congeners. Here, I examine the strength of floral isolation and interspecific pollen-pistil barriers between an invasive apomictic, Taraxacum officinale, and the indigenous sexual alpine dandelion, Taraxacum ceratophorum. Experimental arrays of either native inflorescences or a mixture of native and exotic inflorescences were used to examine insect preference and to track movement of a pollen analog. Using hand-pollinations, conspecific and heterospecific pollen germination success on native stigmas was compared. To additionally test for interspecific pollen competition, T. ceratophorum plants received one of three possible hand-pollinations: control conspecific pollination, concomitant conspecific and heterospecific pollination (mixed), or conspecific pollen followed by heterospecific pollen 15 min later (staggered). Floral isolation was negligible as no insect preference was detected. On a presence/absence basis, florets on native inflorescences received slightly less pollen analog from heterospecific donors than from conspecific donors; however, the amount of dye particles transferred from either Taraxacum species to stigmas on recipient T. ceratophorum inflorescences was equivalent. In contrast to weak floral isolation, strong pollen germination and pollen competition barriers should reduce the potential for hybridization. Heterospecific T. officinale pollen exhibited reduced germination success on T. ceratophorum stigmas in comparison to conspecific pollen. Furthermore, a significant pollen-competition effect on the percentage of hybrid offspring was detected only when T. officinale preceded T. ceratophorum pollen by 15 min. This result indicates that conspecific pollen out-competes heterospecific pollen but further suggests that biotic and abiotic factors reducing pollen accrual rates may partially remove barriers to natural hybridization.
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Biodiversity ensures plant-pollinator phenological synchrony against climate change.
Bartomeus, Ignasi; Park, Mia G; Gibbs, Jason; Danforth, Bryan N; Lakso, Alan N; Winfree, Rachael
2013-11-01
Climate change has the potential to alter the phenological synchrony between interacting mutualists, such as plants and their pollinators. However, high levels of biodiversity might buffer the negative effects of species-specific phenological shifts and maintain synchrony at the community level, as predicted by the biodiversity insurance hypothesis. Here, we explore how biodiversity might enhance and stabilise phenological synchrony between a valuable crop, apple and its native pollinators. We combine 46 years of data on apple flowering phenology with historical records of bee pollinators over the same period. When the key apple pollinators are considered altogether, we found extensive synchrony between bee activity and apple peak bloom due to complementarity among bee species' activity periods, and also a stable trend over time due to differential responses to warming climate among bee species. A simulation model confirms that high biodiversity levels can ensure plant-pollinator phenological synchrony and thus pollination function. © 2013 John Wiley & Sons Ltd/CNRS.
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Conserving pollinators in North American forests: A review
James L. Hanula; Michael D. Ulyshen; Scott Horn
2016-01-01
Bees and butterflies generally favor open forest habitats regardless of forest type, geographic region, or methods used to create these habitats. Dense shrub layers of native or nonnative species beneath forest canopies negatively impact herbaceous plant cover and diversity, and pollinators. The presence of nonnative flowers as a source of nectar, pollen, or larval...
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Orchard Pollination in Capitol Reef National Park, Utah, USA. Honey Bees or Native Bees?
USDA-ARS?s Scientific Manuscript database
Unlike most National Parks in the United States, Capitol Reef National Park in central Utah includes an agricultural component. The Park surrounds 22 rosaceous fruit orchards started over a century ago by Mormon pioneers. During bloom, hives of the alien honey bee are imported to pollinate the flow...
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Ekroos, Johan; Jakobsson, Anna; Wideen, Joel; Herbertsson, Lina; Rundlöf, Maj; Smith, Henrik G
2015-10-01
Bumble bee abundance in agricultural landscapes is known to decrease with increasing distance from seminatural grasslands, but whether the pollination of bumble-bee-pollinated wild plants shows a similar pattern is less well known. In addition, the relative effects of landscape composition (landscape heterogeneity) and landscape configuration (distance from seminatural grassland) on wild plant pollination, and the interaction between these landscape effects, have not been studied using landscape-level replication. We performed a field experiment to disentangle these landscape effects on the pollination of a native herb, the sticky catchfly (Lychnis viscaria), while accounting for the proportion of oilseed rape across landscapes and the local abundance of bee forage flowers. We measured pollen limitation (the degree to which seed set is pollen-limited), seed set, and seed set stability using potted plants placed in landscapes that differed in heterogeneity (composition) and distance from seminatural grassland (configuration). Pollen limitation and seed set in individual plants did not respond to landscape composition, landscape configuration, or proportion of oilseed rape. Instead, seed set increased with increasing local bee forage flower cover. However, we found within-plant variability in pollen limitation and seed set to increase with increasing distance from seminatural pasture. Our results suggest that average within-plant levels of pollen limitation and seed set respond less swiftly than the within-plant variability in pollen limitation and seed set to changes in landscape configuration. Although landscape effects on pollination were less important than predicted, we conclude that landscape configuration and local habitat characteristics play larger roles than landscape composition in the pollination of L. viscaria.
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Railway Embankments as New Habitat for Pollinators in an Agricultural Landscape
Moroń, Dawid; Skórka, Piotr; Lenda, Magdalena; Rożej-Pabijan, Elżbieta; Wantuch, Marta; Kajzer-Bonk, Joanna; Celary, Waldemar; Mielczarek, Łukasz Emil; Tryjanowski, Piotr
2014-01-01
Pollinating insect populations, essential for maintaining wild plant diversity and agricultural productivity, rely on (semi)natural habitats. An increasing human population is encroaching upon and deteriorating pollinator habitats. Thus the population persistence of pollinating insects and their associated ecosystem services may depend upon on man-made novel habitats; however, their importance for ecosystem services is barely understood. We tested if man-made infrastructure (railway embankments) in an agricultural landscape establishes novel habitats that support large populations of pollinators (bees, butterflies, hoverflies) when compared to typical habitats for these insects, i.e., semi-natural grasslands. We also identified key environmental factors affecting the species richness and abundance of pollinators on embankments. Species richness and abundance of bees and butterflies were higher for railway embankments than for grasslands. The occurrence of bare (non-vegetated) ground on embankments positively affected bee species richness and abundance, but negatively affected butterfly populations. Species richness and abundance of butterflies positively depended on species richness of native plants on embankments, whereas bee species richness was positively affected by species richness of non-native flowering plants. The density of shrubs on embankments negatively affected the number of bee species and their abundance. Bee and hoverfly species richness were positively related to wood cover in a landscape surrounding embankments. This is the first study showing that railway embankments constitute valuable habitat for the conservation of pollinators in farmland. Specific conservation strategies involving embankments should focus on preventing habitat deterioration due to encroachment of dense shrubs and maintaining grassland vegetation with patches of bare ground. PMID:25054427
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Albrecht, Matthias; Padrón, Benigno; Bartomeus, Ignasi; Traveset, Anna
2014-01-01
Compartmentalization—the organization of ecological interaction networks into subsets of species that do not interact with other subsets (true compartments) or interact more frequently among themselves than with other species (modules)—has been identified as a key property for the functioning, stability and evolution of ecological communities. Invasions by entomophilous invasive plants may profoundly alter the way interaction networks are compartmentalized. We analysed a comprehensive dataset of 40 paired plant–pollinator networks (invaded versus uninvaded) to test this hypothesis. We show that invasive plants have higher generalization levels with respect to their pollinators than natives. The consequences for network topology are that—rather than displacing native species from the network—plant invaders attracting pollinators into invaded modules tend to play new important topological roles (i.e. network hubs, module hubs and connectors) and cause role shifts in native species, creating larger modules that are more connected among each other. While the number of true compartments was lower in invaded compared with uninvaded networks, the effect of invasion on modularity was contingent on the study system. Interestingly, the generalization level of the invasive plants partially explains this pattern, with more generalized invaders contributing to a lower modularity. Our findings indicate that the altered interaction structure of invaded networks makes them more robust against simulated random secondary species extinctions, but more vulnerable when the typically highly connected invasive plants go extinct first. The consequences and pathways by which biological invasions alter the interaction structure of plant–pollinator communities highlighted in this study may have important dynamical and functional implications, for example, by influencing multi-species reciprocal selection regimes and coevolutionary processes. PMID:24943368
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High species richness of native pollinators in Brazilian tomato crops.
Silva-Neto, C M; Bergamini, L L; Elias, M A S; Moreira, G L; Morais, J M; Bergamini, B A R; Franceschinelli, E V
2017-01-01
Pollinators provide an essential service to natural ecosystems and agriculture. In tomatoes flowers, anthers are poricidal, pollen may drop from their pore when flowers are shaken by the wind. However, bees that vibrate these anthers increase pollen load on the stigma and in fruit production. The present study aimed to identify the pollinator richness of tomato flowers and investigate their morphological and functional traits related to the plant-pollinator interaction in plantations of Central Brazil. The time of anthesis, flower duration, and the number and viability of pollen grains and ovules were recorded. Floral visitors were observed and collected. Flower buds opened around 6h30 and closed around 18h00. They reopened on the following day at the same time in the morning, lasting on average 48 hours. The highest pollen availability occurred during the first hours of anthesis. Afterwards, the number of pollen grains declined, especially between 10h00 to 12h00, which is consistent with the pollinator visitation pattern. Forty bee species were found in the tomato fields, 30 of which were considered pollinators. We found that during the flowering period, plants offered an enormous amount of pollen to their visitors. These may explain the high richness and amount of bees that visit the tomato flowers in the study areas. The period of pollen availability and depletion throughout the day overlapped with the bees foraging period, suggesting that bees are highly effective in removing pollen grains from anthers. Many of these grains probably land on the stigma of the same flower, leading to self-pollination and subsequent fruit development. Native bees (Exomalopsis spp.) are effective pollinators of tomato flowers and are likely to contribute to increasing crop productivity. On the other hand, here tomato flowers offer large amounts of pollen resource to a high richness and amount of bees, showing a strong plant-pollinator interaction in the study agroecosystem.
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Pollination patterns and plant breeding systems in the Galapagos: a review.
Chamorro, Susana; Heleno, Ruben; Olesen, Jens M; McMullen, Conley K; Traveset, Anna
2012-11-01
Despite the importance of the Galápagos Islands for the development of central concepts in ecology and evolution, the understanding of many ecological processes in this archipelago is still very basic. One such process is pollination, which provides an important service to both plants and their pollinators. The rather modest level of knowledge on this subject has so far limited our predictive power on the consequences of the increasing threat of introduced plants and pollinators to this unique archipelago. As a first step toward building a unified view of the state of pollination in the Galápagos, a thorough literature search was conducted on the breeding systems of the archipelago's flora and compiled all documented flower-visitor interactions. Based on 38 studies from the last 100 years, we retrieved 329 unique interactions between 123 flowering plant species (50 endemics, 39 non-endemic natives, 26 introduced and eight of unknown origin) from 41 families and 120 animal species from 13 orders. We discuss the emergent patterns and identify promising research avenues in the field. Although breeding systems are known for <20 % of the flora, most species in our database were self-compatible. Moreover, the incidence of autogamy among endemics, non-endemic natives and alien species did not differ significantly, being high in all groups, which suggests that a poor pollinator fauna does not represent a constraint to the integration of new plant species into the native communities. Most interactions detected (approx. 90 %) come from a single island (most of them from Santa Cruz). Hymenopterans (mainly the endemic carpenter bee Xylocopa darwinii and ants), followed by lepidopterans, were the most important flower visitors. Dipterans were much more important flower visitors in the humid zone than in the dry zone. Bird and lizard pollination has been occasionally reported in the dry zone. Strong biases were detected in the sampling effort dedicated to different islands, time of day, focal plants and functional groups of visitors. Thus, the existing patterns need to be confronted with new and less biased data. The implementation of a community-level approach could greatly increase our understanding of pollination on the islands and our ability to predict the consequences of plant invasions for the natural ecosystems of the Galápagos.
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Pollination patterns and plant breeding systems in the Galápagos: a review
Chamorro, Susana; Heleno, Ruben; Olesen, Jens M.; McMullen, Conley K.; Traveset, Anna
2012-01-01
Background Despite the importance of the Galápagos Islands for the development of central concepts in ecology and evolution, the understanding of many ecological processes in this archipelago is still very basic. One such process is pollination, which provides an important service to both plants and their pollinators. The rather modest level of knowledge on this subject has so far limited our predictive power on the consequences of the increasing threat of introduced plants and pollinators to this unique archipelago. Scope As a first step toward building a unified view of the state of pollination in the Galápagos, a thorough literature search was conducted on the breeding systems of the archipelago's flora and compiled all documented flower–visitor interactions. Based on 38 studies from the last 100 years, we retrieved 329 unique interactions between 123 flowering plant species (50 endemics, 39 non-endemic natives, 26 introduced and eight of unknown origin) from 41 families and 120 animal species from 13 orders. We discuss the emergent patterns and identify promising research avenues in the field. Conclusions Although breeding systems are known for <20 % of the flora, most species in our database were self-compatible. Moreover, the incidence of autogamy among endemics, non-endemic natives and alien species did not differ significantly, being high in all groups, which suggests that a poor pollinator fauna does not represent a constraint to the integration of new plant species into the native communities. Most interactions detected (approx. 90 %) come from a single island (most of them from Santa Cruz). Hymenopterans (mainly the endemic carpenter bee Xylocopa darwinii and ants), followed by lepidopterans, were the most important flower visitors. Dipterans were much more important flower visitors in the humid zone than in the dry zone. Bird and lizard pollination has been occasionally reported in the dry zone. Strong biases were detected in the sampling effort dedicated to different islands, time of day, focal plants and functional groups of visitors. Thus, the existing patterns need to be confronted with new and less biased data. The implementation of a community-level approach could greatly increase our understanding of pollination on the islands and our ability to predict the consequences of plant invasions for the natural ecosystems of the Galápagos. PMID:22691541
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Honey bees are the dominant diurnal pollinator of native milkweed in a large urban park.
MacIvor, James Scott; Roberto, Adriano N; Sodhi, Darwin S; Onuferko, Thomas M; Cadotte, Marc W
2017-10-01
In eastern North America, the field milkweed, Asclepias syriaca L. (Asclepiadaceae), is used in planting schemes to promote biodiversity conservation for numerous insects including the endangered monarch butterfly, Danaus plexippus (Linnaeus) (Nymphalidae). Less is known about its pollinators, and especially in urban habitats where it is planted often despite being under increasing pressure from invasive plant species, such as the related milkweed, the dog-strangling vine (DSV), Vincetoxicum rossicum (Kleopow) Barbar. (Asclepiadaceae). During the A. syriaca flowering period in July 2016, we surveyed bees in open habitats along a DSV invasion gradient and inspected 433 individuals of 25 bee species in 12 genera for pollinia: these were affixed to bees that visited A. syriaca for nectar and contain pollen packets that are vectored (e.g., transferred) between flowers. Of all bees sampled, pollinia were found only on the nonindigenous honeybee, Apis mellifera (43% of all bees identified), as well as one individual bumblebee, Bombus impatiens Cresson. Pollinia were recorded from 45.2% of all honeybees collected. We found no relationship between biomass of DSV and biomass of A. syriaca per site. There was a significant positive correlation between A. syriaca biomass and the number of pollinia, and the proportion vectored. No relationship with DSV biomass was detected for the number of pollinia collected by bees but the proportion of vectored pollinia declined with increasing DSV biomass. Although we find no evidence of DSV flowers attracting potential pollinators away from A. syriaca and other flowering plants, the impacts on native plant-pollinator mutualisms relate to its ability to outcompete native plants. As wild bees do not appear to visit DSV flowers, it could be altering the landscape to one which honeybees are more tolerant than native wild bees.
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The most effective pollinator principle applies to new invasive pollinators.
Medel, Rodrigo; González-Browne, Catalina; Salazar, Daniela; Ferrer, Pedro; Ehrenfeld, Mildred
2018-06-01
G. L. Stebbins' most effective pollinator principle states that when pollinators are not limiting, plants are expected to specialize and adapt to the most abundant and effective pollinator species available. In this study, we quantify the effectiveness of bees, hummingbirds and hawkmoths in a Chilean population of Erythranthe lutea (Phrymaceae), and examine whether flower traits are subject to pollinator-mediated selection by the most effective pollinator species during two consecutive years. Unlike most species in the pollinator community, the visitation rate of the recently arrived Bombus terrestris did not change substantially between years, which together with its high and stable pollen delivery to flower stigmas made this species the most important in the pollinator assemblage, followed by the solitary bee Centris nigerrima Flower traits were under significant selection in the direction expected for short-tongue bees, suggesting that E. lutea is in the initial steps of adaptation to the highly effective exotic bumblebee . Our results illustrate the applicability of Stebbins' principle for new invasive pollinators, and stress their importance in driving flower adaptation of native plant species, a critical issue in the face of biotic exchange and homogenization. © 2018 The Author(s).
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Pollination of Granadilla (Passiflora ligularis) Benefits From Large Wild Insects.
Gutiérrez-Chacón, Catalina; Fornoff, Felix; Ospina-Torres, Rodulfo; Klein, Alexandra-Maria
2018-05-15
The contribution of wild pollinators to food production has recently been assessed for many crops, although it remains unclear for several tropical crops. Granadilla (Passiflora ligularis Juss), a crop native to the tropical Andes, is one such crop where a gap exists regarding comprehensive knowledge about its pollination system. In a field experiment in the Colombian Andes, we 1) describe flower visitors in terms of visit quantity (visitation rate) and quality (touches of flower-reproductive structures), 2) assess the pollination system by comparing fruit set and fruit weight per flower in three pollination treatments: pollinator exclusion, open pollination, and supplementary pollination, and 3) evaluate pollination deficits (difference between open and supplementary pollination) in relation to pollinator density. We observed 12 bee species visiting granadilla flowers, with Apis mellifera Linnaeus being the most frequent species. However, large bees such as Xylocopa lachnea Moure and Epicharis rustica Olivier touched stigmata and anthers more often. Fruit set and fruit weight per flower were significantly lower in the pollinator exclusion treatment compared to open and supplementary pollination, while the latter treatments showed nonsignificant differences. Pollination deficit significantly decreased with the increasing density of large bees and wasps. Our results illustrate the high dependency of granadilla on wild pollinating insects and highlight the crucial role of large insects to granadilla production. This stresses the need to maintain or increase the density of large pollinators in granadilla production areas, which in turn will necessitate better knowledge on their ecological requirements to inform landscape planning and population-management programs.
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The phylogenetic structure of plant-pollinator networks increases with habitat size and isolation.
Aizen, Marcelo A; Gleiser, Gabriela; Sabatino, Malena; Gilarranz, Luis J; Bascompte, Jordi; Verdú, Miguel
2016-01-01
Similarity among species in traits related to ecological interactions is frequently associated with common ancestry. Thus, closely related species usually interact with ecologically similar partners, which can be reinforced by diverse co-evolutionary processes. The effect of habitat fragmentation on the phylogenetic signal in interspecific interactions and correspondence between plant and animal phylogenies is, however, unknown. Here, we address to what extent phylogenetic signal and co-phylogenetic congruence of plant-animal interactions depend on habitat size and isolation by analysing the phylogenetic structure of 12 pollination webs from isolated Pampean hills. Phylogenetic signal in interspecific interactions differed among webs, being stronger for flower-visiting insects than plants. Phylogenetic signal and overall co-phylogenetic congruence increased independently with hill size and isolation. We propose that habitat fragmentation would erode the phylogenetic structure of interaction webs. A decrease in phylogenetic signal and co-phylogenetic correspondence in plant-pollinator interactions could be associated with less reliable mutualism and erratic co-evolutionary change. © 2015 John Wiley & Sons Ltd/CNRS.
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USDA-ARS?s Scientific Manuscript database
The showy black-eyed Susan Rudbeckia fulgida Aiton var. speciosa (Wender.) is an important perennial wildflower native to the Northeast and Midwest regions of the United States. Besides its aesthetic value in the landscape, this native plant attracts pollinators and provides seeds for birds during t...
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Sáez, Agustín; Sabatino, Malena; Aizen, Marcelo A.
2012-01-01
Pollinators for animal pollinated crops can be provided by natural and semi-natural habitats, ranging from large vegetation remnants to small areas of non-crop land in an otherwise highly modified landscape. It is unknown, however, how different small- and large-scale habitat patches interact as pollinator sources. In the intensively managed Argentine Pampas, we studied the additive and interactive effects of large expanses (up to 2200 ha) of natural habitat, represented by untilled isolated “sierras”, and narrow (3–7 m wide) strips of semi-natural habitat, represented by field margins, as pollinator sources for sunflower (Helianthus annus). We estimated visitation rates by feral honey-bees, Apis mellifera, and native flower visitors (as a group) at 1, 5, 25, 50 and 100 m from a field margin in 17 sunflower fields 0–10 km distant from the nearest sierra. Honey-bees dominated the pollinator assemblage accounting for >90% of all visits to sunflower inflorescences. Honey-bee visitation was strongly affected by proximity to the sierras decreasing by about 70% in the most isolated fields. There was also a decline in honey-bee visitation with distance from the field margin, which was apparent with increasing field isolation, but undetected in fields nearby large expanses of natural habitat. The probability of observing a native visitor decreased with isolation from the sierras, but in other respects visitation by flower visitors other than honey-bees was mostly unaffected by the habitat factors assessed in this study. Overall, we found strong hierarchical and interactive effects between the study large and small-scale pollinator sources. These results emphasize the importance of preserving natural habitats and managing actively field verges in the absence of large remnants of natural habitat for improving pollinator services. PMID:22303477
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Sáez, Agustín; Sabatino, Malena; Aizen, Marcelo A
2012-01-01
Pollinators for animal pollinated crops can be provided by natural and semi-natural habitats, ranging from large vegetation remnants to small areas of non-crop land in an otherwise highly modified landscape. It is unknown, however, how different small- and large-scale habitat patches interact as pollinator sources. In the intensively managed Argentine Pampas, we studied the additive and interactive effects of large expanses (up to 2200 ha) of natural habitat, represented by untilled isolated "sierras", and narrow (3-7 m wide) strips of semi-natural habitat, represented by field margins, as pollinator sources for sunflower (Helianthus annus). We estimated visitation rates by feral honey-bees, Apis mellifera, and native flower visitors (as a group) at 1, 5, 25, 50 and 100 m from a field margin in 17 sunflower fields 0-10 km distant from the nearest sierra. Honey-bees dominated the pollinator assemblage accounting for >90% of all visits to sunflower inflorescences. Honey-bee visitation was strongly affected by proximity to the sierras decreasing by about 70% in the most isolated fields. There was also a decline in honey-bee visitation with distance from the field margin, which was apparent with increasing field isolation, but undetected in fields nearby large expanses of natural habitat. The probability of observing a native visitor decreased with isolation from the sierras, but in other respects visitation by flower visitors other than honey-bees was mostly unaffected by the habitat factors assessed in this study. Overall, we found strong hierarchical and interactive effects between the study large and small-scale pollinator sources. These results emphasize the importance of preserving natural habitats and managing actively field verges in the absence of large remnants of natural habitat for improving pollinator services.
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Doubleday, Laura A D; Adler, Lynn S
2017-07-01
Dioecy, a breeding system where individual plants are exclusively male or female, has evolved repeatedly. Extensive theory describes when dioecy should arise from hermaphroditism, frequently through gynodioecy, where females and hermaphrodites coexist, and when gynodioecy should be stable. Both pollinators and herbivores often prefer the pollen-bearing sex, with sex-specific fitness effects that can affect breeding system evolution. Nursery pollination, where adult insects pollinate flowers but their larvae feed on plant reproductive tissues, is a model for understanding mutualism evolution but could also yield insights into plant breeding system evolution. We studied a recently established nursery pollination interaction between native Hadena ectypa moths and introduced gynodioecious Silene vulgaris plants in North America to assess whether oviposition was biased toward females or hermaphrodites, which traits were associated with oviposition, and the effect of oviposition on host plant fitness. Oviposition was hermaphrodite-biased and associated with deeper flowers and more stems. Sexual dimorphism in flower depth, a trait also associated with oviposition on the native host plant ( Silene stellata ), explained the hermaphrodite bias. Egg-receiving plants experienced more fruit predation than plants that received no eggs, but relatively few fruits were lost, and egg receipt did not significantly alter total fruit production at the plant level. Oviposition did not enhance pollination; egg-receiving flowers usually failed to expand and produce seeds. Together, our results suggest that H. ectypa oviposition does not exert a large fitness cost on host plants, sex-biased interactions can emerge from preferences developed on a hermaphroditic host species, and new nursery pollination interactions can arise as negative or neutral rather than as mutualistic for the plant.
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Gillespie, Sandra; Long, Rachael; Williams, Neal
2015-12-01
Pollination in crops, as in native ecosystems, is a stepwise process that can be disrupted at any stage. Healthy pollinator populations are critical for adequate visitation, but pollination still might fail if crop management interferes with the attraction and retention of pollinators. Farmers must balance the direct benefits of applying insecticide and managing irrigation rates against their potential to indirectly interfere with the pollination process. We investigated these issues in hybrid onion seed production, where previous research has shown that high insecticide use reduces pollinator attraction. We conducted field surveys of soil moisture, nectar production, pollinator visitation, pollen-stigma interactions, and seed set at multiple commercial fields across 2 yr. We then examined how management actions, such as irrigation rate (approximated by soil moisture), or insecticide use could affect the pollination process. Onions produced maximum nectar at intermediate soil moisture, and high nectar production attracted more pollinators. Insecticide use weakly affected pollinator visitation, but when applied close to bloom reduced pollen germination and pollen tube growth. Ultimately, neither soil moisture nor insecticide use directly affected seed set, but the high correlation between pollinator visitation and seed set suggests that crop management will ultimately affect yields via indirect effects on the pollination process. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Pollinator-independent orchid attracts biotic pollinators due the production of lipoidal substances.
Pansarin, E R; Bergamo, P J; Ferreira-Caliman, M J
2018-03-01
Flowering plants often depend on the attraction of biotic pollinators for sexual reproduction. Consequently, the emergence and maintenance of selected floral attributes related to pollinator attraction and rewarding are driven by pollinator pressure. In this paper we explore the effect of pollinators, rainfall, temperature and air humidity on the reproduction of a Brazilian terrestrial orchid, Cranichis candida based on data of phenology, flower resources, olfactory and visual attraction cues, pollinators and breeding system. The flowers of C. candida are strongly protandrous and pollinated by workers of the social native bee Tetragonisca angustula. The bees collect labellar lipoidal substances (wax scales), which are transported to the nest. The lipoidal substance is composed of sterols, hydrocarbons and terpenes. The last presumably protects the bees and their nests against pathogens and other arthropods. C. candida sets fruits through biotic self- and cross-pollination, and spontaneously due the action of raindrops on flowers. Our results indicate that in C. candida, although rain-mediated spontaneous self-pollination happens, fructification mediated by biotic pollinations also occurs, which may result in fruit set by cross-pollination. A mixed pollination system must result in higher genetic variability when compared to species whose fruits are produced entirely by self-pollination. On the other hand, autogamy is a form of reproductive assurance, and has commonly evolved where pollination services are rare or absent. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.
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Historical changes in northeastern US bee pollinators related to shared ecological traits.
Bartomeus, Ignasi; Ascher, John S; Gibbs, Jason; Danforth, Bryan N; Wagner, David L; Hedtke, Shannon M; Winfree, Rachael
2013-03-19
Pollinators such as bees are essential to the functioning of terrestrial ecosystems. However, despite concerns about a global pollinator crisis, long-term data on the status of bee species are limited. We present a long-term study of relative rates of change for an entire regional bee fauna in the northeastern United States, based on >30,000 museum records representing 438 species. Over a 140-y period, aggregate native species richness weakly decreased, but richness declines were significant only for the genus Bombus. Of 187 native species analyzed individually, only three declined steeply, all of these in the genus Bombus. However, there were large shifts in community composition, as indicated by 56% of species showing significant changes in relative abundance over time. Traits associated with a declining relative abundance include small dietary and phenological breadth and large body size. In addition, species with lower latitudinal range boundaries are increasing in relative abundance, a finding that may represent a response to climate change. We show that despite marked increases in human population density and large changes in anthropogenic land use, aggregate native species richness declines were modest outside of the genus Bombus. At the same time, we find that certain ecological traits are associated with declines in relative abundance. These results should help target conservation efforts focused on maintaining native bee abundance and diversity and therefore the important ecosystems services that they provide.
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Honeybees Increase Fruit Set in Native Plant Species Important for Wildlife Conservation
NASA Astrophysics Data System (ADS)
Cayuela, Luis; Ruiz-Arriaga, Sarah; Ozers, Christian P.
2011-11-01
Honeybee colonies are declining in some parts of the world. This may have important consequences for the pollination of crops and native plant species. In Spain, as in other parts of Europe, land abandonment has led to a decrease in the number of non professional beekeepers, which aggravates the problem of honeybee decline as a result of bee diseases In this study, we investigated the effects of honeybees on the pollination of three native plant species in northern Spain, namely wildcherry Prunus avium L., hawthorn Crataegus monogyna Jacq., and bilberry Vaccinium myrtillus L. We quantified fruit set of individuals from the target species along transects established from an apiary outwards. Half the samples were bagged in a nylon mesh to avoid insect pollination. Mixed-effects models were used to test the effect of distance to the apiary on fruit set in non-bagged samples. The results showed a negative significant effect of distance from the apiary on fruit set for hawthorn and bilberry, but no significant effects were detected for wildcherry. This suggests that the use of honeybees under traditional farming practices might be a good instrument to increase fruit production of some native plants. This may have important consequences for wildlife conservation, since fruits, and bilberries in particular, constitute an important feeding resource for endangered species, such as the brown bear Ursus arctos L. or the capercaillie Tetrao urogallus cantabricus L.
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Honeybees increase fruit set in native plant species important for wildlife conservation.
Cayuela, Luis; Ruiz-Arriaga, Sarah; Ozers, Christian P
2011-11-01
Honeybee colonies are declining in some parts of the world. This may have important consequences for the pollination of crops and native plant species. In Spain, as in other parts of Europe, land abandonment has led to a decrease in the number of non professional beekeepers, which aggravates the problem of honeybee decline as a result of bee diseases In this study, we investigated the effects of honeybees on the pollination of three native plant species in northern Spain, namely wildcherry Prunus avium L., hawthorn Crataegus monogyna Jacq., and bilberry Vaccinium myrtillus L. We quantified fruit set of individuals from the target species along transects established from an apiary outwards. Half the samples were bagged in a nylon mesh to avoid insect pollination. Mixed-effects models were used to test the effect of distance to the apiary on fruit set in non-bagged samples. The results showed a negative significant effect of distance from the apiary on fruit set for hawthorn and bilberry, but no significant effects were detected for wild cherry. This suggests that the use of honeybees under traditional farming practices might be a good instrument to increase fruit production of some native plants. This may have important consequences for wildlife conservation, since fruits, and bilberries in particular, constitute an important feeding resource for endangered species, such as the brown bear Ursus arctos L. or the capercaillie Tetrao urogallus cantabricus L.
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Anderson, Jill T; Eckhart, Vincent M; Geber, Monica A
2015-09-01
Sister taxa with distinct phenotypes often occupy contrasting environments in parapatric ranges, yet we generally do not know whether trait divergence reflects spatially varying selection. We conducted a reciprocal transplant experiment to test whether selection favors "native phenotypes" in two subspecies of Clarkia xantiana (Onagraceae), an annual plant in California. For four quantitative traits that differ between subspecies, we estimated phenotypic selection in subspecies' exclusive ranges and their contact zone in two consecutive years. We predicted that in the arid, pollinator-scarce eastern region, selection favors phenotypes of the native subspecies parviflora: small leaves, slow leaf growth, early flowering, and diminutive flowers. In the wetter, pollinator-rich, western range of subspecies xantiana, we expected selection for opposite phenotypes. We investigated pollinator contributions to selection by comparing naturally pollinated and pollen-supplemented individuals. For reproductive traits and for subspecies xantiana, selection generally matched expectations. The contact zone sometimes showed distinctive selection, and in ssp. parviflora selection sometimes favored nonnative phenotypes. Pollinators influenced selection on flowering time but not on flower size. Little temporal variation in selection occurred, possibly because of plastic trait responses across years. Though there were exceptions and some causes of selection remain obscure, phenotypic differentiation between subspecies appears to reflect spatially variable selection. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
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USDA-ARS?s Scientific Manuscript database
The blue orchard bee, Osmia lignaria Say, is a solitary, native bee that is an excellent pollinator of tree fruit orchards. Due to the annual rising costs of honey bee hive rentals, many orchardists are eager to develop management tools and practices to support O. lignaria as alternative pollinator...
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M'Gonigle, Leithen K; Ponisio, Lauren C; Cutler, Kerry; Kremen, Claire
2015-09-01
Widespread evidence of pollinator declines has led to policies supporting habitat restoration including in agricultural landscapes. Yet, little is yet known about the effectiveness of these restoration techniques for promoting stable populations and communities of pollinators, especially in intensively managed agricultural landscapes. Introducing floral resources, such as flowering hedgerows, to enhance intensively cultivated agricultural landscapes is known to increase the abundances of native insect pollinators in and around restored areas. Whether this is a result of local short-term concentration at flowers or indicative of true increases in the persistence and species richness of these communities remains unclear. It is also unknown whether this practice supports species of conservation concern (e.g., those with more specialized dietary requirements). Analyzing occupancies of native bees and syrphid flies from 330 surveys across 15 sites over eight years, we found that hedgerow restoration promotes rates of between-season persistence and colonization as compared with unrestored field edges. Enhanced persistence and colonization, in turn, led to the formation of more species-rich communities. We also find that hedgerows benefit floral resource specialists more than generalists, emphasizing the value of this restoration technique for conservation in agricultural landscapes.
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Innate colour preferences of the Australian native stingless bee Tetragonula carbonaria Sm.
Dyer, Adrian G; Boyd-Gerny, Skye; Shrestha, Mani; Lunau, Klaus; Garcia, Jair E; Koethe, Sebastian; Wong, Bob B M
2016-10-01
Innate preferences promote the capacity of pollinators to find flowers. Honeybees and bumblebees have strong preferences for 'blue' stimuli, and flowers of this colour typically present higher nectar rewards. Interestingly, flowers from multiple different locations around the world independently have the same distribution in bee colour space. Currently, however, there is a paucity of data on the innate colour preferences of stingless bees that are often implicated as being key pollinators in many parts of the world. In Australia, the endemic stingless bee Tetragonula carbonaria is widely distributed and known to be an efficient pollinator of both native plants and agricultural crops. In controlled laboratory conditions, we tested the innate colour responses of naïve bees using standard broadband reflectance stimuli representative of common flower colours. Colorimetric analyses considering hymenopteran vision and a hexagon colour space revealed a difference between test colonies, and a significant effect of green contrast and an interaction effect of green contrast with spectral purity on bee choices. We also observed colour preferences for stimuli from the blue and blue-green categorical regions of colour space. Our results are discussed in relation to the similar distribution of flower colours observed from bee pollination around the world.
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Neves, E L; Viana, B F
2011-02-01
Previous studies have shown the superior competitive ability of honeybees compared with native bees in the exploitation of floral resources and nesting sites besides their low efficiency in pollinating native plant species. However, there is little evidence of the effect of this invading species on autochthonous plant populations in natural environments. Thus experiments were performed to test the pollination efficiency of honeybees in two species of Jatropha (Euphorbiaceae), J. mollissima (Pohl) Baill. and J. mutabilis (Pohl) Baill., after a single flower visitation. Samplings were carried out between March and April 2006 in a hyperxerophilous shrub-arboreal Caatinga at Estação Biológica de Canudos, Bahia (9º 56´ 34" S, 38º 59´ 17" W), the property of Fundação Biodiversitas. Apis mellifera was efficient at pollinating J. mollissima (100%) and J. mutabilis (85%). This high efficiency may be explained by 1) the simple floral characteristics of both plant species, which facilitate access to the sexual organs of the plant; and 2) the body size of A. mellifera that fits the flower's dimensions.
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Stingless Bees as Alternative Pollinators of Canola.
Witter, Sidia; Nunes-Silva, Patrícia; Lisboa, Bruno B; Tirelli, Flavia P; Sattler, Aroni; Both Hilgert-Moreira, Suzane; Blochtein, Betina
2015-06-01
Alternative pollinators can ensure pollination services if the availability of the managed or most common pollinator is compromised. In this study, the behavior and pollination efficiency of Apis mellifera L. and two species of stingless bees, Plebeia emerina Friese and Tetragonisca fiebrigi Schwarz, were evaluated and compared in flowers of Brassica napus L. 'Hyola 61'. A. mellifera was an efficient pollinator when collecting nectar because it effectively touched the reproductive organs of the flower. In contrast, stingless bees were efficient pollinators only when collecting pollen. The number of pollen grains deposited on the stigma after a single visit by worker bees of the three species was greater than the number of grains resulting from pollination without the bee visits. On average, the three species deposited enough pollen grains to fertilize all of the flower ovules. A. mellifera and P. emerina had similar pollination efficiency because no significant differences were observed in the characteristics of the siliques produced. Although T. fiebrigi is also an effective pollinator, the seed mass produced by their pollination was lower. Native bees promoted similar rates of fruit set compared with A. mellifera. Thus, P. emerina has potential to be used for pollination in canola crops. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Generalised pollination systems for three invasive milkweeds in Australia.
Ward, M; Johnson, S D
2013-05-01
Because most plants require pollinator visits for seed production, the ability of an introduced plant species to establish pollinator relationships in a new ecosystem may have a central role in determining its success or failure as an invader. We investigated the pollination ecology of three milkweed species - Asclepias curassavica, Gomphocarpus fruticosus and G. physocarpus - in their invaded range in southeast Queensland, Australia. The complex floral morphology of milkweeds has often been interpreted as a general trend towards specialised pollination requirements. Based on this interpretation, invasion by milkweeds contradicts the expectation than plant species with specialised pollination systems are less likely to become invasive that those with more generalised pollination requirements. However, observations of flower visitors in natural populations of the three study species revealed that their pollination systems are essentially specialised at the taxonomic level of the order, but generalised at the species level. Specifically, pollinators of the two Gomphocarpus species included various species of Hymenoptera (particularly vespid wasps), while pollinators of A. curassavica were primarily Lepidoptera (particularly nymphalid butterflies). Pollinators of all three species are rewarded with copious amounts of highly concentrated nectar. It is likely that successful invasion by these three milkweed species is attributable, at least in part, to their generalised pollinator requirements. The results of this study are discussed in terms of how data from the native range may be useful in predicting pollination success of species in a new environment. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Exotic species enhance response diversity to land-use change but modify functional composition.
Stavert, Jamie R; Pattemore, David E; Gaskett, Anne C; Beggs, Jacqueline R; Bartomeus, Ignasi
2017-08-16
Two main mechanisms may buffer ecosystem functions despite biodiversity loss. First, multiple species could share similar ecological roles, thus providing functional redundancy. Second, species may respond differently to environmental change (response diversity). However, ecosystem function would be best protected when functionally redundant species also show response diversity. This linkage has not been studied directly, so we investigated whether native and exotic pollinator species with similar traits (functional redundancy) differed in abundance (response diversity) across an agricultural intensification gradient. Exotic pollinator species contributed most positive responses, which partially stabilized overall abundance of the pollinator community. However, although some functionally redundant species exhibited response diversity, this was not consistent across functional groups and aggregate abundances within each functional group were rarely stabilized. This shows functional redundancy and response diversity do not always operate in concert. Hence, despite exotic species becoming increasingly dominant in human-modified systems, they cannot replace the functional composition of native species. © 2017 The Author(s).
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Scott Horn; James L. Hanula
2004-01-01
In recent years concern over widespread losses in biodiversity has grown to include a possible decline of many native pollinators, primarily bees (Buchmann and Nabhan 1996, The Forgotten Pollinators, Island Press). Factors such as habitat fragmentation, agricultural practices, use of pesticides, the introduction of invasive species, or changes in land use may...
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How exotic plants integrate into pollination networks
Stouffer, Daniel B; Cirtwill, Alyssa R; Bascompte, Jordi; Bartomeus, Ignasi
2014-01-01
Summary There is increasing world-wide concern about the impact of the introduction of exotic species on ecological communities. Since many exotic plants depend on native pollinators to successfully establish, it is of paramount importance that we understand precisely how exotic species integrate into existing plant–pollinator communities. In this manuscript, we have studied a global data base of empirical pollination networks to determine whether community, network, species or interaction characteristics can help identify invaded communities. We found that a limited number of community and network properties showed significant differences across the empirical data sets – namely networks with exotic plants present are characterized by greater total, plant and pollinator richness, as well as higher values of relative nestedness. We also observed significant differences in terms of the pollinators that interact with the exotic plants. In particular, we found that specialist pollinators that are also weak contributors to community nestedness are far more likely to interact with exotic plants than would be expected by chance alone. Synthesis. By virtue of their interactions, it appears that exotic plants may provide a key service to a community's specialist pollinators as well as fill otherwise vacant ‘coevolutionary niches’. PMID:25558089
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Plant-pollinator interactions in tropical monsoon forests in Southeast Asia.
Kato, Makoto; Kosaka, Yasuyuki; Kawakita, Atsushi; Okuyama, Yudai; Kobayashi, Chisato; Phimminith, Thavy; Thongphan, Daovorn
2008-11-01
Forests with different flora and vegetation types harbor different assemblages of flower visitors, and plant-pollinator interactions vary among forests. In monsoon-dominated East and Southeast Asia, there is a characteristic gradient in climate along latitude, creating a broad spectrum of forest types with potentially diverse pollinator communities. To detect a geographical pattern of plant-pollinator interactions, we investigated flowering phenology and pollinator assemblages in the least-studied forest type, i.e., tropical monsoon forest, in the Vientiane plain in Laos. Throughout the 5-year study, we observed 171 plant species blooming and detected flower visitors on 145 species. Flowering occurred throughout the year, although the number of flowering plant species peaked at the end of dry season. The dominant canopy trees, including Dipterocarpaceae, bloomed annually, in contrast to the supra-annual general flowering that occurs in Southeast Asian tropical rain forests. Among the 134 native plant species, 68 were pollinated by hymenopterans and others by lepidopterans, beetles, flies, or diverse insects. Among the observed bees, Xylocopa, megachilids, and honeybees mainly contributed to the pollination of canopy trees, whereas long-tongued Amegilla bees pollinated diverse perennials with long corolla tubes. This is the first community-level study of plant-pollinator interactions in an Asian tropical monsoon forest ecosystem.
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Tomé, Hudson Vaner V.; Martins, Gustavo F.; Lima, Maria Augusta P.; Campos, Lúcio Antonio O.; Guedes, Raul Narciso C.
2012-01-01
Declines in pollinator colonies represent a worldwide concern. The widespread use of agricultural pesticides is recognized as a potential cause of these declines. Previous studies have examined the effects of neonicotinoid insecticides such as imidacloprid on pollinator colonies, but these investigations have mainly focused on adult honey bees. Native stingless bees (Hymenoptera: Apidae: Meliponinae) are key pollinators in neotropical areas and are threatened with extinction due to deforestation and pesticide use. Few studies have directly investigated the effects of pesticides on these pollinators. Furthermore, the existing impact studies did not address the issue of larval ingestion of contaminated pollen and nectar, which could potentially have dire consequences for the colony. Here, we assessed the effects of imidacloprid ingestion by stingless bee larvae on their survival, development, neuromorphology and adult walking behavior. Increasing doses of imidacloprid were added to the diet provided to individual worker larvae of the stingless bee Melipona quadrifasciata anthidioides throughout their development. Survival rates above 50% were only observed at insecticide doses lower than 0.0056 µg active ingredient (a.i.)/bee. No sublethal effect on body mass or developmental time was observed in the surviving insects, but the pesticide treatment negatively affected the development of mushroom bodies in the brain and impaired the walking behavior of newly emerged adult workers. Therefore, stingless bee larvae are particularly susceptible to imidacloprid, as it caused both high mortality and sublethal effects that impaired brain development and compromised mobility at the young adult stage. These findings demonstrate the lethal effects of imidacloprid on native stingless bees and provide evidence of novel serious sublethal effects that may compromise colony survival. The ecological and economic importance of neotropical stingless bees as pollinators, their susceptibility to insecticides and the vulnerability of their larvae to insecticide exposure emphasize the importance of studying these species. PMID:22675559
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Tomé, Hudson Vaner V; Martins, Gustavo F; Lima, Maria Augusta P; Campos, Lúcio Antonio O; Guedes, Raul Narciso C
2012-01-01
Declines in pollinator colonies represent a worldwide concern. The widespread use of agricultural pesticides is recognized as a potential cause of these declines. Previous studies have examined the effects of neonicotinoid insecticides such as imidacloprid on pollinator colonies, but these investigations have mainly focused on adult honey bees. Native stingless bees (Hymenoptera: Apidae: Meliponinae) are key pollinators in neotropical areas and are threatened with extinction due to deforestation and pesticide use. Few studies have directly investigated the effects of pesticides on these pollinators. Furthermore, the existing impact studies did not address the issue of larval ingestion of contaminated pollen and nectar, which could potentially have dire consequences for the colony. Here, we assessed the effects of imidacloprid ingestion by stingless bee larvae on their survival, development, neuromorphology and adult walking behavior. Increasing doses of imidacloprid were added to the diet provided to individual worker larvae of the stingless bee Melipona quadrifasciata anthidioides throughout their development. Survival rates above 50% were only observed at insecticide doses lower than 0.0056 µg active ingredient (a.i.)/bee. No sublethal effect on body mass or developmental time was observed in the surviving insects, but the pesticide treatment negatively affected the development of mushroom bodies in the brain and impaired the walking behavior of newly emerged adult workers. Therefore, stingless bee larvae are particularly susceptible to imidacloprid, as it caused both high mortality and sublethal effects that impaired brain development and compromised mobility at the young adult stage. These findings demonstrate the lethal effects of imidacloprid on native stingless bees and provide evidence of novel serious sublethal effects that may compromise colony survival. The ecological and economic importance of neotropical stingless bees as pollinators, their susceptibility to insecticides and the vulnerability of their larvae to insecticide exposure emphasize the importance of studying these species.
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The risks of introduction of the Amazonian palm Euterpe oleracea in the Atlantic rainforest.
Tiberio, F C S; Sampaio-E-Silva, T A; Matos, D M S; Antunes, A Z
2016-02-01
The introduction of a species may alter ecological processes of native populations, such as pollination and dispersal patterns, leading to changes in population structure. When the introduced and the native species are congeners, interference in pollination can also lead to hybridization. We aimed to understand the ecological aspects of Euterpe oleracea introduction in the Atlantic forest and the possible consequences for the conservation of the native congener Euterpe edulis. We analysed the population structure of palm populations, including hybrids, and observed the interaction with frugivorous birds of both palm species after E. oleracea introduction. We observed that E. edulis had significantly lower density and a smaller number of seedlings when occurring with E. oleracea. Native and introduced Euterpe species shared nine frugivorous bird species. E. oleracea and hybrids had dispersed outside the original planting area. Consequently, the risks of introduction of E. oleracea may mostly be related to the disruption of interactions between E. edulis and frugivorous birds and the spontaneous production of hybrids. Finally, the cultivation of E. oleracea and hybrids in Atlantic rainforest could affect the conservation of the already endangered E. edulis.
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Kimoto, Chiho; DeBano, Sandra J.; Thorp, Robbin W.; Rao, Sujaya; Stephen, William P.
2012-01-01
Native bees are important ecologically and economically because their role as pollinators fulfills a vital ecosystem service. Pollinators are declining due to various factors, including habitat degradation and destruction. Grasslands, an important habitat for native bees, are particularly vulnerable. One highly imperiled and understudied grassland type in the United States is the Pacific Northwest Bunchgrass Prairie. No studies have examined native bee communities in this prairie type. To fill this gap, the bee fauna of the Zumwalt Prairie, a large, relatively intact remnant of the Pacific Northwest Bunchgrass Prairie, was examined. Native bees were sampled during the summers of 2007 and 2008 in sixteen 40-ha study pastures on a plateau in northeastern Oregon, using a sampling method not previously used in grassland studies—blue vane traps. This grassland habitat contained an abundant and diverse community of native bees that experienced marked seasonal and inter-annual variation, which appears to be related to weather and plant phenology. Temporal variability evident over the entire study area was also reflected at the individual trap level, indicating a consistent response across the spatial scale of the study. These results demonstrate that temporal variability in bee communities can have important implications for long-term monitoring protocols. In addition, the blue vane trap method appears to be well-suited for studies of native bees in large expanses of grasslands or other open habitats, and may be a useful tool for monitoring native bee communities in these systems. PMID:23438086
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Kimoto, Chiho; Debano, Sandra J; Thorp, Robbin W; Rao, Sujaya; Stephen, William P
2012-01-01
Native bees are important ecologically and economically because their role as pollinators fulfills a vital ecosystem service. Pollinators are declining due to various factors, including habitat degradation and destruction. Grasslands, an important habitat for native bees, are particularly vulnerable. One highly imperiled and understudied grassland type in the United States is the Pacific Northwest Bunchgrass Prairie. No studies have examined native bee communities in this prairie type. To fill this gap, the bee fauna of the Zumwalt Prairie, a large, relatively intact remnant of the Pacific Northwest Bunchgrass Prairie, was examined. Native bees were sampled during the summers of 2007 and 2008 in sixteen 40-ha study pastures on a plateau in northeastern Oregon, using a sampling method not previously used in grassland studies-blue vane traps. This grassland habitat contained an abundant and diverse community of native bees that experienced marked seasonal and inter-annual variation, which appears to be related to weather and plant phenology. Temporal variability evident over the entire study area was also reflected at the individual trap level, indicating a consistent response across the spatial scale of the study. These results demonstrate that temporal variability in bee communities can have important implications for long-term monitoring protocols. In addition, the blue vane trap method appears to be well-suited for studies of native bees in large expanses of grasslands or other open habitats, and may be a useful tool for monitoring native bee communities in these systems.
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Pollinator specialization and pollination syndromes of three related North American Silene.
Reynolds, Richard J; Westbrook, M Jody; Rohde, Alexandra S; Cridland, Julie M; Fenster, Charles B; Dudash, Michele R
2009-08-01
Community and biogeographic surveys often conclude that plant-pollinator interactions are highly generalized. Thus, a central implication of the pollination syndrome concept, that floral trait evolution occurs primarily via specialized interactions of plants with their pollinators, has been questioned. However, broad surveys may not distinguish whether flower visitors are actual pollen vectors and hence lack power to assess the relationship between syndrome traits and the pollinators responsible for their evolution. Here we address whether the floral traits of three closely related hermaphroditic Silene spp. native to eastern North America (S. caroliniana, S. virginica, and S. stellata) correspond to predicted specialized pollination based on floral differences among the three species and the congruence of these floral features with recognized pollination syndromes. A nocturnal/diurnal pollinator exclusion experiment demonstrated that all three Silene spp. have diurnal pollinators, and only S. stellata has nocturnal pollinators. Multiyear studies of visitation rates demonstrated that large bees, hummingbirds, and nocturnal moths were the most frequent pollinators of S. caroliniana, S. virginica, and S. stellata, respectively. Estimates of pollen grains deposited and removed per visit generally corroborated the visitation rate results for all three species. However, the relatively infrequent diurnal hawkmoth pollinators of S. caroliniana were equally effective and more efficient than the most frequent large bee visitors. Pollinator importance (visitation X deposition) of each of the animal visitors to each species was estimated and demonstrated that in most years large bees and nocturnal moths were the most important pollinators of S. caroliniana and S. stellata, respectively. By quantifying comprehensive aspects of the pollination process we determined that S. virginica and S. stellata were specialized on hummingbirds and nocturnal moths, respectively, and S. caroliniana was the least specialized with diurnal hawkmoth and large bee pollinators. Compared across the Silene species, divergent floral character states are consistent with increasing the attraction and/or pollen transfer efficiency of their respective major pollinators, which suggests that the pollinators are past and/or contemporary selective agents for floral trait evolution in these three Silene species. We conclude that the pollination syndrome concept allows us to effectively relate the functional significance of floral morphology to the major pollinators of these Silene species.
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Larson, Diane L.; Rabie, Paul A.; Droege, Sam; Larson, Jennifer L.; Haar, Milton
2016-01-01
The majority of pollinating insects are generalists whose lifetimes overlap flowering periods of many potentially suitable plant species. Such generality is instrumental in allowing exotic plant species to invade pollination networks. The particulars of how existing networks change in response to an invasive plant over the course of its phenology are not well characterized, but may shed light on the probability of long-term effects on plant-pollinator interactions and the stability of network structure. Here we describe changes in network topology and modular structure of infested and non-infested networks during the flowering season of the generalist non-native flowering plant, Cirsium arvense in mixed-grass prairie at Badlands National Park, South Dakota, USA. Objectives were to compare network-level effects of infestation as they propagate over the season in infested and non-infested (with respect to C. arvense) networks. We characterized plant-pollinator networks on 5 non-infested and 7 infested 1-ha plots during 4 sample periods that collectively covered the length of C. arvense flowering period. Two other abundantly-flowering invasive plants were present during this time: Melilotus officinalis had highly variable floral abundance in both C. arvense-infested and non-infested plots andConvolvulus arvensis, which occurred almost exclusively in infested plots and peaked early in the season. Modularity, including roles of individual species, and network topology were assessed for each sample period as well as in pooled infested and non-infested networks. Differences in modularity and network metrics between infested and non-infested networks were limited to the third and fourth sample periods, during flower senescence of C. arvenseand the other invasive species; generality of pollinators rose concurrently, suggesting rewiring of the network and a lag effect of earlier floral abundance. Modularity was lower and number of connectors higher in infested networks, whether they were assessed in individual sample periods or pooled into infested and non-infested networks over the entire blooming period of C.arvense. Connectors typically did not reside within the same modules as C. arvense, suggesting that effects of the other invasive plants may also influence the modularity results, and that effects of infestation extend to co-flowering native plants. We conclude that the presence of abundantly flowering invasive species is associated with greater network stability due to decreased modularity, but whether this is advantageous for the associated native plant-pollinator communities depends on the nature of perturbations they experience.
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Putra, Ramadhani Eka; Kinasih, Ida
2014-01-01
Tomato (Lycopersicon esculentum Mill.) is considered as one of major agricultural commodity of Indonesia farming. However, monthly production is unstable due to lack of pollination services. Common pollinator agent of tomatoes is bumblebees which is unsuitable for tropical climate of Indonesia and the possibility of alteration of local wild plant interaction with their pollinator. Indonesia is rich with wild bees and some of the species already domesticated for years with prospect as pollinating agent for tomatoes. This research aimed to assess the efficiency of local honey bee (Apis cerana L.) and stingless bee (Trigona iridipennis), as pollinator of tomato. During this research, total visitation rate and total numbers of pollinated flowers by honey bee and stingless bee were compared between them with bagged flowers as control. Total fruit production, average weight and size also measured in order to correlated pollination efficiency with quantity and quality of fruit produced. Result of this research showed that A. cerana has slightly higher rate of visitation (p>0.05) and significantly shorter handling time (p < 0.05) than T. iridipennis due to their larger colony demand and low reward provide by tomato flowers. However, honey bee pollinated tomato flowers more efficient pollinator than stingless bee (80.3 and 70.2% efficiency, respectively; p < 0.05) even though the average weight and size of tomatoes were similar (p>0.05). Based on the results, it is concluded that the use of Apis cerana and Trigona spp., for pollinating tomatoes in tropical climates could be an alternative to the use of non-native Apis mellifera and bumblebees (Bombus spp.). However, more researches are needed to evaluate the cost/benefit on large-scale farming and greenhouse pollination using both bees against other bee species and pollination methods.
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Has pollination mode shaped the evolution of ficus pollen?
Wang, Gang; Chen, Jin; Li, Zong-Bo; Zhang, Feng-Ping; Yang, Da-Rong
2014-01-01
The extent to which co-evolutionary processes shape morphological traits is one of the most fascinating topics in evolutionary biology. Both passive and active pollination modes coexist in the fig tree (Ficus, Moraceae) and fig wasp (Agaonidae, Hymenoptera) mutualism. This classic obligate relationship that is about 75 million years old provides an ideal system to consider the role of pollination mode shifts on pollen evolution. Twenty-five fig species, which cover all six Ficus subgenera, and are native to the Xishuangbanna region of southwest China, were used to investigate pollen morphology with scanning electron microscope (SEM). Pollination mode was identified by the Anther/Ovule ratio in each species. Phylogenetic free regression and a correlated evolution test between binary traits were conducted based on a strong phylogenetic tree. Seventeen of the 25 fig species were actively pollinated and eight species were passively pollinated. Three pollen shape types and three kinds of exine ornamentation were recognized among these species. Pollen grains with ellipsoid shape and rugulate ornamentation were dominant. Ellipsoid pollen occurred in all 17 species of actively pollinated figs, while for the passively pollinated species, two obtuse end shapes were identified: cylinder and sphere shapes were identified in six of the eight species. All passively pollinated figs presented rugulate ornamentation, while for actively pollinated species, the smoother types - psilate and granulate-rugulate ornamentations - accounted for just five and two among the 17 species, respectively. The relationship between pollen shape and pollination mode was shown by both the phylogenetic free regression and the correlated evolution tests. Three pollen shape and ornamentation types were found in Ficus, which show characteristics related to passive or active pollination mode. Thus, the pollen shape is very likely shaped by pollination mode in this unique obligate mutualism.
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Has Pollination Mode Shaped the Evolution of Ficus Pollen?
Wang, Gang; Chen, Jin; Li, Zong-Bo; Zhang, Feng-Ping; Yang, Da-Rong
2014-01-01
Background The extent to which co-evolutionary processes shape morphological traits is one of the most fascinating topics in evolutionary biology. Both passive and active pollination modes coexist in the fig tree (Ficus, Moraceae) and fig wasp (Agaonidae, Hymenoptera) mutualism. This classic obligate relationship that is about 75 million years old provides an ideal system to consider the role of pollination mode shifts on pollen evolution. Methods and Main Findings Twenty-five fig species, which cover all six Ficus subgenera, and are native to the Xishuangbanna region of southwest China, were used to investigate pollen morphology with scanning electron microscope (SEM). Pollination mode was identified by the Anther/Ovule ratio in each species. Phylogenetic free regression and a correlated evolution test between binary traits were conducted based on a strong phylogenetic tree. Seventeen of the 25 fig species were actively pollinated and eight species were passively pollinated. Three pollen shape types and three kinds of exine ornamentation were recognized among these species. Pollen grains with ellipsoid shape and rugulate ornamentation were dominant. Ellipsoid pollen occurred in all 17 species of actively pollinated figs, while for the passively pollinated species, two obtuse end shapes were identified: cylinder and sphere shapes were identified in six of the eight species. All passively pollinated figs presented rugulate ornamentation, while for actively pollinated species, the smoother types - psilate and granulate-rugulate ornamentations - accounted for just five and two among the 17 species, respectively. The relationship between pollen shape and pollination mode was shown by both the phylogenetic free regression and the correlated evolution tests. Conclusions Three pollen shape and ornamentation types were found in Ficus, which show characteristics related to passive or active pollination mode. Thus, the pollen shape is very likely shaped by pollination mode in this unique obligate mutualism. PMID:24465976
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Groom, Scott V C; Tuiwawa, Marika V; Stevens, Mark I; Schwarz, Michael P
2015-08-01
Morphology-based studies have suggested a very depauperate bee fauna for islands in the South West Pacific, and recent genetic studies since have indicated an even smaller endemic fauna with many bee species in this region resulting from human-aided dispersal. These introduced species have the potential to both disrupt native pollinator suites as well as augment crop pollination, but for most species the timings of introduction are unknown. We examined the distribution and nesting biology of the long-tongued bee Braunsapis puangensis that was first recorded from Fiji in 2007. This bee has now become widespread in Fiji and both its local abundance and geographical range are likely to increase dramatically. The impacts of this invasion are potentially enormous for agriculture and native ecosystems, but they also provide opportunities for understanding how social insect species adapt to new environments. We outline the major issues associated with this recent invasion and argue that a long-term monitoring study is needed. © 2014 Institute of Zoology, Chinese Academy of Sciences.
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James, David G.; Seymour, Lorraine; Lauby, Gerry; Buckley, Katie
2016-01-01
Native plant and beneficial insect associations are relatively unstudied yet are important in native habitat restoration programs for improving and sustaining conservation biological control of arthropod pests in agricultural crops. Milkweeds (Asclepias spp.) are currently the focus of restoration programs in the USA aimed at reversing a decline in populations of the milkweed-dependent monarch butterfly (Danaus plexippus); however, little is known of the benefits of these plants to other beneficial insects. Beneficial insects (predators, parasitoids, pollinators) attracted to two milkweed species (Asclepias speciosa, Asclepias fascicularis) in central Washington State, WA, USA were identified and counted on transparent sticky traps attached to blooms over five seasons. Combining all categories of beneficial insects, means of 128 and 126 insects per trap were recorded for A. speciosa and A. fascicularis, respectively. Predatory and parasitic flies dominated trap catches for A. speciosa while parasitic wasps were the most commonly trapped beneficial insects on A. fascicularis. Bees were trapped commonly on both species, especially A. speciosa with native bees trapped in significantly greater numbers than honey bees. Beneficial insect attraction to A. speciosa and A. fascicularis was substantial. Therefore, these plants are ideal candidates for habitat restoration, intended to enhance conservation biological control, and for pollinator conservation. In central Washington, milkweed restoration programs for enhancement of D. plexippus populations should also provide benefits for pest suppression and pollinator conservation. PMID:27367733
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Chakrabarti, Priyadarshini; Sarkar, Sagartirtha; Basu, Parthiba
2018-05-01
Pesticides have been reported to be one of the major drivers in the global pollinator losses. The large-scale decline in honey bees, an important pollinator group, has resulted in comprehensive studies on honey bee colonies. Lack of information on native wild pollinators has paved the way for this study, which highlights the underlying evolutionary changes occurring in the wild honey bee populations exposed to pesticides along an agricultural intensification landscape. The study reports an increased genetic diversity in native Apis cerana Fabricius (Hymenoptera: Apidae) populations continually exposed to pesticide stress. An increased heterozygosity, evidenced by a higher electrophoretic banding pattern, was observed in the pesticide-exposed populations for two isozymes involved with xenobiotic metabolism-esterase and glucose-6-phosphate dehydrogenase. Differential banding patterns also revealed a higher percentage of polymorphic loci, number of polymorphic bands, Nei's genetic distance, etc. observed in these populations in the Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) experiments using three random decamer primers. Higher heterozygosity, being indicative of a more resistant population, implies population survival within the threshold pesticide stress. This study reports such changes for the first time in native wild Indian honey bee populations exposed to pesticides and has far-reaching implications on the population adaptability under pesticide stress.
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James, David G; Seymour, Lorraine; Lauby, Gerry; Buckley, Katie
2016-06-29
Native plant and beneficial insect associations are relatively unstudied yet are important in native habitat restoration programs for improving and sustaining conservation biological control of arthropod pests in agricultural crops. Milkweeds (Asclepias spp.) are currently the focus of restoration programs in the USA aimed at reversing a decline in populations of the milkweed-dependent monarch butterfly (Danaus plexippus); however, little is known of the benefits of these plants to other beneficial insects. Beneficial insects (predators, parasitoids, pollinators) attracted to two milkweed species (Asclepias speciosa, Asclepias fascicularis) in central Washington State, WA, USA were identified and counted on transparent sticky traps attached to blooms over five seasons. Combining all categories of beneficial insects, means of 128 and 126 insects per trap were recorded for A. speciosa and A. fascicularis, respectively. Predatory and parasitic flies dominated trap catches for A. speciosa while parasitic wasps were the most commonly trapped beneficial insects on A. fascicularis. Bees were trapped commonly on both species, especially A. speciosa with native bees trapped in significantly greater numbers than honey bees. Beneficial insect attraction to A. speciosa and A. fascicularis was substantial. Therefore, these plants are ideal candidates for habitat restoration, intended to enhance conservation biological control, and for pollinator conservation. In central Washington, milkweed restoration programs for enhancement of D. plexippus populations should also provide benefits for pest suppression and pollinator conservation.
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Kojima, Yuriko; Toki, Taku; Morimoto, Tomomi; Yoshiyama, Mikio; Kimura, Kiyoshi; Kadowaki, Tatsuhiko
2011-11-01
Invasion of alien species has been shown to cause detrimental effects on habitats of native species. Insect pollinators represent such examples; the introduction of commercial bumble bee species for crop pollination has resulted in competition for an ecological niche with native species, genetic disturbance caused by mating with native species, and pathogen spillover to native species. The European honey bee, Apis mellifera, was first introduced into Japan for apiculture in 1877, and queen bees have been imported from several countries for many years. However, its effects on Japanese native honey bee, Apis cerana japonica, have never been addressed. We thus conducted the survey of honey bee viruses and Acarapis mites using both A. mellifera and A. c. japonica colonies to examine their infestation in native and non-native honey bee species in Japan. Honey bee viruses, Deformed wing virus (DWV), Black queen cell virus (BQCV), Israeli acute paralysis virus (IAPV), and Sacbrood virus (SBV), were found in both A. mellifera and A. c. japonica colonies; however, the infection frequency of viruses in A. c. japonica was lower than that in A. mellifera colonies. Based on the phylogenies of DWV, BQCV, and SBV isolates from A. mellifera and A. c. japonica, DWV and BQCV may infect both honey bee species; meanwhile, SBV has a clear species barrier. For the first time in Japan, tracheal mite (Acarapis woodi) was specifically found in the dead honey bees from collapsing A. c. japonica colonies. This paper thus provides further evidence that tracheal-mite-infested honey bee colonies can die during cool winters with no other disease present. These results demonstrate the infestation of native honey bees by parasite and pathogens of non-native honey bees that are traded globally.
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Sanguinetti, Agustin; Buzatto, Cristiano Roberto; Pedron, Marcelo; Davies, Kevin L.; Ferreira, Pedro Maria de Abreu; Maldonado, Sara; Singer, Rodrigo B.
2012-01-01
Background and Aims The pollination biology of very few Chloraeinae orchids has been studied to date, and most of these studies have focused on breeding systems and fruiting success. Chloraea membranacea Lindl. is one of the few non-Andean species in this group, and the aim of the present contribution is to elucidate the pollination biology, functional floral morphology and breeding system in native populations of this species from Argentina (Buenos Aires) and Brazil (Rio Grande do Sul State). Methods Floral features were examined using light microscopy, and scanning and transmission electron microscopy. The breeding system was studied by means of controlled pollinations applied to plants, either bagged in the field or cultivated in a glasshouse. Pollination observations were made on natural populations, and pollinator behaviour was recorded by means of photography and video. Key Results Both Argentinean and Brazilian plants were very consistent regarding all studied features. Flowers are nectarless but scented and anatomical analysis indicates that the dark, clavate projections on the adaxial labellar surface are osmophores (scent-producing glands). The plants are self-compatible but pollinator-dependent. The fruit-set obtained through cross-pollination and manual self-pollination was almost identical. The main pollinators are male and female Halictidae bees that withdraw the pollinarium when leaving the flower. Remarkably, the bees tend to visit more than one flower per inflorescence, thus promoting self-pollination (geitonogamy). Fruiting success in Brazilian plants reached 60·78 % in 2010 and 46 % in 2011. Some pollinarium-laden female bees were observed transferring pollen from the carried pollinarium to their hind legs. The use of pollen by pollinators is a rare record for Orchidaceae in general. Conclusions Chloraea membrancea is pollinated by deceit. Together, self-compatibility, pollinarium texture, pollinator abundance and behaviour may account for the observed high fruiting success. It is suggested that a reappraisal and re-analysis of important flower features in Chloraeinae orchids is necessary. PMID:23071217
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Sanguinetti, Agustin; Buzatto, Cristiano Roberto; Pedron, Marcelo; Davies, Kevin L; Ferreira, Pedro Maria de Abreu; Maldonado, Sara; Singer, Rodrigo B
2012-12-01
The pollination biology of very few Chloraeinae orchids has been studied to date, and most of these studies have focused on breeding systems and fruiting success. Chloraea membranacea Lindl. is one of the few non-Andean species in this group, and the aim of the present contribution is to elucidate the pollination biology, functional floral morphology and breeding system in native populations of this species from Argentina (Buenos Aires) and Brazil (Rio Grande do Sul State). Floral features were examined using light microscopy, and scanning and transmission electron microscopy. The breeding system was studied by means of controlled pollinations applied to plants, either bagged in the field or cultivated in a glasshouse. Pollination observations were made on natural populations, and pollinator behaviour was recorded by means of photography and video. Both Argentinean and Brazilian plants were very consistent regarding all studied features. Flowers are nectarless but scented and anatomical analysis indicates that the dark, clavate projections on the adaxial labellar surface are osmophores (scent-producing glands). The plants are self-compatible but pollinator-dependent. The fruit-set obtained through cross-pollination and manual self-pollination was almost identical. The main pollinators are male and female Halictidae bees that withdraw the pollinarium when leaving the flower. Remarkably, the bees tend to visit more than one flower per inflorescence, thus promoting self-pollination (geitonogamy). Fruiting success in Brazilian plants reached 60·78 % in 2010 and 46 % in 2011. Some pollinarium-laden female bees were observed transferring pollen from the carried pollinarium to their hind legs. The use of pollen by pollinators is a rare record for Orchidaceae in general. Chloraea membrancea is pollinated by deceit. Together, self-compatibility, pollinarium texture, pollinator abundance and behaviour may account for the observed high fruiting success. It is suggested that a reappraisal and re-analysis of important flower features in Chloraeinae orchids is necessary.
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Understory Responses to Fertilization to Eroded Kisatchie Soil in Louisiana
Ronald E. Thill; John C. Bellemore
1988-01-01
Responses of native vegetation growing on highly eroded Kisatchie soil to a May 1982 application of 672 kg/ha of 16-30-l 3 fertilizer were monitored on two sites through 1985. Herbage increased from 1,133 kg/ha on control plots to 4,956 kg/ha on fertilized plots by August of the first year. Litter accumulations on treated plots provided excellent soil protection...
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Economic Risk of Bee Pollination in Maine Wild Blueberry, Vaccinium angustifolium.
Asare, Eric; Hoshide, Aaron K; Drummond, Francis A; Criner, George K; Chen, Xuan
2017-10-01
Recent pollinator declines highlight the importance of evaluating economic risk of agricultural systems heavily dependent on rented honey bees or native pollinators. Our study analyzed variability of native bees and honey bees, and the risks these pose to profitability of Maine's wild blueberry industry. We used cross-sectional data from organic, low-, medium-, and high-input wild blueberry producers in 1993, 1997-1998, 2005-2007, and from 2011 to 2015 (n = 162 fields). Data included native and honey bee densities (count/m2/min) and honey bee stocking densities (hives/ha). Blueberry fruit set, yield, and honey bee hive stocking density models were estimated. Fruit set is impacted about 1.6 times more by native bees than honey bees on a per bee basis. Fruit set significantly explained blueberry yield. Honey bee stocking density in fields predicted honey bee foraging densities. These three models were used in enterprise budgets for all four systems from on-farm surveys of 23 conventional and 12 organic producers (2012-2013). These budgets formed the basis of Monte Carlo simulations of production and profit. Stochastic dominance of net farm income (NFI) cumulative distribution functions revealed that if organic yields are high enough (2,345 kg/ha), organic systems are economically preferable to conventional systems. However, if organic yields are lower (724 kg/ha), it is riskier with higher variability of crop yield and NFI. Although medium-input systems are stochastically dominant with lower NFI variability compared with other conventional systems, the high-input system breaks even with the low-input system if honey bee hive rental prices triple in the future. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.
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Yakupoglu, Tugrul; Gundogan, Recep; Dindaroglu, Turgay; Kara, Zekeriya
2017-10-29
Land-use change through degrading natural vegetation for agricultural production adversely affects many of soil properties particularly organic carbon content of soils. The native shrub land and grassland of Gaziantep-Adiyaman plateau that is an important pistachio growing eco-region have been cleared to convert into pistachio orchard for the last 50 to 60 years. In this study, the effects of conversion of natural vegetation into agricultural uses on soil erodibility have been investigated. Soil samples were collected from surface of agricultural fields and adjacent natural vegetation areas, and samples were analyzed for some soil erodibility indices such as dispersion ratio (DR), erosion ratio (ER), structural stability index (SSI), Henin's instability index (I s ), and aggregate size distribution after wet sieving (AggSD). According to the statistical evaluation, these two areas were found as different from each other in terms of erosion indices except for I s index (P < 0.001 for DR and ER or P < 0.01 for SSI). In addition, native shrub land and converted land to agriculture were found different in terms of AggSD in all aggregate size groups. As a contrary to expectations, correlation tests showed that there were no any interaction between soil organic carbon and measured erodibility indices in two areas. In addition, significant relationships were determined between measured variables and soil textural fractions as statistical. These obtaining findings were attributed to changing of textural component distribution and initial aggregate size distribution results from land-use change in the study area. Study results were explained about hierarchical aggregate formation mechanism.
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Santos, A O R; Bartelli, B F; Nogueira-Ferreira, F H
2014-06-01
We identified native bees that are floral visitors and potential pollinators of tomato in Cerrado areas, described the foraging behavior of these species, and verified the influence of the visitation of a solitary bee on the quantity and quality of fruits. Three areas of tomato crops, located in Minas Gerais, Brazil, were sampled between March and November 2012. We collected 185 bees belonging to 13 species. Exomalopsis (Exomalopsis) analis Spinola, 1853 (Hymenoptera: Apidae) was the most abundant. Ten species performed buzz pollination. Apis mellifera L. 1758 (Hymenoptera: Apidae) and Paratrigona lineata (Lepeletier, 1836) (Hymenoptera: Apidae) could also act as pollinators. The fruit set and number of seeds obtained from the pollination treatment by E. analis were higher than those in the control group. Our results allowed the identification of potential tomato pollinators in Cerrado areas and also contributed information regarding the impact of a single species (E. analis) on fruit set and quality. Although most of the visiting bees show the ability for tomato pollination, there is an absence of adequate management techniques, and its usage is difficult with the aim of increasing the crop production, which is the case for E. analis. Species such as Melipona quinquefasciata, P. lineata, and A. mellifera, which are easy to handle, are not used for pollination services. Finally, it is suggested that a combination of different bee species that are able to pollinate the tomato is necessary to prevent the super-exploitation of only a single species for pollination services and to guarantee the occurrence of potential pollinators in the crop area.
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Genetic connectivity of the moth pollinated tree Glionnetia sericea in a highly fragmented habitat.
Finger, Aline; Kaiser-Bunbury, Christopher N; Kettle, Chris J; Valentin, Terence; Ghazoul, Jaboury
2014-01-01
Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to adults. A Bayesian structure analysis and a tentative paternity analysis indicate extensive historical and contemporary gene flow among remnant populations. Pollination experiments and a paternity analysis show that Glionnetia sericea is self-compatible. Nevertheless, outcrossing is present with 7% of mating events resulting from pollen transfer between populations. Artificial pollination provided no evidence for pollen limitation in isolated populations. The highly mobile and specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi; Sphingidae) appear to promote extensive gene flow, thus mitigating the potential negative ecological and genetic effects of habitat fragmentation in this species. We conclude that contemporary gene flow is sufficient to maintain genetic connectivity in this rare and restricted Seychelles endemic, in contrast to other island endemic tree species with limited contemporary gene flow.
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Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat
Finger, Aline; Valentin, Terence; Ghazoul, Jaboury
2014-01-01
Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to adults. A Bayesian structure analysis and a tentative paternity analysis indicate extensive historical and contemporary gene flow among remnant populations. Pollination experiments and a paternity analysis show that Glionnetia sericea is self-compatible. Nevertheless, outcrossing is present with 7% of mating events resulting from pollen transfer between populations. Artificial pollination provided no evidence for pollen limitation in isolated populations. The highly mobile and specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi; Sphingidae) appear to promote extensive gene flow, thus mitigating the potential negative ecological and genetic effects of habitat fragmentation in this species. We conclude that contemporary gene flow is sufficient to maintain genetic connectivity in this rare and restricted Seychelles endemic, in contrast to other island endemic tree species with limited contemporary gene flow. PMID:25347541
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Nectar alkaloids decrease pollination and female reproduction in a native plant.
Adler, Lynn S; Irwin, Rebecca E
2012-04-01
The evolution of floral traits may be shaped by a community of floral visitors that affect plant fitness, including pollinators and floral antagonists. The role of nectar in attracting pollinators has been extensively studied, but its effects on floral antagonists are less understood. Furthermore, the composition of non-sugar nectar components, such as secondary compounds, may affect plant reproduction via changes in both pollinator and floral antagonist behavior. We manipulated the nectar alkaloid gelsemine in wild plants of the native perennial vine Gelsemium sempervirens. We crossed nectar gelsemine manipulations with a hand-pollination treatment, allowing us to determine the effect of both the trait and the interaction on plant female reproduction. We measured pollen deposition, pollen removal, and nectar robbing to assess whether gelsemine altered the behavior of mutualists and antagonists. High nectar gelsemine reduced conspecific pollen receipt by nearly half and also reduced the proportion of conspecific pollen grains received, but had no effect on nectar robbing. Although high nectar gelsemine reduced pollen removal, an estimate of male reproduction, by one-third, this effect was not statistically significant. Fruit set was limited by pollen receipt. However, this effect varied across sites such that the sites that were most pollen-limited were also the sites where nectar alkaloids had the least effect on pollen receipt, resulting in no significant effect of nectar alkaloids on fruit set. Finally, high nectar gelsemine significantly reduced seed weight; however, this effect was mediated by a mechanism other than pollen limitation. Taken together, our work suggests that nectar alkaloids are more costly than beneficial in our system, and that relatively small-scale spatial variation in trait effects and interactions could determine the selective impacts of traits such as nectar composition.
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Do managed bees have negative effects on wild bees?: A systematic review of the literature
Gratton, Claudio
2017-01-01
Managed bees are critical for crop pollination worldwide. As the demand for pollinator-dependent crops increases, so does the use of managed bees. Concern has arisen that managed bees may have unintended negative impacts on native wild bees, which are important pollinators in both agricultural and natural ecosystems. The goal of this study was to synthesize the literature documenting the effects of managed honey bees and bumble bees on wild bees in three areas: (1) competition for floral and nesting resources, (2) indirect effects via changes in plant communities, including the spread of exotic plants and decline of native plants, and (3) transmission of pathogens. The majority of reviewed studies reported negative effects of managed bees, but trends differed across topical areas. Of studies examining competition, results were highly variable with 53% reporting negative effects on wild bees, while 28% reported no effects and 19% reported mixed effects (varying with the bee species or variables examined). Equal numbers of studies examining plant communities reported positive (36%) and negative (36%) effects, with the remainder reporting no or mixed effects. Finally, the majority of studies on pathogen transmission (70%) reported potential negative effects of managed bees on wild bees. However, most studies across all topical areas documented the potential for impact (e.g. reporting the occurrence of competition or pathogens), but did not measure direct effects on wild bee fitness, abundance, or diversity. Furthermore, we found that results varied depending on whether managed bees were in their native or non-native range; managed bees within their native range had lesser competitive effects, but potentially greater effects on wild bees via pathogen transmission. We conclude that while this field has expanded considerably in recent decades, additional research measuring direct, long-term, and population-level effects of managed bees is needed to understand their potential impact on wild bees. PMID:29220412
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Do managed bees have negative effects on wild bees?: A systematic review of the literature.
Mallinger, Rachel E; Gaines-Day, Hannah R; Gratton, Claudio
2017-01-01
Managed bees are critical for crop pollination worldwide. As the demand for pollinator-dependent crops increases, so does the use of managed bees. Concern has arisen that managed bees may have unintended negative impacts on native wild bees, which are important pollinators in both agricultural and natural ecosystems. The goal of this study was to synthesize the literature documenting the effects of managed honey bees and bumble bees on wild bees in three areas: (1) competition for floral and nesting resources, (2) indirect effects via changes in plant communities, including the spread of exotic plants and decline of native plants, and (3) transmission of pathogens. The majority of reviewed studies reported negative effects of managed bees, but trends differed across topical areas. Of studies examining competition, results were highly variable with 53% reporting negative effects on wild bees, while 28% reported no effects and 19% reported mixed effects (varying with the bee species or variables examined). Equal numbers of studies examining plant communities reported positive (36%) and negative (36%) effects, with the remainder reporting no or mixed effects. Finally, the majority of studies on pathogen transmission (70%) reported potential negative effects of managed bees on wild bees. However, most studies across all topical areas documented the potential for impact (e.g. reporting the occurrence of competition or pathogens), but did not measure direct effects on wild bee fitness, abundance, or diversity. Furthermore, we found that results varied depending on whether managed bees were in their native or non-native range; managed bees within their native range had lesser competitive effects, but potentially greater effects on wild bees via pathogen transmission. We conclude that while this field has expanded considerably in recent decades, additional research measuring direct, long-term, and population-level effects of managed bees is needed to understand their potential impact on wild bees.
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Erodibility of and dust emissions from bare soil surfaces in the North American Southwest
USDA-ARS?s Scientific Manuscript database
Native plant communities throughout the Southwestern United States are subject to increased abiotic stress due to climate change. As native grass cover is replaced by shrubs, more bare soil surface is susceptible to erosion by wind. The dust record for the last 20 years indicates that wind erosion...
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Martínez-Bauer, Angélica E; Martínez, Gerardo Cerón; Murphy, Daniel J; Burd, Martin
2015-06-01
Plant associations with protective ants are widespread among angiosperms, but carry the risk that ants will deter pollinators as well as herbivores. Such conflict, and adaptations to ameliorate or prevent the conflict, have been documented in African and neotropical acacias. Ant-acacia associations occur in Australia, but little is known of their ecology. Moreover, recent phylogenetic evidence indicates that Australian acacias are only distantly related to African and American acacias, providing an intercontinental natural experiment in the management of ant-pollinator conflict. We examined four populations of Acacia myrtifolia over a 400-km environmental gradient in southeastern Australia using ant and pollinator exclusion as well as direct observation of ants and pollinators to assess the potential for ant-pollinator conflict to affect seed set. Native bees were the only group of floral visitors whose visitation rates were a significant predictor of fruiting success, although beetles and wasps may play an important role as "insurance" pollinators. We found no increase in pollinator visitation or fruiting success following ant exclusion, even with large sample sizes and effective exclusion. Because ants are facultative visitors to A. myrtifolia plants, their presence may be insufficient to interfere greatly with floral visitors. It is also likely that the morphological location of extrafloral nectaries tends to draw ants away from reproductive parts, although we commonly observed ants on inflorescences, so the spatial separation is not strict. A. myrtifolia appears to maintain a generalized mutualism over a wide geographic range without the need for elaborate adaptations to resolve ant-pollinator conflict.
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Otto, Clint R.; O'Dell, Samuel; Bryant, R. B.; Euliss, Ned H. Jr.; Bush, Rachel; Smart, Matthew
2017-01-01
Concern over declining pollinators has led to multiple conservation initiatives for improving forage for bees in agroecosystems. Using data available through the Pollinator Library (npwrc.usgs.gov/pollinator/), we summarize plant–pollinator interaction data collected from 2012–2015 on lands managed by the U.S. Fish and Wildlife Service and private lands enrolled in U.S. Department of Agriculture conservation programs in eastern North Dakota (ND). Furthermore, we demonstrate how plant–pollinator interaction data from the Pollinator Library and seed cost information can be used to evaluate hypothetical seeding mixes for pollinator habitat enhancements. We summarize records of 314 wild bee and 849 honey bee (Apis mellifera L.) interactions detected on 63 different plant species. The wild bee observations consisted of 46 species, 15 genera, and 5 families. Over 54% of all wild bee observations were represented by three genera―Bombus, Lassioglossum, and Melissodes. The most commonly visited forbs by wild bees were Monarda fistulosa, Sonchus arvensis, and Zizia aurea. The most commonly visited forbs by A. mellifera were Cirsium arvense, Melilotus officinalis, and Medicago sativa. Among all interactions, 13% of A. mellifera and 77% of wild bee observations were made on plants native to ND. Our seed mix evaluation shows that mixes may often need to be tailored to meet the unique needs of wild bees and managed honey bees in agricultural landscapes. Our evaluation also demonstrates the importance of incorporating both biologic and economic information when attempting to design cost-effective seeding mixes for supporting pollinators in a critically important part of the United States.
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Briscoe Runquist, Ryan D
2012-07-01
Pollinator visits are essential for reproduction in many plants, yet interspecific movements of pollinators can also lead to competitive interactions between coflowering species. Pollination-mediated reductions in fertility could potentially lead to exclusion of competing plant species, and may generate spatial variation in the associations among coflowering species across a landscape. I documented the potential for heterospecific pollen transfer to cause competitive interactions between two annual grassland species native to California, Limnanthes douglasii subsp. rosea and L. alba, two reproductively incompatible species that have broadly overlapping geographic ranges in the foothills of the Sierra Nevada. I observed pollinator movement in constructed arrays and controlled crosses in the greenhouse and field to investigate the consequences of heterospecific pollen transfer. Pollinators move readily between species when they are presented together in experimental arrays. In the greenhouse, deposition of heterospecific pollen decreased fertility in both species. The decrease in seeds produced per flower was much more pronounced in L. d. rosea (90.6% reduction) than in L. alba (40.8% reduction). In field experiments, L. d. rosea plants that received pollen from heterospecific neighbors first showed >50% reduction in per-flower fertility. Under natural pollination conditions, heterospecific pollen transfer has the ability to decrease the fertility of L. d. rosea when it occurs at low frequency in mixed stands. Accordingly, pollinator-mediated competition may contribute to the locally disjunct distributions of these two species. It may also influence important restoration decisions in vernal pool habitats.
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Tiedeken, Erin Jo; Stout, Jane C.
2015-01-01
Invasive alien plants can compete with native plants for resources, and may ultimately decrease native plant diversity and/or abundance in invaded sites. This could have consequences for native mutualistic interactions, such as pollination. Although invasive plants often become highly connected in plant-pollinator interaction networks, in temperate climates they usually only flower for part of the season. Unless sufficient alternative plants flower outside this period, whole-season floral resources may be reduced by invasion. We hypothesized that the cessation of flowering of a dominant invasive plant would lead to dramatic, seasonal compositional changes in plant-pollinator communities, and subsequent changes in network structure. We investigated variation in floral resources, flower-visiting insect communities, and interaction networks during and after the flowering of invasive Rhododendron ponticum in four invaded Irish woodland sites. Floral resources decreased significantly after R. ponticum flowering, but the magnitude of the decrease varied among sites. Neither insect abundance nor richness varied between the two periods (during and after R. ponticum flowering), yet insect community composition was distinct, mostly due to a significant reduction in Bombus abundance after flowering. During flowering R. ponticum was frequently visited by Bombus; after flowering, these highly mobile pollinators presumably left to find alternative floral resources. Despite compositional changes, however, network structural properties remained stable after R. ponticum flowering ceased: generality increased, but quantitative connectance, interaction evenness, vulnerability, H’2 and network size did not change. This is likely because after R. ponticum flowering, two to three alternative plant species became prominent in networks and insects increased their diet breadth, as indicated by the increase in network-level generality. We conclude that network structure is robust to seasonal changes in floral abundance at sites invaded by alien, mass-flowering plant species, as long as alternative floral resources remain throughout the season to support the flower-visiting community. PMID:25764085
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The worldwide importance of honey bees as pollinators in natural habitats.
Hung, Keng-Lou James; Kingston, Jennifer M; Albrecht, Matthias; Holway, David A; Kohn, Joshua R
2018-01-10
The western honey bee ( Apis mellifera ) is the most frequent floral visitor of crops worldwide, but quantitative knowledge of its role as a pollinator outside of managed habitats is largely lacking. Here we use a global dataset of 80 published plant-pollinator interaction networks as well as pollinator effectiveness measures from 34 plant species to assess the importance of A. mellifera in natural habitats. Apis mellifera is the most frequent floral visitor in natural habitats worldwide, averaging 13% of floral visits across all networks (range 0-85%), with 5% of plant species recorded as being exclusively visited by A. mellifera For 33% of the networks and 49% of plant species, however, A. mellifera visitation was never observed, illustrating that many flowering plant taxa and assemblages remain dependent on non- A. mellifera visitors for pollination. Apis mellifera visitation was higher in warmer, less variable climates and on mainland rather than island sites, but did not differ between its native and introduced ranges. With respect to single-visit pollination effectiveness, A. mellifera did not differ from the average non- A. mellifera floral visitor, though it was generally less effective than the most effective non- A. mellifera visitor. Our results argue for a deeper understanding of how A. mellifera , and potential future changes in its range and abundance, shape the ecology, evolution, and conservation of plants, pollinators, and their interactions in natural habitats. © 2018 The Author(s).
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Hedtke, Shannon M; Blitzer, Eleanor J; Montgomery, Graham A; Danforth, Bryan N
2015-01-01
Bees are essential pollinators for many flowering plants, including agriculturally important crops such as apple. As geographic ranges of bees or their host plants change as a result of human activities, we need to identify pathogens that could be transmitted among newly sympatric species to evaluate and anticipate their effects on bee communities. We used PCR screening and DNA sequencing to evaluate exposure to potentially disease-causing microorganisms in a pollinator of apple, the horned mason bee (Osmia cornifrons). We did not detect microsporidia, Wolbachia, or trypanosomes, which are common pathogens of bees, in any of the hundreds of mason bees screened. We did detect both pathogenic and apathogenic (saprophytic) fungal species in the genus Ascosphaera (chalkbrood), an unidentified species of Aspergillus fungus, and a strain of bacteria in the genus Paenibacillus that is probably apathogenic. We detected pathogenic fungal strains in asymptomatic adult bees that therefore may be carriers of disease. We demonstrate that fungi from the genus Ascosphaera have been transported to North America along with the bee from its native range in Japan, and that O. cornifrons is exposed to fungi previously only identified from nests of other related bee species. Further study will be required to quantify pathogenicity and health effects of these different microbial species on O. cornifrons and on closely-related native North American mason bees that may now be exposed to novel pathogens. A global perspective is required for pathogen research as geographic ranges of insects and microorganisms shift due to intentional or accidental introductions.
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Fire Promotes Pollinator Visitation: Implications for Ameliorating Declines of Pollination Services
Van Nuland, Michael E.; Haag, Elliot N.; Bryant, Jessica A. M.; Read, Quentin D.; Klein, Robert N.; Douglas, Morgan J.; Gorman, Courtney E.; Greenwell, Trey D.; Busby, Mark W.; Collins, Jonathan; LeRoy, Joseph T.; Schuchmann, George; Schweitzer, Jennifer A.; Bailey, Joseph K.
2013-01-01
Pollinators serve critical roles for the functioning of terrestrial ecosystems, and have an estimated annual value of over $150 billion for global agriculture. Mounting evidence from agricultural systems reveals that pollinators are declining in many regions of the world, and with a lack of information on whether pollinator communities in natural systems are following similar trends, identifying factors which support pollinator visitation and services are important for ameliorating the effects of the current global pollinator crisis. We investigated how fire affects resource structure and how that variation influences floral pollinator communities by comparing burn versus control treatments in a southeastern USA old-field system. We hypothesized and found a positive relationship between fire and plant density of a native forb, Verbesina alternifolia, as well as a significant difference in floral visitation of V. alternifolia between burn and control treatments. V. alternifolia density was 44% greater and floral visitation was 54% greater in burned treatments relative to control sites. When the density of V. alternifolia was experimentally reduced in the burn sites to equivalent densities observed in control sites, floral visitation in burned sites declined to rates found in control sites. Our results indicate that plant density is a proximal mechanism by which an imposed fire regime can indirectly impact floral visitation, suggesting its usefulness as a tool for management of pollination services. Although concerns surround the negative impacts of management, indirect positive effects may provide an important direction to explore for managing future ecological and conservation issues. Studies examining the interaction among resource concentration, plant apparency, and how fire affects the evolutionary consequences of altered patterns of floral visitation are overdue. PMID:24265787
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Otto, C R V; O'Dell, S; Bryant, R B; Euliss, N H; Bush, R M; Smart, M D
2017-06-01
Concern over declining pollinators has led to multiple conservation initiatives for improving forage for bees in agroecosystems. Using data available through the Pollinator Library (npwrc.usgs.gov/pollinator/), we summarize plant-pollinator interaction data collected from 2012-2015 on lands managed by the U.S. Fish and Wildlife Service and private lands enrolled in U.S. Department of Agriculture conservation programs in eastern North Dakota (ND). Furthermore, we demonstrate how plant-pollinator interaction data from the Pollinator Library and seed cost information can be used to evaluate hypothetical seeding mixes for pollinator habitat enhancements. We summarize records of 314 wild bee and 849 honey bee (Apis mellifera L.) interactions detected on 63 different plant species. The wild bee observations consisted of 46 species, 15 genera, and 5 families. Over 54% of all wild bee observations were represented by three genera-Bombus, Lassioglossum, and Melissodes. The most commonly visited forbs by wild bees were Monarda fistulosa, Sonchus arvensis, and Zizia aurea. The most commonly visited forbs by A. mellifera were Cirsium arvense, Melilotus officinalis, and Medicago sativa. Among all interactions, 13% of A. mellifera and 77% of wild bee observations were made on plants native to ND. Our seed mix evaluation shows that mixes may often need to be tailored to meet the unique needs of wild bees and managed honey bees in agricultural landscapes. Our evaluation also demonstrates the importance of incorporating both biologic and economic information when attempting to design cost-effective seeding mixes for supporting pollinators in a critically important part of the United States. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.
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Ward, Megan; Johnson, Steven D; Zalucki, Myron P
2013-04-01
One of the essential requirements for an introduced plant species to become invasive is an ability to reproduce outside the native range, particularly when initial populations are small. If a reproductive Allee effect is operating, plants in small populations will have reduced reproductive success relative to plants in larger populations. Alternatively, if plants in small populations experience less competition for pollination than those in large populations, they may actually have higher levels of reproductive success than plants in large populations. To resolve this uncertainty, we investigated how the per capita fecundity of plants was affected by population size in three invasive milkweed species. Field surveys of seed production in natural populations of different sizes but similar densities were conducted for three pollinator-dependent invasive species, namely Asclepias curassavica, Gomphocarpus fruticosus and G. physocarpus. Additionally, supplemental hand-pollinations were performed in small and large populations in order to determine whether reproductive output was limited by pollinator activity in these populations. Reproductive Allee effects were not detected in any of the study species. Instead, plants in small populations exhibited remarkably high levels of reproductive output compared to those in large populations. Increased fruit production following supplemental hand-pollinations suggested that the lower reproductive output of naturally pollinated plants in large populations is a consequence of pollen limitation rather than limitation due to abiotic resources. This is consistent with increased intraspecific competition for pollination amongst plants in large populations. It is likely that the invasion of these milkweed species in Australia has been enhanced because plants in small founding populations experience less intraspecific competition for pollinators than those in large populations, and thus have the ability to produce copious amounts of seeds.
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Economic value of tropical forest to coffee production
Ricketts, Taylor H.; Daily, Gretchen C.; Ehrlich, Paul R.; Michener, Charles D.
2004-01-01
Can economic forces be harnessed for biodiversity conservation? The answer hinges on characterizing the value of nature, a tricky business from biophysical, socioeconomic, and ethical perspectives. Although the societal benefits of native ecosystems are clearly immense, they remain largely unquantified for all but a few services. Here, we estimate the value of tropical forest in supplying pollination services to agriculture. We focus on coffee because it is one of the world's most valuable export commodities and is grown in many of the world's most biodiverse regions. Using pollination experiments along replicated distance gradients, we found that forest-based pollinators increased coffee yields by 20% within ≈1 km of forest. Pollination also improved coffee quality near forest by reducing the frequency of “peaberries” (i.e., small misshapen seeds) by 27%. During 2000–2003, pollination services from two forest fragments (46 and 111 hectares) translated into ≈$60,000 (U.S.) per year for one Costa Rican farm. This value is commensurate with expected revenues from competing land uses and far exceeds current conservation incentive payments. Conservation investments in human-dominated landscapes can therefore yield double benefits: for biodiversity and agriculture. PMID:15306689
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Theodorou, Panagiotis; Radzevičiūtė, Rita; Kahnt, Belinda; Soro, Antonella; Grosse, Ivo; Paxton, Robert J
2018-04-25
Urbanization is considered a global threat to biodiversity; the growth of cities results in an increase in impervious surfaces, soil and air pollution, fragmentation of natural vegetation and invasion of non-native species, along with numerous environmental changes, including the heat island phenomenon. The combination of these effects constitutes a challenge for both the survival and persistence of many native species, while also imposing altered selective regimes. Here, using 110 314 single nucleotide polymorphisms generated by restriction-site-associated DNA sequencing, we investigated the genome-wide effects of urbanization on putative neutral and adaptive genomic diversity in a major insect pollinator, Bombus lapidarius , collected from nine German cities and nine paired rural sites. Overall, genetic differentiation among sites was low and there was no obvious genome-wide genetic structuring, suggesting the absence of strong effects of urbanization on gene flow. We nevertheless identified several loci under directional selection, a subset of which was associated with urban land use, including the percentage of impervious surface surrounding each sampling site. Overall, our results provide evidence of local adaptation to urbanization in the face of gene flow in a highly mobile insect pollinator. © 2018 The Author(s).
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Development of beneficial biological agents for invasive species control.
DOT National Transportation Integrated Search
2013-05-01
Noxious and invasive weeds readily colonize disturbed areas and outcompete and displace native and other desirable vegetation. This can result in a loss of pollinators (i.e. animals such as birds, bees, and other insects that move pollen between plan...
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Oliveira-Rebouças, P; Gimenes, M
2011-05-01
Comolia ovalifolia DC Triana (Melastomataceae) and Chamaecrista ramosa (Vog.) H.S. Irwin and Barneby var. ramosa (Leguminosae-Caesalpinioideae) are tropical plant species found in restinga (herbaceous-shrubby, sandy costal ecosystems). They have flowers with poricidal anthers and are pollinated by bees. The study sought to analyse potential pollinators of both plants during visits to their flowers in a restinga area in Bahia. The flowering displayed by both species was considered continuous and long duration, constantly providing pollen to floral visitors. C. ovalifolia was visited by 17 species of bees and C. ramosa by 16 species, predominantly from the Apidae family (with a similarity index of 74%). The behavior displayed by these visiting bees was of vibrating anthers. The small-sized Euglossa sp. Latreille, 1802 and Florilegus similis Urban, 1970 bees played less of a role as pollinators, since they rarely touched the flower stigma during harvests and were thus considered opportunist visitors or casual pollinators. Centris decolorata Lepetier, 1841 (= C. leprieuri) and Xylocopa subcyanea Perez, 1901 are large bees and were considered efficient pollinators of C. ovalifolia and C. ramosa because of the higher frequency and constancy of their visits, and their favourable behaviour and size for pollen transfer between flowers, which guarantees the survival of these native restinga plant species.
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Phillips, Benjamin W.
2015-01-01
Pumpkin (Cucurbita pepo) production relies on insect-mediated pollination, which is provided by managed and wild pollinators. The goals of this study were to measure the visitation frequency, longevity and temporal activity patterns of pumpkin pollinators and to determine if local habitat management and landscape composition affected this pollination service. We used video surveillance to monitor bee acitivty within male and female pumpkin flowers in 2011 and 2012 across a pollination window of 0600–1200 h. We also quantified the amount of pollen deposited in female flowers across this time period. In 2011, A. mellifera made significantly more floral visits than other bees, and in 2012 Bombus spp. was the dominant pumpkin pollinator. We found variation in visitation among male and female pumpkin flowers, with A. mellifera visiting female flowers more often and spending longer per visit within them than male flowers in both 2011 and 2012. The squash bee P. pruinosa visited male flowers more frequently in 2012, but individuals spent equal time in both flower sexes. We did not find variation in the timing of flower visitation among species across the observed pollination window. In both 2011 and 2012 we found that the majority of pollen deposition occurred within the first two hours (0600–0800 h) of observation; there was no difference between the pollen deposited during this two-hour period and full pollination window (0600–1200 h). Local additions of sweet alyssum floral strips or a field buffer strip of native wildflowers did not have an effect on the foraging activity of bees or pollen deposition. However, semi-natural and urban habitats in the surrounding landscape were positively correlated with the frequency of flower visitation by wild pollinators and the amount of pollen deposited within female flowers. PMID:26587337
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Phillips, Benjamin W; Gardiner, Mary M
2015-01-01
Pumpkin (Cucurbita pepo) production relies on insect-mediated pollination, which is provided by managed and wild pollinators. The goals of this study were to measure the visitation frequency, longevity and temporal activity patterns of pumpkin pollinators and to determine if local habitat management and landscape composition affected this pollination service. We used video surveillance to monitor bee acitivty within male and female pumpkin flowers in 2011 and 2012 across a pollination window of 0600-1200 h. We also quantified the amount of pollen deposited in female flowers across this time period. In 2011, A. mellifera made significantly more floral visits than other bees, and in 2012 Bombus spp. was the dominant pumpkin pollinator. We found variation in visitation among male and female pumpkin flowers, with A. mellifera visiting female flowers more often and spending longer per visit within them than male flowers in both 2011 and 2012. The squash bee P. pruinosa visited male flowers more frequently in 2012, but individuals spent equal time in both flower sexes. We did not find variation in the timing of flower visitation among species across the observed pollination window. In both 2011 and 2012 we found that the majority of pollen deposition occurred within the first two hours (0600-0800 h) of observation; there was no difference between the pollen deposited during this two-hour period and full pollination window (0600-1200 h). Local additions of sweet alyssum floral strips or a field buffer strip of native wildflowers did not have an effect on the foraging activity of bees or pollen deposition. However, semi-natural and urban habitats in the surrounding landscape were positively correlated with the frequency of flower visitation by wild pollinators and the amount of pollen deposited within female flowers.
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USDA-ARS?s Scientific Manuscript database
As part of the Bee-Fungicide Workshop at NACREW, there will be updates on the latest evidence characterizing how fungicides may cause colony declines in native bee species. Findings will cover recent work with Bombus impatiens and Osmia lignaria. Discussions will be focusing on how the US cranberry ...
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Habila, Safia; Leghouchi, Essaid; Valdehita, Ana; Bermejo-Nogales, Azucena; Khelili, Smail; Navas, José M
2017-08-01
EROD and BFCOD activities were measured in liver and gills of barbel (Barbus callensis, a native North African species) captured at Beni Haroun lake, the most important water reservoir in Algeria. This lake receives wastewater from different origins. Thus, we assessed the level of pollution through the induction of detoxification activities in tissues of barbel, evaluating simultaneously the suitability of this species to be used as a sentinel. Fish were collected between March 2015 and January 2016 at three locations taking into account the pollution sources and accessibility. In liver, EROD and BFCOD showed the highest induction in October specially in the location of the dam that received pollutants. In gills, only EROD, but not BFCOD, activity was detected. Maximal EROD induction was noted in samples from January. Fish cell lines (RTG-2 and PLHC-1) were exposed to sediments extracts collected at Beni Haroun lake and enzyme activities (EROD and BFCOD, respectively) were measured. Sediment extracts did not induce BFCOD activity. The EROD induction observed in RTG-2 cells was in line with the results observed in fish tissues. Our results suggest that the lake is at risk from pollution and that Barbus callensis is a good sentinel species. Copyright © 2017 Elsevier Inc. All rights reserved.
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The city as a refuge for insect pollinators.
Hall, Damon M; Camilo, Gerardo R; Tonietto, Rebecca K; Ollerton, Jeff; Ahrné, Karin; Arduser, Mike; Ascher, John S; Baldock, Katherine C R; Fowler, Robert; Frankie, Gordon; Goulson, Dave; Gunnarsson, Bengt; Hanley, Mick E; Jackson, Janet I; Langellotto, Gail; Lowenstein, David; Minor, Emily S; Philpott, Stacy M; Potts, Simon G; Sirohi, Muzafar H; Spevak, Edward M; Stone, Graham N; Threlfall, Caragh G
2017-02-01
Research on urban insect pollinators is changing views on the biological value and ecological importance of cities. The abundance and diversity of native bee species in urban landscapes that are absent in nearby rural lands evidence the biological value and ecological importance of cities and have implications for biodiversity conservation. Lagging behind this revised image of the city are urban conservation programs that historically have invested in education and outreach rather than programs designed to achieve high-priority species conservation results. We synthesized research on urban bee species diversity and abundance to determine how urban conservation could be repositioned to better align with new views on the ecological importance of urban landscapes. Due to insect pollinators' relatively small functional requirements-habitat range, life cycle, and nesting behavior-relative to larger mammals, we argue that pollinators put high-priority and high-impact urban conservation within reach. In a rapidly urbanizing world, transforming how environmental managers view the city can improve citizen engagement and contribute to the development of more sustainable urbanization. © 2016 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.
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Ecology and Economics of Using Native Managed Bees for Almond Pollination.
Koh, Insu; Lonsdorf, Eric V; Artz, Derek R; Pitts-Singer, Theresa L; Ricketts, Taylor H
2018-02-09
Native managed bees can improve crop pollination, but a general framework for evaluating the associated economic costs and benefits has not been developed. We conducted a cost-benefit analysis to assess how managing blue orchard bees (Osmia lignaria Say [Hymenoptera: Megachildae]) alongside honey bees (Apis mellifera Linnaeus [Hymenoptera: Apidae]) can affect profits for almond growers in California. Specifically, we studied how adjusting three strategies can influence profits: (1) number of released O. lignaria bees, (2) density of artificial nest boxes, and (3) number of nest cavities (tubes) per box. We developed an ecological model for the effects of pollinator activity on almond yields, validated the model with published data, and then estimated changes in profits for different management strategies. Our model shows that almond yields increase with O. lignaria foraging density, even where honey bees are already in use. Our cost-benefit analysis shows that profit ranged from -US$1,800 to US$2,800/acre given different combinations of the three strategies. Adding nest boxes had the greatest effect; we predict an increase in profit between low and high nest box density strategies (2.5 and 10 boxes/acre). In fact, the number of released bees and the availability of nest tubes had relatively small effects in the high nest box density strategies. This suggests that growers could improve profits by simply adding more nest boxes with moderate number of tubes in each. Our approach can support grower decisions regarding integrated crop pollination and highlight the importance of a comprehensive ecological economic framework for assessing these decisions. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Rodrigues, Cleiton G; Krüger, Alexandra P; Barbosa, Wagner F; Guedes, Raul Narciso C
2016-04-11
The ongoing concern about bee decline has largely focused on honey bees and neonicotinoid insecticides, while native pollinators such as Neotropical stingless bees and agrochemicals such as other insecticide groups, pesticides in general, and fertilizers-especially leaf fertilizers-remain neglected as potential contributors to pollination decline. In an effort to explore this knowledge gap, we assessed the lethal and sublethal behavioral impact of heavy metal-containing leaf fertilizers in a native pollinator of ecological importance in the Neotropics: the stingless beeFriesella schrottkyi(Friese). Two leaf fertilizers-copper sulfate (24% Cu) and a micronutrient mix (Arrank L: 5% S, 5% Zn, 3% Mn, 0.6% Cu, 0.5% B, and 0.06% Mo)-were used in oral and contact exposure bioassays. The biopesticide spinosad and water were used as positive and negative controls, respectively. Copper sulfate compromised the survival of stingless bee workers, particularly with oral exposure, although less than spinosad under contact exposure. Sublethal exposure to both leaf fertilizers at their field rates also caused significant effects in exposed workers. Copper sulfate enhanced flight take-off on stingless bee workers, unlike workers exposed to the micronutrient mix. There was no significant effect of leaf fertilizers on the overall activity and walking behavior of worker bees. No significant effect was observed for the respiration rate of worker bees under contact exposure, but workers orally exposed to the micronutrient mix exhibited a reduced respiration rate. Therefore, leaf fertilizers do affectF. schrottkyi, what may also occur with other stingless bees, potentially compromising their pollination activity deserving attention. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Páez, David J; Restif, Olivier; Eby, Peggy; Plowright, Raina K
2018-05-05
Bats provide important ecosystem services such as pollination of native forests; they are also a source of zoonotic pathogens for humans and domestic animals. Human-induced changes to native habitats may have created more opportunities for bats to reside in urban settings, thus decreasing pollination services to native forests and increasing opportunities for zoonotic transmission. In Australia, fruit bats ( Pteropus spp. flying foxes) are increasingly inhabiting urban areas where they feed on anthropogenic food sources with nutritional characteristics and phenology that differ from native habitats. We use optimal foraging theory to investigate the relationship between bat residence time in a patch, the time it takes to search for a new patch (simulating loss of native habitat) and seasonal resource production. We show that it can be beneficial to reside in a patch, even when food productivity is low, as long as foraging intensity is low and the expected searching time is high. A small increase in the expected patch searching time greatly increases the residence time, suggesting nonlinear associations between patch residence and loss of seasonal native resources. We also found that sudden increases in resource consumption due to an influx of new bats has complex effects on patch departure times that again depend on expected searching times and seasonality. Our results suggest that the increased use of urban landscapes by bats may be a response to new spatial and temporal configurations of foraging opportunities. Given that bats are reservoir hosts of zoonotic diseases, our results provide a framework to study the effects of foraging ecology on disease dynamics.One contribution of 14 to a theme isssue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'. © 2018 The Author(s).
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Bumble bees of the western United States
USDA-ARS?s Scientific Manuscript database
Bumble bees (genus Bombus) are critical pollinators of flowering plants. Thirty species of bumble bees are native to the western United States and this publication is a guide to the natural history and identification of these species. We present phenology graphs, host-plant associations, detailed ...
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Nosema ceranae in South American Native Stingless Bees and Social Wasp.
Porrini, Martín Pablo; Porrini, Leonardo Pablo; Garrido, Paula Melisa; de Melo E Silva Neto, Carlos; Porrini, Darío Pablo; Muller, Fernando; Nuñez, Laura Alejandra; Alvarez, Leopoldo; Iriarte, Pedro Fernandez; Eguaras, Martín Javier
2017-11-01
Besides the incipient research effort, the role of parasites as drivers of the reduction affecting pollinator populations is mostly unknown. Given the worldwide extension of the beekeeping practice and the diversity of pathogens affecting Apis mellifera populations, honey bee colonies are a certain source of parasite dispersion to other species. Here, we communicate the detection of the microsporidium Nosema ceranae, a relatively new parasite of honey bees, in stingless bees (Meliponini) and the social wasp Polybia scutellaris (Vespidae) samples from Argentina and Brazil by means of duplex PCR. Beyond the geographic location of the nests, N. ceranae was detected in seven from the eight Meliponini species analyzed, while Nosema apis, another common parasite of A. mellifera, was absent in all samples tested. Further research is necessary to determine if the presence of the parasite is also associated with established infection in host tissues. The obtained information enriches the current knowledge about pathologies that can infect or, at least, be vectored by native wild pollinators from South America.
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Gaines-Day, Hannah R; Gratton, Claudio
2017-08-01
The expansion of modern agriculture has led to the loss and fragmentation of natural habitat, resulting in a global decline in biodiversity, including bees. In many countries, farmers can participate in cost-share programs to create natural habitat on their farms for the conservation of beneficial insects, such as bees. Despite their dependence on bee pollinators and the demonstrated commitment to environmental stewardship, participation in such programs by Wisconsin cranberry growers has been low. The objective of this study was to understand the barriers that prevent participation by Wisconsin cranberry growers in cost-share programs for on-farm conservation of native bees. We conducted a survey of cranberry growers (n = 250) regarding farming practices, pollinators, and conservation. Although only 10% of growers were aware of federal pollinator cost-share programs, one third of them were managing habitat for pollinators without federal aid. Once informed of the programs, 50% of growers expressed interest in participating. Fifty-seven percent of growers manage habitat for other wildlife, although none receive cost-share funding to do so. Participation in cost-share programs could benefit from outreach activities that promote the programs, a reduction of bureaucratic hurdles to participate, and technical support for growers on how to manage habitat for wild bees.
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Gratton, Claudio
2017-01-01
The expansion of modern agriculture has led to the loss and fragmentation of natural habitat, resulting in a global decline in biodiversity, including bees. In many countries, farmers can participate in cost-share programs to create natural habitat on their farms for the conservation of beneficial insects, such as bees. Despite their dependence on bee pollinators and the demonstrated commitment to environmental stewardship, participation in such programs by Wisconsin cranberry growers has been low. The objective of this study was to understand the barriers that prevent participation by Wisconsin cranberry growers in cost-share programs for on-farm conservation of native bees. We conducted a survey of cranberry growers (n = 250) regarding farming practices, pollinators, and conservation. Although only 10% of growers were aware of federal pollinator cost-share programs, one third of them were managing habitat for pollinators without federal aid. Once informed of the programs, 50% of growers expressed interest in participating. Fifty-seven percent of growers manage habitat for other wildlife, although none receive cost-share funding to do so. Participation in cost-share programs could benefit from outreach activities that promote the programs, a reduction of bureaucratic hurdles to participate, and technical support for growers on how to manage habitat for wild bees. PMID:28763038
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Morandin, L A; Long, R F; Kremen, C
2016-05-11
Field edge habitat in homogeneous agricultural landscapes can serve multiple purposes including enhanced biodiversity, water quality protection, and habitat for beneficial insects, such as native bees and natural enemies. Despite this ecosystem service value, adoption of field border plantings, such as hedgerows, on large-scale mono-cropped farms is minimal. With profits primarily driving agricultural production, a major challenge affecting hedgerow plantings is linked to establishment costs and the lack of clear economic benefits on the restoration investment. Our study documented that hedgerows are economically viable to growers by enhancing beneficial insects and natural pest control and pollination on farms. With pest control alone, our model shows that it would take 16 yr to break even from insecticide savings on the US$4,000 cost of a typical 300-m hedgerow field edge planting. By adding in pollination benefits by native bees, where honey bees (Apis mellifera L.) may be limiting, the return time is reduced to 7 yr. USDA cost share programs allow for a quicker return on a hedgerow investment. Our study shows that over time, small-scale restoration can be profitable, helping to overcome the barrier of cost associated with field edge habitat restoration on farms. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the United States.
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Geib, Jennifer C; Strange, James P; Galenj, Candace
2015-04-01
Recent reports of global declines in pollinator species imply an urgent need to assess the abundance of native pollinators and density-dependent benefits for linked plants. In this study, we investigated (1) pollinator nest distributions and estimated colony abundances, (2) the relationship between abundances of foraging workers and the number of nests they represent, (3) pollinator foraging ranges, and (4) the relationship between pollinator abundance and plant reproduction. We examined these questions in an alpine ecosystem in the Colorado Rocky Mountains, focusing on four alpine bumble bee species (Bombus balteatus, B. flavifrons, B. bifarius, and B. sylvicola), and two host plants that differ in their degrees of pollinator specialization (Trifolium dasyphyllum and T. parryi). Using microsatellites, we found that estimated colony abundances among Bombus species ranged from ~18 to 78 colonies/0.01 km2. The long-tongued species B. balteatus was most common, especially high above treeline, but the subalpine species B. bifarius was unexpectedly abundant for this elevation range. Nests detected among sampled foragers of each species were correlated with the number of foragers caught. Foraging ranges were smaller than expected for all Bombus species, ranging from 25 to 110 m. Fruit set for the specialized plant, Trifolium parryi, was positively related to the abundance of its Bombus pollinator. In contrast, fruit set for the generalized plant, T. dasyphyllum, was related to abundance of all Bombus species. Because forager abundance was related to nest abundance of each Bombus species and was an equally effective predictor of plant fecundity, forager inventories are probably suitable for assessing the health of outcrossing plant populations. However, nest abundance, rather than forager abundance, better reflects demographic and genetic health in populations of eusocial pollinators such as bumble bees. Development of models incorporating the parameters we have measured here (nest abundance, forager abundance, and foraging distance) could increase the usefulness of foraging worker inventories in nionitoring, managing, and conserving pollinator populations.
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NASA Astrophysics Data System (ADS)
Fogarty, S.; Grogan, D. S.; Hale, S. R.
2013-12-01
A green roof is typically installed for one of two reasons: to mitigate the 'urban heat island' effect, reducing ambient temperatures and creating energy savings, or to reduce both the quantity and intensity of stormwater runoff, which is a major cause of river erosion and eutrophication. The study of green roofs in the United States has focused on commercial systems that use a proprietary expanded shale or clay substrate, along with succulent desert plants (mainly Sedum species). The green roof has the potential not only to provide thermal insulation and reduce storm runoff, but also to reclaim some of the natural habitat that has been lost to the built environment. Of special importance is the loss of habitat for pollinating insects, particularly native bees, which have been in decline for at least two decades. These pollinators are essential for crop production and for the reproduction of at least 65% of wild plants globally. Our study involves the installation of a small (4ft by 4ft), self-designed green roof system built with readily available components from a hardware store. The garden will be filled with a soilless potting mix, combined with 15% compost, and planted with grasses and wildflowers native to the Seacoast, New Hampshire region. Some of the plant species are used by bees for nesting materials, while others provide food in the form of nectar, pollen, and seeds for bees, butterflies, hummingbirds, and granivorous birds. We monitor precipitation on the roof and runoff from the garden on a per storm basis, and test grab samples of runoff for dissolved organic nitrogen and phosphorous. Runoff and nutrient concentration results are compared to a non-vegetated roof surface, and a proprietary Green Grid green roof system. This project is designed to address three main questions of interest: 1) Can these native plant species, which potentially provide greater ecosystem services than Sedum spp. in the form of food and habitat, survive in the conditions on a rooftop? 2) How does this design compare with the performance of the extant Green Grid green roof system on the roof in regard to storm water runoff mitigation and nutrient leaching? and 3) Using GIS, can this information be scaled to a larger region (i.e. UNH campus, the NH Seacoast, NH cities, etc.) to determine areas of particular interest for pollinator conservation? Runoff mitigation, as a percentage of precipitation, is expected to be greater than that on the roof with proprietary substrate, though nutrient leaching may be greater as well due to the higher organic matter content. Paired with GIS data on NH ecoregions, these results will help to identify areas in the state that would benefit from the construction of pollinator habitat corridors, including urban areas that may not have been previously considered.
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Effects of low levels of herbicides on prairie species of the Willamette Valley, Oregon
Non-crop plants (native and introduced) growing adjacent to agricultural fields provide essential habitat for wildlife and pollinators, and may be exposed to low levels of non-target pesticide drift during routine weed control activities. This study evaluated the relative sensiti...
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Response of native insect communities to invasive plants.
Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T
2014-01-01
Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.
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Landaverde-González, Patricia; Quezada-Euán, José Javier G; Theodorou, Panagiotis; Murray, Tomás E; Husemann, Martin; Ayala, Ricardo; Moo-Valle, Humberto; Vandame, Rémy; Paxton, Robert J
2017-12-01
Traditional tropical agriculture often entails a form of slash-and-burn land management that may adversely affect ecosystem services such as pollination, which are required for successful crop yields. The Yucatán Peninsula of Mexico has a >4000 year history of traditional slash-and-burn agriculture, termed 'milpa'. Hot 'Habanero' chilli is a major pollinator-dependent crop that nowadays is often grown in monoculture within the milpa system.We studied 37 local farmers' chilli fields (sites) to evaluate the effects of landscape composition on bee communities. At 11 of these sites, we undertook experimental pollination treatments to quantify the pollination of chilli. We further explored the relationships between landscape composition, bee communities and pollination service provision to chilli.Bee species richness, particularly species of the family Apidae, was positively related to the amount of forest cover. Species diversity decreased with increasing proportion of crop land surrounding each sampling site. Sweat bees of the genus Lasioglossum were the most abundant bee taxon in chilli fields and, in contrast to other bee species, increased in abundance with the proportion of fallow land, gardens and pastures which are an integral part of the milpa system.There was an average pollination shortfall of 21% for chilli across all sites; yet the shortfall was unrelated to the proportion of land covered by crops. Rather, chilli pollination was positively related to the abundance of Lasioglossum bees, probably an important pollinator of chilli, as well indirectly to the proportion of fallow land, gardens and pastures that promote Lasioglossum abundance. Synthesis and applications . Current, low-intensity traditional slash-and-burn ( milpa ) agriculture provides Lasioglossum spp. pollinators for successful chilli production; fallow land, gardens and pasture therefore need to be valued as important habitats for these and related ground-nesting bee species. However, the negative impact of agriculture on total bee species diversity highlights how agricultural intensification is likely to reduce pollination services to crops, including chilli. Indeed, natural forest cover is vital in tropical Yucatán to maintain a rich assemblage of bee species and the provision of pollination services for diverse crops and wild flowers.
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USDA-ARS?s Scientific Manuscript database
Healthy plant communities of the American sagebrush-steppe consist of mostly wind-pollinated shrubs and grasses interspersed with a diverse mix of mostly spring-blooming, herbaceous perennial wildflowers. Native, non-social bees are the common floral visitors, but their floral associations and abund...
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Bashan, Yoav; Salazar, Bernardo G; Moreno, Manuel; Lopez, Blanca R; Linderman, Robert G
2012-07-15
Restoration of highly eroded desert land was attempted in the southern Sonoran Desert that had lost its natural capacity for self-revegetation. In six field experiments, the fields were planted with three native leguminous trees: mesquite amargo Prosopis articulata, and yellow and blue palo verde Parkinsonia microphylla and Parkinsonia florida. Restoration included inoculation with two of plant growth-promoting bacteria (PGPB; Azospirillum brasilense and Bacillus pumilus), native arbuscular mycorrhizal (AM) fungi, and small quantities of compost. Irrigation was applied, when necessary, to reach a rainy year (300 mm) of the area. The plots were maintained for 61 months. Survival of the trees was marginally affected by all supplements after 30 months, in the range of 60-90%. This variation depended on the plant species, where all young trees were established after 3 months. Plant density was a crucial variable and, in general, low plant density enhanced survival. High planting density was detrimental. Survival significantly declined in trees 61 months after planting. No general response of the trees to plant growth-promoting microorganisms and compost was found. Mesquite amargo and yellow palo verde responded well (height, number of branches, and diameter of the main stem) to inoculation with PGPB, AM fungi, and compost supplementation after three months of application. Fewer positive effects were recorded after 30 months. Blue palo verde did not respond to most treatments and had the lowest survival. Specific plant growth parameters were affected to varying degrees to inoculations or amendments, primarily depending on the tree species. Some combinations of tree/inoculant/amendment resulted in small negative effects or no response when measured after extended periods of time. Using native leguminous trees, this study demonstrated that restoration of severely eroded desert lands was possible. Copyright © 2012 Elsevier Ltd. All rights reserved.
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The discovery of 2,5-dialkylcyclohexan-1,3-diones as a new class of natural products
Franke, S.; Ibarra, F.; Schulz, C. M.; Twele, R.; Poldy, J.; Barrow, R. A.; Peakall, R.; Schiestl, F. P.; Francke, W.
2009-01-01
Orchids employing sexual deceit attract males of their pollinator species through specific volatile signals that mimic female-released sex pheromones. One of these signals proved to be 2-ethyl-5-propylcyclohexan-1,3-dione (chiloglottone1), a new natural product that was shown to be most important in the relations between orchids of the genus Chiloglottis, native to Australia, and corresponding pollinator species. Systematic investigations on the mass spectrometric fragmentation pattern of 2,5-dialkylcyclohexan-1,3-diones identified key ions providing information about the structures of the substituents at positions 2 and 5. Results enabled us to identify 2-ethyl-5-pentylcyclohexan-1,3-dione (chiloglottone2) and 2-butyl-5-methylcyclohexan-1,3-dione (chiloglottone3) as new natural products that play a decisive role in the pollination syndrome of some Chiloglottis species. During field bioassays, pure synthetic samples of chiloglottone1–3 or mixtures thereof proved to be attractive to the corresponding orchid pollinators. Because of their likely biogenesis from ubiquitous fatty acid precursors, 2,5-dialkylcyclohexan-1,3-diones may represent a hitherto overlooked, widespread class of natural products. PMID:19470640
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Oxalis debilis in China: Distribution of Flower Morphs, Sterile Pollen and Polyploidy
LUO, SHIXIAO; ZHANG, DIANXIANG; RENNER, SUSANNE S.
2006-01-01
• Background and Aims Oxalis debilis is a South American tristylous species that is currently naturalizing in China. Based on field observations and herbarium data a report is made on its pollination, morph frequencies, pollen viability, seed set and chromosome number. In addition, a new chromosome count for the species in Africa is provided. • Methods Field observations were conducted in six provinces in south-east China. Flower visitors were recorded and nectar sugar was measured with a refractometer. The species' compatibility system was determined by carrying out experimental self- and cross-pollinations on bagged inflorescences. Stigma receptivity and pollen viability was determined using the MTT test. • Key Results and Conclusions Populations of O. debilis in China contain either the mid-style-length morph or the short morph, but not both. Pollination is by nectar- and pollen-foraging bees; pollen viability is low; and seed set in natural and experimentally self- or cross-pollinated flowers is extremely low. Chromosome counts indicate that O. debilis contains diploid and tetraploid forms in its native as well as introduced range, which does not support a previous hypothesis that the predominant vegetative reproduction in this species is an escape from pentaploidy. PMID:16735406
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Bioindicator beetles and plants in desertified and eroded lands in Turkey
USDA-ARS?s Scientific Manuscript database
Xerophilous vegetation with characteristic insect assemblages is described in main agricultural regions and native landscapes of Turkey. Long term, intensive investigations documented vast biotic degradation of soil and vegetation (commonly referred to as desertification) by an overgrazing, construc...
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Petersen, Jessica D.; Reiners, Stephen; Nault, Brian A.
2013-01-01
Pollinators provide an important service in many crops. Managed honey bees (Apis mellifera L.) are used to supplement pollination services provided by wild bees with the assumption that they will enhance pollination, fruit set and crop yield beyond the levels provided by the wild bees. Recent declines in managed honey bee populations have stimulated interest in finding alternative managed pollinators to service crops. In the eastern U.S., managed hives of the native common eastern bumble bee (Bombus impatiens Cresson) may be an excellent choice. To examine this issue, a comprehensive 2-yr study was conducted to compare fruit yield and bee visits to flowers in pumpkin (Cucurbita pepo L.) fields that were either supplemented with A. mellifera hives, B. impatiens hives or were not supplemented. We compared pumpkin yield, A. mellifera flower visitation frequency and B. impatiens flower visitation frequency between treatments. Results indicated that supplementing pumpkin fields with either A. mellifera or B. impatiens hives did not increase their visitation to pumpkin flowers or fruit yield compared with those that were not supplemented. Next, the relationship between frequency of pumpkin flower visitation by the most prominent bee species (Peponapis pruinosa (Say), B. impatiens and A. mellifera) and fruit yield was determined across all pumpkin fields sampled. Fruit yield increased as the frequency of flower visits by A. mellifera and B. impatiens increased in 2011 and 2012, respectively. These results suggest that supplementation with managed bees may not improve pumpkin production and that A. mellifera and B. impatiens are important pollinators of pumpkin in our system. PMID:23894544
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Petersen, Jessica D; Reiners, Stephen; Nault, Brian A
2013-01-01
Pollinators provide an important service in many crops. Managed honey bees (Apis mellifera L.) are used to supplement pollination services provided by wild bees with the assumption that they will enhance pollination, fruit set and crop yield beyond the levels provided by the wild bees. Recent declines in managed honey bee populations have stimulated interest in finding alternative managed pollinators to service crops. In the eastern U.S., managed hives of the native common eastern bumble bee (Bombus impatiens Cresson) may be an excellent choice. To examine this issue, a comprehensive 2-yr study was conducted to compare fruit yield and bee visits to flowers in pumpkin (Cucurbita pepo L.) fields that were either supplemented with A. mellifera hives, B. impatiens hives or were not supplemented. We compared pumpkin yield, A. mellifera flower visitation frequency and B. impatiens flower visitation frequency between treatments. Results indicated that supplementing pumpkin fields with either A. mellifera or B. impatiens hives did not increase their visitation to pumpkin flowers or fruit yield compared with those that were not supplemented. Next, the relationship between frequency of pumpkin flower visitation by the most prominent bee species (Peponapis pruinosa (Say), B. impatiens and A. mellifera) and fruit yield was determined across all pumpkin fields sampled. Fruit yield increased as the frequency of flower visits by A. mellifera and B. impatiens increased in 2011 and 2012, respectively. These results suggest that supplementation with managed bees may not improve pumpkin production and that A. mellifera and B. impatiens are important pollinators of pumpkin in our system.
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Córdova-Acosta, E; Zavala-Hurtado, J A; Golubov, J; Casas, A
2017-09-01
Mexico has one of the highest diversities of barrel cacti species worldwide; however, all are threatened and require conservation policies. Information on their reproductive biology is crucial, but few studies are available. Ferocactus recurvus subsp. recurvus is a barrel cactus endemic to the Tehuacán-Cuicatlán Valley. Our research aimed to characterise its floral and pollination biology. We hypothesised bee pollination, as suggested by its floral morphology and behaviour, and self-incompatibility, like most barrel cacti studied. Three study sites were selected in the semiarid Zapotitlán Valley, Mexico. We examined 190 flowers from 180 plants to determine: morphometry and behaviour of flowers, flower visitors and probable pollinators, and breeding system. Flowers showed diurnal anthesis, lasting 2-5 days, the stigma being receptive on day 2 or 3 after the start of anthesis. Flowers produced scarce/no nectar and main visitors were bees (Apidae), followed by flies (Muscidae), ants (Formicidae), thrips (Thripidae) and hummingbirds (Throchilidae); however, only native bees and occasionally wasps contacted the stigma and anthers. Pollination experiments revealed that this species is self-incompatible and xenogamous. In natural conditions, fruit set was 60% and cross-pollination fruit set was 100%. Percentage seed germination resulting from cross-pollination was higher than in the control treatment. Our results provide ecological information for conservation programmes to ensure a high probability of breeding and seed production in natural populations of F. recurvus. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Creating and Evaluating Artificial Domiciles for Bumble Bees
ERIC Educational Resources Information Center
Golick, Douglas A.; Ellis, Marion D.; Beecham, Brady
2006-01-01
Bumble bees are valuable pollinators of native and cultivated flora. Despite our knowledge of bumble bee nest site selection, most efforts to attract bumble bees to artificial domiciles have been met with limited success. Creating and evaluating artificial domiciles provides students an opportunity to investigate a real problem. In this lesson,…
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Matt Reeves; Paulette Ford; Leonardo Frid; David Augustine; Justin Derner
2016-01-01
The Great Plains grasslands of North America provide a multitude of ecosystem services including clean water, forage, habitat, recreation, and pollination of native and agricultural plants. A general lack of quantitative information regarding the effects of varied management strategies on these spatially heterogeneous landscapes complicates our understanding...
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USDA-ARS?s Scientific Manuscript database
Bees provide vital pollination services to the majority of flowering plants in both natural and agricultural systems. Unfortunately, both native and managed bee populations are experiencing serious declines, threatening the persistence of these plants and crops. Agricultural chemicals are one possib...
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Plant guide: Douglas' dusty-maiden (Chaenactic douglasii)
Derek Tilley; Dan Ogle; Loren St. John
2010-01-01
Douglas' dustymaiden can be used as part of a native forb component in wildland seedings to increase biodiversity, improve wildlife habitat, and provide food for numerous birds and mammals. Douglas' dustymaiden is readily visited by pollinators and other insect species. It is considered an important species for sage grouse during brood rearing because of its...
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James H. Cane
2008-01-01
The summer-blooming annual forbs Cleome lutea and Cleome serrulata (Cleomaceae) are native across the US Intermountain West and Rocky Mountains, respectively. Their farmed seed is sought to help rehabilitate western rangelands in those regions. This study of the reproductive biologies and pollinator faunas of C. lutea...
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USDA-ARS?s Scientific Manuscript database
Most species of bees nest underground. Recent interest in pollinator-friendly gardens and landscaping focuses on planting suitable flowering species for bees, but we know little about providing for the ground-nesting needs of bees other than leaving them bare dirt surfaces. In this study, a surfac...
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Natural and cultural history of beargrass (Xerophyllum tenax)
Susan Hummel; Sarah Foltz-Jordan; Sophia Polasky
2012-01-01
Beargrass (Xerophyllum tenax (Pursh) Nutt.) is a source of food, habitat, and raw material for animals, pollinating insects, and people across its range in the Western United States. The plant has long been used by Native Americans, who harvest the leaves for basketry and other crafts. More recently, beargrass has become an important component of...
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Rykken, Jessica; Rodman, Ann; Droege, Sam; Grundel, Ralph
2014-01-01
In 2010, collaborators from the National Park Service (Ann Rodman, Yellowstone National Park), USGS (Sam Droege and Ralph Grundel), and Harvard University (Jessica Rykken) were awarded funding from the NPS Climate Change Response Program to launch just such an investigation in almost 50 units of the National Park System (fig. 1). The main objectives of this multiyear project were to: Compare bee communities in three “vulnerable” habitats (high elevation, inland arid, coastal) and paired “common” habitats, representative of the landscape matrix, in order to determine whether vulnerable habitats have a distinctive bee fauna that may be at higher risk under climate change scenarios. Inform natural resource managers at each park about the bee fauna at their paired sites, including the presence of rare and endemic species, and make suggestions for active management strategies to promote native bee habitat if warranted. Increase awareness among park natural resource staffs, interpreters, and visitors of native bee diversity and natural history, the essential role of bees in maintaining healthy ecosystems, and potential threats from climate change to pollinator-dependent ecosystems.
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Reproductive biology of the biofuel plant Jatropha curcas in its center of origin
Rincón-Rabanales, Manuel; Vargas-López, Laura I.; Adriano-Anaya, Lourdes; Salvador-Figueroa, Miguel
2016-01-01
In this work, we studied the main characteristics of flowering, reproductive system and diversity of pollinators for the biofuel plant Jatropha curcas (L.) in a site of tropical southeastern Mexico, within its center of origin. The plants were monoecious with inflorescences of unisexual flowers. The male flowers produced from 3062–5016 pollen grains (266–647 per anther). The plants produced fruits with both geitonogamy and xenogamy, although insect pollination significantly increased the number and quality of fruits. A high diversity of flower visiting insects (36 species) was found, of which nine were classified as efficient pollinators. The native stingless bees Scaptotrigona mexicana (Guérin-Meneville) and Trigona (Tetragonisca) angustula (Latreille) were the most frequent visitors and their presence coincided with the hours when the stigma was receptive. It is noteworthy that the female flowers open before the male flowers, favoring xenogamy, which may explain the high genetic variability reported in J. curcas for this region of the world. PMID:26989640
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Geber, Monica A; Eckhart, Vincent M
2005-03-01
Because the range boundary is the locale beyond which a taxon fails to persist, it provides a unique opportunity for studying the limits on adaptive evolution. Adaptive constraints on range expansion are perplexing in view of widespread ecotypic differentiation by habitat and region within a species' range (regional adaptation) and rapid evolutionary response to novel environments. In this study of two parapatric subspecies, Clarkia xantiana ssp. xantiana and C. x. ssp. parviflora, we compared the fitness of population transplants within their native region, in a non-native region within the native range, and in the non-native range to assess whether range expansion might be limited by a greater intensity of selection on colonists of a new range versus a new region within the range. The combined range of the two subspecies spans a west-to-east gradient of declining precipitation in the Sierra Nevada of California, with ssp. xantiana in the west being replaced by ssp. parviflora in the east. Both subspecies had significantly higher fitness in the native range (range adaptation), whereas regional adaptation was weak and was found only in the predominantly outcrossing ssp. xantiana but was absent in the inbreeding ssp. parvifilora. Because selection intensity on transplants was much stronger in the non-native range relative to non-native regions, there is a larger adaptive barrier to range versus regional expansion. Three of five sequential fitness components accounted for regional and range adaptation, but only one of them, survivorship from germination to flowering, contributed to both. Flower number contributed to regional adaptation in ssp. xantiana and fruit set (number of fruits per flower) to range adaptation. Differential survivorship of the two taxa or regional populations of ssp. xantiana in non-native environments was attributable, in part, to biotic interactions, including competition, herbivory, and pollination. For example, low fruit set in ssp. xantiana in the east was likely due to the absence of its principal specialist bee pollinators in ssp. parviflora's range. Thus, convergence on self-fertilization may be necessary for ssp. xantiana to invade ssp. parviflora's range, but the evolution of outcrossing would not be required for ssp. parviflora to invade ssp. xantiana's range.
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Sequential generations of honey bee (Apis mellifera) queens produced using cryopreserved semen.
Hopkins, Brandon K; Herr, Charles; Sheppard, Walter S
2012-01-01
Much of the world's food production is dependent on honey bees for pollination, and expanding food production will further increase the demand for managed pollination services. Apiculturists outside the native range of the honey bee, in the Americas, Australia and eastern Asia, have used only a few of the 27 described subspecies of honey bees (Apis mellifera) for beekeeping purposes. Within the endemic ranges of a particular subspecies, hybridisation can threaten native subspecies when local beekeepers import and propagate non-native honey bees. For many threatened species, cryopreserved germplasm can provide a resource for the preservation of diversity and recovery of endangered populations. However, although instrumental insemination of queen honey bees is well established, the absence of an effective means to cryopreserve honey bee semen has limited the success of efforts to preserve genetic diversity within the species or to develop repositories of honey bee germplasm for breeding purposes. Herein we report that some queens inseminated with cryopreserved semen were capable of producing a substantial number of fertilised offspring. These diploid female larvae were used to produce two additional sequential generations of new queens, which were then back-crossed to the same stock of frozen semen. Our results demonstrate the ability to produce queens using cryopreserved honey bee spermatozoa and the potential for the establishment of a honey bee genetic repository.
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Carbon dynamics within agricultural and native sites in the loess region of Western lowa
Manies, K.L.; Harden, J.W.; Kramer, L.; Parton, W.J.
2001-01-01
In order to quantify the historical changes in carbon storage that result from agricultural conversion, this study compared the carbon dynamics of two sites in the loess region of Iowa: a native prairie and a cropland. Field data were obtained to determine present-day carbon storage and its variability within a landscape (a stable ridgetop vs. eroding upper-midslope vs. depositional lower slope). Models were used to recreate the historical carbon budget of these sites and determine the cropland's potential to be a net CO2 source or sink, relative to the atmosphere. Regardless of slope position, the cropland site contains approximately half the amount of carbon as prairie. Variability in soil carbon storage within a site as a consequence of slope position is as large or larger (variations of 200-300%) than temporal variation (???200% at all slope positions). The most extreme difference in soil carbon storage between the cropland and prairie sites is found in the soil at the upper-midslope, which is the area of greatest erosion. The models estimate that 93-172% of the carbon in the original topsoil has been lost from the cropland's eroding midslope. Much of this carbon is derived from deeper soil horizons. Either a small sink or strong source of carbon to the atmosphere is created, depending on the fate of the eroded sediment and its associated carbon.
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USDA-ARS?s Scientific Manuscript database
The semi-arid and arid rangelands and irrigated pastures of the western U.S. provide a broad array of ecosystem services, includig wildlife/livestock feed, a diversity of native plants, pollinators, wildlife, and recreational activities. However, disturbances by wildfire, livestock, wildlife, and h...
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Penstemons are for Great Basin gardens
Heidi Kratsch
2013-01-01
Penstemons are flowering perennials much loved by the gardening public. Gardeners appreciate their diversity of flower colors that are at peak bloom in June and July, their many shapes and sizes, and their attractiveness to hummingbirds and other native pollinators. You may even have planted some in your own garden. Most people don't realize there are about 280...
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Tao, Zhi-Bin; Ren, Zong-Xin; Bernhardt, Peter; Liang, Huan; Li, Hai-Dong; Zhao, Yan-Hui; Wang, Hong; Li, De-Zhu
2018-06-01
Isolation between species, or taxa sharing a common lineage, depends primarily on the relative strengths of various reproductive barriers. Previous studies on reproductive isolation between orchids emphasized mechanical and ethological barriers in flowers of species showing food and/or sexual mimicry. In this study, we investigated and quantified a series of prepollination and postpollination barriers between pink and white forms of Spiranthes sinensis sl, a nectar-secreting complex. We generated ML trees based on trn S-G and mat K to explore phylogenetic relationships in this species complex. Spiranthes sinensis sl segregated from some other congeners, but the white form constituted a distinct clade in relation to the pink form. The white form secreted 2-Phenylethanol as it is a single-scent compound and was pollinated almost exclusively by native, large-bodied Apis cerana and Bombus species (Apidae). Apis cerana showed a high floral constancy to this form. The scentless, pink form was pollinated primarily by smaller bees in the genera Ceratina (Apidae), and members of the family Halictidae, with infrequent visits by A. cerana and Bombus species. Fruit set and the production of large embryos following interform pollination treatments were significantly lower compared to intraform pollination results for the white form. Our results suggested that pollinator isolation, based on color and scent cues, may result in greater floral constancy in white populations when both forms are sympatric as two different, guilds of pollinators forage selectively preventing or reducing prospective gene flow. Postpollination barriers appear weaker than prepollination barriers but they also play a role in interform isolation, especially in the white form. Our findings suggest that floral color forms in S. sinensis do not represent an unbalanced polymorphism. Interpretations of the evolutionary status of these forms are discussed.
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The Impact of the Invasive Alien Plant, Impatiens glandulifera, on Pollen Transfer Networks
Emer, Carine; Vaughan, Ian P.; Hiscock, Simon; Memmott, Jane
2015-01-01
Biological invasions are a threat to the maintenance of ecological processes, including pollination. Plant-flower visitor networks are traditionally used as a surrogated for pollination at the community level, despite they do not represent the pollination process, which takes place at the stigma of plants where pollen grains are deposited. Here we investigated whether the invasion of the alien plant Impatiens glandulifera (Balsaminaceae) affects pollen transfer at the community level. We asked whether more alien pollen is deposited on the stigmas of plants on invaded sites, whether deposition is affected by stigma type (dry, semidry and wet) and whether the invasion of I. glandulifera changes the structure of the resulting pollen transfer networks. We sampled stigmas of plants on 10 sites invaded by I. glandulifera (hereafter, balsam) and 10 non-invaded control sites. All 20 networks had interactions with balsam pollen, although significantly more balsam pollen was found on plants with dry stigmas in invaded areas. Balsam pollen deposition was restricted to a small subset of plant species, which is surprising because pollinators are known to carry high loads of balsam pollen. Balsam invasion did not affect the loading of native pollen, nor did it affect pollen transfer network properties; networks were modular and poorly nested, both of which are likely to be related to the specificity of pollen transfer interactions. Our results indicate that pollination networks become more specialized when moving from the flower visitation to the level of pollen transfer networks. Therefore, caution is needed when inferring pollination from patterns of insect visitation or insect pollen loads as the relationship between these and pollen deposition is not straightforward. PMID:26633170
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da Silva, Cláudia Inês; Bordon, Natali Gomes; da Rocha Filho, Léo Correia; Garófalo, Carlos Alberto
2012-12-01
The euglossine bee Eulaema nigrita plays an important role for the pollination of native and economically important plants, such as the sweet passion-fruit Passiflora alata. E. nigrita uniquely collects the nectar from the flowers of P. alata, nevertheless, it needs to visit other plants to collect pollen, nectar and other resources for its survival. There are two methods to identify the species of plants used by bees in their diet: by direct observation of the bees in the flowers, and through identification of pollen grains present in brood cells, feces, or in the bees' body. In order to identify the other plants that E. nigrita visits, we analyzed samples of pollen grains removed from the bee's body in the course of the flowering period of P. alata. Among our results, the flora visited by E. nigrita comprised 40 species from 32 genera and 19 families, some of them used as a pollen source or just nectar. In spite of being a polyletic species, E. nigrita exhibited preference for some plant species with poricidal anthers. P. alata which has high sugar concentration nectar was the main source of nectar for this bee in the studied area. Nonetheless, the pollinic analysis indicated that others nectariferous plant species are necessary to keep the populations of E. nigrita. Studies such as this one are important since they indicate supplementary pollen-nectar sources which must be used for the conservation of the populations of E. nigrita in crops neighbouring areas. In the absence of pollinators, growers are forced to pay for hand pollination, which increases production costs; keeping pollinators in cultivated areas is still more feasible to ensure sweet passion fruit production.
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Hoe, Y C; Gibernau, M; Maia, A C D; Wong, S Y
2016-07-01
In this study, the flowering mechanisms and pollination strategies of seven species of the highly diverse genus Homalomena (Araceae) were investigated in native populations of West Sarawak, Borneo. The floral scent compositions were also recorded for six of these species. The selected taxa belong to three out of four complexes of the section Cyrtocladon (Hanneae, Giamensis and Borneensis). The species belonging to the Hanneae complex exhibited longer anthesis (53-62 h) than those of the Giamensis and Borneensis complexes (ca. 30 h). Species belonging to the Hanneae complex underwent two floral scent emission events in consecutive days, during the pistillate and staminate phases of anthesis. In species belonging to the Giamensis and Borneensis complexes, floral scent emission was only evident to the human nose during the pistillate phase. A total of 33 volatile organic compounds (VOCs) were detected in floral scent analyses of species belonging to the Hanneae complex, whereas 26 VOCs were found in samples of those belonging to the Giamensis complex. The floral scent blends contained uncommon compounds in high concentration, which could ensure pollinator discrimination. Our observations indicate that scarab beetles (Parastasia gestroi and P. nigripennis; Scarabaeidae, Rutelinae) are the pollinators of the investigated species of Homalomena, with Chaloenus schawalleri (Chrysomelidae, Galeuricinae) acting as a secondary pollinator. The pollinators utilise the inflorescence for food, mating opportunities and safe mating arena as rewards. Flower-breeding flies (Colocasiomyia nigricauda and C. aff. heterodonta; Diptera, Drosophilidae) and terrestrial hydrophilid beetles (Cycreon sp.; Coleoptera, Hydrophilidae) were also frequently recovered from inflorescences belonging to all studied species (except H. velutipedunculata), but they probably do not act as efficient pollinators. Future studies should investigate the post-mating isolating barriers among syntopically co-flowering Homalomena sharing the same visiting insects. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Saifuddin, Mustafa; Jha, Shalene
2014-04-01
Given that many pollinators have exhibited dramatic declines related to habitat destruction, an improved understanding of pollinator resource collection across human-altered landscapes is essential to conservation efforts. Despite the importance of bumble bees (Bombus spp.) as global pollinators, little is known regarding how pollen collection patterns vary between individuals, colonies, and landscapes. In this study, Vosnesensky bumble bees (Bombus vosnesenskii Radoszkowski) were collected from a range of human-altered and natural landscapes in northern California. Extensive vegetation surveys and Geographic Information System (GIS)-based habitat classifications were conducted at each site, bees were genotyped to identify colony mates, and pollen loads were examined to identify visited plants. In contrast to predictions based on strong competitive interactions, pollen load composition was significantly more similar for bees captured in a shared study region compared with bees throughout the research area but was not significantly more similar for colony mates. Preference analyses revealed that pollen loads were not composed of the most abundant plant species per study region. The majority of ranked pollen preference lists were significantly correlated for pairwise comparisons of colony mates and individuals within a study region, whereas the majority of pairwise comparisons of ranked pollen preference lists between individuals located at separate study regions were uncorrelated. Results suggest that pollen load composition and foraging preferences are similar for bees throughout a shared landscape regardless of colony membership. The importance of native plant species in pollen collection is illustrated through preference analyses, and we suggest prioritization of specific rare native plant species for enhanced bumble bee pollen collection.
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Anttila, C K; Daehler, C C; Rank, N E; Strong, D R
1998-11-01
Hybridization with abundant invaders is a well-known threat to rare native species. Our study addresses mechanisms of hybridization between a rare invader, smooth cordgrass (Spartina alterniflora) and the common native California cordgrass (S. foliosa) in the salt marshes of San Francisco Bay. These species are wind-pollinated and flower in summer. The invader produced 21-fold the viable pollen of the native, and 28% of invader pollen germinated on native stigmas (1.5-fold the rate of the native's own pollen). Invader pollen increased the seed set of native plants almost eightfold over that produced with native pollen, while native pollen failed to increase seed set of the invader. This pollen swamping and superior siring ability by the invader could lead to serial genetic assimilation of a very large native population. Unlike California cordgrass, smooth cordgrass can grow into low intertidal habitats and cover open mud necessary to foraging shorebirds, marine life, navigation, and flood control in channels. To the extent that intertidal range of the hybrids is more similar to the invader than to the native parent, introgression will lead to habitat loss for shore birds and marine life as well to genetic pollution of native California cordgrass.
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Knocking out knotweed: research pins down a rogue invasive
Natasha Vizcarra; Shannon Claeson
2015-01-01
Bohemian knotweed spreads aggressively along rivers. This invasive weed chokes waterways, displaces native plants, erodes riverbanks, and keeps tree seedlings from growing. Communities in the Pacific Northwest spend millions of dollars to eradicate it on the assumption that it harms fish habitats.But knotweed is difficult to kill. It takes...
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A unique ore-placer cluster with high-Hg gold mineralization in the Amur region (Russia)
NASA Astrophysics Data System (ADS)
Stepanov, V. A.; Moyseenko, V. G.; Melnikov, A. V.
2017-02-01
This work presents the geological structure and a description of gold-ore manifestations and gold placers in the Un'ya-Bom ore-placer cluster of the Amur gold-bearing province. The host rocks are Late Paleozoic and Mesozoic black-shale formations. Intrusive formations are rare. The sublatitudinal Un'ya thrust fault, along which Paleozoic sandstones overlap Mesozoic flyschoid deposits, is regarded as an orecontrolling structure. Gold-quartz and low-sulfide ores are confined to quartz-vein zones. Ore minerals are arsenopyrite, scheelite, ferberite, galena, and native gold. Gold-ore manifestations and placers contain high-Hg native gold. The high Hg content in native gold is explained by the occurrence of the eroded frontal part of the gold-ore pipe in the ore cluster, a source of native gold.
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Invasive Species Science Update (No. 10)
Justin Runyon
2018-01-01
In this issue, we cover new research on wide-ranging topics from the longterm effects of drought on competition between native and invasive plant species, to the effects of drought on pollinator visitation to invasive plants, to a novel use of insect pheromones to improve biocontrol of invasive saltcedar. Thereâs also big news to report in weed biocontrol: two new...
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Phenological notes on Latin American Pinus and Abies
William B. Critchfield
1966-01-01
Very little information has been reported on the time of pollen shedding of the many pines and firs native to Mexico and northern Central America. This kind of information is necessary for any breeding operation, and is often of considerable taxonomic and evolutionary interest as well. An example is the difference in pollination time of a month to six weeks between...
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Exposure of native bees foraging in an agricultural landscape to current-use pesticides.
Hladik, Michelle L; Vandever, Mark; Smalling, Kelly L
2016-01-15
The awareness of insects as pollinators and indicators of environmental quality has grown in recent years, partially in response to declines in honey bee (Apis mellifera) populations. While most pesticide research has focused on honey bees, there has been less work on native bee populations. To determine the exposure of native bees to pesticides, bees were collected from an existing research area in northeastern Colorado in both grasslands (2013-2014) and wheat fields (2014). Traps were deployed bi-monthly during the summer at each land cover type and all bees, regardless of species, were composited as whole samples and analyzed for 136 current-use pesticides and degradates. This reconnaissance approach provides a sampling of all species and represents overall pesticide exposure (internal and external). Nineteen pesticides and degradates were detected in 54 composite samples collected. Compounds detected in >2% of the samples included: insecticides thiamethoxam (46%), bifenthrin (28%), clothianidin (24%), chlorpyrifos (17%), imidacloprid (13%), fipronil desulfinyl (7%; degradate); fungicides azoxystrobin (17%), pyraclostrobin (11%), fluxapyroxad (9%), and propiconazole (9%); herbicides atrazine (19%) and metolachlor (9%). Concentrations ranged from 1 to 310 ng/g for individual pesticides. Pesticides were detected in samples collected from both grasslands and wheat fields; the location of the sample and the surrounding land cover at the 1000 m radius influenced the pesticides detected but because of a small number of temporally comparable samples, correlations between pesticide concentration and land cover were not significant. The results show native bees collected in an agricultural landscape are exposed to multiple pesticides, these results can direct future research on routes/timing of pesticide exposure and the design of future conservation efforts for pollinators. Published by Elsevier B.V.
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Exposure of native bees foraging in an agricultural landscape to current-use pesticides
Hladik, Michelle; Vandever, Mark W.; Smalling, Kelly L.
2016-01-01
The awareness of insects as pollinators and indicators of environmental quality has grown in recent years, partially in response to declines in honey bee (Apis mellifera) populations. While most pesticide research has focused on honey bees, there has been less work on native bee populations. To determine the exposure of native bees to pesticides, bees were collected from an existing research area in northeastern Colorado from two land cover types: grasslands (2013-2014) and wheat fields (2014). Traps were deployed bi-monthly during the summer at each land cover type and all bees, regardless of species, were composited as whole samples and analyzed for 136 current-use pesticides and degradates. This reconnaissance approach provides a sampling of all species and represents overall pesticide exposure (internal and external). Nineteen pesticides and degradates were detected in 54 composite samples collected. Compounds detected in >10% of the samples included the insecticides thiamethoxam (46%), bifenthrin (28%), clothianidin (24%), chlorpyrifos (17%), and imidacloprid (13%), the fungicides azoxystrobin (17%), and pyraclostrobin (11%), and the herbicide atrazine (19%). Concentrations ranged from 1.1 to 312 ng/g for individual pesticides. Pesticides were detected in samples collected from both grasslands and wheat fields; the location of the sample and the surrounding land cover at the 1000 m buffer influenced the pesticides detected but because of a small number of temporally comparable samples, correlations between pesticide concentration and land cover were not significant. The results show native bees collected in both grasslands and wheat fields are exposed to multiple pesticides, these results can direct future research on routes/timing of pesticide exposure and the design of future conservation efforts for pollinators.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Horn, S.; Hanula, J., L.
2004-03-10
Horn, Scott, and James L. Hanula. 2004. A survey of cavity-nesting bees and wasps in loblolly pine stands of the Savannah River Site, Aiken County, South Carolina. 39(3): 464-469. Abstract: In recent years concern over widespread losses in biodiversity has grown to include a possible decline of many native pollinators, primarily bees. Factors such as habitat fragmentation, agricultural practices, use of pesticides, the introduction of invasive species, or changes in land use may negatively impact these vital organisims. Most reported studies show that human impacts on pollinators are overwhelmingly negative. Reductions in pollinator populations may profoundly impact plant population dynamicsmore » and ecosystem function. Little baseline data exists on the diversity and relative abundance of bees and wasps in southern forests. The objective of this study was to develop a simple, effective method of surveying cavity-nesting bees and wasps and to determine species diversity in mature forests of loblolly pine, the most widely planted tree species in the southern United States.« less
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Native and Non-Native Supergeneralist Bee Species Have Different Effects on Plant-Bee Networks
Giannini, Tereza C.; Garibaldi, Lucas A.; Acosta, Andre L.; Silva, Juliana S.; Maia, Kate P.; Saraiva, Antonio M.; Guimarães, Paulo R.; Kleinert, Astrid M. P.
2015-01-01
Supergeneralists, defined as species that interact with multiple groups of species in ecological networks, can act as important connectors of otherwise disconnected species subsets. In Brazil, there are two supergeneralist bees: the honeybee Apis mellifera, a non-native species, and Trigona spinipes, a native stingless bee. We compared the role of both species and the effect of geographic and local factors on networks by addressing three questions: 1) Do both species have similar abundance and interaction patterns (degree and strength) in plant-bee networks? 2) Are both species equally influential to the network structure (nestedness, connectance, and plant and bee niche overlap)? 3) How are these species affected by geographic (altitude, temperature, precipitation) and local (natural vs. disturbed habitat) factors? We analyzed 21 plant-bee weighted interaction networks, encompassing most of the main biomes in Brazil. We found no significant difference between both species in abundance, in the number of plant species with which each bee species interacts (degree), and in the sum of their dependencies (strength). Structural equation models revealed the effect of A. mellifera and T. spinipes, respectively, on the interaction network pattern (nestedness) and in the similarity in bee’s interactive partners (bee niche overlap). It is most likely that the recent invasion of A. mellifera resulted in its rapid settlement inside the core of species that retain the largest number of interactions, resulting in a strong influence on nestedness. However, the long-term interaction between native T. spinipes and other bees most likely has a more direct effect on their interactive behavior. Moreover, temperature negatively affected A. mellifera bees, whereas disturbed habitats positively affected T. spinipes. Conversely, precipitation showed no effect. Being positively (T. spinipes) or indifferently (A. mellifera) affected by disturbed habitats makes these species prone to pollinate plant species in these areas, which are potentially poor in pollinators. PMID:26356234
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Takakura, Koh-Ichi; Matsumoto, Takashi; Nishida, Takayoshi; Nishida, Sachiko
2011-03-01
Reproductive interference (RI), defined as the fitness cost of interspecific sexual interactions, such as interspecific pollen transfer (IPT) in plants, is ecologically important. Theoretically, RI could result in competitive exclusion, as it operates in a frequency-dependent manner. Additionally, IPT may have a greater range than resource competition, although information about the range of IPT is lacking. In the present study, we measured the range of IPT exerted by Taraxacum officinale (an alien species) on a native dandelion, T. japonicum. We used two approaches. In one, we analyzed the RI effect on a native seed set at three spatial scales. In the second, we tracked IPT from alien to native flower heads using fluorescent pigments as markers. We estimated that pollination distances were in the order of several meters. These distances exceeded the mean distance from each native plant to the nearest alien. As hypothesized, the effect of RI reached farther than neighboring individuals. These data indicate the spatial range from which alien dandelions should be removed to allow the conservation of natives.
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Schooling's Contribution to Social Capital: Study from a Native Amazonian Society in Bolivia
ERIC Educational Resources Information Center
Godoy, Ricardo; Seyfried, Craig; Reyes-Garcia, Victoria; Huanca, Tomas; Leonard, William R.; McDade, Thomas; Tanner, Susan; Vadez, Vincent
2007-01-01
Understanding why traditional cultures weaken matters because they embody humanity's heritage. Schooling has been singled out as an abrader of traditional culture. We assess whether schooling erodes one aspect of traditional culture: social capital as shown by generosity to people outside the household. In industrial nations researchers find…
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Song, Bo; Stöcklin, Jürg; Gao, Yong-Qian; Peng, De-Li; Sun, Hang
2017-01-01
Studying the drivers of host specificity can contribute to our understanding of the origin and evolution of obligate pollination mutualisms. The preference-performance hypothesis predicts that host plant choice of female insects is related mainly to the performance of their offspring. Soil moisture is thought to be particularly important for the survival of larvae and pupae that inhabit soil. In the high Himalayas, Rheum nobile and R. alexandrae differ in their distribution in terms of soil moisture; that is, R. nobile typically occurs in scree with well-drained soils, R. alexandrae in wetlands. The two plant species are pollinated by their respective mutualistic seed-consuming flies, Bradysia sp1. and Bradysia sp2. We investigated whether soil moisture is important for regulating host specificity by comparing pupation and adult emergence of the two fly species using field and laboratory experiments. Laboratory experiments revealed soil moisture did have significant effects on larval and pupal performances in both fly species, but the two fly species had similar optimal soil moisture requirements for pupation and adult emergence. Moreover, a field reciprocal transfer experiment showed that there was no significant difference in adult emergence for both fly species between their native and non-native habitats. Nevertheless, Bradysia sp1., associated with R. nobile , was more tolerant to drought stress, while Bradysia sp2., associated with R. alexandrae , was more tolerant to flooding stress. These results indicate that soil moisture is unlikely to play a determining role in regulating host specificity of the two fly species. However, their pupation and adult emergence in response to extremely wet or dry soils are habitat-specific.
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USDA-ARS?s Scientific Manuscript database
Apios (Apios americana; “apios”), a tuberous perennial legume in the Phaseoleae tribe, was widely used as a food by Native Americans. Work in the last 40 years has led to several improved breeding lines. Aspects of the pollination biology (complex floral structure and tripping mechanism) have made c...
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Costa e Silva, João; Potts, Brad M.; Lopez, Gustavo A.
2014-01-01
Using native trees from near the northern and southern extremities of the relatively continuous eastern distribution of Eucalyptus globulus in Tasmania, we compared the progenies derived from natural open-pollination (OP) with those generated from within-region and long-distance outcrossing. Controlled outcrossing amongst eight parents - with four parents from each of the northern and southern regions - was undertaken using a diallel mating scheme. The progeny were planted in two field trials located within the species native range in southern Tasmania, and their survival and diameter growth were monitored over a 13-year-period. The survival and growth performances of all controlled cross types exceeded those of the OP progenies, consistent with inbreeding depression due to a combination of selfing and bi-parental inbreeding. The poorer survival of the northern regional (♀N♂N) outcrosses compared with the local southern regional outcrosses (♀S♂S) indicated differential selection against the former. Despite this mal-adaptation of the non-local ♀N♂N crosses at both southern sites, the survival of the inter-regional hybrids (♀N♂S and ♀S♂N) was never significantly different from that of the local ♀S♂S crosses. Significant site-dependent heterosis was detected for the growth of the surviving long-distance hybrids. This was expressed as mid-parent heterosis, particularly at the more northern planting site. Heterosis increased with age, while the difference between the regional ♀N♂N and ♀S♂S crosses remained insignificant at any age at either site. Nevertheless, the results for growth suggest that the fitness of individuals derived from long-distance crossing may be better at the more northern of the planting sites. Our results demonstrate the potential for early-age assessments of pollen dispersal to underestimate realised gene flow, with local inbreeding under natural open-pollination resulting in selection favouring the products of longer-distance pollinations. Indeed, heterosis derived from long-distance pollinations may be sufficient to counter local mal-adaptation, at least in the first generation. PMID:24751722
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Koll Buer; Dave Forwalter; Mike Kissel; Bill Stohlert
1989-01-01
Native plant and wildlife communities along Northern California's middle Sacramento River (Red Bluff to Colusa) originally adapted to a changing pattern of erosion and deposition across a broad meander belt. The erosion-deposition process was in balance, with the river alternately building and eroding terraces. Human-induced changes to the Sacramento River,...
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Recent biodiversity patterns in the Great Plains: Implications for restoration and management
Carolyn Hull Sieg; Curtis H. Flather; Stephen McCanny
1999-01-01
Ecosystem, species and genetic dimensions of biodiversity have eroded since widespread settlement of the Great Plains. Conversion of native vegetation in the region followed the precipitation gradient, with the greatest conversion in the eastern tallgrass prairie and eastern mixed-grass types. Areas now dominated by intensive land uses are "hot spots" for...
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Bushmann, Sara L; Drummond, Francis A
2015-08-01
Insect-mediated pollination is critical for lowbush blueberry (Ericaceae: Vaccinium angustifolium Aiton) fruit development. Past research shows a persistent presence of wild bees (Hymenoptera: Apoidea) providing pollination services even when commercial pollinators are present. We undertook the study to 1) provide a description of bee communities found in lowbush blueberry-growing regions, 2) identify field characteristics or farm management practices that influence those communities, 3) identify key wild bee pollinators that provide pollination services for the blueberry crop, and 4) identify non-crop plants found within the cropping system that provide forage for wild bees. During a 4-year period, we collected solitary and eusocial bees in over 40 fields during and after blueberry bloom, determining a management description for each field. We collected 4,474 solitary bees representing 124 species and 1,315 summer bumble bees representing nine species. No bumble bee species were previously unknown in Maine, yet we document seven solitary bee species new for the state. These include species of the genera Nomada, Lasioglossum, Calliopsis, and Augochloropsis. No field characteristic or farm management practice related to bee community structure, except bumble bee species richness was higher in certified organic fields. Pollen analysis determined scopal loads of 67-99% ericaceous pollen carried by five species of Andrena. Our data suggest two native ericaceous plants, Kalmia angustifolia L. and Gaylussacia baccata (Wangenheim), provide important alternative floral resources. We conclude that Maine blueberry croplands are populated with a species-rich bee community that fluctuates in time and space. We suggest growers develop and maintain wild bee forage and nest sites. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Kartzinel, Tyler R; Shefferson, Richard P; Trapnell, Dorset W
2013-12-01
Populations of many species are isolated within narrow elevation bands of Neotropical mountain habitat, and how well dispersal maintains genetic connectivity is unknown. We asked whether genetic structure of an epiphytic orchid, Epidendrum firmum, corresponds to gaps between Costa Rican mountain ranges, and how these gaps influence pollen and seed flow. We predicted that significant genetic structure exists among mountain ranges due to different colonization histories and limited gene flow. Furthermore, we predicted that pollen movement contributes more to gene flow than seeds because seeds are released into strong winds perpendicular to the narrow northwest-southeast species distribution, while the likely pollinators are strong fliers. Individuals from 12 populations and three mountain ranges were genotyped with nuclear microsatellites (nDNA) and chloroplast sequences (cpDNA). Genetic diversity was high for both markers, while nDNA genetic structure was low (FSTn = 0.020) and cpDNA structure was moderate (FSTc = 0.443). Significant cpDNA barriers occurred within and among mountain ranges, but nDNA barriers were not significant after accounting for geographic distance. Consistent with these contrasting patterns of genetic structure, pollen contributes substantially more to gene flow among populations than seed (mp /ms = 46). Pollinators mediated extensive gene flow, eroding nDNA colonization footprints, while seed flow was comparatively limited, possibly due to directional prevailing winds across linearly distributed populations. Dispersal traits alone may not accurately inform predictions about gene flow or genetic structure, supporting the need for research into the potentially crucial role of pollinators and landscape context in gene flow among isolated populations. © 2013 John Wiley & Sons Ltd.
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Bee Fauna and Floral Abundance Within Lawn-Dominated Suburban Yards in Springfield, MA.
Lerman, S B; Milam, J
2016-09-01
Private yards comprise a significant component of urban lands, with managed lawns representing the dominant land cover. Lawns blanket > 163,000 km 2 of the United States, and 50% of urban and suburban areas. When not treated with herbicides, lawns have the capacity to support a diversity of spontaneous (e.g., not planted) flowers, with the potential to provide nectar and pollen resources for pollinators such as native bees. In order to determine the extent to which suburban lawns support these important species, we surveyed lawns in 17 suburban yards in Springfield, MA, between May and September 2013 and 2014. Householders participating in the study did not apply chemical pesticides or herbicides to lawns for the duration of the study. We collected 5,331 individual bees, representing 111 species, and 29% of bee species reported for the state. The majority of species were native to North America (94.6%), nested in soil (73%), and solitary (48.6%). Species richness was lower for oligolectic (specialists on a single plant; 9.9%) and parasitic species (12.6%). Abundance percentages for number of individuals were similar. We documented 63 plant species in the lawns, the majority of which were not intentionally planted. The most abundant lawn flowers were dandelion ( Taraxacum officinale ) and clover ( Trifolium sp. ). Nearly 30% of the spontaneous plant species growing in the lawns were native to North America. Our study suggests that the spontaneous lawn flowers could be viewed as supplemental floral resources and support pollinators, thereby enhancing the value of urban green spaces.
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Complete mitochondrial genome sequence of Melipona scutellaris, a Brazilian stingless bee.
Pereira, Ulisses de Padua; Bonetti, Ana Maria; Goulart, Luiz Ricardo; Santos, Anderson Rodrigues Dos; Oliveira, Guilherme Correa de; Cuadros-Orellana, Sara; Ueira-Vieira, Carlos
2016-09-01
Melipona scutellaris is a Brazilian stingless bee species and a highly important native pollinator besides its use in rational rearing for honey production. In this study, we present the whole mitochondrial DNA sequence of M. scutellaris from a haploid male. The mitogenome has a size of 14,862 bp and harbors 13 protein-coding genes (PCGs), 2 rRNA genes and 21 tRNA genes.
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Drossart, Maxime; Michez, Denis; Vanderplanck, Maryse
2017-11-24
It is now well established that invasive plants may induce drifts in the quantity and/or quality of floral resources. They are then often pointed out as a potential driver of bee decline. However, their impact on bee population remains quite unclear and still controversial, as bee responses are highly variable among species. Here, we compared the amino acid composition of pollen from three native and two invasive plant species included in diets of common pollinators in NW Europe. Moreover, the nutritional intake (i.e., pollen and amino acid intakes) of Bombus terrestris colonies and the pollen foraging behaviour of workers (i.e., visiting rate, number of foraging trips, weight of pollen loads) were considered. We found significant differences in pollen nutrients among the studied species according to the plant invasive behaviour. We also found significant differences in pollen foraging behaviour according to the plant species, from few to several foraging trips carrying small or large pollen loads. Such behavioural differences directly impacted the pollen intake but depended more likely on plant morphology rather than on plant invasive behaviour. These results suggest that common generalist bumble bees might not always suffer from plant invasions, depending on their behavioural plasticity and nutritional requirements.
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Dyer, Adrian G.; Boyd-Gerny, Skye; McLoughlin, Stephen; Rosa, Marcello G. P.; Simonov, Vera; Wong, Bob B. M.
2012-01-01
Flowering plants in Australia have been geographically isolated for more than 34 million years. In the Northern Hemisphere, previous work has revealed a close fit between the optimal discrimination capabilities of hymenopteran pollinators and the flower colours that have most frequently evolved. We collected spectral data from 111 Australian native flowers and tested signal appearance considering the colour discrimination capabilities of potentially important pollinators. The highest frequency of flower reflectance curves is consistent with data reported for the Northern Hemisphere. The subsequent mapping of Australian flower reflectances into a bee colour space reveals a very similar distribution of flower colour evolution to the Northern Hemisphere. Thus, flowering plants in Australia are likely to have independently evolved spectral signals that maximize colour discrimination by hymenoptera. Moreover, we found that the degree of variability in flower coloration for particular angiosperm species matched the range of reflectance colours that can only be discriminated by bees that have experienced differential conditioning. This observation suggests a requirement for plasticity in the nervous systems of pollinators to allow generalization of flowers of the same species while overcoming the possible presence of non-rewarding flower mimics. PMID:22673351
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Are ecosystem services stabilized by differences among species? A test using crop pollination.
Winfree, Rachael; Kremen, Claire
2009-01-22
Biological diversity could enhance ecosystem service provision by increasing the mean level of services provided, and/or by providing more consistent (stable) services over space and time. Ecological theory predicts that when an ecosystem service is provided by many species, it will be stabilized against disturbance by a variety of 'stabilizing mechanisms.' However, few studies have investigated whether stabilizing mechanisms occur in real landscapes affected by human disturbance. We used two datasets on crop pollination by wild native bees to screen for and differentiate among three stabilizing mechanisms: density compensation (negative co-variance among species' abundances); response diversity (differential response to environmental variables among species); and cross-scale resilience (response to the same environmental variable at different scales by different species). In both datasets, we found response diversity and cross-scale resilience, but not density compensation. We conclude that stabilizing mechanisms may contribute to the stability of pollination services in our study areas, emphasizing the insurance value of seemingly 'redundant' species. Furthermore, the absence of density compensation that we found at the landscape scale contrasts with findings of previous small-scale experimental and modelling work, suggesting that we should not assume that density compensation will stabilize ecosystem services in real landscapes.
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Towards Biological Control of Kudzu Through an Improved Understanding of Insect-Kudzu Interactions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Orr, D.; Barber, G.; DeBarr, G.
2001-08-03
The authors evaluated various approaches to the biological control of kudzu and exotic weed that infests the SRS. A large number of native pollinators were found to be attracted to kudzu. The viability of seed was found to be low, between 2% and 11%. This is the result of native Hemiptera. The results suggest that seed feeding insects should not be targeted for importation. Both kudzu and soybeans had the same level of abundance and diversity of herbivore insects and the same levels of defoliation. No vine or root damaging species were found. Efforts should be targeted to the lattermore » insects to control kudzu.« less
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Fagúndez, Jaime; Olea, Pedro P; Tejedo, Pablo; Mateo-Tomás, Patricia; Gómez, David
2016-07-01
The intensification of agriculture has increased production at the cost of environment and biodiversity worldwide. To increase crop yield in dry cereal systems, vast farmland areas of high conservation value are being converted into irrigation, especially in Mediterranean countries. We analyze the effect of irrigation-driven changes on the farm biota by comparing species diversity, community composition, and species traits of arable plants within crop fields from two contrasting farming systems (dry and irrigated) in Spain. We sampled plant species within 80 fields of dry wheat, irrigated wheat, and maize (only cultivated under irrigation). Wheat crops held higher landscape and per field species richness, and beta diversity than maize. Within the same type of crop, irrigated wheat hosted lower plant diversity than dry wheat at both field and landscape scales. Floristic composition differed between crop types, with higher frequencies of perennials, cosmopolitan, exotic, wind-pollinated and C4 species in maize. Our results suggest that irrigation projects, that transform large areas of dry cereal agro-ecosystems into irrigated crop systems dominated by maize, erode plant diversity. An adequate planning on the type and proportion of crops used in the irrigated agro-ecosystems is needed in order to balance agriculture production and biodiversity conservation.
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A non-destructive method for dating human remains
Lail, Warren K.; Sammeth, David; Mahan, Shannon; Nevins, Jason
2013-01-01
The skeletal remains of several Native Americans were recovered in an eroded state from a creek bank in northeastern New Mexico. Subsequently stored in a nearby museum, the remains became lost for almost 36 years. In a recent effort to repatriate the remains, it was necessary to fit them into a cultural chronology in order to determine the appropriate tribe(s) for consultation pursuant to the Native American Grave Protection and Repatriation Act (NAGPRA). Because the remains were found in an eroded context with no artifacts or funerary objects, their age was unknown. Having been asked to avoid destructive dating methods such as radiocarbon dating, the authors used Optically Stimulated Luminescence (OSL) to date the sediments embedded in the cranium. The OSL analyses yielded reliable dates between A.D. 1415 and A.D. 1495. Accordingly, we conclude that the remains were interred somewhat earlier than A.D. 1415, but no later than A.D. 1495. We believe the remains are from individuals ancestral to the Ute Mouache Band, which is now being contacted for repatriation efforts. Not only do our methods contribute to the immediate repatriation efforts, they provide archaeologists with a versatile, non-destructive, numerical dating method that can be used in many burial contexts.
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Nishida, Sachiko; Hashimoto, Keisuke; Kanaoka, Masahiro M; Takakura, Ko-Ichi; Nishida, Takayoshi
2017-01-01
Reproductive interference (RI) may be a contributing factor to the displacement of native species by an alien congener, and RI strength has been shown theoretically to affect distributional relationships between species. Thus, variations in RI strength from alien to native species result in different consequences of invasions and efforts to conserve native species, but the variations have seldom been examined empirically. We therefore investigated RI strength variations from the alien species Taraxacum officinale and its hybrids to eight populations of native dandelions, four T. japonicum populations and two populations each of two subspecies of T. platycarpum. We examined the association between alien relative abundance and native seed set in field surveys, and we also performed hand-pollination experiments to investigate directly the sensitivity of native flowers to alien pollen. We found that the effect of alien relative abundance on native seed set of even the same native species could differ greatly in different regions, and that the sensitivity of native flowers to alien pollen was also dependent on region. Our results, together with those of previous studies, show that RI from the alien to the native species is strong in regions where the alien species outnumbers the native species and marginal where it does not; this result suggests that alien RI can critically affect distributional relationships between native and alien species. Our study highlights the importance of performing additional empirical investigations of RI strength variation and of giving due attention to alien RI in efforts to conserve regional native biodiversity.
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Ecology, Behaviour and Control of Apis cerana with a Focus on Relevance to the Australian Incursion
Koetz, Anna H.
2013-01-01
Apis cerana Fabricius is endemic to most of Asia, where it has been used for honey production and pollination services for thousands of years. Since the 1980s, A. cerana has been introduced to areas outside its natural range (namely New Guinea, the Solomon Islands, and Australia), which sparked fears that it may become a pest species that could compete with, and negatively affect, native Australian fauna and flora, as well as commercially kept A. mellifera and commercial crops. This literature review is a response to these concerns and reviews what is known about the ecology and behaviour of A. cerana. Differences between temperate and tropical strains of A. cerana are reviewed, as are A. cerana pollination, competition between A. cerana and A. mellifera, and the impact and control strategies of introduced A. cerana, with a particular focus on gaps of current knowledge. PMID:26462524
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Cauich, Orlando; Quezada-Euán, José Javier G; Macias-Macias, José Octavio; Reyes-Oregel, Vicente; Medina-Peralta, Salvador; Parra-Tabla, Victor
2004-04-01
The acclimation, foraging behavior, and pollination efficiency of stingless bees of the species Nannotrigona perilampoides Cresson were evaluated in tomato (Lycopersicon esculentum Mill.) plants cultivated in two greenhouses. The greenhouses were divided into three areas of 16 m2, and one of the following treatments was used for pollination: stingless bees (SB), mechanical vibration (MV), and no pollination (NP). Observations were conducted once a week from 0800 to 1600 hours during 2 mo. The acclimation of the bees to the greenhouses was estimated by the number of bees that did not return to the hive (lost bees) and by comparing the population of the colonies (brood and adults). The foraging activity of the bees across the day was evaluated by comparing the number of foragers per hour. The influence of environmental variables on the foraging activity was also analyzed. The pollination efficiency was compared among treatments through the percentage of fruit set, weight of individual fruit, kilograms of fruit produced per square meter, and the number of seed per fruit. The bees started foraging on the flowers approximately 7 d after the colonies were introduced to the greenhouse. There was a decline in the population of the colonies across the experiment, but colonies did not die out. Correlations of environmental variables with the foraging activity of the bees showed that none of them had a significant influence on pollen foraging. However, water collection was positively correlated with the temperature and negatively correlated with the humidity inside the greenhouse. The estimation of the pollination efficiency per treatment showed that there were significant differences in fruit set in SB (83 +/- 4.2) and MV (78.5 +/- 6.4) compared with NP (52.6 +/- 7.6). However, the average weight of the fruit was similar for the three treatments (65 g). There were significant differences for seed number in SB (200 +/- 15.3) and MV (232 +/- 21.4) compared with NP (120 +/- 16.6). The productivity in kilograms of fruit per square meter was higher in SB (5.72 +/- 0.61) and MV (5.66 +/- 0.58 kg) compared with NP (3.34 +/- 0.72). The number of seed was positively correlated with the weight of the fruit. We conclude that the use of Nannotrigona testaceicornis Rondani, for pollinating greenhouse tomatoes in tropical climates, could be an alternative to the use of highly defensive African-derived Apis mellifera or non-native bumble bees (Bombus spp.). However, more research is needed to evaluate the cost/benefit on large-scale greenhouse pollination using N. perilampoides Cresson against other bee species and pollination methods.
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Pieper, Sara J; Nicholls, Allison A; Freeland, Joanna R; Dorken, Marcel E
2017-07-01
Cattails (Typha spp.) have become an increasingly dominant component of wetlands in eastern North America and this dominance is largely attributable to the high frequency of Typha × glauca, the hybrid of native Typha latifolia and putatively introduced Typha angustifolia. Hybridization in this group is asymmetric, with T. angustifolia nearly always the maternal parent of F1 hybrids. However, the magnitude of hybrid infertility and whether mating asymmetries extend to the formation of advanced-generation hybrids have not been examined. We used hand-crosses to measure seed set and germination success. We found that mating asymmetries extend to the formation of back-crosses, with ~0 seeds set when T. latifolia was pollinated by hybrid cattails. Seed set was unaffected by pollen source for T. × glauca or T. angustifolia. However, seed production by T. angustifolia was consistently high while that of T. × glauca was variable and when pollinated by other T. × glauca more than 75% lower than for any other intraspecific cross indicating reduced hybrid fertility. We used these results to parameterize a model of hybrid zone evolution in which mating patterns and fertility were governed by interactions between alleles at nuclear and cytoplasmic loci. The model revealed that asymmetric mating and reduced hybrid fertility should favor the maintenance of T. latifolia over T. angustifolia compared to null expectations. However, the model also indicated restrictive conditions for the long-term maintenance of T. latifolia within populations, indicating that asymmetric mating might only stall rather than prevent the displacement of native cattails by hybrids. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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George R. Parker; Charles M. Ruffner
2004-01-01
We review the historical and current status of forests in the Hoosier-Shawnee Ecological Assessment Area. Native American people influenced the vegetation through fire and agricultural clearing across the region until the early 1800s when European settlers arrived. Clearing of the land for agriculture peaked in the early 1900s after which badly eroded land was...
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Williams, Neal M; Ward, Kimiora L; Pope, Nathaniel; Isaacs, Rufus; Wilson, Julianna; May, Emily A; Ellis, Jamie; Daniels, Jaret; Pence, Akers; Ullmann, Katharina; Peters, Jeff
2015-12-01
Global trends in pollinator-dependent crops have raised awareness of the need to support managed and wild bee populations to ensure sustainable crop production. Provision of sufficient forage resources is a key element for promoting bee populations within human impacted landscapes, particularly those in agricultural lands where demand for pollination service is high and land use and management practices have reduced available flowering resources. Recent government incentives in North America and Europe support the planting of wildflowers to benefit pollinators; surprisingly, in North America there has been almost no rigorous testing of the performance of wildflower mixes, or their ability to support wild bee abundance and diversity. We tested different wildflower mixes in a spatially replicated, multiyear study in three regions of North America where production of pollinator-dependent crops is high: Florida, Michigan, and California. In each region, we quantified flowering among wildflower mixes composed of annual and perennial species, and with high and low relative diversity. We measured the abundance and species richness of wild bees, honey bees, and syrphid flies at each mix over two seasons. In each region, some but not all wildflower mixes provided significantly greater floral display area than unmanaged weedy control plots. Mixes also attracted greater abundance and richness of wild bees, although the identity of best mixes varied among regions. By partitioning floral display size from mix identity we show the importance of display size for attracting abundant and diverse wild bees. Season-long monitoring also revealed that designing mixes to provide continuous bloom throughout the growing season is critical to supporting the greatest pollinator species richness. Contrary to expectation, perennials bloomed in their first season, and complementarity in attraction of pollinators among annuals and perennials suggests that inclusion of functionally diverse species may provide the greatest benefit. Wildflower mixes may be particularly important for providing resources for some taxa, such as bumble bees, which are known to be in decline in several regions of North America. No mix consistently attained the full diversity that was planted. Further study is needed on how to achieve the desired floral display and diversity from seed mixes.
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1983-08-01
Program Acquisition Schedule A-8 LIST OF TABLES TABLE TITLE Page 1 Evolution of the ELF Communications Ecological 2 Moni tori ng Program 2 Summary of...performed on plots in maple-dominant, mixed hardwood stands in Michigan. NATIVE BEES Bees are important pollinators of flowering plants and are...SMALL MAMMALS AND NESTING BIRDS Small mammals and nesting birds represent an ecological level inter- mediate between plants and strict carnivores
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Evans, E C; Spivak, M
2006-06-01
Honey bees, Apis mellifera L., are frequently used to pollinate commercial cranberries, Vaccinium macrocarpon Ait., but information is lacking on the relative contribution of honey bees and native bees, the effects of surrounding vegetation on bee visitation, and on optimal timing for honey bee introduction. We begin with a descriptive study of numbers of honey bees, bumble bees, and other bees visiting cranberry blossoms, and their subsequent effect on cranberry yield, on three cranberry properties in 1999. The property surrounded by agricultural land, as opposed to wetlands and woodlands, had fewer numbers of all bee types. In 2000, one property did not introduce honey bee colonies, providing an opportunity to document the effect of lack of honey bees on yield. With no honey bees, plants along the edge of the bed had significantly higher berry weights compared with nonedge plants, suggesting that wild pollinators were only effective along the edge. Comparing the same bed between 1999, with three honey bee colonies per acre, and 2000, with no honey bees, we found a significant reduction in average berry size. In 2000, we compared stigma loading on properties with and without honey bees. Significantly more stigmas received the minimum number of tetrads required for fruit set on the property with honey bees. Significantly more tetrads were deposited during mid-bloom compared with early bloom, indicating that mid-bloom was the best time to have honey bees present. This study emphasizes the importance and effectiveness of honey bees as pollinators of commercial size cranberry plantings.
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Tillman, P G; Carpenter, J E
2014-04-01
In peanut-cotton farmscapes in Georgia, the stink bugs Nezara viridula (L.) and Chinavia hilaris (Say) (Hemiptera: Pentatomidae) and the leaffooted bug, Leptoglossus phyllopus (L.) (Hemiptera: Coreidae), disperse at crop-to-crop interfaces to feed on bolls in cotton. The main objective of this study was to determine whether insecticide-free tropical milkweed (Asclepias curassavica L.), a nectar-producing plant, can increase parasitism of these bugs by Trichopoda pennipes (F.) (Diptera: Tachinidae) and provide nectar to monarch butterflies and insect pollinators in these farmscapes. Peanut-cotton plots with and without flowering milkweed plants were established in 2009 and 2010. Adult T. pennipes, monarch butterflies, honey bees, and native insect pollinators readily fed on floral nectar of milkweed. Monarch larvae feeding on milkweed vegetation successfully developed into pupae. In 2009, N. viridula was the primary host of T. pennipes in cotton, and parasitism of this pest by the parasitoid was significantly higher in milkweed cotton (61.6%) than in control cotton (13.3%). In 2010, parasitism of N. viridula, C. hilaris, and L. phyllopus by T. pennipes was significantly higher in milkweed cotton (24.0%) than in control cotton (1.1%). For both years of the study, these treatment differences were not owing to a response by the parasitoid to differences in host density, because density of hosts was not significantly different between treatments. In conclusion, incorporation of milkweed in peanut-cotton plots increased stink bug parasitism in cotton and provided nectar to insect pollinators and monarch butterflies.
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'Bee hotels' as tools for native pollinator conservation: a premature verdict?
MacIvor, J Scott; Packer, Laurence
2015-01-01
Society is increasingly concerned with declining wild bee populations. Although most bees nest in the ground, considerable effort has centered on installing 'bee hotels'--also known as nest boxes or trap nests--which artificially aggregate nest sites of above ground nesting bees. Campaigns to 'save the bees' often promote these devices despite the absence of data indicating they have a positive effect. From a survey of almost 600 bee hotels set up over a period of three years in Toronto, Canada, introduced bees nested at 32.9% of sites and represented 24.6% of more than 27,000 total bees and wasps recorded (47.1% of all bees recorded). Native bees were parasitized more than introduced bees and females of introduced bee species provisioned nests with significantly more female larva each year. Native wasps were significantly more abundant than both native and introduced bees and occupied almost 3/4 of all bee hotels each year; further, introduced wasps were the only group to significantly increase in relative abundance year over year. More research is needed to elucidate the potential pitfalls and benefits of using bee hotels in the conservation and population dynamics of wild native bees.
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‘Bee Hotels’ as Tools for Native Pollinator Conservation: A Premature Verdict?
MacIvor, J. Scott; Packer, Laurence
2015-01-01
Society is increasingly concerned with declining wild bee populations. Although most bees nest in the ground, considerable effort has centered on installing ‘bee hotels’—also known as nest boxes or trap nests—which artificially aggregate nest sites of above ground nesting bees. Campaigns to ‘save the bees’ often promote these devices despite the absence of data indicating they have a positive effect. From a survey of almost 600 bee hotels set up over a period of three years in Toronto, Canada, introduced bees nested at 32.9% of sites and represented 24.6% of more than 27,000 total bees and wasps recorded (47.1% of all bees recorded). Native bees were parasitized more than introduced bees and females of introduced bee species provisioned nests with significantly more female larva each year. Native wasps were significantly more abundant than both native and introduced bees and occupied almost 3/4 of all bee hotels each year; further, introduced wasps were the only group to significantly increase in relative abundance year over year. More research is needed to elucidate the potential pitfalls and benefits of using bee hotels in the conservation and population dynamics of wild native bees. PMID:25785609
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Schuck, Stefan; Baldwin, Ian T.
2014-01-01
The wild tobacco species Nicotiana attenuata has been intensively used as a model plant to study its interaction with insect herbivores and pollinators in nature, however very little is known about its native pathogen community. We describe a fungal disease outbreak in a native N. attenuata population comprising 873 plants growing in an area of about 1500 m2. The population was divided into 14 subpopulations and disease symptom development in the subpopulations was monitored for 16 days, revealing a waxing and waning of visible disease symptoms with some diseased plants recovering fully. Native fungal N. attenuata pathogens were isolated from diseased plants, characterized genetically, chemotaxonomically and morphologically, revealing several isolates of the ascomycete genera Fusarium and Alternaria, that differed in the type and strength of the disease symptoms they caused in bioassays on either detached leaves or intact soil-grown plants. These isolates and the bioassays will empower the study of N. attenuata-pathogen interactions in a realistic ecological context. PMID:25036191
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Giannini, Tereza C; Tambosi, Leandro R; Acosta, André L; Jaffé, Rodolfo; Saraiva, Antonio M; Imperatriz-Fonseca, Vera L; Metzger, Jean Paul
2015-01-01
Ecosystem services provided by mobile agents are increasingly threatened by the loss and modification of natural habitats and by climate change, risking the maintenance of biodiversity, ecosystem functions, and human welfare. Research oriented towards a better understanding of the joint effects of land use and climate change over the provision of specific ecosystem services is therefore essential to safeguard such services. Here we propose a methodological framework, which integrates species distribution forecasts and graph theory to identify key conservation areas, which if protected or restored could improve habitat connectivity and safeguard ecosystem services. We applied the proposed framework to the provision of pollination services by a tropical stingless bee (Melipona quadrifasciata), a key pollinator of native flora from the Brazilian Atlantic Forest and important agricultural crops. Based on the current distribution of this bee and that of the plant species used to feed and nest, we projected the joint distribution of bees and plants in the future, considering a moderate climate change scenario (following IPPC). We then used this information, the bee's flight range, and the current mapping of Atlantic Forest remnants to infer habitat suitability and quantify local and regional habitat connectivity for 2030, 2050 and 2080. Our results revealed north to south and coastal to inland shifts in the pollinator distribution during the next 70 years. Current and future connectivity maps unraveled the most important corridors, which if protected or restored, could facilitate the dispersal and establishment of bees during distribution shifts. Our results also suggest that coffee plantations from eastern São Paulo and southern Minas Gerais States could suffer a pollinator deficit in the future, whereas pollination services seem to be secured in southern Brazil. Landowners and governmental agencies could use this information to implement new land use schemes. Overall, our proposed methodological framework could help design novel conservational and agricultural practices that can be crucial to conserve ecosystem services by buffering the joint effect of habitat configuration and climate change.
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Winkler, Kathrin A; Pamminger-Lahnsteiner, Barbara; Wanzenböck, Josef; Weiss, Steven
2011-01-01
Translocations of Baltic whitefish (Coregonus sp.) into Austrian Alpine lakes have created ‘artificial hybrid zones’, threatening the genetic integrity of native lineages. We evaluate the genetic structure of Coregonus in Austrian lakes and characterize hybridization and introgression between native and introduced lineages. Fifteen populations (N= 747) were assessed for allelic variation at eight microsatellite loci and a reduced set (N= 253) for variation across two mtDNA genes (cyt b and NADH-3). Bayesian approaches were used to estimate individual admixture proportions (q-values) and classify genotypes as native, introduced or hybrids. q-value distributions varied among populations highlighting differential hybridization and introgression histories. Many lakes revealed a clear distinction between native and introduced genotypes despite hybridization, whereas some locations revealed hybrid swarms. Genetic structure among lakes was congruent with morphological divergence and novelty raising speculation of multiple taxa, including a population south of the Alps, outside the putative native range of Coregonus. Although statistically congruent with inferences based on nuclear markers, mitochondrial haplotype data was not diagnostic with respect to native and non-native lineages, supporting that the Alpine region was colonized post-glacially by an admixture of mtDNA lineages, which coalesce >1 Ma. Mechanisms promoting or eroding lineage isolation are discussed, as well as a high potential to conserve native Alpine lineages despite the extensive historical use of introduced Baltic stocks. PMID:21199024
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Erosional Consequence of Saltcedar Control
NASA Astrophysics Data System (ADS)
Vincent, Kirk R.; Friedman, Jonathan M.; Griffin, Eleanor R.
2009-08-01
Removal of nonnative riparian trees is accelerating to conserve water and improve habitat for native species. Widespread control of dominant species, however, can lead to unintended erosion. Helicopter herbicide application in 2003 along a 12-km reach of the Rio Puerco, New Mexico, eliminated the target invasive species saltcedar ( Tamarix spp.), which dominated the floodplain, as well as the native species sandbar willow ( Salix exigua Nuttall), which occurred as a fringe along the channel. Herbicide application initiated a natural experiment testing the importance of riparian vegetation for bank stability along this data-rich river. A flood three years later eroded about 680,000 m3 of sediment, increasing mean channel width of the sprayed reach by 84%. Erosion upstream and downstream from the sprayed reach during this flood was inconsequential. Sand eroded from channel banks was transported an average of 5 km downstream and deposited on the floodplain and channel bed. Although vegetation was killed across the floodplain in the sprayed reach, erosion was almost entirely confined to the channel banks. The absence of dense, flexible woody stems on the banks reduced drag on the flow, leading to high shear stress at the toe of the banks, fluvial erosion, bank undercutting, and mass failure. The potential for increased erosion must be included in consideration of phreatophyte control projects.
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Erosional consequence of saltcedar control
Vincent, K.R.; Friedman, J.M.; Griffin, E.R.
2009-01-01
Removal of nonnative riparian trees is accelerating to conserve water and improve habitat for native species. Widespread control of dominant species, however, can lead to unintended erosion. Helicopter herbicide application in 2003 along a 12-km reach of the Rio Puerco, New Mexico, eliminated the target invasive species saltcedar (Tamarix spp.), which dominated the floodplain, as well as the native species sandbar willow (Salix exigua Nuttall), which occurred as a fringe along the channel. Herbicide application initiated a natural experiment testing the importance of riparian vegetation for bank stability along this data-rich river. A flood three years later eroded about 680,000 m3 of sediment, increasing mean channel width of the sprayed reach by 84%. Erosion upstream and downstream from the sprayed reach during this flood was inconsequential. Sand eroded from channel banks was transported an average of 5 km downstream and deposited on the floodplain and channel bed. Although vegetation was killed across the floodplain in the sprayed reach, erosion was almost entirely confined to the channel banks. The absence of dense, flexible woody stems on the banks reduced drag on the flow, leading to high shear stress at the toe of the banks, fluvial erosion, bank undercutting, and mass failure. The potential for increased erosion must be included in consideration of phreatophyte control projects. ?? 2009 U.S. Government.
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Local bumble bee decline linked to recovery of honey bees, drought effects on floral resources.
Thomson, Diane M
2016-10-01
Time series of abundances are critical for understanding how abiotic factors and species interactions affect population dynamics, but are rarely linked with experiments and also scarce for bee pollinators. This gap is important given concerns about declines in some bee species. I monitored honey bee (Apis mellifera) and bumble bee (Bombus spp.) foragers in coastal California from 1999, when feral A. mellifera populations were low due to Varroa destructor, until 2014. Apis mellifera increased substantially, except between 2006 and 2011, coinciding with declines in managed populations. Increases in A. mellifera strongly correlated with declines in Bombus and reduced diet overlap between them, suggesting resource competition consistent with past experimental results. Lower Bombus numbers also correlated with diminished floral resources. Declines in floral abundances were associated with drought and reduced spring rainfall. These results illustrate how competition with an introduced species may interact with climate to drive local decline of native pollinators. © 2016 John Wiley & Sons Ltd/CNRS.
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Reynaldi, Francisco J; Lucia, Mariano; Genchi Garcia, María L
2015-01-01
Nowadays several invertebrate pollinators of crops and wild plants are in decline as result of multiple and, sometimes, unknown factors; among them, the modern agricultural practices, pests and diseases are postulated as the most important factors. Bees of the genus Xylocopa are considered effective pollinators of passion fruit crops in tropical regions, as well as important pollinators in wild plants, but these bees are attacked by several pathogens that affect different stages in their life cycle. The fungal species of the genus Ascosphaera are commonly associated with social and solitary bee larvae causing chalkbrood disease. The aim of the present study was to demonstrate the presence of Ascosphaera apis affecting larvae of Xylocopa augusti in South America. For this purpose, A. apis was isolated from affected larvae in YGPSA medium. Final identification was run out by three techniques: (1) Microscopic examination of the hyphae and sizes of the fruiting bodies; (2) Mating test, and specific sexual compatibility test, and (3) PCR detection, using specific primers. This study demonstrates for the first time the presence of A. apis affecting larvae of X. augusti in South America. The evidence of A. apis affecting the larvae of X. augusti, and the fact that the sharing of pathogens between different bee species has been underestimated, suggests the need for further epidemiological studies in order to determine not only the prevalence of this pathogen among wild pollinators, but also its relationship to the sudden collapse of honey bee colonies in this region. Copyright © 2014 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.
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Marks, Timothy R.; Seaton, Philip T.; Pritchard, Hugh W.
2014-01-01
Background and Aims Pollinator-limited seed-set in some terrestrial orchids is compensated for by the presence of long-lived flowers. This study tests the hypothesis that pollen from these insect-pollinated orchids should be desiccation tolerant and relatively long lived using four closely related UK terrestrial species; Anacamptis morio, Dactylorhiza fuchsii, D. maculata and Orchis mascula. Methods Pollen from the four species was harvested from inflorescences and germinated in vitro, both immediately and also after drying to simulate interflower transit. Their tolerance to desiccation and short-term survival was additionally assessed after 3 d equilibration at a range of relative humidities (RHs), and related to constructed sorption isotherms (RH vs. moisture content, MC). Ageing of D. fuchsii pollen was further tested over 2 months against temperature and RH, and the resultant survival curves were subjected to probit analysis, and the distribution of pollen death in time (σ) was determined. The viability and siring ability, following artificial pollinations, were determined in D. fuchsii pollen following storage for 6 years at –20 °C. Key Results The pollen from all four species exhibited systematic increases in germinability and desiccation tolerance as anthesis approached, and pollen from open flowers generally retained high germinability. Short-term storage revealed sensitivity to low RH, whilst optimum survival occurred at comparable RHs in all species. Similarly, estimated pollen life spans (σ) at differing temperatures were longest under the dry conditions. Despite a reduction in germination and seeds per capsule, long-term storage of D. fuchsii pollen did not impact on subsequent seed germination in vitro. Conclusions Substantial pollen desiccation tolerance and life span of the four entomophilous orchids reflects a resilient survival strategy in response to unpredictable pollinator visitation, and presents an alternative approach to germplasm conservation. PMID:25006180
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Buhne Point Shoreline Erosion Demonstration Project. Volume 1. Appendices A-D.
1987-08-01
for repairing damage to highways and preventing damage to highways resulting from shoreline erosion." A four- year , four-phase program was implemented...program included experimental collecting and growing of 20 different native and naturalized species for a two- year period, and then extensive...King Salmon forming a bay side boundary between the shoal area and King Salmon. Over the past decade, Buhne Spit shoal has eroded to the point where
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Glaum, Paul; Simao, Maria-Carolina; Vaidya, Chatura; Fitch, Gordon; Iulinao, Benjamin
2017-05-01
Native bee populations are critical sources of pollination. Unfortunately, native bees are declining in abundance and diversity. Much of this decline comes from human land-use change. While the effects of large-scale agriculture on native bees are relatively well understood, the effects of urban development are less clear. Understanding urbanity's effect on native bees requires consideration of specific characteristics of both particular bee species and their urban landscape. We surveyed bumble-bee ( Bombus spp.) abundance and diversity in gardens across multiple urban centres in southeastern Michigan. There are significant declines in Bombus abundance and diversity associated with urban development when measured on scales in-line with Bombus flight ability. These declines are entirely driven by declines in females; males showed no response to urbanization. We hypothesize that this is owing to differing foraging strategies between the sexes, and it suggests reduced Bombus colony density in more urban areas. While urbanity reduced Bombus prevalence, results in Detroit imply that 'shrinking cities' potentially offer unique urban paradigms that must be considered when studying wild bee ecology. Results show previously unidentified differences in the effects of urbanity on female and male bumble-bee populations and suggest that urban landscapes can be managed to support native bee conservation.
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Simao, Maria-Carolina; Vaidya, Chatura; Fitch, Gordon; Iulinao, Benjamin
2017-01-01
Native bee populations are critical sources of pollination. Unfortunately, native bees are declining in abundance and diversity. Much of this decline comes from human land-use change. While the effects of large-scale agriculture on native bees are relatively well understood, the effects of urban development are less clear. Understanding urbanity's effect on native bees requires consideration of specific characteristics of both particular bee species and their urban landscape. We surveyed bumble-bee (Bombus spp.) abundance and diversity in gardens across multiple urban centres in southeastern Michigan. There are significant declines in Bombus abundance and diversity associated with urban development when measured on scales in-line with Bombus flight ability. These declines are entirely driven by declines in females; males showed no response to urbanization. We hypothesize that this is owing to differing foraging strategies between the sexes, and it suggests reduced Bombus colony density in more urban areas. While urbanity reduced Bombus prevalence, results in Detroit imply that ‘shrinking cities’ potentially offer unique urban paradigms that must be considered when studying wild bee ecology. Results show previously unidentified differences in the effects of urbanity on female and male bumble-bee populations and suggest that urban landscapes can be managed to support native bee conservation. PMID:28573023
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Barbosa, Wagner F; Tomé, Hudson Vaner V; Bernardes, Rodrigo C; Siqueira, Maria Augusta L; Smagghe, Guy; Guedes, Raul Narciso C
2015-09-01
Because of their natural origin, biopesticides are assumed to be less harmful to beneficial insects, including bees, and therefore their use has been widely encouraged for crop protection. There is little evidence, however, to support this ingrained notion of biopesticide safety to pollinators. Because larval exposure is still largely unexplored in ecotoxicology and risk assessment on bees, an investigation was performed on the lethal and sublethal effects of a diet treated with 2 bioinsecticides, azadirachtin and spinosad, on the stingless bee, Melipona quadrifasciata, which is one of the most important pollinators in the Neotropics. Survival of stingless bee larvae was significantly compromised at doses above 210 ng a.i./bee for azadirachtin and 114 ng a.i./bee for spinosad. No sublethal effect was observed on larvae developmental time, but doses of both compounds negatively affected pupal body mass. Azadirachtin produced deformed pupae and adults as a result of its insect growth regulator properties, but spinosad was more harmful and produced greater numbers of deformed individuals. Only spinosad compromised walking activity of the adult workers at doses as low as 2.29 ng a.i./bee, which is 1/5000 of the maximum field recommended rate. In conclusion, the results demonstrated that bioinsecticides can pose significant risks to native pollinators with lethal and sublethal effects; future investigations are needed on the likelihood of such effects under field conditions. © 2015 SETAC.
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Bumble Bee Fauna of Palouse Prairie: Survey of Native Bee Pollinators in a Fragmented Ecosystem
Hatten, T. D.; Looney, C.; Strange, J. P.; Bosque-Pérez, N. A.
2013-01-01
Bumble bees, Bombus Latreille (Hymenoptera: Apidae:), are dominant pollinators in the northern hemisphere, providing important pollination services for commercial crops and innumerable wild plants. Nationwide declines in several bumble bee species and habitat losses in multiple ecosystems have raised concerns about conservation of this important group. In many regions, such as the Palouse Prairie, relatively little is known about bumble bee communities, despite their critical ecosystem functions. Pitfall trap surveys for ground beetles in Palouse prairie remnants conducted in 2002–2003 contained considerable by-catch of bumble bees. The effects of landscape context, remnant features, year, and season on bumble bee community composition were examined. Additionally, bees captured in 2002–2003 were compared with historic records for the region to assess changes in the presence of individual species. Ten species of bumble bee were captured, representing the majority of the species historically known from the region. Few detectable differences in bumble bee abundances were found among remnants. Community composition differed appreciably, however, based on season, landscape context, and elevation, resulting in different bee assemblages between western, low-lying remnants and eastern, higherelevation remnants. The results suggest that conservation of the still species-rich bumble bee fauna should take into account variability among prairie remnants, and further work is required to adequately explain bumble bee habitat associations on the Palouse. PMID:23902138
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Ficus (Moraceae) and fig wasps (Hymenoptera: Chalcidoidea) in Taiwan.
Bain, Anthony; Tzeng, Hsy-Yu; Wu, Wen-Jer; Chou, Lien-Siang
2015-12-01
Although Ficus-associated wasp fauna have been extensively researched in Australasia, information on these fauna in Taiwan is not well accessible to scientists worldwide. In this study, we compiled records on the Ficus flora of Taiwan and its associated wasp fauna. Initial agronomic research reports on Ficus were published in Japanese in 1917, followed by reports on applied biochemistry, taxonomy, and phenology in Chinese. On the basis of the phenological knowledge of 15 species of the Ficus flora of Taiwan, recent research has examined the pollinating and nonpollinating agaonid and chalcid wasps (Hymenoptera: Chalcidoidea). Updating records according to the current nomenclature revealed that there are 30 taxa (27 species) of native or naturalized Ficus with an unusually high proportion of dioecious species (78%). Four species were observed to exhibit mutualism with more than one pollinating wasp species, and 18 of the 27 Ficus species were reported with nonpollinating wasp species. The number of nonpollinating wasp species associated with specific Ficus species ranges from zero (F. pumila) to 24 (F. microcarpa). Approximately half of the Taiwanese fig tree species have been studied with basic information on phenology and biology described in peer-reviewed journals or theses. This review provides a solid basis for future in-depth comparative studies. This summary of knowledge will encourage and facilitate continuing research on the pollination dynamics of Ficus and the associated insect fauna in Taiwan.
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Tan, Ken; Chen, Weiwen; Dong, Shihao; Liu, Xiwen; Wang, Yuchong; Nieh, James C.
2015-01-01
Xenobiotics such as the neonicotinoid pesticide, imidacloprid, are used globally, but their effects on native bee species are poorly understood. We studied the effects of sublethal doses of imidacloprid on olfactory learning in the native honey bee species, Apis cerana, an important pollinator of agricultural and native plants throughout Asia. We provide the first evidence that imidacloprid can impair learning in A. cerana workers exposed as adults or as larvae. Adults that ingested a single imidacloprid dose as low as 0.1 ng/bee had significantly reduced olfactory learning acquisition, which was 1.6-fold higher in control bees. Longer-term learning (1-17 h after the last learning trial) was also impaired. Bees exposed as larvae to a total dose of 0.24 ng/bee did not have reduced survival to adulthood. However, these larval-treated bees had significantly impaired olfactory learning when tested as adults: control bees exhibited up to 4.8-fold better short-term learning acquisition, though longer-term learning was not affected. Thus, sublethal cognitive deficits elicited by neonicotinoids on a broad range of native bee species deserve further study. PMID:26086769
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Giannini, Tereza C.; Tambosi, Leandro R.; Acosta, André L.; Jaffé, Rodolfo; Saraiva, Antonio M.; Imperatriz-Fonseca, Vera L.; Metzger, Jean Paul
2015-01-01
Ecosystem services provided by mobile agents are increasingly threatened by the loss and modification of natural habitats and by climate change, risking the maintenance of biodiversity, ecosystem functions, and human welfare. Research oriented towards a better understanding of the joint effects of land use and climate change over the provision of specific ecosystem services is therefore essential to safeguard such services. Here we propose a methodological framework, which integrates species distribution forecasts and graph theory to identify key conservation areas, which if protected or restored could improve habitat connectivity and safeguard ecosystem services. We applied the proposed framework to the provision of pollination services by a tropical stingless bee (Melipona quadrifasciata), a key pollinator of native flora from the Brazilian Atlantic Forest and important agricultural crops. Based on the current distribution of this bee and that of the plant species used to feed and nest, we projected the joint distribution of bees and plants in the future, considering a moderate climate change scenario (following IPPC). We then used this information, the bee’s flight range, and the current mapping of Atlantic Forest remnants to infer habitat suitability and quantify local and regional habitat connectivity for 2030, 2050 and 2080. Our results revealed north to south and coastal to inland shifts in the pollinator distribution during the next 70 years. Current and future connectivity maps unraveled the most important corridors, which if protected or restored, could facilitate the dispersal and establishment of bees during distribution shifts. Our results also suggest that coffee plantations from eastern São Paulo and southern Minas Gerais States could suffer a pollinator deficit in the future, whereas pollination services seem to be secured in southern Brazil. Landowners and governmental agencies could use this information to implement new land use schemes. Overall, our proposed methodological framework could help design novel conservational and agricultural practices that can be crucial to conserve ecosystem services by buffering the joint effect of habitat configuration and climate change. PMID:26091014
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Spatial variability of soil properties and soil erodibility in the Alqueva reservoir watershed
NASA Astrophysics Data System (ADS)
Ferreira, V.; Panagopoulos, T.; Andrade, R.; Guerrero, C.; Loures, L.
2015-04-01
The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this end, three areas representative of different land uses (agroforestry grassland, lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while the K factor increased with intensive cultivation. The HJ-Biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. The K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.
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Spatial variability of soil properties and soil erodibility in the Alqueva dam watershed, Portugal
NASA Astrophysics Data System (ADS)
Ferreira, V.; Panagopoulos, T.; Andrade, R.; Guerrero, C.; Loures, L.
2015-01-01
The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this, three areas representative of different land uses (agroforestry grassland, Lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while K factor increased with intensive cultivation. The HJ-biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.
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Pollination and reproduction of an invasive plant inside and outside its ancestral range
NASA Astrophysics Data System (ADS)
Petanidou, Theodora; Price, Mary V.; Bronstein, Judith L.; Kantsa, Aphrodite; Tscheulin, Thomas; Kariyat, Rupesh; Krigas, Nikos; Mescher, Mark C.; De Moraes, Consuelo M.; Waser, Nickolas M.
2018-05-01
Comparing traits of invasive species within and beyond their ancestral range may improve our understanding of processes that promote aggressive spread. Solanum elaeagnifolium (silverleaf nightshade) is a noxious weed in its ancestral range in North America and is invasive on other continents. We compared investment in flowers and ovules, pollination success, and fruit and seed set in populations from Arizona, USA ("AZ") and Greece ("GR"). In both countries, the populations we sampled varied in size and types of present-day disturbance. Stature of plants increased with population size in AZ samples whereas GR plants were uniformly tall. Taller plants produced more flowers, and GR plants produced more flowers for a given stature and allocated more ovules per flower. Similar functional groups of native bees pollinated in AZ and GR populations, but visits to flowers decreased with population size and we observed no visits in the largest GR populations. As a result, plants in large GR populations were pollen-limited, and estimates of fecundity were lower on average in GR populations despite the larger allocation to flowers and ovules. These differences between plants in our AZ and GR populations suggest promising directions for further study. It would be useful to sample S. elaeagnifolium in Mediterranean climates within the ancestral range (e.g., in California, USA), to study asexual spread via rhizomes, and to use common gardens and genetic studies to explore the basis of variation in allocation patterns and of relationships between visitation and fruit set.
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Dick, Christopher W; Etchelecu, Gabriela; Austerlitz, Frédéric
2003-03-01
Tropical rainforest trees typically occur in low population densities and rely on animals for cross-pollination. It is of conservation interest therefore to understand how rainforest fragmentation may alter the pollination and breeding structure of remnant trees. Previous studies of the Amazonian tree Dinizia excelsa (Fabaceae) found African honeybees (Apis mellifera scutellata) as the predominant pollinators of trees in highly disturbed habitats, transporting pollen up to 3.2 km between pasture trees. Here, using microsatellite genotypes of seed arrays, we compare outcrossing rates and pollen dispersal distances of (i) remnant D. excelsa in three large ranches, and (ii) a population in undisturbed forest in which African honeybees were absent. Self-fertilization was more frequent in the disturbed habitats (14%, n = 277 seeds from 12 mothers) than in undisturbed forest (10%, n = 295 seeds from 13 mothers). Pollen dispersal was extensive in all three ranches compared to undisturbed forest, however. Using a twogener analysis, we estimated a mean pollen dispersal distance of 1509 m in Colosso ranch, assuming an exponential dispersal function, and 212 m in undisturbed forest. The low effective density of D. excelsa in undisturbed forest (approximately 0.1 trees/ha) indicates that large areas of rainforest must be preserved to maintain minimum viable populations. Our results also suggest, however, that in highly disturbed habitats Apis mellifera may expand genetic neighbourhood areas, thereby linking fragmented and continuous forest populations.
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Smithers, Cherice; Irvin, Allyn; Stanley-Stahr, Cory; Daniels, Jaret C.; Ellis, James D.
2017-01-01
Wildflower strip plantings in intensive agricultural systems have become a widespread tool for promoting pollination services and biological conservation because of their use by wasps and bees. Many of the trap-nesting wasps are important predators of common crop pests, and cavity-nesting bees that utilize trap-nests are important pollinators for native plants and many crops. The impact of wildflower strips on the nesting frequency of trap-nesting wasps or bees within localized areas has not been thoroughly investigated. Trap-nests made of bamboo reeds (Bambusa sp.) were placed adjacent to eight 0.1 ha wildflower plots and paired fallow areas (control plots) to determine if wildflower strips encourage the nesting of wasps and bees. From August 2014 to November 2015, occupied reeds were gathered and adults were collected as they emerged from the trap-nests. Treatment (wildflower or fallow plots) did not impact the number of occupied reeds or species richness of trap-nesting wasps using the occupied reeds. The wasps Pachodynerus erynnis, Euodynerus megaera, Parancistrocerus pedestris, and Isodontia spp. were the most common trap-nesting species collected. Less than 2% of the occupied reeds contained bees, and all were from the genus Megachile. The nesting wasp and bee species demonstrated preferences for reeds with certain inside diameters (IDs). The narrow range of ID preferences exhibited by each bee/wasp may provide opportunities to take advantage of their natural histories for biological control and/or pollination purposes. PMID:28994726
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The Complex Demographic History and Evolutionary Origin of the Western Honey Bee, Apis Mellifera
Tsutsui, Neil D.; Ramírez, Santiago R.
2017-01-01
The western honey bee, Apis mellifera, provides critical pollination services to agricultural crops worldwide. However, despite substantial interest and prior investigation, the early evolution and subsequent diversification of this important pollinator remain uncertain. The primary hypotheses place the origin of A. mellifera in either Asia or Africa, with subsequent radiations proceeding from one of these regions. Here, we use two publicly available whole-genome data sets plus newly sequenced genomes and apply multiple population genetic analysis methods to investigate the patterns of ancestry and admixture in native honey bee populations from Europe, Africa, and the Middle East. The combination of these data sets is critical to the analyses, as each contributes samples from geographic locations lacking in the other, thereby producing the most complete set of honey bee populations available to date. We find evidence supporting an origin of A. mellifera in the Middle East or North Eastern Africa, with the A and Y lineages representing the earliest branching lineages. This finding has similarities with multiple contradictory hypotheses and represents a disentangling of genetic relationships, geographic proximity, and secondary contact to produce a more accurate picture of the origins of A. mellifera. We also investigate how previous studies came to their various conclusions based on incomplete sampling of populations, and illustrate the importance of complete sampling in understanding evolutionary processes. These results provide fundamental knowledge about genetic diversity within Old World honey bee populations and offer insight into the complex history of an important pollinator. PMID:28164223
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Bernauer, Olivia M; Gaines-Day, Hannah R; Steffan, Shawn A
2015-06-01
Bees provide vital pollination services to the majority of flowering plants in both natural and agricultural systems. Unfortunately, both native and managed bee populations are experiencing declines, threatening the persistence of these plants and crops. Agricultural chemicals are one possible culprit contributing to bee declines. Even fungicides, generally considered safe for bees, have been shown to disrupt honey bee development and impair bumble bee behavior. Little is known, however, how fungicides may affect bumble bee colony growth. We conducted a controlled cage study to determine the effects of fungicide exposure on colonies of a native bumble bee species (Bombus impatiens). Colonies of B. impatiens were exposed to flowers treated with field-relevant levels of the fungicide chlorothalonil over the course of one month. Colony success was assessed by the number and biomass of larvae, pupae, and adult bumble bees. Bumble bee colonies exposed to fungicide produced fewer workers, lower total bee biomass, and had lighter mother queens than control colonies. Our results suggest that fungicides negatively affect the colony success of a native bumble bee species and that the use of fungicides during bloom has the potential to severely impact the success of native bumble bee populations foraging in agroecosystems.
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Pollination crisis in the butterfly-pollinated wild carnation Dianthus carthusianorum?
Bloch, Daniel; Werdenberg, Niels; Erhardt, Andreas
2006-01-01
Knowledge of pollination services provided by flower visitors is a prerequisite for understanding (co)evolutionary processes between plants and their pollinators, for evaluating the degree of specialization in the pollination system, and for assessing threats from a potential pollination crisis. This study examined pollination efficiency and visitation frequency of pollinators--key traits of pollinator-mediated fecundity--in a natural population of the wild carnation Dianthus carthusianorum. The five lepidopteran pollinator species observed differed in pollination efficiency and visitation frequency. Pollinator importance, the product of pollination efficiency and visitation frequency, was determined by the pollinator's visitation frequency. Pollination of D. carthusianorum depended essentially on only two of the five recorded pollinator species. Seed set was pollen-limited and followed a saturating dose-response function with a threshold of c. 50 deposited pollen grains for fruit development. Our results confirm that D. carthusianorum is specialized to lepidopteran pollinators, but is not particularly adapted to the two main pollinator species identified. The local persistence of D. carthusianorum is likely to be at risk as its reproduction depends essentially on only two of the locally abundant, but generally vulnerable, butterfly species.
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Crowther, Liam P; Hein, Pierre-Louis; Bourke, Andrew F G
2014-01-01
Bumblebees (Bombus species) are major pollinators of commercial crops and wildflowers but factors affecting their abundance, including causes of recent population declines, remain unclear. Investigating the ecology of species with expanding ranges provides a potentially powerful means of elucidating these factors. Such species may also bring novel pollination services to their new ranges. We therefore investigated landscape-scale habitat use and foraging preferences of the Tree Bumblebee, B. hypnorum, a recent natural colonist that has rapidly expanded its range in the UK over the past decade. Counts of B. hypnorum and six other Bombus species were made in March-June 2012 within a mixed landscape in south-eastern Norfolk, UK. The extent of different landscape elements around each transect was quantified at three scales (250 m, 500 m and 1500 m). We then identified the landscape elements that best predicted the density of B. hypnorum and other Bombus species. At the best fitting scale (250 m), B. hypnorum density was significantly positively associated with extent of both urban and woodland cover and significantly negatively associated with extent of oilseed rape cover. This combination of landscape predictors was unique to B. hypnorum. Urban and woodland cover were associated with B. hypnorum density at three and two, respectively, of the three scales studied. Relative to other Bombus species, B. hypnorum exhibited a significantly higher foraging preference for two flowering trees, Crataegus monogyna and Prunus spinosa, and significantly lower preferences for Brassica napus, Glechoma hederacea and Lamium album. Our study provides novel, quantitative support for an association of B. hypnorum with urban and woodland landscape elements. Range expansion in B. hypnorum appears to depend, on exploitation of widespread habitats underutilised by native Bombus species, suggesting B. hypnorum will readily co-exist with these species. These findings suggest that management could target bumblebee species with distinctive habitat requirements to help maintain pollination services.
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Marks, Timothy R; Seaton, Philip T; Pritchard, Hugh W
2014-09-01
Pollinator-limited seed-set in some terrestrial orchids is compensated for by the presence of long-lived flowers. This study tests the hypothesis that pollen from these insect-pollinated orchids should be desiccation tolerant and relatively long lived using four closely related UK terrestrial species; Anacamptis morio, Dactylorhiza fuchsii, D. maculata and Orchis mascula. Pollen from the four species was harvested from inflorescences and germinated in vitro, both immediately and also after drying to simulate interflower transit. Their tolerance to desiccation and short-term survival was additionally assessed after 3 d equilibration at a range of relative humidities (RHs), and related to constructed sorption isotherms (RH vs. moisture content, MC). Ageing of D. fuchsii pollen was further tested over 2 months against temperature and RH, and the resultant survival curves were subjected to probit analysis, and the distribution of pollen death in time (σ) was determined. The viability and siring ability, following artificial pollinations, were determined in D. fuchsii pollen following storage for 6 years at -20 °C. The pollen from all four species exhibited systematic increases in germinability and desiccation tolerance as anthesis approached, and pollen from open flowers generally retained high germinability. Short-term storage revealed sensitivity to low RH, whilst optimum survival occurred at comparable RHs in all species. Similarly, estimated pollen life spans (σ) at differing temperatures were longest under the dry conditions. Despite a reduction in germination and seeds per capsule, long-term storage of D. fuchsii pollen did not impact on subsequent seed germination in vitro. Substantial pollen desiccation tolerance and life span of the four entomophilous orchids reflects a resilient survival strategy in response to unpredictable pollinator visitation, and presents an alternative approach to germplasm conservation. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Wragg, Peter D; Johnson, Steven D
2011-09-01
Transitions from wind pollination to insect pollination were pivotal to the radiation of land plants, yet only a handful are known and the trait shifts required are poorly understood. We tested the hypothesis that a transition to insect pollination took place in the ancestrally wind-pollinated sedges (Cyperaceae) and that floral traits modified during this transition have functional significance. We paired putatively insect-pollinated Cyperus obtusiflorus and Cyperus sphaerocephalus with related, co-flowering, co-occurring wind-pollinated species, and compared pairs in terms of pollination mode and functional roles of floral traits. Experimentally excluding insects reduced seed set by 56-89% in putatively insect-pollinated species but not in intermingled wind-pollinated species. The pollen of putatively insect-pollinated species was less motile in a wind tunnel than that of wind-pollinated species. Bees, beetles and flies preferred inflorescences, and color-matched white or yellow models, of putatively insect-pollinated species over inflorescences, or color-matched brown models, of wind-pollinated species. Floral scents of putatively insect-pollinated species were chemically consistent with those of other insect-pollinated plants, and attracted pollinators; wind-pollinated species were unscented. These results show that a transition from wind pollination to insect pollination occurred in sedges and shed new light on the function of traits involved in this important transition. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.
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Li, Jiao-Kun; Huang, Shuang-Quan
2009-01-01
Background and Aims If stabilizing selection by pollinators is a prerequisite for pollinator-mediated floral evolution, spatiotemporal variation in the pollinator assemblage may confuse the plant–pollinator interaction in a given species. Here, effective pollinators in a living fossil plant Nelumbo nucifera (Nelumbonaceae) were examined to test whether beetles are major pollinators as predicted by its pollination syndrome. Methods Pollinators of N. nucifera were investigated in 11 wild populations and one cultivated population, and pollination experiments were conducted to examine the pollinating role of two major pollinators (bees and beetles) in three populations. Key Results Lotus flowers are protogynous, bowl shaped and without nectar. The fragrant flowers can be self-heating during anthesis and produce around 1 million pollen grains per flower. It was found that bees and flies were the most frequent flower visitors in wild populations, contributing on average 87·9 and 49·4 % of seed set in Mishan and Lantian, respectively. Beetles were only found in one wild population and in the cultivated population, but the pollinator exclusion experiments showed that beetles were effective pollinators of Asian sacred lotus. Conclusions This study indicated that in their pollinating role, beetles, probable pollinators for this thermoregulating plant, had been replaced by some generalist insects in the wild. This finding implies that contemporary pollinators may not reflect the pollination syndrome. PMID:19617594
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Friedman, Jannice; Barrett, Spencer C H
2009-06-01
The rich literature that characterizes the field of pollination biology has focused largely on animal-pollinated plants. At least 10 % of angiosperms are wind pollinated, and this mode of pollination has evolved on multiple occasions among unrelated lineages, and hence this discrepancy in research interest is surprising. Here, the evolution and functional ecology of pollination and mating in wind-pollinated plants are discussed, a theoretical framework for modelling the selection of wind pollination is outlined, and pollen capture and the occurrence of pollen limitation in diverse wind-pollinated herbs are investigated experimentally. Wind pollination may commonly evolve to provide reproductive assurance when pollinators are scarce. Evidence is presented that pollen limitation in wind-pollinated plants may not be as common as it is in animal-pollinated species. The studies of pollen capture in wind-pollinated herbs demonstrate that pollen transfer efficiency is not substantially lower than in animal-pollinated plants as is often assumed. These findings challenge the explanation that the evolution of few ovules in wind-pollinated flowers is associated with low pollen loads. Floral and inflorescence architecture is crucial to pollination and mating because of the aerodynamics of wind pollination. Evidence is provided for the importance of plant height, floral position, and stamen and stigma characteristics in promoting effective pollen dispersal and capture. Finally, it is proposed that geitonogamous selfing may alleviate pollen limitation in many wind-pollinated plants with unisexual flowers.
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Friedman, Jannice; Barrett, Spencer C. H.
2009-01-01
Background The rich literature that characterizes the field of pollination biology has focused largely on animal-pollinated plants. At least 10 % of angiosperms are wind pollinated, and this mode of pollination has evolved on multiple occasions among unrelated lineages, and hence this discrepancy in research interest is surprising. Here, the evolution and functional ecology of pollination and mating in wind-pollinated plants are discussed, a theoretical framework for modelling the selection of wind pollination is outlined, and pollen capture and the occurrence of pollen limitation in diverse wind-pollinated herbs are investigated experimentally. Scope and Conclusions Wind pollination may commonly evolve to provide reproductive assurance when pollinators are scarce. Evidence is presented that pollen limitation in wind-pollinated plants may not be as common as it is in animal-pollinated species. The studies of pollen capture in wind-pollinated herbs demonstrate that pollen transfer efficiency is not substantially lower than in animal-pollinated plants as is often assumed. These findings challenge the explanation that the evolution of few ovules in wind-pollinated flowers is associated with low pollen loads. Floral and inflorescence architecture is crucial to pollination and mating because of the aerodynamics of wind pollination. Evidence is provided for the importance of plant height, floral position, and stamen and stigma characteristics in promoting effective pollen dispersal and capture. Finally, it is proposed that geitonogamous selfing may alleviate pollen limitation in many wind-pollinated plants with unisexual flowers. PMID:19218583
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Modeling carbon dynamics in vegetation and soil under the impact of soil erosion and deposition
NASA Astrophysics Data System (ADS)
Liu, Shuguang; Bliss, Norman; Sundquist, Eric; Huntington, Thomas G.
2003-06-01
Soil erosion and deposition may play important roles in balancing the global atmospheric carbon budget through their impacts on the net exchange of carbon between terrestrial ecosystems and the atmosphere. Few models and studies have been designed to assess these impacts. In this study, we developed a general ecosystem model, Erosion-Deposition-Carbon-Model (EDCM), to dynamically simulate the influences of rainfall-induced soil erosion and deposition on soil organic carbon (SOC) dynamics in soil profiles. EDCM was applied to several landscape positions in the Nelson Farm watershed in Mississippi, including ridge top (without erosion or deposition), eroding hillslopes, and depositional sites that had been converted from native forests to croplands in 1870. Erosion reduced the SOC storage at the eroding sites and deposition increased the SOC storage at the depositional areas compared with the site without erosion or deposition. Results indicated that soils were consistently carbon sources to the atmosphere at all landscape positions from 1870 to 1950, with lowest source strength at the eroding sites (13 to 24 gC m-2 yr-1), intermediate at the ridge top (34 gC m-2 yr-1), and highest at the depositional sites (42 to 49 gC m-2 yr-1). During this period, erosion reduced carbon emissions via dynamically replacing surface soil with subsurface soil that had lower SOC contents (quantity change) and higher passive SOC fractions (quality change). Soils at all landscape positions became carbon sinks from 1950 to 1997 due to changes in management practices (e.g., intensification of fertilization and crop genetic improvement). The sink strengths were highest at the eroding sites (42 to 44 gC m-2 yr-1), intermediate at the ridge top (35 gC m-2 yr-1), and lowest at the depositional sites (26 to 29 gC m-2 yr-1). During this period, erosion enhanced carbon uptake at the eroding sites by continuously taking away a fraction of SOC that can be replenished with enhanced plant residue input. Overall, soil erosion and deposition reduced CO2 emissions from the soil into the atmosphere by exposing low carbon-bearing soil at eroding sites and by burying SOC at depositional sites. The results suggest that failing to account for the impact of soil erosion and deposition may potentially contribute to an overestimation of both the total historical carbon released from soils owing to land use change and the contemporary carbon sequestration rates at the eroding sites.
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Modeling carbon dynamics in vegetation and soil under the impact of soil erosion and deposition
Liu, S.; Bliss, N.; Sundquist, E.; Huntington, T.G.
2003-01-01
Soil erosion and deposition may play important roles in balancing the global atmospheric carbon budget through their impacts on the net exchange of carbon between terrestrial ecosystem and the atmosphere. Few models and studies have been designed to assess these impacts. In this study, we developed a general ecosystem model, Erosion-Deposition-Carbon-Model (EDCM), to dynamically simulate the influences of rainfall-induced soil erosion and deposition on soil organic carbon (SOC) dynamics in soil profiles. EDCM was applied to several landscape positions in the Nelson Farm watershed in Mississippi, including ridge top (without erosion or deposition), eroding hillslopes, and depositional sites that had been converted from native forests to croplands in 1870. Erosion reduced the SOC storage at the eroding sites and deposition increased the SOC storage at the depositional areas compared with the site without erosion or deposition. Results indicated that soils were consistently carbon sources to the atmosphere at all landscape positions from 1870 to 1950, with lowest source strength at the eroding sites (13 to 24 gC m-2 yr-1), intermediate at the ridge top (34 gC m-2 yr-1), and highest at the depositional sites (42 to 49 gC m-2 yr-1). During this period, erosion reduced carbon emissions via dynamically replacing surface soil with subsurface soil that had lower SOC contents (quantity change) and higher passive SOC fractions (quality change). Soils at all landscape positions became carbon sinks from 1950 to 1997 due to changes in management practices (e.g., intensification of fertilization and crop genetic improvement). The sink strengths were highest at the eroding sites (42 to 44 gC m-2 yr-1 , intermediate at the ridge top (35 gC m-2 yr-1), and lowest at the depositional sites (26 to 29 gC m-2 yr-1). During this period, erosion enhanced carbon uptake at the eroding sites by continuously taking away a fraction of SOC that can be replenished with enhanced plant residue input. Overall, soil erosion and deposition reduced CO2 emissions from the soil into the atmosphere by exposing low carbon-bearing soil at eroding sites and by burying SOC at depositional sites. The results suggest that failing to account for the impact of soil erosion and deposition may potentially contribute to an overestimation of both the total historical carbon released from soils owing to land use change and the contemporary carbon sequestration rates at the eroding sites.
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Scopece, Giovanni; Campese, Lucia; Duffy, Karl J; Cozzolino, Salvatore
2018-02-01
Plants involved in specialized pollinator interactions, such as nursery pollination, may experience trade-offs in their female fitness, as the larvae of their pollinators may also consume seeds produced by the flowers they pollinate. These interactions could potentially shift between mutualism and parasitism, depending on the presence and abundance of both the nursery pollinator and of other pollinators. We investigated the fitness trade-off in a Mediterranean plant ( Silene latifolia ), which has a specialist nocturnal nursery pollinator moth ( Hadena bicruris ) and is also visited by several diurnal pollinators. We estimated the pollination rates and fecundity of S. latifolia in both natural and experimental populations in the Mediterranean. We estimated natural pollination rates in different flowering times and with presence/absence of the H. bicruis moth. Then by exposing plants to each pollinator group either during the day or at night, we quantified the contribution of other diurnal pollinators and the specialized nocturnal nursery pollinator to plant female fitness. We found no difference in plant fruit set mediated by diurnal versus nocturnal pollinators, indicating that non-specialist pollinators contribute to plant female fitness. However, in both natural and experimental populations, H. bicruris was the most efficient pollinator in terms of seeds produced per fruit. These results suggest that the female fitness costs generated by nursery pollination can be overcome through higher fertilization rates relative to predation rates, even in the presence of co-pollinators. Quantifying such interactions is important for our understanding of the selective pressures that promote highly specialized mutualisms, such as nursery pollination, in the Mediterranean region, a centre of diversification of the carnation family.
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Johnson, Karen A.
2013-01-01
Background and Aims Convergent floral traits hypothesized as attracting particular pollinators are known as pollination syndromes. Floral diversity suggests that the Australian epacrid flora may be adapted to pollinator type. Currently there are empirical data on the pollination systems for 87 species (approx. 15 % of Australian epacrids). This provides an opportunity to test for pollination syndromes and their important morphological traits in an iconic element of the Australian flora. Methods Data on epacrid–pollinator relationships were obtained from published literature and field observation. A multivariate approach was used to test whether epacrid floral attributes related to pollinator profiles. Statistical classification was then used to rank floral attributes according to their predictive value. Data sets excluding mixed pollination systems were used to test the predictive power of statistical classification to identify pollination models. Key Results Floral attributes are correlated with bird, fly and bee pollination. Using floral attributes identified as correlating with pollinator type, bird pollination is classified with 86 % accuracy, red flowers being the most important predictor. Fly and bee pollination are classified with 78 and 69 % accuracy, but have a lack of individually important floral predictors. Excluding mixed pollination systems improved the accuracy of the prediction of both bee and fly pollination systems. Conclusions Although most epacrids have generalized pollination systems, a correlation between bird pollination and red, long-tubed epacrids is found. Statistical classification highlights the relative importance of each floral attribute in relation to pollinator type and proves useful in classifying epacrids to bird, fly and bee pollination systems. PMID:23681546
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Hallett, Allysa C.; Mitchell, Randall J.; Chamberlain, Evan R.
2017-01-01
Abstract Pollinator abundance is declining worldwide and may lower the quantity and quality of pollination services to flowering plant populations. Loss of an important pollinator is often assumed to reduce the amount of pollen received by stigmas of a focal species (pollination success), yet this assumption has rarely been tested experimentally. The magnitude of the effect, if any, may depend on the relative efficiency of the remaining pollinators, and on whether the loss of one pollinator leads to changes in visitation patterns by other pollinators. To explore how a change in pollinator composition influences pollination of Asclepias verticillata, we excluded bumble bees from plots in large and small populations of this milkweed species. We then quantified pollinator visitation rates, pollen export and pollen receipt for control plots and for plots where bumble bees were experimentally excluded. We found that exclusion of bumble bees did not reduce pollen receipt by A. verticillata flowers. Visitation by Polistes wasps increased markedly following bumble bee exclusion, both in small populations (186 % increase) and in large populations (400 % increase). Because Polistes wasps were as efficient as bumble bees at pollen transfer, increased wasp visitation offset lost bumble bee pollination services. Thus, loss of a frequent pollinator will not necessarily lead to a decline in pollination success. When pollinator loss is followed by a shift in the composition and abundance of remaining pollinators, pollination success will depend on the net change in the quantity and quality of pollination services. PMID:28798863
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Perspectives on trans-Pacific biological invasions
Guo, Q.
2002-01-01
Trans-Pacific biological invasion is one of the most striking and influential biological phenomena occurring in modern times and the process is still accelerating, and the associated invasives form neo-disjuncts (cf. many well-known paleo-disjuncts) between eastern Asia and North America. To better understand this phenomenon and the related taxa, I address the following questions: 1) what types of species (e.g., life/growth form) have been, or are likely to be, associated with trans-Pacific (eastern Asia, North America) invasions; 2) what has happened or may happen to these species after their remote geographic separation, and 3) what aspects of these species and their native and non-native habitats should be better understood for improved control. To answer these questions, comparisons of the invasive species' characteristics in their native and invaded habitats need to be examined, including: l) genetics, 2) life history/morphology (e.g., plant size, seed size, etc.), 3) ecology (e.g., life/growth forms, pollinators, competitors), 4) distributions (e.g., range size, shape, latitude) in their native (source) and introduced (target) ranges or habitats, and 5) physical factors such as soil, water, and climate. The purpose of these studies is 1) to identify the limiting factors that restrict the distributions of exotic species in native ranges, 2) to understand why invasive species are successful in the introduced ranges, 3) to predict possible future invasions, and, ultimately, 4) to provide information for more efficient and effective management.
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Lim, Voon-Ching; Ramli, Rosli; Bhassu, Subha; Wilson, John-James
2018-01-01
Intense landscaping often alters the plant composition in urban areas. Knowing which plant species that pollinators are visiting in urban areas is necessary for understanding how landscaping impacts biodiversity and associated ecosystem services. The cave nectar bat, Eonycteris spelaea , is an important pollinator for many plants and is often recorded in human-dominated habitats. Previous studies of the diet of E. spelaea relied on morphological identification of pollen grains found in faeces and on the body of bats and by necessity disregarded other forms of digested plant material present in the faeces (i.e., plant juice and remnants). The main objective of this study was to examine the diet of the nectarivorous bat, E. spelaea, roosting in an urban cave at Batu Caves, Peninsular Malaysia by identifying the plant material present in the faeces of bats using DNA metabarcoding. Faeces were collected under the roost of E. spelaea once a week from December 2015 to March 2016. Plant DNA was extracted from the faeces, Polymerase chain reaction (PCR) amplified at ITS2 and rbcL regions and mass sequenced. The resultant plant operational taxonomic units were searched against NCBI GenBank for identification. A total of 55 species of plants were detected from faeces of E. spelaea including Artocarpus heterophyllus, Duabanga grandiflora and Musa spp. which are likely to be important food resources for the cave nectar bat. Many native plant species that had not been reported in previous dietary studies of E. spelaea were detected in this study including Bauhinia strychnoidea and Urophyllum leucophlaeum , suggesting that E. spelaea remains a crucial pollinator for these plants even in highly disturbed habitats. The detection of many introduced plant species in the bat faeces indicates that E. spelaea are exploiting them, particularly Xanthostemon chrysanthus, as food resources in urban area. Commercial food crops were detected from all of the faecal samples, suggesting that E. spelaea feed predominantly on the crops particularly jackfruit and banana and play a significant role in pollination of economically important plants. Ferns and figs were also detected in the faeces of E. spelaea suggesting future research avenues to determine whether the 'specialised nectarivorous' E. spelaea feed opportunistically on other parts of plants.
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Floral resource availability from groundcover promotes bee abundance in coffee agroecosystems.
Fisher, Kaleigh; Gonthier, David J; Ennis, Katherine K; Perfecto, Ivette
2017-09-01
Patterns of bee abundance and diversity across different spatial scales have received thorough research consideration. However, the impact of short- and long-term temporal resource availability on biodiversity has been less explored. This is highly relevant in tropical agricultural systems for pollinators, as many foraging periods of pollinators extend beyond flowering of any single crop species. In this study, we sought to understand how bee communities in tropical agroecosystems changed between seasons, and if short- and long-term floral resource availability influenced their diversity and abundance. We used a threshold analysis approach in order to explore this relationship at two time scales. This study took place in a region dominated by coffee agroecosystems in Southern Mexico. This was an ideal system because the landscape offers a range of coffee management regimes that maintain heterogeneity in floral resource availability spatially and temporally. We found that the bee community varies significantly between seasons. There were higher abundances of native social, solitary and managed honey bees during the dry season when coffee flowers. Additionally, we found that floral resources from groundcover, but not trees, were associated with bee abundance. Further, the temporal scale of the availability of these resources is important, whereby short-term floral resource availability appears particularly important in maintaining high bee abundance at sites with lower seasonal complementarity. We argue that in addition to spatial resource heterogeneity, temporal resource heterogeneity is critical in explaining bee community patterns, and should thus be considered to promote pollinator conservation. © 2017 by the Ecological Society of America.
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The Complex Demographic History and Evolutionary Origin of the Western Honey Bee, Apis Mellifera.
Cridland, Julie M; Tsutsui, Neil D; Ramírez, Santiago R
2017-02-01
The western honey bee, Apis mellifera, provides critical pollination services to agricultural crops worldwide. However, despite substantial interest and prior investigation, the early evolution and subsequent diversification of this important pollinator remain uncertain. The primary hypotheses place the origin of A. mellifera in either Asia or Africa, with subsequent radiations proceeding from one of these regions. Here, we use two publicly available whole-genome data sets plus newly sequenced genomes and apply multiple population genetic analysis methods to investigate the patterns of ancestry and admixture in native honey bee populations from Europe, Africa, and the Middle East. The combination of these data sets is critical to the analyses, as each contributes samples from geographic locations lacking in the other, thereby producing the most complete set of honey bee populations available to date. We find evidence supporting an origin of A. mellifera in the Middle East or North Eastern Africa, with the A and Y lineages representing the earliest branching lineages. This finding has similarities with multiple contradictory hypotheses and represents a disentangling of genetic relationships, geographic proximity, and secondary contact to produce a more accurate picture of the origins of A. mellifera. We also investigate how previous studies came to their various conclusions based on incomplete sampling of populations, and illustrate the importance of complete sampling in understanding evolutionary processes. These results provide fundamental knowledge about genetic diversity within Old World honey bee populations and offer insight into the complex history of an important pollinator. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
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Does habitat fragmentation influence nest predation in the shortgrass prairie?
Howard, M.N.; Skagen, S.K.; Kennedy, P.L.
2001-01-01
We examined the effects of habitat fragmentation and vegetation structure of shortgrass prairie and Conservation Reserve Program (CRP) lands on predation rates of artificial and natural nests in northeastern Colorado. The CRP provides federal payments to landowners to take highly erodible cropland out of agricultural production. In our study area, CRP lands have been reseeded primarily with non-native grasses, and this vegetation is taller than native shortgrass prairie. We measured three indices of habitat fragmentation (patch size, degree of matrix fragmentation, and distance from edge), none of which influenced mortality rates of artificial or natural nests. Vegetation structure did influence predation rates of artificial nests; daily mortality decreased significantly with increasing vegetation height. Vegetation structure did not influence predation rates of natural nests. CRP lands and shortgrass sites did not differ with respect to mortality rates of artificial nests. Our study area is only moderately fragmented; 62% of the study area is occupied by native grassland. We conclude that the extent of habitat fragmentation in our study area does not result in increased predation in remaining patches of shortgrass prairie habitat.
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Diversity of wild bees supports pollination services in an urbanized landscape.
Lowenstein, David M; Matteson, Kevin C; Minor, Emily S
2015-11-01
Plantings in residential neighborhoods can support wild pollinators. However, it is unknown how effectively wild pollinators maintain pollination services in small, urban gardens with diverse floral resources. We used a 'mobile garden' experimental design, whereby potted plants of cucumber, eggplant, and purple coneflower were brought to 30 residential yards in Chicago, IL, USA, to enable direct assessment of pollination services provided by wild pollinator communities. We measured fruit and seed set and investigated the effect of within-yard characteristics and adjacent floral resources on plant pollination. Increased pollinator visitation and taxonomic richness generally led to increases in fruit and seed set for all focal plants. Furthermore, fruit and seed set were correlated across the three species, suggesting that pollination services vary across the landscape in ways that are consistent among different plant species. Plant species varied in terms of which pollinator groups provided the most visits and benefit for pollination. Cucumber pollination was linked to visitation by small sweat bees (Lasioglossum spp.), whereas eggplant pollination was linked to visits by bumble bees. Purple coneflower was visited by the most diverse group of pollinators and, perhaps due to this phenomenon, was more effectively pollinated in florally-rich gardens. Our results demonstrate how a diversity of wild bees supports pollination of multiple plant species, highlighting the importance of pollinator conservation within cities. Non-crop resources should continue to be planted in urban gardens, as these resources have a neutral and potentially positive effect on crop pollination.
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Effects of invasive parasites on bumble bee declines.
Meeus, Ivan; Brown, Mark J F; De Graaf, Dirk C; Smagghe, Guy
2011-08-01
Bumble bees are a group of pollinators that are both ecologically and economically important and declining worldwide. Numerous mechanisms could be behind this decline, and the spread of parasites from commercial colonies into wild populations has been implicated recently in North America. Commercial breeding may lead to declines because commercial colonies may have high parasite loads, which can lead to colonization of native bumble bee populations; commercial rearing may allow higher parasite virulence to evolve; and global movement of commercial colonies may disrupt spatial patterns in local adaptation between hosts and parasites. We assessed parasite virulence, transmission mode, and infectivity. Microparasites and so-called honey bee viruses may pose the greatest threat to native bumble bee populations because certain risk factors are present; for example, the probability of horizontal transmission of the trypanosome parasite Crithidia bombi is high. The microsporidian parasite Nosema bombi may play a role in declines of bumble bees in the United States. Preliminary indications that C. bombi and the neogregarine Apicystis bombi may not be native in parts of South America. We suggest that the development of molecular screening protocols, thorough sanitation efforts, and cooperation among nongovernmental organizations, governments, and commercial breeders might immediately mitigate these threats. © 2011 Society for Conservation Biology.
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Reverté, Sara; Retana, Javier; Gómez, José M.; Bosch, Jordi
2016-01-01
Background and aims Colour is one of the main floral traits used by pollinators to locate flowers. Although pollinators show innate colour preferences, the view that the colour of a flower may be considered an important predictor of its main pollinators is highly controversial because flower choice is highly context-dependent, and initial innate preferences may be overridden by subsequent associative learning. Our objective is to establish whether there is a relationship between flower colour and pollinator composition in natural communities. Methods We measured the flower reflectance spectrum and pollinator composition in four plant communities (85 plant species represented by 109 populations, and 32 305 plant–pollinator interactions in total). Pollinators were divided into six taxonomic groups: bees, ants, wasps, coleopterans, dipterans and lepidopterans. Key Results We found consistent associations between pollinator groups and certain colours. These associations matched innate preferences experimentally established for several pollinators and predictions of the pollination syndrome theory. However, flowers with similar colours did not attract similar pollinator assemblages. Conclusions The explanation for this paradoxical result is that most flower species are pollination generalists. We conclude that although pollinator colour preferences seem to condition plant–pollinator interactions, the selective force behind these preferences has not been strong enough to mediate the appearance and maintenance of tight colour-based plant–pollinator associations. PMID:27325897
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Persistence of pollination mutualisms in the presence of ants.
Wang, Yuanshi; Wang, Shikun
2015-01-01
This paper considers plant-pollinator-ant systems in which the plant-pollinator interaction is mutualistic but ants have both positive and negative effects on plants. The ants also interfere with pollinators by preventing them from accessing plants. While a Beddington-DeAngelis (BD) formula can describe the plant-pollinator interaction, the formula is extended in this paper to characterize the pollination mutualism under the ant interference. Then, a plant-pollinator-ant system with the extended BD functional response is discussed, and global dynamics of the model demonstrate the mechanisms by which pollination mutualism can persist in the presence of ants. When the ant interference is strong, it can result in extinction of pollinators. Moreover, if the ants depend on pollination mutualism for survival, the strong interference could drive pollinators into extinction, which consequently lead to extinction of the ants themselves. When the ant interference is weak, a cooperation between plant-ant and plant-pollinator mutualisms could occur, which promotes survival of both ants and pollinators, especially in the case that ants (respectively, pollinators) cannot survive in the absence of pollinators (respectively, ants). Even when the level of ant interference remains invariant, varying ants' negative effect on plants can result in survival/extinction of both ants and pollinators. Therefore, our results provide an explanation for the persistence of pollination mutualism when there exist ants.
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Spatial and Temporal Trends of Global Pollination Benefit
Lautenbach, Sven; Seppelt, Ralf; Liebscher, Juliane; Dormann, Carsten F.
2012-01-01
Pollination is a well-studied and at the same time a threatened ecosystem service. A significant part of global crop production depends on or profits from pollination by animals. Using detailed information on global crop yields of 60 pollination dependent or profiting crops, we provide a map of global pollination benefits on a 5′ by 5′ latitude-longitude grid. The current spatial pattern of pollination benefits is only partly correlated with climate variables and the distribution of cropland. The resulting map of pollination benefits identifies hot spots of pollination benefits at sufficient detail to guide political decisions on where to protect pollination services by investing in structural diversity of land use. Additionally, we investigated the vulnerability of the national economies with respect to potential decline of pollination services as the portion of the (agricultural) economy depending on pollination benefits. While the general dependency of the agricultural economy on pollination seems to be stable from 1993 until 2009, we see increases in producer prices for pollination dependent crops, which we interpret as an early warning signal for a conflict between pollination service and other land uses at the global scale. Our spatially explicit analysis of global pollination benefit points to hot spots for the generation of pollination benefits and can serve as a base for further planning of land use, protection sites and agricultural policies for maintaining pollination services. PMID:22563427
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Sletvold, Nina; Trunschke, Judith; Wimmergren, Carolina; Agren, Jon
2012-08-01
Most plants attract multiple flower visitors that may vary widely in their effectiveness as pollinators. Floral evolution is expected to reflect interactions with the most important pollinators, but few studies have quantified the contribution of different pollinators to current selection on floral traits. To compare selection mediated by diurnal and nocturnal pollinators on floral display and spur length in the rewarding orchid Gymnadenia conopsea, we manipulated the environment by conducting supplemental hand-pollinations and selective pollinator exclusions in two populations in central Norway. In both populations, the exclusion of diurnal pollinators significantly reduced seed production compared to open pollination, whereas the exclusion of nocturnal pollinators did not. There was significant selection on traits expected to influence pollinator attraction and pollination efficiency in both the diurnal and nocturnal pollination treatment. The relative strength of selection among plants exposed to diurnal and nocturnal visitors varied among traits and populations, but the direction of selection was consistent. The results suggest that diurnal pollinators are more important than nocturnal pollinators for seed production in the study populations, but that both categories contribute to selection on floral morphology. The study illustrates how experimental manipulations can link specific categories of pollinators to observed selection on floral traits, and thus improve our understanding of how species interactions shape patterns of selection.
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Flacher, Floriane; Raynaud, Xavier; Hansart, Amandine; Motard, Eric; Dajoz, Isabelle
2015-01-01
Plant traits related to attractiveness to pollinators (e.g. flowers and nectar) can be sensitive to abiotic or biotic conditions. Soil nutrient availability, as well as interactions among insect-pollinated plants species, can induce changes in flower and nectar production. However, further investigations are needed to determine the impact of interactions between insect-pollinated species and abiotically pollinated species on such floral traits, especially floral rewards. We carried out a pot experiment in which three insect-pollinated plant species were grown in binary mixtures with four wind-pollinated plant species, differing in their competitive ability. Along the flowering period, we measured floral traits of the insect-pollinated species involved in attractiveness to pollinators (i.e. floral display size, flower size, daily and total 1) flower production, 2) nectar volume, 3) amount of sucrose allocated to nectar). Final plant biomass was measured to quantify competitive interactions. For two out of three insect-pollinated species, we found that the presence of a wind-pollinated species can negatively impact floral traits involved in attractiveness to pollinators. This effect was stronger with wind-pollinated species that induced stronger competitive interactions. These results stress the importance of studying the whole plant community (and not just the insect-pollinated plant community) when working on plant-pollinator interactions. PMID:26335409
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Tripp, Erin A; Manos, Paul S
2008-07-01
Pollination systems frequently reflect adaptations to particular groups of pollinators. Such systems are indicative of evolutionary specialization and have been important in angiosperm diversification. We studied the evolution of pollination systems in the large genus Ruellia. Phylogenetic analyses, morphological ordinations, ancestral state reconstructions, and a character mapping simulation were conducted to reveal key patterns in the direction and lability of floral characters associated with pollination. We found significant floral morphological differences among species that were generally associated with different groups of floral visitors. Floral evolution has been highly labile and also directional. Some specialized systems such as hawkmoth or bat pollination are likely evolutionary dead-ends. In contrast, specialized pollination by hummingbirds is clearly not a dead-end. We found evidence for multiple reverse transitions from presumed ancestral hummingbird pollination to more derived bee or insect pollination. These repeated origins of insect pollination from hummingbird-pollinated ancestors have not evolved without historical baggage. Flowers of insect-pollinated species derived from hummingbird-pollinated ancestors are morphologically more similar to hummingbird flowers than they are to other more distantly related insect-pollinated flowers. Finally, some pollinator switches were concomitant with changes in floral morphology that are associated with those pollinators. These observations are consistent with the hypothesis that some transitions have been adaptive in the evolution of Ruellia.
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Courgette Production: Pollination Demand, Supply, and Value.
Knapp, Jessica L; Osborne, Juliet L
2017-10-01
Courgette (Cucurbita pepo L.) production in the United Kingdom is estimated to be worth £6.7 million. However, little is known about this crop's requirement for insect-mediated pollination (pollinator dependence) and if pollinator populations in a landscape are able to fulfil its pollination needs (pollination deficit). Consequently, pollination experiments were conducted over 2 yr to explore pollinator dependence and pollination deficit in field-grown courgette in the United Kingdom. Results showed that pollination increased yield by 39% and there was no evidence of pollination limitation on crop yield. This was evidenced by a surprisingly low pollination deficit (of just 3%) and no statistical difference in yield (length grown, circumference, and weight) between open- and hand-pollinated crops. Nonetheless, the high economic value of courgettes means that reducing even the small pollination deficit could still increase profit by ∼£166/ha. Interestingly, 56% of fruit was able to reach marketable size and shape without any pollination. Understanding a crop's requirement for pollinators can aid growers in their decision-making about what varieties and sites should be used. In doing so, they may increase their agricultural resilience and further their economic advantage. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.
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Astegiano, Julia; Massol, François; Vidal, Mariana Morais; Cheptou, Pierre-Olivier; Guimarães, Paulo R.
2015-01-01
Most flowering plants depend on pollinators to reproduce. Thus, evaluating the robustness of plant-pollinator assemblages to species loss is a major concern. How species interaction patterns are related to species sensitivity to partner loss may influence the robustness of plant-pollinator assemblages. In plants, both reproductive dependence on pollinators (breeding system) and dispersal ability may modulate plant sensitivity to pollinator loss. For instance, species with strong dependence (e.g. dioecious species) and low dispersal (e.g. seeds dispersed by gravity) may be the most sensitive to pollinator loss. We compared the interaction patterns of plants differing in dependence on pollinators and dispersal ability in a meta-dataset comprising 192 plant species from 13 plant-pollinator networks. In addition, network robustness was compared under different scenarios representing sequences of plant extinctions associated with plant sensitivity to pollinator loss. Species with different dependence on pollinators and dispersal ability showed similar levels of generalization. Although plants with low dispersal ability interacted with more generalized pollinators, low-dispersal plants with strong dependence on pollinators (i.e. the most sensitive to pollinator loss) interacted with more particular sets of pollinators (i.e. shared a low proportion of pollinators with other plants). Only two assemblages showed lower robustness under the scenario considering plant generalization, dependence on pollinators and dispersal ability than under the scenario where extinction sequences only depended on plant generalization (i.e. where higher generalization level was associated with lower probability of extinction). Overall, our results support the idea that species generalization and network topology may be good predictors of assemblage robustness to species loss, independently of plant dispersal ability and breeding system. In contrast, since ecological specialization among partners may increase the probability of disruption of interactions, the fact that the plants most sensitive to pollinator loss interacted with more particular pollinator assemblages suggest that the persistence of these plants and their pollinators might be highly compromised. PMID:25646762
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Valuing Insect Pollination Services with Cost of Replacement
Allsopp, Mike H.; de Lange, Willem J.; Veldtman, Ruan
2008-01-01
Value estimates of ecosystem goods and services are useful to justify the allocation of resources towards conservation, but inconclusive estimates risk unsustainable resource allocations. Here we present replacement costs as a more accurate value estimate of insect pollination as an ecosystem service, although this method could also be applied to other services. The importance of insect pollination to agriculture is unequivocal. However, whether this service is largely provided by wild pollinators (genuine ecosystem service) or managed pollinators (commercial service), and which of these requires immediate action amidst reports of pollinator decline, remains contested. If crop pollination is used to argue for biodiversity conservation, clear distinction should be made between values of managed- and wild pollination services. Current methods either under-estimate or over-estimate the pollination service value, and make use of criticised general insect and managed pollinator dependence factors. We apply the theoretical concept of ascribing a value to a service by calculating the cost to replace it, as a novel way of valuing wild and managed pollination services. Adjusted insect and managed pollinator dependence factors were used to estimate the cost of replacing insect- and managed pollination services for the Western Cape deciduous fruit industry of South Africa. Using pollen dusting and hand pollination as suitable replacements, we value pollination services significantly higher than current market prices for commercial pollination, although lower than traditional proportional estimates. The complexity associated with inclusive value estimation of pollination services required several defendable assumptions, but made estimates more inclusive than previous attempts. Consequently this study provides the basis for continued improvement in context specific pollination service value estimates. PMID:18781196
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Reverté, Sara; Retana, Javier; Gómez, José M; Bosch, Jordi
2016-08-01
Colour is one of the main floral traits used by pollinators to locate flowers. Although pollinators show innate colour preferences, the view that the colour of a flower may be considered an important predictor of its main pollinators is highly controversial because flower choice is highly context-dependent, and initial innate preferences may be overridden by subsequent associative learning. Our objective is to establish whether there is a relationship between flower colour and pollinator composition in natural communities. We measured the flower reflectance spectrum and pollinator composition in four plant communities (85 plant species represented by 109 populations, and 32 305 plant-pollinator interactions in total). Pollinators were divided into six taxonomic groups: bees, ants, wasps, coleopterans, dipterans and lepidopterans. We found consistent associations between pollinator groups and certain colours. These associations matched innate preferences experimentally established for several pollinators and predictions of the pollination syndrome theory. However, flowers with similar colours did not attract similar pollinator assemblages. The explanation for this paradoxical result is that most flower species are pollination generalists. We conclude that although pollinator colour preferences seem to condition plant-pollinator interactions, the selective force behind these preferences has not been strong enough to mediate the appearance and maintenance of tight colour-based plant-pollinator associations. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Sandhu, Harpinder; Waterhouse, Benjamin; Boyer, Stephane; Wratten, Steve
2016-01-01
Ecosystem services (ES) such as pollination are vital for the continuous supply of food to a growing human population, but the decline in populations of insect pollinators worldwide poses a threat to food and nutritional security. Using a pollinator (honeybee) exclusion approach, we evaluated the impact of pollinator scarcity on production in four brassica fields, two producing hybrid seeds and two producing open-pollinated ones. There was a clear reduction in seed yield as pollination rates declined. Open-pollinated crops produced significantly higher yields than did the hybrid ones at all pollination rates. The hybrid crops required at least 0.50 of background pollination rates to achieve maximum yield, whereas in open-pollinated crops, 0.25 pollination rates were necessary for maximum yield. The total estimated economic value of pollination services provided by honeybees to the agricultural industry in New Zealand is NZD $1.96 billion annually. This study indicates that loss of pollination services can result in significant declines in production and have serious implications for the market economy in New Zealand. Depending on the extent of honeybee population decline, and assuming that results in declining pollination services, the estimated economic loss to New Zealand agriculture could be in the range of NZD $295-728 million annually.
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Pollination services enhanced with urbanization despite increasing pollinator parasitism.
Theodorou, Panagiotis; Radzevičiūtė, Rita; Settele, Josef; Schweiger, Oliver; Murray, Tomás E; Paxton, Robert J
2016-06-29
Animal-mediated pollination is required for the reproduction of the majority of angiosperms, and pollinators are therefore essential for ecosystem functioning and the economy. Two major threats to insect pollinators are anthropogenic land-use change and the spread of pathogens, whose effects may interact to impact pollination. Here, we investigated the relative effects on the ecosystem service of pollination of (i) land-use change brought on by agriculture and urbanization as well as (ii) the prevalence of pollinator parasites, using experimental insect pollinator-dependent plant species in natural pollinator communities. We found that pollinator habitat (i.e. availability of nesting resources for ground-nesting bees and local flower richness) was strongly related to flower visitation rates at the local scale and indirectly influenced plant pollination success. At the landscape scale, pollination was positively related to urbanization, both directly and indirectly via elevated visitation rates. Bumblebees were the most abundant pollinator group visiting experimental flowers. Prevalence of trypanosomatids, such as the common bumblebee parasite Crithidia bombi, was higher in urban compared with agricultural areas, a relationship which was mediated through higher Bombus abundance. Yet, we did not find any top-down, negative effects of bumblebee parasitism on pollination. We conclude that urban areas can be places of high transmission of both pollen and pathogens. © 2016 The Author(s).
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Pollination services enhanced with urbanization despite increasing pollinator parasitism
Radzevičiūtė, Rita; Murray, Tomás E.
2016-01-01
Animal-mediated pollination is required for the reproduction of the majority of angiosperms, and pollinators are therefore essential for ecosystem functioning and the economy. Two major threats to insect pollinators are anthropogenic land-use change and the spread of pathogens, whose effects may interact to impact pollination. Here, we investigated the relative effects on the ecosystem service of pollination of (i) land-use change brought on by agriculture and urbanization as well as (ii) the prevalence of pollinator parasites, using experimental insect pollinator-dependent plant species in natural pollinator communities. We found that pollinator habitat (i.e. availability of nesting resources for ground-nesting bees and local flower richness) was strongly related to flower visitation rates at the local scale and indirectly influenced plant pollination success. At the landscape scale, pollination was positively related to urbanization, both directly and indirectly via elevated visitation rates. Bumblebees were the most abundant pollinator group visiting experimental flowers. Prevalence of trypanosomatids, such as the common bumblebee parasite Crithidia bombi, was higher in urban compared with agricultural areas, a relationship which was mediated through higher Bombus abundance. Yet, we did not find any top-down, negative effects of bumblebee parasitism on pollination. We conclude that urban areas can be places of high transmission of both pollen and pathogens. PMID:27335419
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Moonlight pollination in the gymnosperm Ephedra (Gnetales).
Rydin, Catarina; Bolinder, Kristina
2015-04-01
Most gymnosperms are wind-pollinated, but some are insect-pollinated, and in Ephedra (Gnetales), both wind pollination and insect pollination occur. Little is, however, known about mechanisms and evolution of pollination syndromes in gymnosperms. Based on four seasons of field studies, we show an unexpected correlation between pollination and the phases of the moon in one of our studied species, Ephedra foeminea. It is pollinated by dipterans and lepidopterans, most of them nocturnal, and its pollination coincides with the full moon of July. This may be adaptive in two ways. Many nocturnal insects navigate using the moon. Further, the spectacular reflection of the full-moonlight in the pollination drops is the only apparent means of nocturnal attraction of insects in these plants. In the sympatric but wind-pollinated Ephedra distachya, pollination is not correlated to the full moon but occurs at approximately the same dates every year. The lunar correlation has probably been lost in most species of Ephedra subsequent an evolutionary shift to wind pollination in the clade. When the services of insects are no longer needed for successful pollination, the adaptive value of correlating pollination with the full moon is lost, and conceivably also the trait. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
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Waterhouse, Benjamin; Wratten, Steve
2016-01-01
Ecosystem services (ES) such as pollination are vital for the continuous supply of food to a growing human population, but the decline in populations of insect pollinators worldwide poses a threat to food and nutritional security. Using a pollinator (honeybee) exclusion approach, we evaluated the impact of pollinator scarcity on production in four brassica fields, two producing hybrid seeds and two producing open-pollinated ones. There was a clear reduction in seed yield as pollination rates declined. Open-pollinated crops produced significantly higher yields than did the hybrid ones at all pollination rates. The hybrid crops required at least 0.50 of background pollination rates to achieve maximum yield, whereas in open-pollinated crops, 0.25 pollination rates were necessary for maximum yield. The total estimated economic value of pollination services provided by honeybees to the agricultural industry in New Zealand is NZD $1.96 billion annually. This study indicates that loss of pollination services can result in significant declines in production and have serious implications for the market economy in New Zealand. Depending on the extent of honeybee population decline, and assuming that results in declining pollination services, the estimated economic loss to New Zealand agriculture could be in the range of NZD $295–728 million annually. PMID:27441108
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Pollinators visit related plant species across 29 plant–pollinator networks
Vamosi, Jana C; Moray, Clea M; Garcha, Navdeep K; Chamberlain, Scott A; Mooers, Arne Ø
2014-01-01
Understanding the evolution of specialization in host plant use by pollinators is often complicated by variability in the ecological context of specialization. Flowering communities offer their pollinators varying numbers and proportions of floral resources, and the uniformity observed in these floral resources is, to some degree, due to shared ancestry. Here, we find that pollinators visit related plant species more so than expected by chance throughout 29 plant–pollinator networks of varying sizes, with “clade specialization” increasing with community size. As predicted, less versatile pollinators showed more clade specialization overall. We then asked whether this clade specialization varied with the ratio of pollinator species to plant species such that pollinators were changing their behavior when there was increased competition (and presumably a forced narrowing of the realized niche) by examining pollinators that were present in at least three of the networks. Surprisingly, we found little evidence that variation in clade specialization is caused by pollinator species changing their behavior in different community contexts, suggesting that clade specialization is observed when pollinators are either restricted in their floral choices due to morphological constraints or innate preferences. The resulting pollinator sharing between closely related plant species could result in selection for greater pollinator specialization. PMID:25360269
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Salas-Arcos, Lucía; Ornelas, Juan Francisco
2017-01-01
Background In many plant species, pollination syndromes predict the most effective pollinator. However, other floral visitors may also offer effective pollination services and promote mixed pollination systems. Several species of the species-rich Penstemon (Plantaginaceae) exhibit a suite of floral traits that suggest adaptation for pollination by both hymenopterans and hummingbirds. Transitions from the ancestral hymenopteran pollination syndrome to more derived hummingbird pollination syndrome may be promoted if the quantity or quality of visits by hummingbirds is increased and if the ancestral pollinator group performs less efficiently. The quantification of such shifts in pollination systems in the group is still limited. We aimed to investigate floral traits linked to this pollination syndrome in Penstemon gentianoides with flowers visited by bumblebees and hummingbirds. Methods We investigated the floral biology, pollinator assemblages, breeding system and nectar production patterns ofP. gentianoides inhabiting a temperate montane forest in central Mexico. Pollination experiments were also conducted to assess the pollinator effectiveness of bumblebees and hummingbirds. Results P. gentianoides flowers are protandrous, with 8-d male phase (staminate) flowers, followed by the ∼1–7 d female phase (pistillate phase). Flowers display traits associated with hymenopteran pollination, including purple flowers abruptly ampliate-ventricose to a broad throat with anthers and stigmas included, and long lifespans. However, the nectar available in the morning hours was abundant and dilute, traits linked to flowers with a hummingbird pollination syndrome. Two hummingbird species made most of the visits to flowers, Selasphorus platycercus (30.3% of all visits), followed by Archilochus colubris (11.3%). Bumblebees (Bombus ephippiatus, B. huntii and B. weisi) accounted for 51.8% of all recorded visits, but their foraging activity was restricted to the warmer hours. Hummingbirds made more foraging bouts and visited more flowers than hymenopteran species. Flowers experimentally pollinated by B. ephippiatus produced significantly more fruits than those pollinated by S. platycercus. However, there was no statistical difference in the number of seeds produced per fruit when a bumblebee or a hummingbird was the pollinator. Conclusions We have shown that bumblebees and hummingbirds visit and pollinate P. gentianoides flowers. Despite floral traits resembling the hymenoptera pollination syndrome, flowers of P. gentianoides offer characteristic nectar rewards to flowers with a hummingbird pollination syndrome. Although pollination efficiency is higher among flowers visited by hymenoptera, the noteworthy percentage of fruit production and number of seeds per fruit derived from hummingbird pollination highlights the importance of hummingbirds as a functional group of pollinators that might have potential evolutionary consequences to the plants. PMID:28828248
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Orchid sexual deceit provokes ejaculation.
Gaskett, A C; Winnick, C G; Herberstein, M E
2008-06-01
Sexually deceptive orchids lure pollinators by mimicking female insects. Male insects fooled into gripping or copulating with orchids unwittingly transfer the pollinia. The effect of deception on pollinators has been considered negligible, but we show that pollinators may suffer considerable costs. Insects pollinating Australian tongue orchids (Cryptostylis species) frequently ejaculate and waste copious sperm. The costs of sperm wastage could select for pollinator avoidance of orchids, thereby driving and maintaining sexual deception via antagonistic coevolution or an arms race between pollinator learning and escalating orchid mimicry. However, we also show that orchid species provoking such extreme pollinator behavior have the highest pollination success. How can deception persist, given the costs to pollinators? Sexually-deceptive-orchid pollinators are almost exclusively solitary and haplodiploid species. Therefore, female insects deprived of matings by orchid deception could still produce male offspring, which may even enhance orchid pollination.
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Kosior, Grzegorz; Steinnes, Eiliv; Samecka-Cymerman, Aleksandra; Lierhagen, Syverin; Kolon, Krzysztof; Dołhańczuk-Śródka, Agnieszka; Ziembik, Zbigniew
2017-03-01
The past uranium/polymetallic mining activities in the Sudety (SW Poland) left abandoned mines, pits, and dumps of waste rocks with trace elements and radionuclides which may erode or leach out and create a potential risk for the aquatic ecosystem, among others. In the present work four rivers affected by effluents from such mines were selected to evaluate the application of aquatic mosses for the bioindication of 56 elements. Naturally growing F. antipyretica and P. riparioides were compared with transplanted samples of the same species. The results demonstrate serious pollution of the examined rivers, especially with As, Ba, Fe, Mn, Pb, Ti, U and Zn, reaching extremely high concentrations in native moss samples. In the most polluted rivers native F. antipyretica and P. riparioides samples showed significantly higher concentrations of As, Ba, Cu, Fe, La, Nd, Ni, Pb, U and Zn than corresponding transplanted samples, whereas at less polluted sites a reverse situation was sometimes observed. Transplanted moss moved from clean to extremely polluted rivers probably protects itself against the accumulation of toxic elements by reducing their uptake. Selection of native or transplanted F. antipyretica and P. riparioides depended on the pollution load. Copyright © 2016. Published by Elsevier Ltd.
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Pollinator Foraging Adaptation and Coexistence of Competing Plants.
Revilla, Tomás A; Křivan, Vlastimil
2016-01-01
We use the optimal foraging theory to study coexistence between two plant species and a generalist pollinator. We compare conditions for plant coexistence for non-adaptive vs. adaptive pollinators that adjust their foraging strategy to maximize fitness. When pollinators have fixed preferences, we show that plant coexistence typically requires both weak competition between plants for resources (e.g., space or nutrients) and pollinator preferences that are not too biased in favour of either plant. We also show how plant coexistence is promoted by indirect facilitation via the pollinator. When pollinators are adaptive foragers, pollinator's diet maximizes pollinator's fitness measured as the per capita population growth rate. Simulations show that this has two conflicting consequences for plant coexistence. On the one hand, when competition between pollinators is weak, adaptation favours pollinator specialization on the more profitable plant which increases asymmetries in plant competition and makes their coexistence less likely. On the other hand, when competition between pollinators is strong, adaptation promotes generalism, which facilitates plant coexistence. In addition, adaptive foraging allows pollinators to survive sudden loss of the preferred plant host, thus preventing further collapse of the entire community.
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Wiemer, A P; Sérsic, A N; Marino, S; Simões, A O; Cocucci, A A
2012-01-01
BACKGROUND AND AIMS The extreme complexity of asclepiad flowers (Asclepiadoideae-Apocynaceae) has generated particular interest in the pollination biology of this group of plants especially in the mechanisms involved in the pollination processes. This study compares two South American species, Morrenia odorata and Morrenia brachystephana, with respect to morphology and anatomy of flower structures, dynamic aspects of the pollination mechanism, diversity of visitors and effectiveness of pollinators. Floral structure was studied with fresh and fixed flowers following classical techniques. The pollination mechanism was studied by visiting fresh flowers in the laboratory with artificial pollinator body parts created with an eyelash. Morphometric and nectar measurements were also taken. Pollen transfer efficiency in the flowers was calculated by recording the frequency of removed and inserted pollinia. Visitor activity was recorded in the field, and floral visitors were captured for subsequent analysis of pollen loads. Finally, pollinator effectiveness was calculated with an index. The detailed structure of the flowers revealed a complex system of guide rails and chambers precisely arranged in order to achieve effective pollinaria transport. Morrenia odorata is functionally specialized for wasp pollination, and M. brachystephana for wasp and bee pollination. Pollinators transport chains of pollinaria adhered to their mouthparts. Morrenia odorata and M. brachystephana present differences in the morphology and size of their corona, gynostegium and pollinaria, which explain the differences in details of the functioning of the general pollination mechanism. Pollination is performed by different groups of highly effective pollinators. Morrenia species are specialized for pollination mainly by several species of wasps, a specialized pollination which has been poorly studied. In particular, pompilid wasps are reported as important pollinators in other regions outside South Africa. A putative new function of nectar in asclepiads is presented, as it would be contributing to the pollination mechanism.
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More than euglossines: the diverse pollinators and floral scents of Zygopetalinae orchids.
Nunes, Carlos E P; Wolowski, Marina; Pansarin, Emerson Ricardo; Gerlach, Günter; Aximoff, Izar; Vereecken, Nicolas J; Salvador, Marcos José; Sazima, Marlies
2017-10-13
Floral volatile organic compounds (VOCs) play important roles in plant-pollinator interactions. We investigated the reproductive ecology and floral VOCs of Zygopetalinae orchids to understand the relationship between floral scents and pollinators. We performed focal observations, phenological censuses and breeding system experiments in eight species in southeast Brazil. Floral scents were collected and analysed using SPME/GC-MS. We performed multivariate analyses to group species according to affinities of their VOCs and define compounds associated to each plant. Dichaea cogniauxiana was pollinated by weevils which use their developing ovules, while D. pendula was pollinated by the same weevils and perfume-collecting male euglossine bees. The other species were deceit-pollinated by bees. Zygopetalum crinitum was pollinated by carpenter bees, while W. warreana, Z. mackayi and Z. maxillare were bumblebee-pollinated. The latter was also pollinated by Centris confusa. Breeding system varied widely with no association to any pollinator group. Most VOCs are common to other floral scents. Zygopetalum crinitum presented an exclusive blend of VOCs, mainly composed of benzenoids. The scents of Pabstia jugosa, Promenaea xanthina and the Zygopetalum spp. were similar. The bumblebee-pollinated species have flowering periods partially overlapped, thus neither phenology nor pollinators constitute hybridization barriers among these species. Euglossines are not the only pollinators of Zygopetalinae. Different VOCs, size and lifespan of flowers are associated with distinct pollinators. A distinctive VOC bouquet may determine specialisation in carpenter bees or male euglossines within bee-pollinated flowers. Finally, visitation of deceit-pollinated flowers by perfume-collecting euglossines allows us to hypothesise how pollination by this group of bees had evolved.
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Apple Pollination: Demand Depends on Variety and Supply Depends on Pollinator Identity
Garratt, M. P. D.; Breeze, T. D.; Boreux, V.; Coston, D. J.; Jenner, N.; Dean, R.; Westbury, D. B.; Biesmeijer, J. C.; Potts, S. G.
2016-01-01
Insect pollination underpins apple production but the extent to which different pollinator guilds supply this service, particularly across different apple varieties, is unknown. Such information is essential if appropriate orchard management practices are to be targeted and proportional to the potential benefits pollinator species may provide. Here we use a novel combination of pollinator effectiveness assays (floral visit effectiveness), orchard field surveys (flower visitation rate) and pollinator dependence manipulations (pollinator exclusion experiments) to quantify the supply of pollination services provided by four different pollinator guilds to the production of four commercial varieties of apple. We show that not all pollinators are equally effective at pollinating apples, with hoverflies being less effective than solitary bees and bumblebees, and the relative abundance of different pollinator guilds visiting apple flowers of different varieties varies significantly. Based on this, the taxa specific economic benefits to UK apple production have been established. The contribution of insect pollinators to the economic output in all varieties was estimated to be £92.1M across the UK, with contributions varying widely across taxa: solitary bees (£51.4M), honeybees (£21.4M), bumblebees (£18.6M) and hoverflies (£0.7M). This research highlights the differences in the economic benefits of four insect pollinator guilds to four major apple varieties in the UK. This information is essential to underpin appropriate investment in pollination services management and provides a model that can be used in other entomolophilous crops to improve our understanding of crop pollination ecology. PMID:27152628
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Apple Pollination: Demand Depends on Variety and Supply Depends on Pollinator Identity.
Garratt, M P D; Breeze, T D; Boreux, V; Fountain, M T; McKerchar, M; Webber, S M; Coston, D J; Jenner, N; Dean, R; Westbury, D B; Biesmeijer, J C; Potts, S G
2016-01-01
Insect pollination underpins apple production but the extent to which different pollinator guilds supply this service, particularly across different apple varieties, is unknown. Such information is essential if appropriate orchard management practices are to be targeted and proportional to the potential benefits pollinator species may provide. Here we use a novel combination of pollinator effectiveness assays (floral visit effectiveness), orchard field surveys (flower visitation rate) and pollinator dependence manipulations (pollinator exclusion experiments) to quantify the supply of pollination services provided by four different pollinator guilds to the production of four commercial varieties of apple. We show that not all pollinators are equally effective at pollinating apples, with hoverflies being less effective than solitary bees and bumblebees, and the relative abundance of different pollinator guilds visiting apple flowers of different varieties varies significantly. Based on this, the taxa specific economic benefits to UK apple production have been established. The contribution of insect pollinators to the economic output in all varieties was estimated to be £92.1M across the UK, with contributions varying widely across taxa: solitary bees (£51.4M), honeybees (£21.4M), bumblebees (£18.6M) and hoverflies (£0.7M). This research highlights the differences in the economic benefits of four insect pollinator guilds to four major apple varieties in the UK. This information is essential to underpin appropriate investment in pollination services management and provides a model that can be used in other entomolophilous crops to improve our understanding of crop pollination ecology.
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Dar, Saleem; del Coro Arizmendi, Ma; Valiente-Banuet, Alfonso
2006-03-01
Chiropterophillous and ornithophillous characteristics can form part of a single reproductive strategy in plants that have flowers with diurnal and nocturnal anthesis. This broader pollination strategy can ensure seed set when pollinators are scarce or unpredictable. This appears to be true of hummingbirds, which presumably pollinate Marginatocereus marginatus, a columnar cactus with red nocturnal and diurnal flowers growing as part of dense bat-pollinated columnar cacti forests in arid regions of central Mexico. The aim of this study was to study the floral biology of M. marginatus, and evaluate the effectiveness of nocturnal vs. diurnal pollinators and the contribution of each pollinator group to overall plant fitness. Individual flower buds were marked and followed to evaluate flower phenology and anthesis time. Flowers and nectar production were measured. An exclusion experiment was conducted to measure the relative contribution of nocturnal and diurnal pollinators to seed set. Marginatocereus marginatus has red hermaphroditic flowers with nocturnal and diurnal anthesis. The plant cannot produce seeds by selfing and was pollinated during the day by hummingbirds and during the night by bats, demonstrating that both pollinator groups were important for plant reproduction. Strong pollen limitation was found in the absence of one of the pollinator guilds. Marginatocereus marginatus has an open pollination system in which both diurnal and nocturnal pollinators are needed to set seeds. This represents a fail-safe pollination system that can ensure both pollination, in a situation of low abundance of one of the pollinator groups (hummingbirds), and high competition for nocturnal pollinators with other columnar cacti that bloom synchronously with M. marginatus in the Tehuacan Valley, Mexico.
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Wu, Yun; Li, Qing-Jun
2017-10-01
Floral traits have largely been attributed to phenotypic selection in plant-pollinator interactions. However, the strength of this link has rarely been ascertained with real pollinators. We conducted pollinator observations and estimated selection through female fitness on flowering phenology and floral traits between two Primula secundiflora populations. We quantified pollinator-mediated selection by subtracting estimates of selection gradients of plants receiving supplemental hand pollination from those of plants receiving open pollination. There was net directional selection for an earlier flowering start date at populations where the dominant pollinators were syrphid flies, and flowering phenology was also subjected to stabilized quadratic selection. However, a later flowering start date was significantly selected at populations where the dominant pollinators were legitimate (normal pollination through the corolla tube entrance) and illegitimate bumblebees (abnormal pollination through nectar robbing hole which located at the corolla tube), and flowering phenology was subjected to disruptive quadratic selection. Wider corolla tube entrance diameter was selected at both populations. Furthermore, the strength of net directional selection on flowering start date and corolla tube entrance diameter was stronger at the population where the dominant pollinators were syrphid flies. Pollinator-mediated selection explained most of the between-population variations in the net directional selection on flowering phenology and corolla tube entrance diameter. Our results suggested the important influence of pollinator-mediated selection on floral evolution. Variations in pollinator assemblages not only resulted in variation in the direction of selection but also the strength of selection on floral traits.
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Landowner and practitioner perspectives on private land conservation programs
Lute, Michelle L.; Gillespie, Caitlyn R.; Fontaine, Joseph J.; Martin, Dustin R.
2018-01-01
Efforts to reverse declines in native grasslands benefit from agricultural policies that encourage private land conservation. The U.S. Department of Agriculture’s Conservation Reserve Program (CRP) improved conservation across landscapes but enrollment has declined. We used sequential exploratory mixed methods to compare landowner and conservation practitioners’ perceptions, evaluate perceived benefits, and identify potential improvements to CRP. Focus groups of practitioners informed a quantitative survey of landowners who had properties >160 total acres in Nebraska. Results suggest potential misalignment in perceptions between practitioners and landowners. Practitioners were concerned that conservation, especially of wildlife, was secondary to profit. But the majority of landowners valued CRP-related ecosystem services, including native pollinators. Practitioners posited that younger landowners were primarily profit motivated, but CRP enrollment did not differ by demographics. Practitioners and landowners identified rule complexity as a major challenge and practitioner–landowner relationships as critical to success. Findings suggest that practitioners may underestimate non-economic motivations and illuminate opportunities to encourage private land conservation.
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Scott, Zachary; Ginsberg, Howard; Alm, Steven R.
2016-01-01
We identified 41 species of native bees from a total of 1,083 specimens collected at cultivated highbush blueberry plantings throughout Rhode Island in 2014 and 2015. Andrena spp., Bombus spp., and Xylocopa virginica (L.) were collected most often. Bombus griseocollis (DeGeer), B. impatiens Cresson, B. bimaculatus Cresson, B. perplexus Cresson, and Andrena vicina Smith collected the largest mean numbers of blueberry pollen tetrads. The largest mean percent blueberry pollen loads were carried by the miner bees Andrena bradleyi Viereck (91%), A. carolina Viereck (90%), and Colletes validus Cresson (87%). The largest mean total pollen grain loads were carried by B. griseocollis (549,844), B. impatiens (389,558), X. virginica (233,500), and B. bimaculatus (193,132). Xylocopa virginica was the fourth and fifth most commonly collected bee species in 2014 and 2015, respectively. They exhibit nectar robbing and females carried relatively low blueberry pollen loads (mean 33%). Overall, we found 10 species of bees to be the primary pollinators of blueberries in Rhode Island.
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Organic Farming Improves Pollination Success in Strawberries
Andersson, Georg K. S.; Rundlöf, Maj; Smith, Henrik G.
2012-01-01
Pollination of insect pollinated crops has been found to be correlated to pollinator abundance and diversity. Since organic farming has the potential to mitigate negative effects of agricultural intensification on biodiversity, it may also benefit crop pollination, but direct evidence of this is scant. We evaluated the effect of organic farming on pollination of strawberry plants focusing on (1) if pollination success was higher on organic farms compared to conventional farms, and (2) if there was a time lag from conversion to organic farming until an effect was manifested. We found that pollination success and the proportion of fully pollinated berries were higher on organic compared to conventional farms and this difference was already evident 2–4 years after conversion to organic farming. Our results suggest that conversion to organic farming may rapidly increase pollination success and hence benefit the ecosystem service of crop pollination regarding both yield quantity and quality. PMID:22355380
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Lau, Jenny Y. Y.; Guo, Xing; Pang, Chun-Chiu; Tang, Chin Cheung; Thomas, Daniel C.; Saunders, Richard M. K.
2017-01-01
Several evolutionary lineages in the early divergent angiosperm family Annonaceae possess flowers with a distinctive pollinator trapping mechanism, in which floral phenological events are very precisely timed in relation with pollinator activity patterns. This contrasts with previously described angiosperm pollinator traps, which predominantly function as pitfall traps. We assess the circadian rhythms of pollinators independently of their interactions with flowers, and correlate these data with detailed assessments of floral phenology. We reveal a close temporal alignment between patterns of pollinator activity and the floral phenology driving the trapping mechanism (termed ‘circadian trapping’ here). Non-trapping species with anthesis of standard duration (c. 48 h) cannot be pollinated effectively by pollinators with a morning-unimodal activity pattern; non-trapping species with abbreviated anthesis (23–27 h) face limitations in utilizing pollinators with a bimodal circadian activity; whereas species that trap pollinators (all with short anthesis) can utilize a broader range of potential pollinators, including those with both unimodal and bimodal circadian rhythms. In addition to broadening the range of potential pollinators based on their activity patterns, circadian trapping endows other selective advantages, including the possibility of an extended staminate phase to promote pollen deposition, and enhanced interfloral movement of pollinators. The relevance of the alignment of floral phenological changes with peaks in pollinator activity is furthermore evaluated for pitfall trap pollination systems. PMID:28713403
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Interaction intensity and pollinator-mediated selection.
Trunschke, Judith; Sletvold, Nina; Ågren, Jon
2017-05-01
In animal-pollinated plants, the opportunity for selection and the strength of pollinator-mediated selection are expected to increase with the degree of pollen limitation. However, whether differences in pollen limitation can explain variation in pollinator-mediated and net selection among animal-pollinated species is poorly understood. In the present study, we quantified pollen limitation, variance in relative fitness and pollinator-mediated selection on five traits important for pollinator attraction (flowering start, plant height, flower number, flower size) and pollination efficiency (spur length) in natural populations of 12 orchid species. Pollinator-mediated selection was quantified by subtracting estimates of selection gradients for plants receiving supplemental hand-pollination from estimates obtained for open-pollinated control plants. Mean pollen limitation ranged from zero to 0.96. Opportunity for selection, pollinator-mediated selection and net selection were all positively related to pollen limitation, whereas nonpollinator-mediated selection was not. Opportunity for selection varied five-fold, strength of pollinator-mediated selection varied three-fold and net selection varied 1.5-fold among species. Supplemental hand-pollination reduced both opportunity for selection and selection on floral traits. The results show that the intensity of biotic interactions is an important determinant of the selection regime, and indicate that the potential for pollinator-mediated selection and divergence in floral traits is particularly high in species that are strongly pollen-limited. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.
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NASA Astrophysics Data System (ADS)
Valido, Alfredo; Dupont, Yoko L.; Hansen, Dennis M.
2002-12-01
In this paper, we report observations of flower visitors of the endemic Echium wildpretii in Tenerife, Canary Islands. This plant inhabits the high altitudinal sub-alpine zone, which is characterized by a harsh climate, low species diversity and a short growing season. Echium wildpretii is a monocarpic perennial, producing a 2-3 m column-shaped, red-flowered, nectar-rich inflorescence. Although these floral traits have previously been suggested as being typical of ornithophilous flowers, this is the first study reporting observations of native birds ( Phylloscopus collybita and Serinus canarius) in addition to insects visiting the flowers for nectar. The purposes of this study were firstly to investigate levels of visitation by native birds, native insects, and introduced honey bees. Secondly, we studied the influence of floral display (plant height and number of flowers), nearest neighbours (distance and size) and local vegetation structure on visitation rate. Finally, we discuss the evolution of ornithophily in an otherwise entomophilous plant lineage. We found that the level of bird visitation was relatively high early in the flowering season, but decreased in mid/late season, while the opposite pattern was found for introduced honey bees. For native insects, the frequency of visits was similar in early and late season. Bird visits were correlated with floral display. In the early season, visitation rates of honey bees and the two most common native bee species were correlated with size of the plant or its nearest neighbours, consistent with preference patterns for larger resource patches. Since only insects visit the flowers of other species in the Echium clade, E. wildpretii appears to have evolved from a truly insect-pollinated lineage.
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Chapurlat, Elodie; Ågren, Jon; Sletvold, Nina
2015-12-01
Spatial variation in plant-pollinator interactions may cause variation in pollinator-mediated selection on floral traits, but to establish this link conclusively experimental studies are needed. We quantified pollinator-mediated selection on flowering phenology and morphology in four populations of the fragrant orchid Gymnadenia conopsea, and compared selection mediated by diurnal and nocturnal pollinators in two of the populations. Variation in pollinator-mediated selection explained most of the among-population variation in the strength of directional and correlational selection. Pollinators mediated correlational selection on pairs of display traits, and on one display trait and spur length, a trait affecting pollination efficiency. Only nocturnal pollinators selected for longer spurs, and mediated stronger selection on the number of flowers compared with diurnal pollinators in one population. The two types of pollinators caused correlational selection on different pairs of traits and selected for different combinations of spur length and number of flowers. The results demonstrate that spatial variation in interactions with pollinators may result in differences in directional and correlational selection on floral traits in a plant with a semi-generalized pollination system, and suggest that differences in the relative importance of diurnal and nocturnal pollinators can cause variation in selection. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
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Wind-dragged corolla enhances self-pollination: a new mechanism of delayed self-pollination.
Qu, Rongming; Li, Xiaojie; Luo, Yibo; Dong, Ming; Xu, Huanli; Chen, Xuan; Dafni, Amots
2007-12-01
Delayed self-pollination is a mechanism that allows animal-pollinated plants to outcross while ensuring seed production in the absence of pollinators. This study aims to explore a new mechanism of delayed self-pollination facilitated by wind-driven corolla abscission in Incarvillea sinensis var. sinensis. Floral morphology and development, and the process of delayed self-pollination were surveyed. Experiments dealing with pollinator and wind exclusion, pollination manipulations, and pollinator observations were conducted in the field. Delayed self-pollination occurs when the abscising corolla driven by wind drags the adherent epipetalous stamens, thus leading to contact of anthers with stigma in late anthesis. There is no dichogamy and self-incompatibility in this species. The significantly higher proportion of abscised corolla under natural conditions as compared with that in wind-excluding tents indicates the importance of wind in corolla abscission. When pollinators were excluded, corolla abscission significantly increased the number of pollen grains deposited on the stigma and, as a result, the fruit and seed set. Only half of the flowers in plots were visited by pollinators, and the fruit set of emasculated flowers was significantly lower than that of untreated flowers in open pollination. This species has a sensitive stigma, and its two open stigmatic lobes closed soon after being touched by a pollinator, but always reopened if no or only little pollen was deposited. This delayed self-pollination, which involved the movement of floral parts, the active participation of the wind and sensitive stigma, is quite different from that reported previously. This mechanism provides reproductive assurance for this species. The sensitive stigma contributes to ensuring seed production and reducing the interference of selfing with outcrossing. The pollination pattern, which combines actions by bees with indirect participation by wind, is also a new addition to ambophily.
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DAR, SALEEM; ARIZMENDI, Ma. del CORO; VALIENTE-BANUET, ALFONSO
2006-01-01
• Background and Aims Chiropterophillous and ornithophillous characteristics can form part of a single reproductive strategy in plants that have flowers with diurnal and nocturnal anthesis. This broader pollination strategy can ensure seed set when pollinators are scarce or unpredictable. This appears to be true of hummingbirds, which presumably pollinate Marginatocereus marginatus, a columnar cactus with red nocturnal and diurnal flowers growing as part of dense bat-pollinated columnar cacti forests in arid regions of central Mexico. The aim of this study was to study the floral biology of M. marginatus, and evaluate the effectiveness of nocturnal vs. diurnal pollinators and the contribution of each pollinator group to overall plant fitness. • Methods Individual flower buds were marked and followed to evaluate flower phenology and anthesis time. Flowers and nectar production were measured. An exclusion experiment was conducted to measure the relative contribution of nocturnal and diurnal pollinators to seed set. • Key Results Marginatocereus marginatus has red hermaphroditic flowers with nocturnal and diurnal anthesis. The plant cannot produce seeds by selfing and was pollinated during the day by hummingbirds and during the night by bats, demonstrating that both pollinator groups were important for plant reproduction. Strong pollen limitation was found in the absence of one of the pollinator guilds. • Conclusions Marginatocereus marginatus has an open pollination system in which both diurnal and nocturnal pollinators are needed to set seeds. This represents a fail-safe pollination system that can ensure both pollination, in a situation of low abundance of one of the pollinator groups (hummingbirds), and high competition for nocturnal pollinators with other columnar cacti that bloom synchronously with M. marginatus in the Tehuacan Valley, Mexico. PMID:16394025
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Management of arthropod pathogen vectors in North America: Minimizing adverse effects on pollinators
Ginsberg, Howard; Bargar, Timothy A.; Hladik, Michelle L.; Lubelczyk, Charles
2017-01-01
Tick and mosquito management is important to public health protection. At the same time, growing concerns about declines of pollinator species raise the question of whether vector control practices might affect pollinator populations. We report the results of a task force of the North American Pollinator Protection Campaign (NAPPC) that examined potential effects of vector management practices on pollinators, and how these programs could be adjusted to minimize negative effects on pollinating species. The main types of vector control practices that might affect pollinators are landscape manipulation, biocontrol, and pesticide applications. Some current practices already minimize effects of vector control on pollinators (e.g., short-lived pesticides and application-targeting technologies). Nontarget effects can be further diminished by taking pollinator protection into account in the planning stages of vector management programs. Effects of vector control on pollinator species often depend on specific local conditions (e.g., proximity of locations with abundant vectors to concentrations of floral resources), so planning is most effective when it includes collaborations of local vector management professionals with local experts on pollinators. Interventions can then be designed to avoid pollinators (e.g., targeting applications to avoid blooming times and pollinator nesting habitats), while still optimizing public health protection. Research on efficient targeting of interventions, and on effects on pollinators of emerging technologies, will help mitigate potential deleterious effects on pollinators in future management programs. In particular, models that can predict effects of integrated pest management on vector-borne pathogen transmission, along with effects on pollinator populations, would be useful for collaborative decision-making.
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Radiation of Pollination Systems in the Iridaceae of sub-Saharan Africa
GOLDBLATT, PETER; MANNING, JOHN C.
2006-01-01
• Background Seventeen distinct pollination systems are known for genera of sub-Saharan African Iridaceae and recurrent shifts in pollination system have evolved in those with ten or more species. Pollination by long-tongued anthophorine bees foraging for nectar and coincidentally acquiring pollen on some part of their bodies is the inferred ancestral pollination strategy for most genera of the large subfamilies Iridoideae and Crocoideae and may be ancestral for the latter. Derived strategies include pollination by long-proboscid flies, large butterflies, night-flying hovering and settling moths, hopliine beetles and sunbirds. Bee pollination is diverse, with active pollen collection by female bees occurring in several genera, vibratile systems in a few and non-volatile oil as a reward in one species. Long-proboscid fly pollination, which is apparently restricted to southern Africa, includes four separate syndromes using different sets of flies and plant species in different parts of the subcontinent. Small numbers of species use bibionid flies, short-proboscid flies or wasps for their pollination; only about 2 % of species use multiple pollinators and can be described as generalists. • Scope Using pollination observations for 375 species and based on repeated patterns of floral attractants and rewards, we infer pollination mechanisms for an additional 610 species. Matching pollination system to phylogeny or what is known about species relationships based on shared derived features, we infer repeated shifts in pollination system in some genera, as frequently as one shift for every five or six species of southern African Babiana or Gladiolus. Specialized systems using pollinators of one pollination group, or even a single pollinator species are the rule in the family. Shifts in pollination system are more frequent in genera of Crocoideae that have bilaterally symmetric flowers and a perianth tube, features that promote adaptive radiation by facilitating precise shifts in pollen placement, in conjunction with changes in flower colour, scent and tube length. • Conclusions Diversity of pollination systems explains in part the huge species diversity of Iridaceae in sub-Saharan Africa, and permits species packing locally. Pollination shifts are, however, seen as playing a secondary role in speciation by promoting reproductive isolation in peripheral, ecologically distinct populations in areas of diverse topography, climate and soils. Pollination of Iridaceae in Eurasia and the New World, where the family is also well represented, is poorly studied but appears less diverse, although pollination by both pollen- and oil-collecting bees is frequent and bird pollination rare. PMID:16377653
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Radiation of pollination systems in the Iridaceae of sub-Saharan Africa.
Goldblatt, Peter; Manning, John C
2006-03-01
Seventeen distinct pollination systems are known for genera of sub-Saharan African Iridaceae and recurrent shifts in pollination system have evolved in those with ten or more species. Pollination by long-tongued anthophorine bees foraging for nectar and coincidentally acquiring pollen on some part of their bodies is the inferred ancestral pollination strategy for most genera of the large subfamilies Iridoideae and Crocoideae and may be ancestral for the latter. Derived strategies include pollination by long-proboscid flies, large butterflies, night-flying hovering and settling moths, hopliine beetles and sunbirds. Bee pollination is diverse, with active pollen collection by female bees occurring in several genera, vibratile systems in a few and non-volatile oil as a reward in one species. Long-proboscid fly pollination, which is apparently restricted to southern Africa, includes four separate syndromes using different sets of flies and plant species in different parts of the subcontinent. Small numbers of species use bibionid flies, short-proboscid flies or wasps for their pollination; only about 2 % of species use multiple pollinators and can be described as generalists. Using pollination observations for 375 species and based on repeated patterns of floral attractants and rewards, we infer pollination mechanisms for an additional 610 species. Matching pollination system to phylogeny or what is known about species relationships based on shared derived features, we infer repeated shifts in pollination system in some genera, as frequently as one shift for every five or six species of southern African Babiana or Gladiolus. Specialized systems using pollinators of one pollination group, or even a single pollinator species are the rule in the family. Shifts in pollination system are more frequent in genera of Crocoideae that have bilaterally symmetric flowers and a perianth tube, features that promote adaptive radiation by facilitating precise shifts in pollen placement, in conjunction with changes in flower colour, scent and tube length. Diversity of pollination systems explains in part the huge species diversity of Iridaceae in sub-Saharan Africa, and permits species packing locally. Pollination shifts are, however, seen as playing a secondary role in speciation by promoting reproductive isolation in peripheral, ecologically distinct populations in areas of diverse topography, climate and soils. Pollination of Iridaceae in Eurasia and the New World, where the family is also well represented, is poorly studied but appears less diverse, although pollination by both pollen- and oil-collecting bees is frequent and bird pollination rare.
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Orchid pollination by sexual deception: pollinator perspectives.
Gaskett, A C
2011-02-01
The extraordinary taxonomic and morphological diversity of orchids is accompanied by a remarkable range of pollinators and pollination systems. Sexually deceptive orchids are adapted to attract specific male insects that are fooled into attempting to mate with orchid flowers and inadvertently acting as pollinators. This review summarises current knowledge, explores new hypotheses in the literature, and introduces some new approaches to understanding sexual deception from the perspective of the duped pollinator. Four main topics are addressed: (1) global patterns in sexual deception, (2) pollinator identities, mating systems and behaviours, (3) pollinator perception of orchid deceptive signals, and (4) the evolutionary implications of pollinator responses to orchid deception, including potential costs imposed on pollinators by orchids. A global list of known and putative sexually deceptive orchids and their pollinators is provided and methods for incorporating pollinator perspectives into sexual deception research are provided and reviewed. At present, almost all known sexually deceptive orchid taxa are from Australia or Europe. A few sexually deceptive species and genera are reported for New Zealand and South Africa. In Central and Southern America, Asia, and the Pacific many more species are likely to be identified in the future. Despite the great diversity of sexually deceptive orchid genera in Australia, pollination rates reported in the literature are similar between Australian and European species. The typical pollinator of a sexually deceptive orchid is a male insect of a species that is polygynous, monandrous, haplodiploid, and solitary rather than social. Insect behaviours involved in the pollination of sexually deceptive orchids include pre-copulatory gripping of flowers, brief entrapment, mating, and very rarely, ejaculation. Pollinator behaviour varies within and among pollinator species. Deception involving orchid mimicry of insect scent signals is becoming well understood for some species, but visual and tactile signals such as colour, shape, and texture remain neglected. Experimental manipulations that test for function, multi-signal interactions, and pollinator perception of these signals are required. Furthermore, other forms of deception such as exploitation of pollinator sensory biases or mating preferences merit more comprehensive investigation. Application of molecular techniques adapted from model plants and animals is likely to deliver new insights into orchid signalling, and pollinator perception and behaviour. There is little current evidence that sexual deception drives any species-level selection on pollinators. Pollinators do learn to avoid deceptive orchids and their locations, but this is not necessarily a response specific to orchids. Even in systems where evidence suggests that orchids do interfere with pollinator mating opportunities, considerable further research is required to determine whether this is sufficient to impose selection on pollinators or generate antagonistic coevolution or an arms race between orchids and their pollinators. Botanists, taxonomists and chemical ecologists have made remarkable progress in the study of deceptive orchid pollination. Further complementary investigations from entomology and behavioural ecology perspectives should prove fascinating and engender a more complete understanding of the evolution and maintenance of such enigmatic plant-animal interactions. © 2010 The Author. Biological Reviews © 2010 Cambridge Philosophical Society.
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Cone and seed yields from controlled breeding of southern pines
E. B. Snyder; A. E. Squillace
1966-01-01
Over a 10-year period, survivals of cones from controlled cross-pollinations were less than 40 percent, and seed yields per cone averaged about half those from wind-pollinations. Self-pollinations produced about 15 percent as much seed as cross-pollinations. Interspecific pollinations were generally less productive than intraspecific pollinations.
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Wiemer, A. P.; Sérsic, A. N.; Marino, S.; Simões, A. O.; Cocucci, A. A.
2012-01-01
Background and Aims The extreme complexity of asclepiad flowers (Asclepiadoideae–Apocynaceae) has generated particular interest in the pollination biology of this group of plants especially in the mechanisms involved in the pollination processes. This study compares two South American species, Morrenia odorata and Morrenia brachystephana, with respect to morphology and anatomy of flower structures, dynamic aspects of the pollination mechanism, diversity of visitors and effectiveness of pollinators. Methods Floral structure was studied with fresh and fixed flowers following classical techniques. The pollination mechanism was studied by visiting fresh flowers in the laboratory with artificial pollinator body parts created with an eyelash. Morphometric and nectar measurements were also taken. Pollen transfer efficiency in the flowers was calculated by recording the frequency of removed and inserted pollinia. Visitor activity was recorded in the field, and floral visitors were captured for subsequent analysis of pollen loads. Finally, pollinator effectiveness was calculated with an index. Key Results The detailed structure of the flowers revealed a complex system of guide rails and chambers precisely arranged in order to achieve effective pollinaria transport. Morrenia odorata is functionally specialized for wasp pollination, and M. brachystephana for wasp and bee pollination. Pollinators transport chains of pollinaria adhered to their mouthparts. Conclusions Morrenia odorata and M. brachystephana present differences in the morphology and size of their corona, gynostegium and pollinaria, which explain the differences in details of the functioning of the general pollination mechanism. Pollination is performed by different groups of highly effective pollinators. Morrenia species are specialized for pollination mainly by several species of wasps, a specialized pollination which has been poorly studied. In particular, pompilid wasps are reported as important pollinators in other regions outside South Africa. A putative new function of nectar in asclepiads is presented, as it would be contributing to the pollination mechanism. PMID:22025522
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Effects of pollination timing and distance on seed production in a dioecious weed Silene latifolia
NASA Astrophysics Data System (ADS)
Anderson, Jay F.; Duddu, Hema S. N.; Shirtliffe, Steven J.; Benaragama, Dilshan; Syrovy, Lena D.; Stanley, Katherine A.; Haile, Teketel A.
2015-11-01
Silene latifolia Poir. (white cockle or white campion) is an important invasive weed in North American agriculture. It exhibits dioecy, therefore, both male and female plants are required in order for seed production to occur. However, dioecious species being invasive is not common because of their limitations in pollination and subsequent seed production. The objective of this study is to determine the effect of pollination timing and distance on seed production of Silene latifolia. A series of experiments including pollination exclusion, timing and pollination distance were conducted in 2009 and 2010 at or around Saskatoon, Saskatchewan. For pollination exclusion, exclosures were built around the natural female plants for exclosure, sham-exclosure, and male and female combined treatments. Pollination timing was studied by applying exclosure, non-exclosure, night-exclosure, and day-exclosure treatments to individual female plants. Female plants were transplanted along a linear interval at six different distances from the pollen source to study the effect of pollination distance. S. latifolia was exclusively insect-pollinated and pollination occurred both day and night; however, in one year, pollination occurred mainly at night. Female plants that were in the range of 0-4 m from a compatible pollen source experienced no limitation to pollination. However, when the distance was increased further up to 128 m, pollination levels and subsequent seed production were declined. Moreover, there were differences in seed production between years suggesting that pollination was affected by the environmental conditions during pollination and the crop that white cockle was grown in. These experiments indicate that seed production in S. latifolia is limited by insect-pollination. Although there was pollination limitation for seed production at greater distances from a pollen source, the high fecundity rate (3000-18000 seeds per plant) resulted in a large seed output. Thus, we believe that a dioecious species may require characteristics that compensate the pollination limitation for a successful invasion.
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Dynamics of an ant-plant-pollinator model
NASA Astrophysics Data System (ADS)
Wang, Yuanshi; DeAngelis, Donald L.; Nathaniel Holland, J.
2015-03-01
In this paper, we consider plant-pollinator-ant systems in which plant-pollinator interaction and plant-ant interaction are both mutualistic, but there also exists interference of pollinators by ants. The plant-pollinator interaction can be described by a Beddington-DeAngelis formula, so we extend the formula to characterize plant-pollinator mutualisms, including the interference by ants, and form a plant-pollinator-ant model. Using dynamical systems theory, we show uniform persistence of the model. Moreover, we demonstrate conditions under which boundary equilibria are globally asymptotically stable. The dynamics exhibit mechanisms by which the three species could coexist when ants interfere with pollinators. We define a threshold in ant interference. When ant interference is strong, it can drive plant-pollinator mutualisms to extinction. Furthermore, if the ants depend on pollination mutualism for their persistence, then sufficiently strong ant interference could lead to their own extinction as well. Yet, when ant interference is weak, plant-ant and plant-pollinator mutualisms can promote the persistence of one another.
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Johnson, Steven D.
2010-01-01
The flora of southern Africa has exceptional species richness and endemism, making it an ideal system for studying the patterns and processes of evolutionary diversification. Using a wealth of recent case studies, I examine the evidence for pollinator-driven diversification in this flora. Pollination systems, which represent available niches for ecological diversification, are characterized in southern Africa by a high level of ecological and evolutionary specialization on the part of plants, and, in some cases, by pollinators as well. These systems are asymmetric, with entire plant guilds commonly specialized for a particular pollinator species or functional type, resulting in obvious convergent floral evolution among guild members. Identified modes of plant lineage diversification involving adaptation to pollinators in these guilds include (i) shifts between pollination systems, (ii) divergent use of the same pollinator, (iii) coevolution, (iv) trait tracking, and (v) floral mimicry of different model species. Microevolutionary studies confirm that pollinator shifts can be precipitated when a plant species encounters a novel pollinator fauna on its range margin, and macroevolutionary studies confirm frequent pollinator shifts associated with lineage diversification. As Darwin first noted, evolutionary specialization for particular pollinators, when resulting in ecological dependency, may increase the risk of plant extinction. I thus also consider the evidence that disturbance provokes pollination failure in some southern African plants with specialized pollination systems. PMID:20047876
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Competition for pollinators and intra-communal spectral dissimilarity of flowers.
van der Kooi, C J; Pen, I; Staal, M; Stavenga, D G; Elzenga, J T M
2016-01-01
Competition for pollinators occurs when, in a community of flowering plants, several simultaneously flowering plant species depend on the same pollinator. Competition for pollinators increases interspecific pollen transfer rates, thereby reducing the number of viable offspring. In order to decrease interspecific pollen transfer, plant species can distinguish themselves from competitors by having a divergent phenotype. Floral colour is an important signalling cue to attract potential pollinators and thus a major aspect of the flower phenotype. In this study, we analysed the amount of spectral dissimilarity of flowers among pollinator-competing plants in a Dutch nature reserve. We expected pollinator-competing plants to exhibit more spectral dissimilarity than non-competing plants. Using flower visitation data of 2 years, we determined the amount of competition for pollinators by different plant species. Plant species that were visited by the same pollinator were considered specialist and competing for that pollinator, whereas plant species visited by a broad array of pollinators were considered non-competing generalists. We used principal components analysis to quantify floral reflectance, and found evidence for enhanced spectral dissimilarity among plant species within specialist pollinator guilds (i.e. groups of plant species competing for the same pollinator). This is the first study that examined intra-communal dissimilarity in floral reflectance with a focus on the pollination system. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Johnson, Steven D
2010-02-12
The flora of southern Africa has exceptional species richness and endemism, making it an ideal system for studying the patterns and processes of evolutionary diversification. Using a wealth of recent case studies, I examine the evidence for pollinator-driven diversification in this flora. Pollination systems, which represent available niches for ecological diversification, are characterized in southern Africa by a high level of ecological and evolutionary specialization on the part of plants, and, in some cases, by pollinators as well. These systems are asymmetric, with entire plant guilds commonly specialized for a particular pollinator species or functional type, resulting in obvious convergent floral evolution among guild members. Identified modes of plant lineage diversification involving adaptation to pollinators in these guilds include (i) shifts between pollination systems, (ii) divergent use of the same pollinator, (iii) coevolution, (iv) trait tracking, and (v) floral mimicry of different model species. Microevolutionary studies confirm that pollinator shifts can be precipitated when a plant species encounters a novel pollinator fauna on its range margin, and macroevolutionary studies confirm frequent pollinator shifts associated with lineage diversification. As Darwin first noted, evolutionary specialization for particular pollinators, when resulting in ecological dependency, may increase the risk of plant extinction. I thus also consider the evidence that disturbance provokes pollination failure in some southern African plants with specialized pollination systems.
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Van der Niet, Timotheüs; Pirie, Michael D.; Shuttleworth, Adam; Johnson, Steven D.; Midgley, Jeremy J.
2014-01-01
Background and Aims According to the Grant–Stebbins model of pollinator-driven divergence, plants that disperse beyond the range of their specialized pollinator may adapt to a new pollination system. Although this model provides a compelling explanation for pollination ecotype formation, few studies have directly tested its validity in nature. Here we investigate the distribution and pollination biology of several subspecies of the shrub Erica plukenetii from the Cape Floristic Region in South Africa. We analyse these data in a phylogenetic context and combine these results with information on pollinator ranges to test whether the evolution of pollination ecotypes is consistent with the Grant–Stebbins model. Methods and Key Results Pollinator observations showed that the most common form of E. plukenetii with intermediate corolla length is pollinated by short-billed Orange-breasted sunbirds. Populations at the northern fringe of the distribution are characterized by long corollas, and are mainly pollinated by long-billed Malachite sunbirds. A population with short corollas in the centre of the range was mainly pollinated by insects, particularly short-tongued noctuid moths. Bird exclusion in this population did not have an effect on fruit set, while insect exclusion reduced fruit set. An analysis of floral scent across the range, using coupled gas chromatography–mass spectrometry, showed that the scent bouquets of flowers from moth-pollinated populations are characterized by a larger number of scent compounds and higher emission rates than those in bird-pollinated populations. This was also reflected in clear separation of moth- and bird-pollinated populations in a two-dimensional phenotype space based on non-metric multidimensional scaling analysis of scent data. Phylogenetic analyses of chloroplast and nuclear DNA sequences strongly supported monophyly of E. plukenetii, but not of all the subspecies. Reconstruction of ancestral character states suggests two shifts from traits associated with short-billed Orange-breasted sunbird pollination: one towards traits associated with moth pollination, and one towards traits associated with pollination by long-billed Malachite sunbirds. The latter shift coincided with the colonization of Namaqualand in which Orange-breasted sunbirds are absent. Conclusions Erica plukenetii is characterized by three pollination ecotypes, but only the evolutionary transition from short- to long-billed sunbird pollination can be clearly explained by the Grant–Stebbins model. Corolla length is a key character for both ecotype transitions, while floral scent emission was important for the transition from bird to moth pollination. PMID:24071499
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Modularity, pollination systems, and interaction turnover in plant-pollinator networks across space.
Carstensen, Daniel W; Sabatino, Malena; Morellato, Leonor Patricia C
2016-05-01
Mutualistic interaction networks have been shown to be structurally conserved over space and time while pairwise interactions show high variability. In such networks, modularity is the division of species into compartments, or modules, where species within modules share more interactions with each other than they do with species from other modules. Such a modular structure is common in mutualistic networks and several evolutionary and ecological mechanisms have been proposed as underlying drivers. One prominent explanation is the existence of pollination syndromes where flowers tend to attract certain pollinators as determined by a set of traits. We investigate the modularity of seven community level plant-pollinator networks sampled in rupestrian grasslands, or campos rupestres, in SE Brazil. Defining pollination systems as corresponding groups of flower syndromes and pollinator functional groups, we test the two hypotheses that (1) interacting species from the same pollination system are more often assigned to the same module than interacting species from different pollination systems and; that (2) interactions between species from the same pollination system are more consistent across space than interactions between species from different pollination systems. Specifically we ask (1) whether networks are consistently modular across space; (2) whether interactions among species of the same pollination system occur more often inside modules, compared to interactions among species of different pollination systems, and finally; (3) whether the spatial variation in interaction identity, i.e., spatial interaction rewiring, is affected by trait complementarity among species as indicated by pollination systems. We confirm that networks are consistently modular across space and that interactions within pollination systems principally occur inside modules. Despite a strong tendency, we did not find a significant effect of pollination systems on the spatial consistency of pairwise interactions. These results indicate that the spatial rewiring of interactions could be constrained by pollination systems, resulting in conserved network structures in spite of high variation in pairwise interactions. Our findings suggest a relevant role of pollination systems in structuring plant-pollinator networks and we argue that structural patterns at the sub-network level can help us to fully understand how and why interactions vary across space and time.
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Azuma, Hiroshi; Harrison, Rhett D; Nakamura, Keiko; Su, Zhi-Hui
2010-01-01
The interaction between figs (Ficus, Moraceae) and fig-pollinating wasps (Chalcidoidea, Agaonidae) is one of the most specific mutualisms, and thus is a model system for studying coevolution and cospeciation. In this study we focused on figs and their associated fig-wasps found in the Ryukyu and Bonin (Ogasawara) Islands, Japan, because it has been suggested that breakdown in the specificity may occur in islands or at edge of a species' distribution. We collected 136 samples of 15 native fig species and 95 samples of 13 associated fig-wasps from all major islands in the Ryukyu Islands, including two fig species and one fig-wasp species endemic to the Bonin Islands. We performed molecular phylogenetic analyses using plastid DNA and nuclear ITS sequences for the figs and nuclear 28S rRNA and mitochondrial COI genes for the fig-wasps to investigate the interspecific phylogenies and intraspecific variation within the mutualism. Our phylogenetic analyses using multiple samples per species show the single clade of each fig (except the Bonin endemic species) and fig-pollinating wasp species. Fig species belonging to the same subgenera formed well-supported clades in both plastid and ITS trees, except for the subgenus Urostigma. Likewise, fig wasps emerging from host fig species belonging to the same subgenera formed mostly well supported clades in both 28S and COI trees. Host specificity between the figs and fig-wasps functions strictly in these islands. There was very little sequence variation within species, and that no major geographic structure was found. The two Bonin endemic species (F. boninsimae and F. nishimurae) or their common ancestor and the associated fig-wasps (Blastophaga sp.) are apparently derived from F. erecta and its associated fig-wasps (B. nipponica), respectively, and probably migrated from the Ryukyu Islands.
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NASA Astrophysics Data System (ADS)
Proffit, Magali; Bessière, Jean-Marie; Schatz, Bertrand; Hossaert-McKey, Martine
2018-07-01
Volatile organic compounds (VOCs) emitted by flowers play an essential role in mediating the attraction of pollinators. However, they also attract other species exploiting resources associated with flowers. For instance, VOCs emitted by figs play a major role in encounters between Ficus spp., their mutualistic pollinating wasps, and all the members of the community of non-pollinating fig wasps (NPFWs) that exploit the mutualistic interaction. Because pollinators might be in limited supply for a tree bearing many inflorescences, the plant might maximize its individual reproductive success by reducing the attractiveness of inflorescences once they are pollinated, so that pollinators orient only towards the tree's unpollinated figs. Changes in VOCs emission that bring this about could represent an important cue for NPFWs that exploit particular stages of fig development. In this study, by monitoring precisely the presence of fig-associated wasps on figs of F. racemosa, a common widespread fig species, we demonstrated that 4-5 days and 15 days following pollination represent two critical transitional steps in the succession of different wasp species. Then, focusing on the first one of these transitional steps, by investigating the composition of fig VOCs at receptivity and from 1 to 5 days following pollination, we detected progressive quantitative and qualitative variation of floral scent following pollination. These changes are significant at 5 days following pollination. The qualitative changes are mainly due to an increase in the relative proportions of two monoterpenes (α-pinene and limonene). These variations of the floral VOCs following pollination could explain why pollinating wasps stop visiting figs very shortly after the first pollinators enter receptive figs. They also possibly explain the succession of non-pollinating wasps on the figs following pollination.
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Fang, Qiang; Huang, Shuangquan
2016-05-01
Plant-pollinator interactions can be highly variable across years in natural communities. Although variation in the species composition and its basic structure has been investigated to understand the dynamic nature of pollination networks, little is known about the temporal dynamic of interaction strength between the same plant and pollinator species in any natural community. Pollinator-mediated selection on the evolution of floral traits could be diminished if plant-pollinator interactions vary temporally. To quantify the temporal variation in plant-pollinator interactions and the interaction strength (observed visits), we compared weighted networks between plants and pollinators in a biodiverse alpine meadow in Shangri-La, southwest China for 3 consecutive years. Although plant-pollinator interactions were highly dynamic such that identical interactions only accounted for 10.7% of the total between pair years, the diversity of interactions was stable. These identical interactions contributed 41.2% of total visits and were similar in strength and weighted nestedness. For plant species, 72.6% of species were visited by identical pollinator species between pair years, accounting for over half of the total visits and three-quarters at the functional group level. More generalized pollinators contributed more connectiveness and were more central in networks across years. However, there was no similar or even opposite trend for plant species, which suggested that specialized plant species may also be central in pollinator networks. The variation in pollinator composition decreased as pollinator species numbers increased, suggesting that generalized plants experienced stable pollinator partition. The stable, tight interactions between generalized pollinators and specialized plants represent cornerstones of the studied community. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.
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Lay, C. R.; Linhart, Y. B.; Diggle, P. K.
2011-01-01
Background and Aims Plants are sessile organisms that face selection by both herbivores and pollinators. Herbivores and pollinators may select on the same traits and/or mediate each others' effects. Erysimum capitatum (Brassicaceae) is a widespread and variable plant species with generalized pollination that is attacked by a number of herbivores. The following questions were addressed. (a) Are pollinators and herbivores attracted by similar plant traits? (b) Does herbivory affect pollinator preferences? (c) Do pollinators and/or herbivores affect fitness and select on plant traits? (d) Do plant compensatory responses affect the outcome of interactions among plants, pollinators and herbivores? (e) Do interactions among E. capitatum and its pollinators and herbivores differ among sites and years? Methods In 2005 and 2006, observational and experimental studies were combined in four populations at different elevations to examine selection by pollinators and herbivores on floral traits of E. capitatum. Key Results Pollinator and herbivore assemblages varied spatially and temporally, as did their effects on plant fitness and selection. Both pollinators and herbivores preferred plants with more flowers, and herbivory sometimes reduced pollinator visitation. Pollinators did not select on plant traits in any year or population and E. capitatum was not pollen limited; however, supplemental pollen resulted in altered plant resource allocation. Herbivores reduced fitness and selected for plant traits in some populations, and these effects were mediated by plant compensatory responses. Conclusions Individuals of Erysimum capitatum are visited by diverse groups of pollinators and herbivores that shift in abundance and importance in time and space. Compensatory reproductive mechanisms mediate interactions with both pollinators and herbivores and may allow E. capitatum to succeed in this complex selective environment. PMID:21724655
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Gómez, J. M.; Muñoz-Pajares, A. J.; Abdelaziz, M.; Lorite, J.; Perfectti, F.
2014-01-01
Background and Aims How generalist plants diverge in response to pollinator selection without becoming specialized is still unknown. This study explores this question, focusing on the evolution of the pollination system in the pollination generalist Erysimum mediohispanicum (Brassicaceae). Methods Pollinator assemblages were surveyed from 2001 to 2010 in 48 geo-referenced populations covering the entire geographic distribution of E. mediohispanicum. Bipartite modularity, a complex network tool, was used to find the pollination niche of each population. Evolution of the pollination niches and the correlated evolution of floral traits and pollination niches were explored using within-species comparative analyses. Key Results Despite being generalists, the E. mediohispanicum populations studied can be classified into five pollination niches. The boundaries between niches were not sharp, the niches differing among them in the relative frequencies of the floral visitor functional groups. The absence of spatial autocorrelation and phylogenetic signal indicates that the niches were distributed in a phylogeographic mosaic. The ancestral E. mediohispanicum populations presumably belonged to the niche defined by a high number of beetle and ant visits. A correlated evolution was found between pollination niches and some floral traits, suggesting the existence of generalist pollination ecotypes. Conclusions It is conjectured that the geographic variation in pollination niches has contributed to the observed floral divergence in E. mediohispanicum. The process mediating this floral divergence presumably has been adaptive wandering, but the adaptation to the local pollinator faunas has been not universal. The outcome is a landscape where a few populations locally adapted to their pollination environment (generalist pollination ecotypes) coexist with many populations where this local adaptation has failed and where the plant phenotype is not primarily shaped by pollinators. PMID:23965614
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Pollination and Plant Resources Change the Nutritional Quality of Almonds for Human Health
Brittain, Claire; Kremen, Claire; Garber, Andrea; Klein, Alexandra-Maria
2014-01-01
Insect-pollinated crops provide important nutrients for human health. Pollination, water and nutrients available to crops can influence yield, but it is not known if the nutritional value of the crop is also influenced. Almonds are an important source of critical nutrients for human health such as unsaturated fat and vitamin E. We manipulated the pollination of almond trees and the resources available to the trees, to investigate the impact on the nutritional composition of the crop. The pollination treatments were: (a) exclusion of pollinators to initiate self-pollination and (b) hand cross-pollination; the plant resource treatments were: (c) reduced water and (d) no fertilizer. In an orchard in northern California, trees were exposed to a single treatment or a combination of two (one pollination and one resource). Both the fat and vitamin E composition of the nuts were highly influenced by pollination. Lower proportions of oleic to linoleic acid, which are less desirable from both a health and commercial perspective, were produced by the self-pollinated trees. However, higher levels of vitamin E were found in the self-pollinated nuts. In some cases, combined changes in pollination and plant resources sharpened the pollination effects, even when plant resources were not influencing the nutrients as an individual treatment. This study highlights the importance of insects as providers of cross-pollination for fruit quality that can affect human health, and, for the first time, shows that other environmental factors can sharpen the effect of pollination. This contributes to an emerging field of research investigating the complexity of interactions of ecosystem services affecting the nutritional value and commercial quality of crops. PMID:24587215
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Fisogni, A; Rossi, M; Sgolastra, F; Bortolotti, L; Bogo, G; de Manincor, N; Quaranta, M; Galloni, M
2016-05-01
The interplay between insect and plant traits outlines the patterns of pollen transfer and the subsequent plant reproductive fitness. We studied the factors that affect the pollination efficiency of a pollinator community of Dictamnus albus L. by evaluating insect behaviour and morphological characteristics in relation to flowering phenology. In order to extrapolate the pollinator importance of single taxa and of the whole pollinator guild, we calculated an index distinguishing between potential (PPI) and realized (RPI) pollinator importance. Although the pollinator species spectrum appeared rather constant, we found high intra- and inter-annual variability of pollinator frequency and importance within the insect community. Flower visitation rate strictly depended on insect abundance and on the overlap between their flying period and flower blooming. All the pollinators visited flowers from the bottom to the top of the racemes, excluding intra-plant geitonogamous pollination, and most of them showed high pollen fidelity. Only medium large-sized bees could contact the upward bending stiles while feeding on nectar, highlighting a specialisation of the plant towards bigger pollinators. Moreover, we found evidence of functional specialisation, since all pollinators were restricted to a single taxonomic group (order: Hymenoptera; superfamily: Apoidea). Both the PPI and RPI indices indicate Habropoda tarsata as the most important pollinator of D. albus. Following hand cross-pollination experiments we revealed the presence of pollination limitation in 1 of the 3 years of field study. We discuss this result in relation to flowering abundance and to possible mismatches of phenological periods between plants and insects. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Polce, Chiara; Garratt, Michael P; Termansen, Mette; Ramirez-Villegas, Julian; Challinor, Andrew J; Lappage, Martin G; Boatman, Nigel D; Crowe, Andrew; Endalew, Ayenew Melese; Potts, Simon G; Somerwill, Kate E; Biesmeijer, Jacobus C
2014-01-01
Understanding how climate change can affect crop-pollinator systems helps predict potential geographical mismatches between a crop and its pollinators, and therefore identify areas vulnerable to loss of pollination services. We examined the distribution of orchard species (apples, pears, plums and other top fruits) and their pollinators in Great Britain, for present and future climatic conditions projected for 2050 under the SRES A1B Emissions Scenario. We used a relative index of pollinator availability as a proxy for pollination service. At present, there is a large spatial overlap between orchards and their pollinators, but predictions for 2050 revealed that the most suitable areas for orchards corresponded to low pollinator availability. However, we found that pollinator availability may persist in areas currently used for fruit production, which are predicted to provide suboptimal environmental suitability for orchard species in the future. Our results may be used to identify mitigation options to safeguard orchard production against the risk of pollination failure in Great Britain over the next 50 years; for instance, choosing fruit tree varieties that are adapted to future climatic conditions, or boosting wild pollinators through improving landscape resources. Our approach can be readily applied to other regions and crop systems, and expanded to include different climatic scenarios. PMID:24638986
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Evolution of pollination niches in a generalist plant clade.
Gómez, José María; Perfectti, Francisco; Abdelaziz, Mohamed; Lorite, Juan; Muñoz-Pajares, Antonio Jesús; Valverde, Javier
2015-01-01
It is widely assumed that floral diversification occurs by adaptive shifts between pollination niches. In contrast to specialized flowers, identifying pollination niches of generalist flowers is a challenge. Consequently, how generalist pollination niches evolve is largely unknown. We apply tools from network theory and comparative methods to investigate the evolution of pollination niches among generalist species belonging to the genus Erysimum. These species have similar flowers. We found that the studied species may be grouped in several multidimensional niches separated not by a shift of pollinators, but instead by quantitative variation in the relative abundance of pollinator functional groups. These pollination niches did not vary in generalization degree; we did not find any evolutionary trend toward specialization within the studied clade. Furthermore, the evolution of pollination niche fitted to a Brownian motion model without phylogenetic signal, and was characterized by frequent events of niche convergences and divergences. We presume that the evolution of Erysimum pollination niches has occurred mostly by recurrent shifts between slightly different generalized pollinator assemblages varying spatially as a mosaic and without any change in specialization degree. Most changes in pollination niches do not prompt floral divergence, a reason why adaptation to pollinators is uncommon in generalist plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.
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Geib, Jennifer C; Galen, Candace
2012-07-01
Partner abundance affects costs and benefits in obligate mutualisms, but its role in facultative partnerships is less clear. We address this gap in a pollination web consisting of two clovers (Trifolium) that differ in specialization on a bumble bee pollinator Bombus balteatus. We examine how pollination niche breadth affects plant responses to pollinator abundance, comparing early-flowering (specialized) and late-flowering (generalized) cohorts of T. parryi and early T. parryi to T. dasyphyllum, a pollination generalist. Co-pollinators disrupt the link between B. halteatus visitation and pollination rate for both clovers. Only for early-flowering T. parryi do visitation, pollination, and seed set increase with density of B. balteatus. Bumble bee density also alters timing of seed germination in T. parryi, with seeds from plants receiving augmented B. balteatus germinating sooner than seeds of open-pollinated counterparts. Benefits saturate at intermediate bumble bee densities. Despite strong effects of B. balteatus density on individual plant fitness components, population models suggest little impact of B. balteatus density on lamda in T. parryi or T. dasyphyllum. Findings show that functional redundancy in a pollinator guild mediates host-plant responses to partner density. Unexpected effects of pollinator density on life history schedule have implications for recruitment under pollinator decline.
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Pollinator-mediated natural selection in Penstemon digitalis.
Parachnowitsch, Amy; Kessler, André
2010-12-01
Measuring the agents of natural selection is important because it allows us to understand not only which traits are expected to evolve but also why they will evolve. Natural selection by pollinators on floral traits is often assumed because in outcrossing animal-pollinated plants flowers are generally thought to function as advertisements of rewards directed at pollinators. We tested the role of bee pollinators in selection on Penstemon digitalis and found that pollinators were driving selection for larger and more flowers. However, what makes our publication unique is the additional information we gained from reviewing the few other studies that also directly tested whether pollinators were agents of selection on floral traits. As we would expect if pollinators are important agents of selection, selection on floral traits was significantly stronger when pollinators were present than when they were experimentally removed. Taken together, these results suggest that pollinators can be important drivers of selection in contemporary populations.
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Real-time divergent evolution in plants driven by pollinators
Gervasi, Daniel D. L.; Schiestl, Florian P
2017-01-01
Pollinator-driven diversification is thought to be a major source of floral variation in plants. Our knowledge of this process is, however, limited to indirect assessments of evolutionary changes. Here, we employ experimental evolution with fast cycling Brassica rapa plants to demonstrate adaptive evolution driven by different pollinators. Our study shows pollinator-driven divergent selection as well as divergent evolution in plant traits. Plants pollinated by bumblebees evolved taller size and more fragrant flowers with increased ultraviolet reflection. Bumblebees preferred bumblebee-pollinated plants over hoverfly-pollinated plants at the end of the experiment, showing that plants had adapted to the bumblebees' preferences. Plants with hoverfly pollination became shorter, had reduced emission of some floral volatiles, but increased fitness through augmented autonomous self-pollination. Our study demonstrates that changes in pollinator communities can have rapid consequences on the evolution of plant traits and mating system. PMID:28291771
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A heterogeneous landscape does not guarantee high crop pollination
Hambäck, Peter A.; Lemessa, Debissa; Nemomissa, Sileshi; Hylander, Kristoffer
2016-01-01
The expansion of pollinator-dependent crops, especially in the developing world, together with reports of worldwide pollinator declines, raises concern of possible yield gaps. Farmers directly reliant on pollination services for food supply often live in regions where our knowledge of pollination services is poor. In a manipulative experiment replicated at 23 sites across an Ethiopian agricultural landscape, we found poor pollination services and severe pollen limitation in a common oil crop. With supplementary pollination, the yield increased on average by 91%. Despite the heterogeneous agricultural matrix, we found a low bee abundance, which may explain poor pollination services. The variation in pollen limitation was unrelated to surrounding forest cover, local bee richness and bee abundance. While practices that commonly increase pollinators (restricted pesticide use, flower strips) are an integral part of the landscape, these elements are apparently insufficient. Management to increase pollination services is therefore in need of urgent investigation. PMID:27629036
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Pollination effects on antioxidant content of Perilla frutescens seeds analysed by NMR spectroscopy.
Ferrazzi, Paola; Vercelli, Monica; Chakir, Amina; Romane, Abderrahmane; Mattana, Monica; Consonni, Roberto
2017-12-01
The effects of Perilla frutescens pollination on the content of seed antioxidants were analysed by agronomical and pollination trials, comparing seeds produced from bagged plants in 2013 (A) to prevent access to pollinating insects, and seeds from open-pollinated plants in 2013 (B) and 2015 (C). The seeds of open-pollinated plants were significantly more numerous and heavier than those of self-pollinated plants. 1 H NMR seed analysis showed a higher presence of phenolic compounds in open-pollinated seeds, mainly rosmarinic acid and flavonoids, apigenin and luteolin. Flavonoids were present in the glucosylated form in seeds (A) and (C), and in the aglycone form in seeds from (B) plants. Saturated and unsaturated fatty acids (palmitic, linoleic and linolenic) were more abundant in seeds from self-pollinated flowers. Pollination performed almost exclusively by the honeybee notably increased the antioxidant content in perilla seeds and gave rise to a reduction in the fatty acid content.
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Bennett, Jonathan A; Cahill, James F
2018-06-01
Pollination is critical for plant fitness and population dynamics, yet little attention is paid to the role of flowering and plant-pollinator interactions in structuring plant communities, including community responses to environmental change. Changes in arbuscular mycorrhizal fungi (AMF), nutrient abundances, and plant litter all affect plant access to different resources, and are known regulators of community structure. Each factor can also affect flowering and plant-pollinator interactions, potentially contributing to changes in community structure. To test whether AMF, nutrients, and litter influenced the relationship between pollination and community structure, we conducted a 5-yr field experiment applying fungicide, adding fertilizer, and removing plant litter in native grassland. We measured the distribution of flowers and floral visits among species in year three and linked these measures to changes in plant composition and species richness between years three and five. We hypothesized that an uneven distribution of flowers and visits among species would lead to greater community change, but that the treatments would disrupt this relationship by altering sexual allocation and recruitment. Consistent with our hypothesis, communities with uneven flower distributions exhibited greater changes in community composition and richness under ambient conditions. However, AMF suppression neutralized this relationship and regulated the other treatment effects, highlighting the potential importance of AMF for stabilizing recruitment dynamics. Combined, AMF suppression and nutrient addition caused species losses when few species flowered, likely by compounding stresses for those species. The treatment effects on the relationship between flowering and community composition were more nuanced, but were likely driven by increased competition and altered flowering among species. By contrast, community composition was more stable when visitation rates were uneven among species, irrespective of any treatments. This suggests that some species require high visitation rates to maintain their populations due to greater dependence on sexual reproduction. Combined, these results highlight the importance of flowering and floral visitation to the dynamics of grassland communities. They also suggest that altered recruitment dynamics is a major, yet understudied, mechanism by which environmental change affects communities. Consequently, understanding the effects of environmental change on plant communities will require study of both plant growth and sexual reproduction. © 2018 by the Ecological Society of America.
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Naqqash, Muhammad Nadir; Saeed, Qamar; Ghouri, Fozia
2016-01-01
Background: Pollination has a great effect on the yield of fruit trees. Blow flies are considered as an effective pollinator compared to hand pollination in fruit orchards. Therefore, this study was designed to evaluate the effect of different pollination methods in mango orchards. Methodology: The impact of pollination on quantity and quality of mango yield by blow flies was estimated by using three treatments, i.e., open pollinated trees, trees were covered by a net in the presence of blow flies for pollination, and trees were covered with a net but without insects. Results: The maximum number of flowers was recorded in irregular types of inflorescence, i.e., 434.80 flowers/inflorescence. Fruit setting (bud) was higher in open pollinated mango trees (i.e. 37.00/inflorescence) than enclosed pollination by blow flies (i.e. 22.34/inflorescence). The size of the mango fruit was the highest (5.06 mm) in open pollinated tree than those pollinated by blow flies (3.93 mm) and followed by without any pollinator (3.18 mm) at marble stage. We found that the maximum weight of mango fruit (201.19 g) was in open pollinated trees. Discussion: The results demonstrated that blow flies can be used as effective mango pollinators along with other flies and bees. The blow flies have shown a positive impact on the quality and quantity of mango. This study will be helpful in future and also applicable at farm level to use blow flies as pollinators that are cheap and easy to rear. PMID:27441107
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Steenhuisen, S-L; Raguso, R A; Johnson, S D
2012-12-01
Evolutionary shifts between pollination systems are often accompanied by modifications of floral traits, including olfactory cues. We investigated the implications of a shift from passerine bird to beetle pollination in Protea for floral scent chemistry, and also explored the functional significance of Protea scent for pollinator attraction. Using headspace sampling and gas chromatography-mass spectrometry, we found distinct differences in the emission rates and chemical composition of floral scents between eight bird- and four beetle-pollinated species. The amount of scent emitted from inflorescences of beetle-pollinated species was, on average, about 10-fold greater than that of bird-pollinated species. Floral scent of bird-pollinated species consists mainly of small amounts of "green-leaf volatiles" and benzenoid compounds, including benzaldehyde, anisole and benzyl alcohol. The floral scent of beetle-pollinated species is dominated by emissions of linalool, a wide variety of other monoterpenes and the benzenoid methyl benzoate, which imparts a fruity odour to the human nose. The number of compounds recorded in the scent of beetle-pollinated species was, on average, greater than in bird-pollinated species (45 versus 29 compounds, respectively). Choice experiments using a Y-maze showed that a primary pollinator of Protea species, the cetoniine beetle Atrichelaphinis tigrina, strongly preferred the scent of inflorescences of the beetle-pollinated Protea simplex over those of the bird-pollinated sympatric congener, Protea roupelliae. This study shows that a shift from passerine bird- to insect-pollination can be associated with marked up-regulation and compositional changes in floral scent emissions. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Moody-Weis, J M; Heywood, J S
2001-09-01
Habitat fragmentation may result in plant populations that are less attractive to pollinators and thus susceptible to reduced reproductive output due to pollination limitation. Pollination limitation was investigated in three Missouri populations of Oenothera macrocarpa, a hawk-moth-pollinated, perennial herb. The populations represented extremes in size and habitat quality. Following supplemental pollination, mean fertilization success (proportion of ovules fertilized) across populations increased from 24.3 to 44.8% and mean seed set (proportion of ovules that matured into seed) increased from 14.7 to 27.9%. These increases were statistically significant in two of the three populations. Failure to achieve 100% fertilization and seed set following supplementation indicates that other factors, in addition to pollination, were limiting to female reproductive success. Fruit set was pollination limited in only one population. Fruits matured with as few as one seed, suggesting that fruit set was not resource limited. The degree of pollination limitation was greatest in the most disturbed population. The population located in the highest-quality habitat was not significantly pollination limited. This suggests that pollination limitation is occurring, at least in part, because of reduced pollinator activity in degraded habitats.
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Boberg, Elin; Alexandersson, Ronny; Jonsson, Magdalena; Maad, Johanne; Ågren, Jon; Nilsson, L Anders
2014-01-01
Plant-pollinator interactions are thought to have shaped much of floral evolution. Yet the relative importance of pollinator shifts and coevolutionary interactions for among-population variation in floral traits in animal-pollinated species is poorly known. This study examined the adaptive significance of spur length in the moth-pollinated orchid Platanthera bifolia. Geographical variation in the length of the floral spur of P. bifolia was documented in relation to variation in the pollinator fauna across Scandinavia, and a reciprocal translocation experiment was conducted in south-east Sweden between a long-spurred woodland population and a short-spurred grassland population. Spur length and pollinator fauna varied among regions and habitats, and spur length was positively correlated with the proboscis length of local pollinators. In the reciprocal translocation experiment, long-spurred woodland plants had higher pollination success than short-spurred grassland plants at the woodland site, while no significant difference was observed at the grassland site. The results are consistent with the hypothesis that optimal floral phenotype varies with the morphology of the local pollinators, and that the evolution of spur length in P. bifolia has been largely driven by pollinator shifts.
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Pollinator shifts and the evolution of spur length in the moth-pollinated orchid Platanthera bifolia
Boberg, Elin; Alexandersson, Ronny; Jonsson, Magdalena; Maad, Johanne; Ågren, Jon; Nilsson, L. Anders
2014-01-01
Background and Aims Plant–pollinator interactions are thought to have shaped much of floral evolution. Yet the relative importance of pollinator shifts and coevolutionary interactions for among-population variation in floral traits in animal-pollinated species is poorly known. This study examined the adaptive significance of spur length in the moth-pollinated orchid Platanthera bifolia. Methods Geographical variation in the length of the floral spur of P. bifolia was documented in relation to variation in the pollinator fauna across Scandinavia, and a reciprocal translocation experiment was conducted in south-east Sweden between a long-spurred woodland population and a short-spurred grassland population. Key Results Spur length and pollinator fauna varied among regions and habitats, and spur length was positively correlated with the proboscis length of local pollinators. In the reciprocal translocation experiment, long-spurred woodland plants had higher pollination success than short-spurred grassland plants at the woodland site, while no significant difference was observed at the grassland site. Conclusions The results are consistent with the hypothesis that optimal floral phenotype varies with the morphology of the local pollinators, and that the evolution of spur length in P. bifolia has been largely driven by pollinator shifts. PMID:24169591
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Power, Eileen F.; Kelly, Daniel L.; Stout, Jane C.
2012-01-01
Parallel declines in insect-pollinated plants and their pollinators have been reported as a result of agricultural intensification. Intensive arable plant communities have previously been shown to contain higher proportions of self-pollinated plants compared to natural or semi-natural plant communities. Though intensive grasslands are widespread, it is not known whether they show similar patterns to arable systems nor whether local and/or landscape factors are influential. We investigated plant community composition in 10 pairs of organic and conventional dairy farms across Ireland in relation to the local and landscape context. Relationships between plant groups and local factors (farming system, position in field and soil parameters) and landscape factors (e.g. landscape complexity) were investigated. The percentage cover of unimproved grassland was used as an inverse predictor of landscape complexity, as it was negatively correlated with habitat-type diversity. Intensive grasslands (organic and conventional) contained more insect-pollinated forbs than non-insect pollinated forbs. Organic field centres contained more insect-pollinated forbs than conventional field centres. Insect-pollinated forb richness in field edges (but not field centres) increased with increasing landscape complexity (% unimproved grassland) within 1, 3, 4 and 5km radii around sites, whereas non-insect pollinated forb richness was unrelated to landscape complexity. Pollination systems within intensive grassland communities may be different from those in arable systems. Our results indicate that organic management increases plant richness in field centres, but that landscape complexity exerts strong influences in both organic and conventional field edges. Insect-pollinated forb richness, unlike that for non-insect pollinated forbs, showed positive relationships to landscape complexity reflecting what has been documented for bees and other pollinators. The insect-pollinated forbs, their pollinators and landscape context are clearly linked. This needs to be taken into account when managing and conserving insect-pollinated plant and pollinator communities. PMID:22666450
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Potts, Simon G.; Steffan-Dewenter, Ingolf; Vaissière, Bernard E.; Woyciechowski, Michal; Krewenka, Kristin M.; Tscheulin, Thomas; Roberts, Stuart P.M.; Szentgyörgyi, Hajnalka; Westphal, Catrin; Bommarco, Riccardo
2014-01-01
Background. Up to 75% of crop species benefit at least to some degree from animal pollination for fruit or seed set and yield. However, basic information on the level of pollinator dependence and pollinator contribution to yield is lacking for many crops. Even less is known about how insect pollination affects crop quality. Given that habitat loss and agricultural intensification are known to decrease pollinator richness and abundance, there is a need to assess the consequences for different components of crop production. Methods. We used pollination exclusion on flowers or inflorescences on a whole plant basis to assess the contribution of insect pollination to crop yield and quality in four flowering crops (spring oilseed rape, field bean, strawberry, and buckwheat) located in four regions of Europe. For each crop, we recorded abundance and species richness of flower visiting insects in ten fields located along a gradient from simple to heterogeneous landscapes. Results. Insect pollination enhanced average crop yield between 18 and 71% depending on the crop. Yield quality was also enhanced in most crops. For instance, oilseed rape had higher oil and lower chlorophyll contents when adequately pollinated, the proportion of empty seeds decreased in buckwheat, and strawberries’ commercial grade improved; however, we did not find higher nitrogen content in open pollinated field beans. Complex landscapes had a higher overall species richness of wild pollinators across crops, but visitation rates were only higher in complex landscapes for some crops. On the contrary, the overall yield was consistently enhanced by higher visitation rates, but not by higher pollinator richness. Discussion. For the four crops in this study, there is clear benefit delivered by pollinators on yield quantity and/or quality, but it is not maximized under current agricultural intensification. Honeybees, the most abundant pollinator, might partially compensate the loss of wild pollinators in some areas, but our results suggest the need of landscape-scale actions to enhance wild pollinator populations. PMID:24749007
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Bartomeus, Ignasi; Potts, Simon G; Steffan-Dewenter, Ingolf; Vaissière, Bernard E; Woyciechowski, Michal; Krewenka, Kristin M; Tscheulin, Thomas; Roberts, Stuart P M; Szentgyörgyi, Hajnalka; Westphal, Catrin; Bommarco, Riccardo
2014-01-01
Background. Up to 75% of crop species benefit at least to some degree from animal pollination for fruit or seed set and yield. However, basic information on the level of pollinator dependence and pollinator contribution to yield is lacking for many crops. Even less is known about how insect pollination affects crop quality. Given that habitat loss and agricultural intensification are known to decrease pollinator richness and abundance, there is a need to assess the consequences for different components of crop production. Methods. We used pollination exclusion on flowers or inflorescences on a whole plant basis to assess the contribution of insect pollination to crop yield and quality in four flowering crops (spring oilseed rape, field bean, strawberry, and buckwheat) located in four regions of Europe. For each crop, we recorded abundance and species richness of flower visiting insects in ten fields located along a gradient from simple to heterogeneous landscapes. Results. Insect pollination enhanced average crop yield between 18 and 71% depending on the crop. Yield quality was also enhanced in most crops. For instance, oilseed rape had higher oil and lower chlorophyll contents when adequately pollinated, the proportion of empty seeds decreased in buckwheat, and strawberries' commercial grade improved; however, we did not find higher nitrogen content in open pollinated field beans. Complex landscapes had a higher overall species richness of wild pollinators across crops, but visitation rates were only higher in complex landscapes for some crops. On the contrary, the overall yield was consistently enhanced by higher visitation rates, but not by higher pollinator richness. Discussion. For the four crops in this study, there is clear benefit delivered by pollinators on yield quantity and/or quality, but it is not maximized under current agricultural intensification. Honeybees, the most abundant pollinator, might partially compensate the loss of wild pollinators in some areas, but our results suggest the need of landscape-scale actions to enhance wild pollinator populations.
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Wind-Dragged Corolla Enhances Self-Pollination: A New Mechanism of Delayed Self-Pollination
Qu, Rongming; Li, Xiaojie; Luo, Yibo; Dong, Ming; Xu, Huanli; Chen, Xuan; Dafni, Amots
2007-01-01
Background and Aims Delayed self-pollination is a mechanism that allows animal-pollinated plants to outcross while ensuring seed production in the absence of pollinators. This study aims to explore a new mechanism of delayed self-pollination facilitated by wind-driven corolla abscission in Incarvillea sinensis var. sinensis. Methods Floral morphology and development, and the process of delayed self-pollination were surveyed. Experiments dealing with pollinator and wind exclusion, pollination manipulations, and pollinator observations were conducted in the field. Key Results Delayed self-pollination occurs when the abscising corolla driven by wind drags the adherent epipetalous stamens, thus leading to contact of anthers with stigma in late anthesis. There is no dichogamy and self-incompatibility in this species. The significantly higher proportion of abscised corolla under natural conditions as compared with that in wind-excluding tents indicates the importance of wind in corolla abscission. When pollinators were excluded, corolla abscission significantly increased the number of pollen grains deposited on the stigma and, as a result, the fruit and seed set. Only half of the flowers in plots were visited by pollinators, and the fruit set of emasculated flowers was significantly lower than that of untreated flowers in open pollination. This species has a sensitive stigma, and its two open stigmatic lobes closed soon after being touched by a pollinator, but always reopened if no or only little pollen was deposited. Conclusions This delayed self-pollination, which involved the movement of floral parts, the active participation of the wind and sensitive stigma, is quite different from that reported previously. This mechanism provides reproductive assurance for this species. The sensitive stigma contributes to ensuring seed production and reducing the interference of selfing with outcrossing. The pollination pattern, which combines actions by bees with indirect participation by wind, is also a new addition to ambophily. PMID:17881336
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Relative stability of core groups in pollination networks in a biodiversity hotspot over four years.
Fang, Qiang; Huang, Shuang-Quan
2012-01-01
Plants and their pollinators form pollination networks integral to the evolution and persistence of species in communities. Previous studies suggest that pollination network structure remains nested while network composition is highly dynamic. However, little is known about temporal variation in the structure and function of plant-pollinator networks, especially in species-rich communities where the strength of pollinator competition is predicted to be high. Here we quantify temporal variation of pollination networks over four consecutive years in an alpine meadow in the Hengduan Mountains biodiversity hotspot in China. We found that ranked positions and idiosyncratic temperatures of both plants and pollinators were more conservative between consecutive years than in non-consecutive years. Although network compositions exhibited high turnover, generalized core groups--decomposed by a k-core algorithm--were much more stable than peripheral groups. Given the high rate of turnover observed, we suggest that identical plants and pollinators that persist for at least two successive years sustain pollination services at the community level. Our data do not support theoretical predictions of a high proportion of specialized links within species-rich communities. Plants were relatively specialized, exhibiting less variability in pollinator composition at pollinator functional group level than at the species level. Both specialized and generalized plants experienced narrow variation in functional pollinator groups. The dynamic nature of pollination networks in the alpine meadow demonstrates the potential for networks to mitigate the effects of fluctuations in species composition in a high biodiversity area.
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Lázaro, Amparo; Hegland, Stein Joar; Totland, Orjan
2008-08-01
The pollination syndrome hypothesis has provided a major conceptual framework for how plants and pollinators interact. However, the assumption of specialization in pollination systems and the reliability of floral traits in predicting the main pollinators have been questioned recently. In addition, the relationship between ecological and evolutionary specialization in pollination interactions is still poorly understood. We used data of 62 plant species from three communities across southern Norway to test: (1) the relationships between floral traits and the identity of pollinators, (2) the association between floral traits (evolutionary specialization) and ecological generalization, and (3) the consistency of both relationships across communities. Floral traits significantly affected the identity of pollinators in the three communities in a way consistent with the predictions derived from the pollination syndrome concept. However, hover flies and butterflies visited flowers with different shapes in different communities, which we mainly attribute to among-community variation in pollinator assemblages. Interestingly, ecological generalization depended more on the community-context (i.e. the plant and pollinator assemblages in the communities) than on specific floral traits. While open yellow and white flowers were the most generalist in two communities, they were the most specialist in the alpine community. Our results warn against the use of single measures of ecological generalization to question the pollination syndrome concept, and highlight the importance of community comparisons to assess the pollination syndromes, and to understand the relationships between ecological and evolutionary specialization in plant-pollinator interactions.
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Brys, Rein; Geens, Bram; Beeckman, Tom; Jacquemyn, Hans
2013-01-01
Background and Aims The establishment of plant populations in novel environments may generate pronounced shifts in floral traits and plant mating systems, particularly when pollinators are scarce. In this study, floral morphology and mating system functioning are compared between recently established and older populations of the annual plant Blackstonia perfoliata that occur in different pollinator environments. Methods Hand-pollination and emasculation experiments were conducted to assess the extent of pollinator-mediated pollen deposition and pollen limitation, and the contribution of autonomous selfing to total seed production. Detailed measurements of key floral traits were performed to compare the flower morphology and mating system functioning between plants from both pollination environments. Key Results Pollinator-mediated pollen deposition was about twice as low in the recently colonized and pollinator-poor environment compared with the old and pollinator-rich sites, but total seed set was little affected by any type of pollen limitation. The contribution of autonomous selfing to total seed production was higher in the pollinator-poor sites than in the pollinator-rich sites (index of reproductive assurance = 0·56 and 0·17, respectively), and seed production was only poorly affected by selfing, whereas in the pollinator-rich populations selfing reduced total reproductive output by about 40 % compared with outcross pollination. Plants originating from pollinator-poor environments produced smaller flowers that showed significantly lower levels of dichogamy (i.e. protogyny) and herkogamy. These reductions resulted in a 2-fold higher capacity for autonomous selfing under pollinator-free conditions (index of autonomous selfing = 0·81 and 0·41 in plants originating from the pollinator-poor and pollinator-rich environment, respectively). Conclusions The results illustrate that plant populations colonizing novel environments can differ markedly in floral morphology and mating system functioning. Due to a temporal shift in the male phase, the breeding system of B. perfoliata shifted from delayed selfing under pollinator-rich conditions towards competing selfing in recently established populations, providing greater reproductive assurance when pollinators and/or reproductive partners are limited. PMID:23408833
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Avoiding a bad apple: Insect pollination enhances fruit quality and economic value☆
Garratt, M.P.D.; Breeze, T.D.; Jenner, N.; Polce, C.; Biesmeijer, J.C.; Potts, S.G.
2014-01-01
Insect pollination is important for food production globally and apples are one of the major fruit crops which are reliant on this ecosystem service. It is fundamentally important that the full range of benefits of insect pollination to crop production are understood, if the costs of interventions aiming to enhance pollination are to be compared against the costs of the interventions themselves. Most previous studies have simply assessed the benefits of pollination to crop yield and ignored quality benefits and how these translate through to economic values. In the present study we examine the influence of insect pollination services on farmgate output of two important UK apple varieties; Gala and Cox. Using field experiments, we quantify the influence of insect pollination on yield and importantly quality and whether either may be limited by sub-optimal insect pollination. Using an expanded bioeconomic model we value insect pollination to UK apple production and establish the potential for improvement through pollination service management. We show that insects are essential in the production of both varieties of apple in the UK and contribute a total of £36.7 million per annum, over £6 million more than the value calculated using more conventional dependence ratio methods. Insect pollination not only affects the quantity of production but can also have marked impacts on the quality of apples, influencing size, shape and effecting their classification for market. These effects are variety specific however. Due to the influence of pollination on both yield and quality in Gala, there is potential for insect pollination services to improve UK output by up to £5.7 million per annum. Our research shows that continued pollinator decline could have serious financial implications for the apple industry but there is considerable scope through management of wild pollinators or using managed pollinator augmentation, to improve the quality of production. Furthermore, we show that it is critically important to consider all production parameters including quality, varietal differences and management costs when valuing the pollination service of any crop so investment in pollinator management can be proportional to its contribution. PMID:24748698
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Avoiding a bad apple: Insect pollination enhances fruit quality and economic value.
Garratt, M P D; Breeze, T D; Jenner, N; Polce, C; Biesmeijer, J C; Potts, S G
2014-02-01
Insect pollination is important for food production globally and apples are one of the major fruit crops which are reliant on this ecosystem service. It is fundamentally important that the full range of benefits of insect pollination to crop production are understood, if the costs of interventions aiming to enhance pollination are to be compared against the costs of the interventions themselves. Most previous studies have simply assessed the benefits of pollination to crop yield and ignored quality benefits and how these translate through to economic values. In the present study we examine the influence of insect pollination services on farmgate output of two important UK apple varieties; Gala and Cox. Using field experiments, we quantify the influence of insect pollination on yield and importantly quality and whether either may be limited by sub-optimal insect pollination. Using an expanded bioeconomic model we value insect pollination to UK apple production and establish the potential for improvement through pollination service management. We show that insects are essential in the production of both varieties of apple in the UK and contribute a total of £36.7 million per annum, over £6 million more than the value calculated using more conventional dependence ratio methods. Insect pollination not only affects the quantity of production but can also have marked impacts on the quality of apples, influencing size, shape and effecting their classification for market. These effects are variety specific however. Due to the influence of pollination on both yield and quality in Gala, there is potential for insect pollination services to improve UK output by up to £5.7 million per annum. Our research shows that continued pollinator decline could have serious financial implications for the apple industry but there is considerable scope through management of wild pollinators or using managed pollinator augmentation, to improve the quality of production. Furthermore, we show that it is critically important to consider all production parameters including quality, varietal differences and management costs when valuing the pollination service of any crop so investment in pollinator management can be proportional to its contribution.
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Spigler, Rachel B
2017-01-01
Plasticity of floral traits in response to pollination can enable plants to maximize opportunities for pollen import and export under poor pollination conditions, while minimizing costs under favourable ones. Both floral longevity and display are key traits influencing pollination. While pollination-induced flower wilting is widely documented, we lack an understanding of the multifactorial complexity of this response, including the influence of other pollination components, costs of extended longevity and subsequent impacts on floral display. Plasticity of floral longevity was experimentally evaluated in Sabatia angularis in response to multiple pollination factors: pollen addition, removal, and source (self, single-donor outcross, multiple-donor outcross) and timing of pollination. Effects of pollen quantity were further evaluated by exploiting variation in autonomous self-pollen deposition. Delayed pollination costs were tested comparing seed set from early versus late pollinations. Finally, I compared floral display metrics (peak floral display, time to peak flower, flowering duration, mean flowering rate) between experimentally pollinated and control plants. Floral longevity was highly plastic in response to pollen addition and its timing, and the response was dose-dependent but insensitive to pollen source. Pollen removal tended to extend floral longevity, but only insofar as it precluded pollination-induced wilting via autonomous self-pollination. Under delayed pollination, the wilting response was faster and no cost was detected. Pollination further led to reduced peak floral displays and condensed flowering periods. Floral longevity and display plasticity could optimize fitness in S. angularis, a species prone to pollen limitation and high inbreeding depression. Under pollinator scarcity, extended floral longevities offer greater opportunities for pollen receipt and export at no cost to seed set, reproductive assurance via autonomous self-pollination and larger, more attractive floral displays. Under high pollinator availability, shortened longevities lead to smaller displays that should lower the risk of geitonogamy. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Repeated evolution of vertebrate pollination syndromes in a recently diverged Andean plant clade.
Lagomarsino, Laura P; Forrestel, Elisabeth J; Muchhala, Nathan; Davis, Charles C
2017-08-01
Although specialized interactions, including those involving plants and their pollinators, are often invoked to explain high species diversity, they are rarely explored at macroevolutionary scales. We investigate the dynamic evolution of hummingbird and bat pollination syndromes in the centropogonid clade (Lobelioideae: Campanulaceae), an Andean-centered group of ∼550 angiosperm species. We demonstrate that flowers hypothesized to be adapted to different pollinators based on flower color fall into distinct regions of morphospace, and this is validated by morphology of species with known pollinators. This supports the existence of pollination syndromes in the centropogonids, an idea corroborated by ecological studies. We further demonstrate that hummingbird pollination is ancestral, and that bat pollination has evolved ∼13 times independently, with ∼11 reversals. This convergence is associated with correlated evolution of floral traits within selective regimes corresponding to pollination syndrome. Collectively, our results suggest that floral morphological diversity is extremely labile, likely resulting from selection imposed by pollinators. Finally, even though this clade's rapid diversification is partially attributed to their association with vertebrate pollinators, we detect no difference in diversification rates between hummingbird- and bat-pollinated lineages. Our study demonstrates the utility of pollination syndromes as a proxy for ecological relationships in macroevolutionary studies of certain species-rich clades. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.
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Lilies at the limit: Variation in plant-pollinator interactions across an elevational range.
Theobald, Elli J; Gabrielyan, Hrach; HilleRisLambers, Janneke
2016-02-01
Many studies assume climatic factors are paramount in determining species' distributions, however, biotic interactions may also play a role. For example, pollinators may limit species' ranges if floral abundance or floral attractiveness is reduced at range margins, thus causing lower pollinator visitation and reduced reproductive output. To test if pollinators influence the altitudinal distribution of Erythronium montanum (Liliaceae) at Mount Rainier National Park, we asked whether (1) seed production in this species relies on pollinators, (2) seed production and pollen limitation is greatest at range limits, and (3) pollinator visitation rates (either overall or by individual taxonomic groups) reflect patterns of seed production and pollen limitation. From this three-year study, we established that this plant does rely on pollinators for fruit set and we found that pollen limitation trended toward being higher at the upper range limit in some years, but not consistently year to year. Insect visitation rates did not mirror spatial patterns of pollen limitation, but annually variable pollinator composition suggested differential importance of some pollinator taxonomic groups (specifically, bumblebees may be better pollinators than syrphid flies). Overall, these results suggest that while pollinators are critical for the reproductive success of this high mountain wildflower, plant-pollinator interactions do not obviously drive the distribution of this species. Nonetheless, high spatio-temporal variability in range-wide plant-pollinator dynamics may complicate responses to climate change. © 2016 Botanical Society of America.
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Rolland, Jonathan; Clark, John L.; Salamin, Nicolas
2017-01-01
The effects of specific functional groups of pollinators in the diversification of angiosperms are still to be elucidated. We investigated whether the pollination shifts or the specific association with hummingbirds affected the diversification of a highly diverse angiosperm lineage in the Neotropics. We reconstructed a phylogeny of 583 species from the Gesneriaceae family and detected diversification shifts through time, inferred the timing and amount of transitions among pollinator functional groups, and tested the association between hummingbird pollination and speciation and extinction rates. We identified a high frequency of pollinator transitions, including reversals to insect pollination. Diversification rates of the group increased through time since 25 Ma, coinciding with the evolution of hummingbird-adapted flowers and the arrival of hummingbirds in South America. We showed that plants pollinated by hummingbirds have a twofold higher speciation rate compared with plants pollinated by insects, and that transitions among functional groups of pollinators had little impact on the diversification process. We demonstrated that floral specialization on hummingbirds for pollination has triggered rapid diversification in the Gesneriaceae family since the Early Miocene, and that it represents one of the oldest identified plant–hummingbird associations. Biotic drivers of plant diversification in the Neotropics could be more related to this specific type of pollinator (hummingbirds) than to shifts among different functional groups of pollinators. PMID:28381621
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Serrano-Serrano, Martha Liliana; Rolland, Jonathan; Clark, John L; Salamin, Nicolas; Perret, Mathieu
2017-04-12
The effects of specific functional groups of pollinators in the diversification of angiosperms are still to be elucidated. We investigated whether the pollination shifts or the specific association with hummingbirds affected the diversification of a highly diverse angiosperm lineage in the Neotropics. We reconstructed a phylogeny of 583 species from the Gesneriaceae family and detected diversification shifts through time, inferred the timing and amount of transitions among pollinator functional groups, and tested the association between hummingbird pollination and speciation and extinction rates. We identified a high frequency of pollinator transitions, including reversals to insect pollination. Diversification rates of the group increased through time since 25 Ma, coinciding with the evolution of hummingbird-adapted flowers and the arrival of hummingbirds in South America. We showed that plants pollinated by hummingbirds have a twofold higher speciation rate compared with plants pollinated by insects, and that transitions among functional groups of pollinators had little impact on the diversification process. We demonstrated that floral specialization on hummingbirds for pollination has triggered rapid diversification in the Gesneriaceae family since the Early Miocene, and that it represents one of the oldest identified plant-hummingbird associations. Biotic drivers of plant diversification in the Neotropics could be more related to this specific type of pollinator (hummingbirds) than to shifts among different functional groups of pollinators. © 2017 The Author(s).
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Importance of pollinators in changing landscapes for world crops
Klein, Alexandra-Maria; Vaissière, Bernard E; Cane, James H; Steffan-Dewenter, Ingolf; Cunningham, Saul A; Kremen, Claire; Tscharntke, Teja
2006-01-01
The extent of our reliance on animal pollination for world crop production for human food has not previously been evaluated and the previous estimates for countries or continents have seldom used primary data. In this review, we expand the previous estimates using novel primary data from 200 countries and found that fruit, vegetable or seed production from 87 of the leading global food crops is dependent upon animal pollination, while 28 crops do not rely upon animal pollination. However, global production volumes give a contrasting perspective, since 60% of global production comes from crops that do not depend on animal pollination, 35% from crops that depend on pollinators, and 5% are unevaluated. Using all crops traded on the world market and setting aside crops that are solely passively self-pollinated, wind-pollinated or parthenocarpic, we then evaluated the level of dependence on animal-mediated pollination for crops that are directly consumed by humans. We found that pollinators are essential for 13 crops, production is highly pollinator dependent for 30, moderately for 27, slightly for 21, unimportant for 7, and is of unknown significance for the remaining 9. We further evaluated whether local and landscape-wide management for natural pollination services could help to sustain crop diversity and production. Case studies for nine crops on four continents revealed that agricultural intensification jeopardizes wild bee communities and their stabilizing effect on pollination services at the landscape scale. PMID:17164193
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Importance of pollinators in changing landscapes for world crops.
Klein, Alexandra-Maria; Vaissière, Bernard E; Cane, James H; Steffan-Dewenter, Ingolf; Cunningham, Saul A; Kremen, Claire; Tscharntke, Teja
2007-02-07
The extent of our reliance on animal pollination for world crop production for human food has not previously been evaluated and the previous estimates for countries or continents have seldom used primary data. In this review, we expand the previous estimates using novel primary data from 200 countries and found that fruit, vegetable or seed production from 87 of the leading global food crops is dependent upon animal pollination, while 28 crops do not rely upon animal pollination. However, global production volumes give a contrasting perspective, since 60% of global production comes from crops that do not depend on animal pollination, 35% from crops that depend on pollinators, and 5% are unevaluated. Using all crops traded on the world market and setting aside crops that are solely passively self-pollinated, wind-pollinated or parthenocarpic, we then evaluated the level of dependence on animal-mediated pollination for crops that are directly consumed by humans. We found that pollinators are essential for 13 crops, production is highly pollinator dependent for 30, moderately for 27, slightly for 21, unimportant for 7, and is of unknown significance for the remaining 9. We further evaluated whether local and landscape-wide management for natural pollination services could help to sustain crop diversity and production. Case studies for nine crops on four continents revealed that agricultural intensification jeopardizes wild bee communities and their stabilizing effect on pollination services at the landscape scale.
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Melen, Miranda K; Herman, Julie A; Lucas, Jessica; O'Malley, Rachel E; Parker, Ingrid M; Thom, Aaron M; Whittall, Justen B
2016-11-01
Self incompatibility (SI) in rare plants presents a unique challenge-SI protects plants from inbreeding depression, but requires a sufficient number of mates and xenogamous pollination. Does SI persist in an endangered polyploid? Is pollinator visitation sufficient to ensure reproductive success? Is there evidence of inbreeding/outbreeding depression? We characterized the mating system, primary pollinators, pollen limitation, and inbreeding/outbreeding depression in Erysimum teretifolium to guide conservation efforts. We compared seed production following self pollination and within- and between-population crosses. Pollen tubes were visualized after self pollinations and between-population pollinations. Pollen limitation was tested in the field. Pollinator observations were quantified using digital video. Inbreeding/outbreeding depression was assessed in progeny from self and outcross pollinations at early and later developmental stages. Self-pollination reduced seed set by 6.5× and quadrupled reproductive failure compared with outcross pollination. Pollen tubes of some self pollinations were arrested at the stigmatic surface. Seed-set data indicated strong SI, and fruit-set data suggested partial SI. Pollinator diversity and visitation rates were high, and there was no evidence of pollen limitation. Inbreeding depression (δ) was weak for early developmental stages and strong for later developmental stages, with no evidence of outbreeding depression. The rare hexaploid E. teretifolium is largely self incompatible and suffers from late-acting inbreeding depression. Reproductive success in natural populations was accomplished through high pollinator visitation rates consistent with a lack of pollen limitation. Future reproductive health for this species will require large population sizes with sufficient mates and a robust pollinator community. © 2016 Melen et al. Published by the Botanical Society of America. This work is licensed under a Creative Commons Attribution License (CC-BY).
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Nunes, Carlos E P; Peñaflor, Maria Fernanda G V; Bento, José Maurício S; Salvador, Marcos José; Sazima, Marlies
2016-12-01
Volatile organic compounds (VOCs) mediate both mutualistic and antagonistic plant-animal interactions; thus, the attraction of mutualists and antagonists by floral VOCs constitutes an important trade-off in the evolutionary ecology of angiosperms. Here, we evaluate the role of VOCs in mediating communication between the plant and its mutualist and antagonist floral visitors. To assess the evolutionary consequences of VOC-mediated signalling to distinct floral visitors, we studied the reproductive ecology of Dichaea pendula, assessing the effects of florivores on fruit set, the pollination efficiency of pollinators and florivores, the floral scent composition and the attractiveness of the major VOC to pollinators and florivores. The orchid depends entirely on orchid-bees for sexual reproduction, and the major florivores, the weevils, feed on corollas causing self-pollination, triggering abortion of 26.4 % of the flowers. Floral scent was composed of approximately 99 % 2-methoxy-4-vinylphenol, an unusual floral VOC attractive to pollinators and florivores. The low fruit set from natural pollination (5.6 %) compared to hand cross-pollination (45.5 %) and low level of pollinator visitation [0.02 visits (flower hour) -1 ] represent the limitations to pollination. Our research found that 2-methoxy-4-vinylphenol mediates both mutualistic and antagonistic interactions, which could result in contrary evolutionary pressures on novo-emission. The scarcity of pollinators, not florivory, was the major constraint to fruit set. Our results suggest that, rather than anti-florivory adaptations, adaptations to enhance pollinator attraction and cross-pollination might be the primary drivers of the evolution of VOC emission in euglossine-pollinated flowers.
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Araújo, F G; Morado, C N; Parente, T T E; Paumgartten, F J R; Gomes, I D
2018-05-01
The Funil Reservoir receives a large amount of xenobiotics from the Paraíba do Sul River (PSR) from large number of industries and municipalities in the watershed. This study aimed to assess environmental quality along the longitudinal profile of the Paraíba do Sul River-Funil Reservoir system, by using biomarkers and bioindicators in a selected fish species. The raised hypothesis is that Funil Reservoir acts as a filter for the xenobiotics of the PSR waters, improving river water quality downstream the dam. Two biomarkers, the ethoxyresorufin-O-deethylase activity (EROD), measured as fluorimetricly in S9 hepatic fraction, and the micronuclei frequency (MN), observed in erythrocytes of the cytoplasm, and three bioindicators, the hepatosomatic index (HSI), gonadosomatic index (GSI) and condition factor (CF) were used in Pimelodus maculatus, a fish species widely distributed in the system. Four zones were searched through a longitudinal gradient: 1, river upstream from the reservoir; 2, upper reservoir; 3, lower reservoir; 4, river downstream of the reservoir. EROD activity and HSI and GSI had significant differences among the zones (P<0.05). The upper reservoir had the lowest EROD activity and HSI, whereas the river downstream of the reservoir had the highest EROD and lowest GSI. The river upstream from the reservoir showed the highest HSI and GSI. It is suggested that the lowest environmental condition occur at the river downstream of the reservoir, where it seems to occur more influence of xenobiotics, which could be associated with hydroelectric plant operation. The hypothesis that Funil reservoir acts as a filter decanting pollution from the Paraíba do Sul River waters was rejected. These results are novel information on this subject for a native fish species and could be useful for future comparisons with other environments.
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Pollinators exert natural selection on flower size and floral display in Penstemon digitalis.
Parachnowitsch, Amy L; Kessler, André
2010-10-01
• A major gap in our understanding of floral evolution, especially micro-evolutionary processes, is the role of pollinators in generating patterns of natural selection on floral traits. Here we explicitly tested the role of pollinators in selecting floral traits in a herbaceous perennial, Penstemon digitalis. • We manipulated the effect of pollinators on fitness through hand pollinations and compared phenotypic selection in open- and hand-pollinated plants. • Despite the lack of pollen limitation in our population, pollinators mediated selection on floral size and floral display. Hand pollinations removed directional selection for larger flowers and stabilizing selection on flower number, suggesting that pollinators were the agents of selection on both of these traits. • We reviewed studies that measured natural selection on floral traits by biotic agents and generally found stronger signatures of selection imposed by pollinators than by herbivores and co-flowering plant species. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).
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Great Lakes clams find refuge from zebra mussels in restored, lake-connected marsh (Ohio)
Nichols, S. Jerrine; Wilcox, Douglas A.
2004-01-01
Since the early 1990s, more than 95 percent of the freshwater clams once found in Lake Erie have died due to the exotic zebara mussel (Dreissena polymorpha). Zebra mussels attach themselves to native clams in large numbers, impeding the ability of the clams to eat and burrow. However, in 1996, we discovered a population of native clams in Metzger Marsh in western Lake Erie (about 50 miles [80 km] east of Toledo) that were thriving despite the longtime presence of zebra mussel in surrounding waters. At that time, Metzger Marsh was undergoing extensive restoration, including construction of a dike to replace the eroded barrier beach and of a water-control structure to maintain hydrologic connections with the lake (Wilcox and Whillans 1999). The restoration plan called for a drawdown of water levels to promote plant growth from the seedbank -- a process that would also destroy most of the clam population. State and federal resource managers recommended removing as many clams as possible to a site that was isolated from zebra mussels, and then returning them to the marsh after it was restored. We removed about 7,000 native clams in 1996 and moved them back to Metzger Marsh in 1999.
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Synergistic effects of non-Apis bees and honey bees for pollination services
Brittain, Claire; Williams, Neal; Kremen, Claire; Klein, Alexandra-Maria
2013-01-01
In diverse pollinator communities, interspecific interactions may modify the behaviour and increase the pollination effectiveness of individual species. Because agricultural production reliant on pollination is growing, improving pollination effectiveness could increase crop yield without any increase in agricultural intensity or area. In California almond, a crop highly dependent on honey bee pollination, we explored the foraging behaviour and pollination effectiveness of honey bees in orchards with simple (honey bee only) and diverse (non-Apis bees present) bee communities. In orchards with non-Apis bees, the foraging behaviour of honey bees changed and the pollination effectiveness of a single honey bee visit was greater than in orchards where non-Apis bees were absent. This change translated to a greater proportion of fruit set in these orchards. Our field experiments show that increased pollinator diversity can synergistically increase pollination service, through species interactions that alter the behaviour and resulting functional quality of a dominant pollinator species. These results of functional synergy between species were supported by an additional controlled cage experiment with Osmia lignaria and Apis mellifera. Our findings highlight a largely unexplored facilitative component of the benefit of biodiversity to ecosystem services, and represent a way to improve pollinator-dependent crop yields in a sustainable manner. PMID:23303545
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A horizon scan of future threats and opportunities for pollinators and pollination.
Brown, Mark J F; Dicks, Lynn V; Paxton, Robert J; Baldock, Katherine C R; Barron, Andrew B; Chauzat, Marie-Pierre; Freitas, Breno M; Goulson, Dave; Jepsen, Sarina; Kremen, Claire; Li, Jilian; Neumann, Peter; Pattemore, David E; Potts, Simon G; Schweiger, Oliver; Seymour, Colleen L; Stout, Jane C
2016-01-01
Background. Pollinators, which provide the agriculturally and ecologically essential service of pollination, are under threat at a global scale. Habitat loss and homogenisation, pesticides, parasites and pathogens, invasive species, and climate change have been identified as past and current threats to pollinators. Actions to mitigate these threats, e.g., agri-environment schemes and pesticide-use moratoriums, exist, but have largely been applied post-hoc. However, future sustainability of pollinators and the service they provide requires anticipation of potential threats and opportunities before they occur, enabling timely implementation of policy and practice to prevent, rather than mitigate, further pollinator declines. Methods.Using a horizon scanning approach we identified issues that are likely to impact pollinators, either positively or negatively, over the coming three decades. Results.Our analysis highlights six high priority, and nine secondary issues. High priorities are: (1) corporate control of global agriculture, (2) novel systemic pesticides, (3) novel RNA viruses, (4) the development of new managed pollinators, (5) more frequent heatwaves and drought under climate change, and (6) the potential positive impact of reduced chemical use on pollinators in non-agricultural settings. Discussion. While current pollinator management approaches are largely driven by mitigating past impacts, we present opportunities for pre-emptive practice, legislation, and policy to sustainably manage pollinators for future generations.
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A horizon scan of future threats and opportunities for pollinators and pollination
Dicks, Lynn V.; Paxton, Robert J.; Baldock, Katherine C.R.; Barron, Andrew B.; Chauzat, Marie-Pierre; Freitas, Breno M.; Goulson, Dave; Jepsen, Sarina; Kremen, Claire; Li, Jilian; Neumann, Peter; Pattemore, David E.; Potts, Simon G.; Schweiger, Oliver; Seymour, Colleen L.; Stout, Jane C.
2016-01-01
Background. Pollinators, which provide the agriculturally and ecologically essential service of pollination, are under threat at a global scale. Habitat loss and homogenisation, pesticides, parasites and pathogens, invasive species, and climate change have been identified as past and current threats to pollinators. Actions to mitigate these threats, e.g., agri-environment schemes and pesticide-use moratoriums, exist, but have largely been applied post-hoc. However, future sustainability of pollinators and the service they provide requires anticipation of potential threats and opportunities before they occur, enabling timely implementation of policy and practice to prevent, rather than mitigate, further pollinator declines. Methods.Using a horizon scanning approach we identified issues that are likely to impact pollinators, either positively or negatively, over the coming three decades. Results.Our analysis highlights six high priority, and nine secondary issues. High priorities are: (1) corporate control of global agriculture, (2) novel systemic pesticides, (3) novel RNA viruses, (4) the development of new managed pollinators, (5) more frequent heatwaves and drought under climate change, and (6) the potential positive impact of reduced chemical use on pollinators in non-agricultural settings. Discussion. While current pollinator management approaches are largely driven by mitigating past impacts, we present opportunities for pre-emptive practice, legislation, and policy to sustainably manage pollinators for future generations. PMID:27602260
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The betrayed thief – the extraordinary strategy of Aristolochia rotunda to deceive its pollinators
Oelschlägel, Birgit; Nuss, Matthias; von Tschirnhaus, Michael; Pätzold, Claudia; Neinhuis, Christoph; Dötterl, Stefan; Wanke, Stefan
2015-01-01
Pollination of several angiosperms is based on deceit. In such systems, the flowers advertise a reward that ultimately is not provided. We report on a previously unknown pollination/mimicry system discovered in deceptive Aristolochia rotunda (Aristolochiaceae). Pollinators were collected in the natural habitat and identified. Flower scent and the volatiles of insects (models) potentially mimicked were analyzed by chemical analytical techniques. Electrophysiological and behavioral tests on the pollinators identified the components that mediate the plant–pollinator interaction and revealed the model of the mimicry system. The main pollinators of A. rotunda were female Chloropidae. They are food thieves that feed on secretions of true bugs (Miridae) while these are eaten by arthropod predators. Freshly killed mirids and Aristolochia flowers released the same scent components that chloropids use to find their food sources. Aristolochia exploits these components to deceive their chloropid pollinators. Aristolochia and other trap flowers were believed to lure saprophilous flies and mimic brood sites of pollinators. We demonstrate for A. rotunda, and hypothesize for other deceptive angiosperms, the evolution of a different, kleptomyiophilous pollination strategy. It involves scent mimicry and the exploitation of kleptoparasitic flies as pollinators. Our findings suggest a reconsideration of plants assumed to show sapromyiophilous pollination. PMID:25488155
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The betrayed thief - the extraordinary strategy of Aristolochia rotunda to deceive its pollinators.
Oelschlägel, Birgit; Nuss, Matthias; von Tschirnhaus, Michael; Pätzold, Claudia; Neinhuis, Christoph; Dötterl, Stefan; Wanke, Stefan
2015-04-01
Pollination of several angiosperms is based on deceit. In such systems, the flowers advertise a reward that ultimately is not provided. We report on a previously unknown pollination/mimicry system discovered in deceptive Aristolochia rotunda (Aristolochiaceae). Pollinators were collected in the natural habitat and identified. Flower scent and the volatiles of insects (models) potentially mimicked were analyzed by chemical analytical techniques. Electrophysiological and behavioral tests on the pollinators identified the components that mediate the plant-pollinator interaction and revealed the model of the mimicry system. The main pollinators of A. rotunda were female Chloropidae. They are food thieves that feed on secretions of true bugs (Miridae) while these are eaten by arthropod predators. Freshly killed mirids and Aristolochia flowers released the same scent components that chloropids use to find their food sources. Aristolochia exploits these components to deceive their chloropid pollinators. Aristolochia and other trap flowers were believed to lure saprophilous flies and mimic brood sites of pollinators. We demonstrate for A. rotunda, and hypothesize for other deceptive angiosperms, the evolution of a different, kleptomyiophilous pollination strategy. It involves scent mimicry and the exploitation of kleptoparasitic flies as pollinators. Our findings suggest a reconsideration of plants assumed to show sapromyiophilous pollination. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.
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Walston, Leroy J; Mishra, Shruti K; Hartmann, Heidi M; Hlohowskyj, Ihor; McCall, James; Macknick, Jordan
2018-06-13
Of the many roles insects serve for ecosystem function, pollination is possibly the most important service directly linked to human well-being. However, land use changes have contributed to the decline of pollinators and their habitats. In agricultural landscapes that also support renewable energy developments such as utility-scale solar energy [USSE] facilities, opportunities may exist to conserve insect pollinators and locally restore their ecosystem services through the implementation of vegetation management approaches that aim to provide and maintain pollinator habitat at USSE facilities. As a first step toward understanding the potential agricultural benefits of solar-pollinator habitat, we identified areas of overlap between USSE facilities and surrounding pollinator-dependent crop types in the United States (U.S.). Using spatial data on solar energy developments and crop types across the U.S., and assuming a pollinator foraging distance of 1.5 km, we identified over 3,500 km 2 of agricultural land near existing and planned USSE facilities that may benefit from increased pollination services through the creation of pollinator habitat at the USSE facilities. The following five pollinator-dependent crop types accounted for over 90% of the agriculture near USSE facilities, and these could benefit most from the creation of pollinator habitat at existing and planned USSE facilities: soybeans, alfalfa, cotton, almonds, and citrus. We discuss how our results may be used to understand potential agro-economic implications of solar-pollinator habitat. Our results show that ecosystem service restoration through the creation of pollinator habitat could improve the sustainability of large-scale renewable energy developments in agricultural landscapes.
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Artificial light at night as a new threat to pollination.
Knop, Eva; Zoller, Leana; Ryser, Remo; Gerpe, Christopher; Hörler, Maurin; Fontaine, Colin
2017-08-10
Pollinators are declining worldwide and this has raised concerns for a parallel decline in the essential pollination service they provide to both crops and wild plants. Anthropogenic drivers linked to this decline include habitat changes, intensive agriculture, pesticides, invasive alien species, spread of pathogens and climate change. Recently, the rapid global increase in artificial light at night has been proposed to be a new threat to terrestrial ecosystems; the consequences of this increase for ecosystem function are mostly unknown. Here we show that artificial light at night disrupts nocturnal pollination networks and has negative consequences for plant reproductive success. In artificially illuminated plant-pollinator communities, nocturnal visits to plants were reduced by 62% compared to dark areas. Notably, this resulted in an overall 13% reduction in fruit set of a focal plant even though the plant also received numerous visits by diurnal pollinators. Furthermore, by merging diurnal and nocturnal pollination sub-networks, we show that the structure of these combined networks tends to facilitate the spread of the negative consequences of disrupted nocturnal pollination to daytime pollinator communities. Our findings demonstrate that artificial light at night is a threat to pollination and that the negative effects of artificial light at night on nocturnal pollination are predicted to propagate to the diurnal community, thereby aggravating the decline of the diurnal community. We provide perspectives on the functioning of plant-pollinator communities, showing that nocturnal pollinators are not redundant to diurnal communities and increasing our understanding of the human-induced decline in pollinators and their ecosystem service.
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Pollination drop in Juniperus communis: response to deposited material.
Mugnaini, Serena; Nepi, Massimo; Guarnieri, Massimo; Piotto, Beti; Pacini, Ettore
2007-12-01
The pollination drop is a liquid secretion produced by the ovule and exposed outside the micropyle. In many gymnosperms, pollen lands on the surface of the pollination drop, rehydrates and enters the ovule as the drop retracts. The objective of this work was to study the formation of the pollination drop in Juniperus communis, its carbohydrate composition and the response to deposition of conspecific pollen, foreign pollen and other particulate material, in an attempt to clarify the mechanism of pollination drop retraction. Branches with female cones close to pollination drop secretion were collected. On the first day of pollination drop exposure, an eyelash mounted on a wooden stick with paraffin was used to collect pollen or silica gel particles, which were then deposited by contact with the drop. Volume changes in pollination drops were measured by using a stereomicroscope with a micrometer eyepiece 3 h after deposition. The volume of non-pollinated control drops was also recorded. On the first day of secretion, drops were also collected for sugar analysis by high-performance liquid chromatography. The pollination drop persisted for about 12 d if not pollinated, and formed again after removal for up to four consecutive days. After pollination with viable conspecific pollen, the drop retracted quickly and did not form again. Partial withdrawal occurred after deposition of other biological and non-biological material. Fructose was the dominant sugar; glucose was also present but at a much lower percentage. Sugar analysis confirmed the general trend of fructose dominance in gymnosperm pollination drops. Complete pollination drop withdrawal appears to be triggered by a biochemical mechanism resulting from interaction between pollen and drop constituents. The results of particle deposition suggest the existence of a non-specific, particle-size-dependent mechanism that induces partial pollination drop withdrawal. These results suggest that the non-specific response may decrease the probability of pollen landing on the drop, reducing pollination efficiency.
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Pollination Drop in Juniperus communis: Response to Deposited Material
Mugnaini, Serena; Nepi, Massimo; Guarnieri, Massimo; Piotto, Beti; Pacini, Ettore
2007-01-01
Background and Aims The pollination drop is a liquid secretion produced by the ovule and exposed outside the micropyle. In many gymnosperms, pollen lands on the surface of the pollination drop, rehydrates and enters the ovule as the drop retracts. The objective of this work was to study the formation of the pollination drop in Juniperus communis, its carbohydrate composition and the response to deposition of conspecific pollen, foreign pollen and other particulate material, in an attempt to clarify the mechanism of pollination drop retraction. Method Branches with female cones close to pollination drop secretion were collected. On the first day of pollination drop exposure, an eyelash mounted on a wooden stick with paraffin was used to collect pollen or silica gel particles, which were then deposited by contact with the drop. Volume changes in pollination drops were measured by using a stereomicroscope with a micrometer eyepiece 3 h after deposition. The volume of non-pollinated control drops was also recorded. On the first day of secretion, drops were also collected for sugar analysis by high-performance liquid chromatography. Key Results The pollination drop persisted for about 12 d if not pollinated, and formed again after removal for up to four consecutive days. After pollination with viable conspecific pollen, the drop retracted quickly and did not form again. Partial withdrawal occurred after deposition of other biological and non-biological material. Fructose was the dominant sugar; glucose was also present but at a much lower percentage. Conclusions Sugar analysis confirmed the general trend of fructose dominance in gymnosperm pollination drops. Complete pollination drop withdrawal appears to be triggered by a biochemical mechanism resulting from interaction between pollen and drop constituents. The results of particle deposition suggest the existence of a non-specific, particle-size-dependent mechanism that induces partial pollination drop withdrawal. These results suggest that the non-specific response may decrease the probability of pollen landing on the drop, reducing pollination efficiency. PMID:17942592
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Pollinator Partnership | Pollinator.org
about us Pollinator Partnership's mission is to promote the health of pollinators, critical to food and three bites of food. They also sustain our ecosystems and produce our natural resources by helping plants reproduce. Without the actions of pollinators agricultural economies, our food supply, and
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2014-09-09
CAPE CANAVERAL, Fla. – A bee goes about his business pollinating the flowers off Schwartz Road on NASA's Kennedy Space Center in Florida. There are 4,000 species of native bees in the United States. The members of the five most common families - Apidae, Halictidae, Andrenidae, Megachilidae, and Colletidae - can be found throughout North America, including in Florida. The undeveloped property on Kennedy Space Center is managed by the U.S. Fish and Wildlife Service through the Merritt Island National Wildlife Refuge. For information on the refuge, visit http://www.fws.gov/merrittisland/Index.html. For information on the alligators prowling the waterways at Kennedy, visit http://www.nasa.gov/content/ancient-creatures-on-the-prowl/. Photo credit: NASA/Daniel Casper
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ELF communications system ecological monitoring program: Pollinating insect studies
NASA Astrophysics Data System (ADS)
Strickler, Karen; Schriber, J. Mark
1994-11-01
High voltage transmission lines and the earth's and other magnetic fields have been shown to affect honeybee reproduction, survival, orientation, and nest structure. ELY EM fields could have similar effects on native megachilid bees. Two species in the genus Megachile were abundant in artificial nests at experimental and control areas in Dickinson and Iron Counties in Michigan. Data on their nest architecture, nest activity, and emergence/mortality were collected between 1983 and 1993. Eight hypotheses concerning the possible effects of ELY EM fields were considered using these data. The ELY antenna has been fully operational since the summer of 1989. Tests of the hypotheses compare control vs. experimental areas before and after the ELY antenna became fully operational.
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NASA Astrophysics Data System (ADS)
Kjellberg, Finn; Suleman, Nazia; Raja, Shazia; Tayou, Abelouahad; Hossaert-McKey, Martine; Compton, Stephen G.
2014-05-01
The nursery pollination system of fig trees (Ficus) results in the plants providing resources for pollinator fig wasp larvae as part of their male reproductive investment, with selection determining relative investment into pollinating wasps and the pollen they carry. The small size of Ficus pollen suggests that the quantities of pollen transported by individual wasps often limits male reproductive success. We assessed variation in fig wasp pollen loads and its influence on seed production in actively pollinated (Ficus montana) and passively pollinated (Ficus carica) dioecious fig trees.
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Safeguarding pollinators and their values to human well-being.
Potts, Simon G; Imperatriz-Fonseca, Vera; Ngo, Hien T; Aizen, Marcelo A; Biesmeijer, Jacobus C; Breeze, Thomas D; Dicks, Lynn V; Garibaldi, Lucas A; Hill, Rosemary; Settele, Josef; Vanbergen, Adam J
2016-12-08
Wild and managed pollinators provide a wide range of benefits to society in terms of contributions to food security, farmer and beekeeper livelihoods, social and cultural values, as well as the maintenance of wider biodiversity and ecosystem stability. Pollinators face numerous threats, including changes in land-use and management intensity, climate change, pesticides and genetically modified crops, pollinator management and pathogens, and invasive alien species. There are well-documented declines in some wild and managed pollinators in several regions of the world. However, many effective policy and management responses can be implemented to safeguard pollinators and sustain pollination services.
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Uni-directional interaction and plant-pollinator-robber coexistence.
Wang, Yuanshi; DeAngelis, Donald L; Holland, J Nathaniel
2012-09-01
A mathematical model for the plant-pollinator-robber interaction is studied to understand the factors leading to the widespread occurrence and stability of such interactions. In the interaction, a flowering plant provides resource for its pollinator and the pollinator has both positive and negative effects on the plant. A nectar robber acts as a plant predator, consuming a common resource with the pollinator, but with a different functional response. Using dynamical systems theory, mechanisms of species coexistence are investigated to show how a robber could invade the plant-pollinator system and persist stably with the pollinator. In addition, circumstances are demonstrated in which the pollinator's positive and negative effects on the plant could determine the robber's invasibility and the three-species coexistence.
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Floral advertisement and the competition for pollination services.
Fishman, Michael A; Hadany, Lilach
2015-06-01
Flowering plants are a major component of terrestrial ecosystems, and most of them depend on animal pollinators for reproduction. Thus, the mutualism between flowering plants and their pollinators is a keystone ecological relationship in both natural and agricultural ecosystems. Though plant-pollinator interactions have received considerable amount of attention, there are still many unanswered questions. In this paper, we use methods of evolutionary game theory to investigate the co-evolution of floral advertisement and pollinator preferences Our results indicate that competition for pollination services among plant species can in some cases lead to specialization of the pollinator population to a single plant species (oligolecty). However, collecting pollen from multiple plants - at least at the population level - is evolutionarily stable under a wider parameter range. Finally, we show that, in the presence of pollinators, plants that optimize their investment in attracting vs. rewarding visiting pollinators outcompete plants that do not. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
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Bee pollination improves crop quality, shelf life and commercial value.
Klatt, Björn K; Holzschuh, Andrea; Westphal, Catrin; Clough, Yann; Smit, Inga; Pawelzik, Elke; Tscharntke, Teja
2014-01-22
Pollination improves the yield of most crop species and contributes to one-third of global crop production, but comprehensive benefits including crop quality are still unknown. Hence, pollination is underestimated by international policies, which is particularly alarming in times of agricultural intensification and diminishing pollination services. In this study, exclusion experiments with strawberries showed bee pollination to improve fruit quality, quantity and market value compared with wind and self-pollination. Bee-pollinated fruits were heavier, had less malformations and reached higher commercial grades. They had increased redness and reduced sugar-acid-ratios and were firmer, thus improving the commercially important shelf life. Longer shelf life reduced fruit loss by at least 11%. This is accounting for 0.32 billion US$ of the 1.44 billion US$ provided by bee pollination to the total value of 2.90 billion US$ made with strawberry selling in the European Union 2009. The fruit quality and yield effects are driven by the pollination-mediated production of hormonal growth regulators, which occur in several pollination-dependent crops. Thus, our comprehensive findings should be transferable to a wide range of crops and demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.
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Bee species diversity enhances productivity and stability in a perennial crop.
Rogers, Shelley R; Tarpy, David R; Burrack, Hannah J
2014-01-01
Wild bees provide important pollination services to agroecoystems, but the mechanisms which underlie their contribution to ecosystem functioning--and, therefore, their importance in maintaining and enhancing these services-remain unclear. We evaluated several mechanisms through which wild bees contribute to crop productivity, the stability of pollinator visitation, and the efficiency of individual pollinators in a highly bee-pollination dependent plant, highbush blueberry. We surveyed the bee community (through transect sampling and pan trapping) and measured pollination of both open- and singly-visited flowers. We found that the abundance of managed honey bees, Apis mellifera, and wild-bee richness were equally important in describing resulting open pollination. Wild-bee richness was a better predictor of pollination than wild-bee abundance. We also found evidence suggesting pollinator visitation (and subsequent pollination) are stabilized through the differential response of bee taxa to weather (i.e., response diversity). Variation in the individual visit efficiency of A. mellifera and the southeastern blueberry bee, Habropoda laboriosa, a wild specialist, was not associated with changes in the pollinator community. Our findings add to a growing literature that diverse pollinator communities provide more stable and productive ecosystem services.
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Pollinator Foraging Adaptation and Coexistence of Competing Plants
Revilla, Tomás A.; Křivan, Vlastimil
2016-01-01
We use the optimal foraging theory to study coexistence between two plant species and a generalist pollinator. We compare conditions for plant coexistence for non-adaptive vs. adaptive pollinators that adjust their foraging strategy to maximize fitness. When pollinators have fixed preferences, we show that plant coexistence typically requires both weak competition between plants for resources (e.g., space or nutrients) and pollinator preferences that are not too biased in favour of either plant. We also show how plant coexistence is promoted by indirect facilitation via the pollinator. When pollinators are adaptive foragers, pollinator’s diet maximizes pollinator’s fitness measured as the per capita population growth rate. Simulations show that this has two conflicting consequences for plant coexistence. On the one hand, when competition between pollinators is weak, adaptation favours pollinator specialization on the more profitable plant which increases asymmetries in plant competition and makes their coexistence less likely. On the other hand, when competition between pollinators is strong, adaptation promotes generalism, which facilitates plant coexistence. In addition, adaptive foraging allows pollinators to survive sudden loss of the preferred plant host, thus preventing further collapse of the entire community. PMID:27505254
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A novel mutualism between an ant-plant and its resident pollinator
NASA Astrophysics Data System (ADS)
Shenoy, Megha; Borges, Renee M.
2008-01-01
Pollination systems in which the host plant provides breeding sites for pollinators, invariably within flowers, are usually highly specialized mutualisms. We found that the pollinating bee Braunsapis puangensis breeds within the caulinary domatia of the semi-myrmecophyte Humboldtia brunonis (Fabaceae), an unusual ant-plant that is polymorphic for the presence of domatia and harbours a diverse invertebrate fauna including protective and non-protective ants in its domatia. B. puangensis is the most common flower visitor that carries the highest proportion of H. brunonis pollen. This myrmecophyte is pollen limited and cross-pollinated by bees in the daytime. Hence, the symbiotic pollinator could provide a benefit to trees bearing domatia by alleviating this limitation. We therefore report for the first time an unspecialised mutualism in which a pollinator is housed in a plant structure other than flowers. Here, the cost to the plant is lower than for conventional brood-site pollination mutualisms where the pollinator develops at the expense of plant reproductive structures. Myrmecophytes housing resident pollinators are unusual, as ants are known to be enemies of pollinators, and housing them together may decrease the benefits that these residents could individually provide to the host plant.
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Bee Species Diversity Enhances Productivity and Stability in a Perennial Crop
Rogers, Shelley R.; Tarpy, David R.; Burrack, Hannah J.
2014-01-01
Wild bees provide important pollination services to agroecoystems, but the mechanisms which underlie their contribution to ecosystem functioning—and, therefore, their importance in maintaining and enhancing these services—remain unclear. We evaluated several mechanisms through which wild bees contribute to crop productivity, the stability of pollinator visitation, and the efficiency of individual pollinators in a highly bee-pollination dependent plant, highbush blueberry. We surveyed the bee community (through transect sampling and pan trapping) and measured pollination of both open- and singly-visited flowers. We found that the abundance of managed honey bees, Apis mellifera, and wild-bee richness were equally important in describing resulting open pollination. Wild-bee richness was a better predictor of pollination than wild-bee abundance. We also found evidence suggesting pollinator visitation (and subsequent pollination) are stabilized through the differential response of bee taxa to weather (i.e., response diversity). Variation in the individual visit efficiency of A. mellifera and the southeastern blueberry bee, Habropoda laboriosa, a wild specialist, was not associated with changes in the pollinator community. Our findings add to a growing literature that diverse pollinator communities provide more stable and productive ecosystem services. PMID:24817218
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Cozzolino, Salvatore; Schiestl, Florian P; Müller, Andreas; De Castro, Olga; Nardella, Antonio Marco; Widmer, Alex
2005-01-01
Pollinator specificity has traditionally been considered the main reproductive isolation mechanism in orchids. Among Mediterranean orchids, however, many species attract and deceive pollinators by mimicking nectar-rewarding plants. To test the extent to which deceptive orchid species share pollinators, we collected and identified hemipollinaria-carrying insects, and used ribosomal sequences to identify the orchid species from which hemipollinaria were removed. We found that social and solitary bees, and also flies, carried hemipollinaria belonging to nine orchid species with different degrees of specialization. In particular, Anacamptis morio, Dactylorhiza romana and Orchis mascula used a large set of pollinator species, whereas others such as Orchis quadripunctata seemed to be pollinated by one pollinator species only. Out of the insects with hemipollinaria, 19% were found to carry hemipollinaria from more than one orchid species, indicating that sympatric food-deceptive orchids can share pollinators. This sharing was apparent even among orchid sister-species, thus revealing an effective overlap in pollinator sets among closely related species. These results suggest varying degrees of pollinator specificity in these orchids, and indicate that pollinator specificity cannot always act as the main isolation mechanism in food-deceptive temperate orchids. PMID:16024392
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The pollination ecology of an assemblage of grassland asclepiads in South Africa.
Ollerton, Jeff; Johnson, Steven D; Cranmer, Louise; Kellie, Sam
2003-12-01
The KwaZulu-Natal region of South Africa hosts a large diversity of asclepiads (Apocynaceae: Asclepiadoideae), many of which are endemic to the area. The asclepiads are of particular interest because of their characteristically highly evolved floral morphology. During 3 months of fieldwork (November 2000 to January 2001) the flower visitors and pollinators to an assemblage of nine asclepiads at an upland grassland site were studied. These observations were augmented by laboratory studies of flower morphology (including scanning electron microscopy) and flower colour (using a spectrometer). Two of the specialized pollination systems that were documented are new to the asclepiads: fruit chafer pollination and pompilid wasp pollination. The latter is almost unique in the angiosperms. Taxa possessing these specific pollination systems cluster together in multidimensional phenotype space, suggesting that there has been convergent evolution in response to similar selection to attract identical pollinators. Pollination niche breadth varied from the very specialized species, with only one pollinator, to the more generalized, with up to ten pollinators. Pollinator sharing by the specialized taxa does not appear to have resulted in niche differentiation in terms of the temporal or spatial dimensions, or with regards to placement of pollinaria. Nestedness analysis of the data set showed that there was predictability and structure to the pattern of plant-pollinator interactions, with generalist insects visiting specialized plants and vice versa. The research has shown that there is still much to be learned about plant-pollinator interactions in areas of high plant diversity such as South Africa.
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Chiang, Gustavo; Barra, Ricardo; Díaz-Jaramillo, Mauricio; Rivas, Meyling; Bahamonde, Paulina; Munkittrick, Kelly R
2015-07-01
Pulp and paper mill effluents (PPMEs) have been shown to increase gonad size, cause early maturation, and disrupt hormone functions in native and non-native Chilean fish. In this study, we assessed reproductive (plasma vitellogenin; VTG, gonad development) and metabolic (ethoxyresorufin-O-deethylase activity; EROD) end points, relative liver size (LSI) and condition factor (K) of juvenile female and male rainbow trout exposed to effluents. Unlike previous studies, which have focus either on the specific effects of effluent on fish in laboratory exposures or biotic population statuses downstream of discharge sites, we simultaneously assessed the impacts of PPMES on trout using two approaches: (1) laboratory exposures of tertiary treated PPME produced from processing Eucalyptus globulus or Pinus radiata; and (2) in situ bioassay downstream of the combined discharge of the same pulp mill. Despite an increase in the average gonadosomatic index (GSI) in exposed fish, no statistical differences in gonad size between exposed and unexposed individuals was detected. However, both female and male fish exposed to effluents showed significantly higher concentrations of plasma VTG, so more in fish exposed to Eucalyptus-based effluent when compared to Pinus PPME. In addition, male fish showed intersex characteristics in all exposure assays (Eucaliptus and Pinus) and, despite the low concentration of effluent in the river (<1% [v/v]), similar responses were observed in the caged fish. Finally, EROD activity was induced in both in situ exposures and laboratory assays at the higher PPME concentration (60-85% PPME). This study confirms estrogenic effects in Chilean fish exposed to PPME and the necessity for biological effects monitoring in addition to the assessment of physical-chemical endpoints as required in current government regulations. Copyright © 2015 Elsevier B.V. All rights reserved.
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Effects of a Possible Pollinator Crisis on Food Crop Production in Brazil
Nunes, Cássio A.; Santos, Natália B.; D`Amico, Ana R.; Fernandes, G. Wilson; Quesada, Maurício; Braga, Rodrigo F.; Neves, Ana Carolina O.
2016-01-01
Animal pollinators contribute to human food production and security thereby ensuring an important component of human well-being. The recent decline of these agents in Europe and North America has aroused the concern of a potential global pollinator crisis. In order to prioritize efforts for pollinator conservation, we evaluated the extent to which food production depends on animal pollinators in Brazil—one of the world’s agriculture leaders—by comparing cultivated area, produced volume and yield value of major food crops that are pollinator dependent with those that are pollinator non-dependent. In addition, we valued the ecosystem service of pollination based on the degree of pollinator dependence of each crop and the consequence of a decline in food production to the Brazilian Gross Domestic Product and Brazilian food security. A total of 68% of the 53 major food crops in Brazil depend to some degree on animals for pollination. Pollinator non-dependent crops produce a greater volume of food, mainly because of the high production of sugarcane, but the cultivated area and monetary value of pollinator dependent crops are higher (59% of total cultivated area and 68% of monetary value). The loss of pollination services for 29 of the major food crops would reduce production by 16.55–51 million tons, which would amount to 4.86–14.56 billion dollars/year, and reduce the agricultural contribution to the Brazilian GDP by 6.46%– 19.36%. These impacts would be largely absorbed by family farmers, which represent 74.4% of the agricultural labor force in Brazil. The main effects of a pollinator crisis in Brazil would be felt by the poorer and more rural classes due to their lower income and direct or exclusive dependence on this ecosystem service. PMID:27902787
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Duarte, M O; Mendes-Rodrigues, C; Alves, M F; Oliveira, P E; Sampaio, D S
2017-03-01
Mixed cross and self-pollen load on the stigma (mixed pollination) of species with late-acting self-incompatibility system (LSI) can lead to self-fertilized seed production. This "cryptic self-fertility" may allow selfed seedling development in species otherwise largely self-sterile. Our aims were to check if mixed pollinations would lead to fruit set in LSI Adenocalymma peregrinum, and test for evidence of early-acting inbreeding depression in putative selfed seeds from mixed pollinations. Experimental pollinations were carried out in a natural population. Fruit and seed set from self-, cross and mixed pollinations were analysed. Further germination tests were carried out for the seeds obtained from treatments. Our results confirm self-incompatibility, and fruit set from cross-pollinations was three-fold that from mixed pollinations. This low fruit set in mixed pollinations is most likely due to a greater number of self- than cross-fertilized ovules, which promotes LSI action and pistil abortion. Likewise, higher percentage of empty seeds in surviving fruits from mixed pollinations compared with cross-pollinations is probably due to ovule discounting caused by self-fertilization. Moreover, germinability of seeds with developed embryos was lower in fruits from mixed than from cross-pollinations, and the non-viable seeds from mixed pollinations showed one-third of the mass of those from cross-pollinations. The great number of empty seeds, lower germinability, lower mass of non-viable seeds, and higher variation in seed mass distribution in mixed pollinations, strongly suggests early-acing inbreeding depression in putative selfed seeds. In this sense, LSI and inbreeding depression acting together probably constrain self-fertilized seedling establishment in A. peregrinum. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.
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On the success of a swindle: pollination by deception in orchids
NASA Astrophysics Data System (ADS)
Schiestl, Florian P.
2005-06-01
A standing enigma in pollination ecology is the evolution of pollinator attraction without offering reward in about one third of all orchid species. Here I review concepts of pollination by deception, and in particular recent findings in the pollination syndromes of food deception and sexual deception in orchids. Deceptive orchids mimic floral signals of rewarding plants (food deception) or mating signals of receptive females (sexual deception) to attract pollen vectors. In some food deceptive orchids, similarities in the spectral reflectance visible to the pollinator in a model plant and its mimic, and increased reproductive success of the mimic in the presence of the model have been demonstrated. Other species do not mimic specific model plants but attract pollinators with general attractive floral signals. In sexually deceptive orchids, floral odor is the key trait for pollinator attraction, and behaviorally active compounds in the orchids are identical to the sex pheromone of the pollinator species. Deceptive orchids often show high variability in floral signals, which may be maintained by negative frequency-dependent selection, since pollinators can learn and subsequently avoid common deceptive morphs more quickly than rare ones. The evolution of obligate deception in orchids seems paradoxical in the light of the typically lower fruit set than in rewarding species. Pollination by deception, however, can reduce self-pollination and encourage pollen flow over longer distances, thus promoting outbreeding. Although some food deceptive orchids are isolated through postzygotic reproductive barriers, sexually deceptive orchids lack post-mating barriers and species isolation is achieved via specific pollinator attraction. Recent population genetic and phylogenetic investigations suggest gene-flow within subgeneric clades, but pollinator-mediated selection may maintain species-specific floral traits.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
McCall, James D; Macknick, Jordan E; Walston, Leroy J.
Of the many roles insects serve for ecosystem function, pollination is possibly the most important service directly linked to human well-being. However, land use changes have contributed to the decline of pollinators and their habitats. In agricultural landscapes that also support renewable energy developments such as utility-scale solar energy [USSE] facilities, opportunities may exist to conserve insect pollinators and locally restore their ecosystem services through the implementation of vegetation management approaches that aim to provide and maintain pollinator habitat at USSE facilities. As a first step toward understanding the potential agricultural benefits of solar-pollinator habitat, we identified areas of overlapmore » between USSE facilities and surrounding pollinator-dependent crop types in the United States (U.S.). Using spatial data on solar energy developments and crop types across the U.S., and assuming a pollinator foraging distance of 1.5 km, we identified over 3,500 km2 of agricultural land near existing and planned USSE facilities that may benefit from increased pollination services through the creation of pollinator habitat at the USSE facilities. The following five pollinator-dependent crop types accounted for over 90% of the agriculture near USSE facilities, and these could benefit most from the creation of pollinator habitat at existing and planned USSE facilities: soybeans, alfalfa, cotton, almonds, and citrus. We discuss how our results may be used to understand potential agro-economic implications of solar-pollinator habitat. Our results show that ecosystem service restoration through the creation of pollinator habitat could improve the sustainability of large-scale renewable energy developments in agricultural landscapes.« less
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Effects of a Possible Pollinator Crisis on Food Crop Production in Brazil.
Novais, Samuel M A; Nunes, Cássio A; Santos, Natália B; D Amico, Ana R; Fernandes, G Wilson; Quesada, Maurício; Braga, Rodrigo F; Neves, Ana Carolina O
2016-01-01
Animal pollinators contribute to human food production and security thereby ensuring an important component of human well-being. The recent decline of these agents in Europe and North America has aroused the concern of a potential global pollinator crisis. In order to prioritize efforts for pollinator conservation, we evaluated the extent to which food production depends on animal pollinators in Brazil-one of the world's agriculture leaders-by comparing cultivated area, produced volume and yield value of major food crops that are pollinator dependent with those that are pollinator non-dependent. In addition, we valued the ecosystem service of pollination based on the degree of pollinator dependence of each crop and the consequence of a decline in food production to the Brazilian Gross Domestic Product and Brazilian food security. A total of 68% of the 53 major food crops in Brazil depend to some degree on animals for pollination. Pollinator non-dependent crops produce a greater volume of food, mainly because of the high production of sugarcane, but the cultivated area and monetary value of pollinator dependent crops are higher (59% of total cultivated area and 68% of monetary value). The loss of pollination services for 29 of the major food crops would reduce production by 16.55-51 million tons, which would amount to 4.86-14.56 billion dollars/year, and reduce the agricultural contribution to the Brazilian GDP by 6.46%- 19.36%. These impacts would be largely absorbed by family farmers, which represent 74.4% of the agricultural labor force in Brazil. The main effects of a pollinator crisis in Brazil would be felt by the poorer and more rural classes due to their lower income and direct or exclusive dependence on this ecosystem service.
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Pollination niche overlap between a parasitic plant and its host.
Ollerton, Jeff; Stott, Adrian; Allnutt, Emma; Shove, Sam; Taylor, Chloe; Lamborn, Ellen
2007-03-01
Niche theory predicts that species which share resources should evolve strategies to minimise competition for those resources, or the less competitive species would be extirpated. Some plant species are constrained to co-occur, for example parasitic plants and their hosts, and may overlap in their pollination niche if they flower at the same time and attract the same pollinators. Using field observations and experiments between 1996 and 2006, we tested a series of hypotheses regarding pollination niche overlap between a specialist parasitic plant Orobanche elatior (Orobanchaceae) and its host Centaurea scabiosa (Asteraceae). These species flower more or less at the same time, with some year-to-year variation. The host is pollinated by a diverse range of insects, which vary in their effectiveness, whilst the parasite is pollinated by a single species of bumblebee, Bombus pascuorum, which is also an effective pollinator of the host plant. The two species therefore have partially overlapping pollination niches. These niches are not finely subdivided by differential pollen placement, or by diurnal segregation of the niches. We therefore found no evidence of character displacement within the pollination niches of these species, possibly because pollinators are not a limiting resource for these plants. Direct observation of pollinator movements, coupled with experimental manipulations of host plant inflorescence density, showed that Bombus pascuorum only rarely moves between inflorescences of the host and the parasite and therefore the presence of one plant is unlikely to be facilitating pollination in the other. This is the first detailed examination of pollination niche overlap in a plant parasite system and we suggest avenues for future research in relation to pollination and other shared interactions between parasitic plants and their hosts.
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Viruses of commercialized insect pollinators.
Gisder, Sebastian; Genersch, Elke
2017-07-01
Managed insect pollinators are indispensable in modern agriculture. They are used worldwide not only in the open field but also in greenhouses to enhance fruit set, seed production, and crop yield. Managed honey bee (Apis mellifera, Apis cerana) colonies provide the majority of commercial pollination although other members of the superfamily Apoidea are also exploited and commercialized as managed pollinators. In the recent past, it became more and more evident that viral diseases play a key role in devastating honey bee colony losses and it was also recognized that many viruses originally thought to be honey bee specific can also be detected in other pollinating insects. However, while research on viruses infecting honey bees started more than 50years ago and the knowledge on these viruses is growing ever since, little is known on virus diseases of other pollinating bee species. Recent virus surveys suggested that many of the viruses thought to be honey bee specific are actually circulating in the pollinator community and that pollinator management and commercialization of pollinators provide ample opportunity for viral diseases to spread. However, the direction of disease transmission is not always clear and the impact of these viral diseases on the different hosts remains elusive in many cases. With our review we want to provide an up-to-date overview on the viruses detected in different commercialized pollinators in order to encourage research in the field of pollinator virology that goes beyond molecular detection of viruses. A deeper understanding of this field of virology is urgently needed to be able to evaluate the impact of viruses on pollinator health and the role of different pollinators in spreading viral diseases and to be able to decide on appropriate measures to prevent virus-driven pollinator decline. Copyright © 2016 Elsevier Inc. All rights reserved.
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Experimental evidence that wildflower strips increase pollinator visits to crops.
Feltham, Hannah; Park, Kirsty; Minderman, Jeroen; Goulson, Dave
2015-08-01
Wild bees provide a free and potentially diverse ecosystem service to farmers growing pollination-dependent crops. While many crops benefit from insect pollination, soft fruit crops, including strawberries are highly dependent on this ecosystem service to produce viable fruit. However, as a result of intensive farming practices and declining pollinator populations, farmers are increasingly turning to commercially reared bees to ensure that crops are adequately pollinated throughout the season. Wildflower strips are a commonly used measure aimed at the conservation of wild pollinators. It has been suggested that commercial crops may also benefit from the presence of noncrop flowers; however, the efficacy and economic benefits of sowing flower strips for crops remain relatively unstudied. In a study system that utilizes both wild and commercial pollinators, we test whether wildflower strips increase the number of visits to adjacent commercial strawberry crops by pollinating insects. We quantified this by experimentally sowing wildflower strips approximately 20 meters away from the crop and recording the number of pollinator visits to crops with, and without, flower strips. Between June and August 2013, we walked 292 crop transects at six farms in Scotland, recording a total of 2826 pollinators. On average, the frequency of pollinator visits was 25% higher for crops with adjacent flower strips compared to those without, with a combination of wild and commercial bumblebees (Bombus spp.) accounting for 67% of all pollinators observed. This effect was independent of other confounding effects, such as the number of flowers on the crop, date, and temperature. Synthesis and applications. This study provides evidence that soft fruit farmers can increase the number of pollinators that visit their crops by sowing inexpensive flower seed mixes nearby. By investing in this management option, farmers have the potential to increase and sustain pollinator populations over time.
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Experimental evidence that wildflower strips increase pollinator visits to crops
Feltham, Hannah; Park, Kirsty; Minderman, Jeroen; Goulson, Dave
2015-01-01
Wild bees provide a free and potentially diverse ecosystem service to farmers growing pollination-dependent crops. While many crops benefit from insect pollination, soft fruit crops, including strawberries are highly dependent on this ecosystem service to produce viable fruit. However, as a result of intensive farming practices and declining pollinator populations, farmers are increasingly turning to commercially reared bees to ensure that crops are adequately pollinated throughout the season. Wildflower strips are a commonly used measure aimed at the conservation of wild pollinators. It has been suggested that commercial crops may also benefit from the presence of noncrop flowers; however, the efficacy and economic benefits of sowing flower strips for crops remain relatively unstudied. In a study system that utilizes both wild and commercial pollinators, we test whether wildflower strips increase the number of visits to adjacent commercial strawberry crops by pollinating insects. We quantified this by experimentally sowing wildflower strips approximately 20 meters away from the crop and recording the number of pollinator visits to crops with, and without, flower strips. Between June and August 2013, we walked 292 crop transects at six farms in Scotland, recording a total of 2826 pollinators. On average, the frequency of pollinator visits was 25% higher for crops with adjacent flower strips compared to those without, with a combination of wild and commercial bumblebees (Bombus spp.) accounting for 67% of all pollinators observed. This effect was independent of other confounding effects, such as the number of flowers on the crop, date, and temperature. Synthesis and applications. This study provides evidence that soft fruit farmers can increase the number of pollinators that visit their crops by sowing inexpensive flower seed mixes nearby. By investing in this management option, farmers have the potential to increase and sustain pollinator populations over time. PMID:26380683
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Bird pollination of Canary Island endemic plants
NASA Astrophysics Data System (ADS)
Ollerton, Jeff; Cranmer, Louise; Stelzer, Ralph J.; Sullivan, Steve; Chittka, Lars
2009-02-01
The Canary Islands are home to a guild of endemic, threatened bird-pollinated plants. Previous work has suggested that these plants evolved floral traits as adaptations to pollination by flower specialist sunbirds, but subsequently, they appear to have co-opted generalist passerine birds as sub-optimal pollinators. To test this idea, we carried out a quantitative study of the pollination biology of three of the bird-pollinated plants, Canarina canariensis (Campanulaceae), Isoplexis canariensis (Veronicaceae) and Lotus berthelotii (Fabaceae), on the island of Tenerife. Using colour vision models, we predicted the detectability of flowers to bird and bee pollinators. We measured pollinator visitation rates, nectar standing crops as well as seed-set and pollen removal and deposition. These data showed that the plants are effectively pollinated by non-flower specialist passerine birds that only occasionally visit flowers. The large nectar standing crops and extended flower longevities (>10 days) of Canarina and Isoplexis suggests that they have evolved a bird pollination system that effectively exploits these low frequency non-specialist pollen vectors and is in no way sub-optimal. Seed set in two of the three species was high and was significantly reduced or zero in flowers where pollinator access was restricted. In L. berthelotii, however, no fruit set was observed, probably because the plants were self-incompatible horticultural clones of a single genet. We also show that, while all three species are easily detectable for birds, the orange Canarina and the red Lotus (but less so the yellow-orange Isoplexis) should be difficult to detect for insect pollinators without specialised red receptors, such as bumblebees. Contrary to expectations if we accept that the flowers are primarily adapted to sunbird pollination, the chiffchaff ( Phylloscopus canariensis) was an effective pollinator of these species.
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Neither insects nor wind: ambophily in dioecious Chamaedorea palms (Arecaceae).
Rios, L D; Fuchs, E J; Hodel, D R; Cascante-Marín, A
2014-07-01
Pollination of Neotropical dioecious trees is commonly related to generalist insects. Similar data for non-tree species with separated genders are inconclusive. Recent studies on pollination of dioecious Chamaedorea palms (Arecaceae) suggest that species are either insect- or wind-pollinated. However, the wide variety of inflorescence and floral attributes within the genus suggests mixed pollination mode involving entomophily and anemophily. To evaluate this hypothesis, we studied the pollination of Chamaedorea costaricana, C. macrospadix, C. pinnatifrons and C. tepejilote in two montane forests in Costa Rica. A complementary morphological analysis of floral traits was carried out to distinguish species groups within the genus according to their most probable pollination mechanism. We conducted pollinator exclusion experiments, field observations on visitors to pistillate and staminate inflorescences, and trapped airborne pollen. A cluster analysis using 18 floral traits selected for their association with wind and insect pollination syndromes was carried out using 52 Chamaedorea species. Exclusion experiments showed that both wind and insects, mostly thrips (Thysanoptera), pollinated the studied species. Thrips used staminate inflorescences as brood sites and pollinated pistillate flowers by deception. Insects caught on pistillate inflorescences transported pollen, while traps proved that pollen is wind-borne. Our empirical findings clearly suggest that pollination of dioecious Chamaedorea palms is likely to involve both insects and wind. A cluster analysis showed that the majority of studied species have a combination of floral traits that allow for both pollination modes. Our pollination experiments and morphological analysis both suggest that while some species may be completely entomophilous or anemophilous, ambophily might be a common condition within Chamaedorea. Our results propose a higher diversity of pollination mechanisms of Neotropical dioecious species than previously suggested. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Twenty-five years of progress in understanding pollination mechanisms in palms (Arecaceae)
Barfod, Anders S.; Hagen, Melanie; Borchsenius, Finn
2011-01-01
Background With more than 90 published studies of pollination mechanisms, the palm family is one of the better studied tropical families of angiosperms. Understanding palm–pollinator interactions has implications for tropical silviculture, agroforestry and horticulture, as well as for our understanding of palm evolution and diversification. We review the rich literature on pollination mechanisms in palms that has appeared since the last review of palm pollination studies was published 25 years ago. Scope and Conclusions Visitors to palm inflorescences are attracted by rewards such as food, shelter and oviposition sites. The interaction between the palm and its visiting fauna represents a trade-off between the services provided by the potential pollinators and the antagonistic activities of other insect visitors. Evidence suggests that beetles constitute the most important group of pollinators in palms, followed by bees and flies. Occasional pollinators include mammals (e.g. bats and marsupials) and even crabs. Comparative studies of palm–pollinator interactions in closely related palm species document transitions in floral morphology, phenology and anatomy correlated with shifts in pollination vectors. Synecological studies show that asynchronous flowering and partitioning of pollinator guilds may be important regulators of gene flow between closely related sympatric taxa and potential drivers of speciation processes. Studies of larger plant–pollinator networks point out the importance of competition for pollinators between palms and other flowering plants and document how the insect communities in tropical forest canopies probably influence the reproductive success of palms. However, published studies have a strong geographical bias towards the South American region and a taxonomic bias towards the tribe Cocoseae. Future studies should try to correct this imbalance to provide a more representative picture of pollination mechanisms and their evolutionary implications across the entire family. PMID:21831852
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Modelling pollination services across agricultural landscapes
Lonsdorf, Eric; Kremen, Claire; Ricketts, Taylor; Winfree, Rachael; Williams, Neal; Greenleaf, Sarah
2009-01-01
Background and Aims Crop pollination by bees and other animals is an essential ecosystem service. Ensuring the maintenance of the service requires a full understanding of the contributions of landscape elements to pollinator populations and crop pollination. Here, the first quantitative model that predicts pollinator abundance on a landscape is described and tested. Methods Using information on pollinator nesting resources, floral resources and foraging distances, the model predicts the relative abundance of pollinators within nesting habitats. From these nesting areas, it then predicts relative abundances of pollinators on the farms requiring pollination services. Model outputs are compared with data from coffee in Costa Rica, watermelon and sunflower in California and watermelon in New Jersey–Pennsylvania (NJPA). Key Results Results from Costa Rica and California, comparing field estimates of pollinator abundance, richness or services with model estimates, are encouraging, explaining up to 80 % of variance among farms. However, the model did not predict observed pollinator abundances on NJPA, so continued model improvement and testing are necessary. The inability of the model to predict pollinator abundances in the NJPA landscape may be due to not accounting for fine-scale floral and nesting resources within the landscapes surrounding farms, rather than the logic of our model. Conclusions The importance of fine-scale resources for pollinator service delivery was supported by sensitivity analyses indicating that the model's predictions depend largely on estimates of nesting and floral resources within crops. Despite the need for more research at the finer-scale, the approach fills an important gap by providing quantitative and mechanistic model from which to evaluate policy decisions and develop land-use plans that promote pollination conservation and service delivery. PMID:19324897
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Dáttilo, Wesley; Aguirre, Armando; Quesada, Mauricio; Dirzo, Rodolfo
2015-01-01
Despite increasing knowledge about the effects of habitat loss on pollinators in natural landscapes, information is very limited regarding the underlying mechanisms of forest fragmentation affecting plant-pollinator interactions in such landscapes. Here, we used a network approach to describe the effects of forest fragmentation on the patterns of interactions involving the understory dominant palm Astrocaryum mexicanum (Arecaceae) and its floral visitors (including both effective and non-effective pollinators) at the individual level in a Mexican tropical rainforest landscape. Specifically, we asked: (i) Does fragment size affect the structure of individual-based plant-pollinator networks? (ii) Does the core of highly interacting visitor species change along the fragmentation size gradient? (iii) Does forest fragment size influence the abundance of effective pollinators of A. mexicanum? We found that fragment size did not affect the topological structure of the individual-based palm-pollinator network. Furthermore, while the composition of peripheral non-effective pollinators changed depending on fragment size, effective core generalist species of pollinators remained stable. We also observed that both abundance and variance of effective pollinators of male and female flowers of A. mexicanum increased with forest fragment size. These findings indicate that the presence of effective pollinators in the core of all forest fragments could keep the network structure stable along the gradient of forest fragmentation. In addition, pollination of A. mexicanum could be more effective in larger fragments, since the greater abundance of pollinators in these fragments may increase the amount of pollen and diversity of pollen donors between flowers of individual plants. Given the prevalence of fragmentation in tropical ecosystems, our results indicate that the current patterns of land use will have consequences on the underlying mechanisms of pollination in remnant forests.
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Jin, Xiao-Fang; Ye, Zhong-Ming; Amboka, Grace M; Wang, Qing-Feng; Yang, Chun-Feng
2017-01-01
A sensitive bilobed stigma is thought to assure reproduction, avoid selfing and promote outcrossing. In addition, it may also play a role in pollinator selection since only pollinators with the appropriate body size can trigger this mechanism. However, no experimental study has investigated how the sensitive stigma responds to different pollinators and its potential effects on pollination. Mazus miquelii (Phrymaceae), a plant with a bilobed stigma was studied to investigate the relationship between stigma behaviors and its multiple insect pollinators. The reaction time of stigma closure after touched, duration of temporary closure, and factors determining permanent closure of the stigma were studied when flowers were exposed to different visitors and conducted with hand pollination. Manual stimulation was also used to detect the potential differences in stigmas when touched with different degrees of external forces. Results indicated that, compared to pollinators with a small body size, larger pollinators transferred more pollen grains to the stigma, causing a rapid stigma response and resulting in a higher percentage of permanent closures. Duration of temporary closure was negatively correlated with the speed of stigma closure; a stigma that closed more rapidly reopened more slowly. Manual stimulation showed that reaction time of stigma closure was likely a response to external mechanical forces. Hand pollination treatments revealed that the permanent closure of a stigma was determined by the size of stigmatic pollen load. For large pollinators, the speedy reaction of the stigma might help to reduce pollen loss, enhance pollen germination and avoid obstructing pollen export. Stigmas showed low sensitivity when touched by inferior pollinators, which may have increased the possibility of pollen deposition by subsequent visits. Therefore, the stigma behavior in M. miquelii is likely a mechanism of pollinator selection to maximize pollination success.
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Arroyo, Mary T K; Dudley, Leah S; Jespersen, Gus; Pacheco, Diego A; Cavieres, Lohengrin A
2013-12-01
How high-alpine plants confront stochastic conditions for animal pollination is a critical question. We investigated the effect of temperature on potential flower longevity (FL) measured in pollinator-excluded flowers and actual FL measured in pollinated flowers in self-incompatible Oxalis compacta and evaluated if plastically prolonged potential FL can ameliorate slow pollination under cool conditions. Pollinator-excluded and hand-pollinated flowers were experimentally warmed with open-top chambers (OTCs) on a site at 3470 m above sea level (asl). Flower-specific temperatures, and pollinator-excluded and open-pollination flower life-spans were measured at six alpine sites between 3100 and 3470 m asl. Fruit set was analyzed in relation to inferred pollination time. Warming reduced potential FL. Variable thermal conditions across the alpine landscape predicted potential and actual FL; flower senescence was pollination-regulated. Actual FL and potential FL were coupled. Prolonged potential FL generally increased fruit set under cooler conditions. Plastic responses permit virgin flowers of O. compacta to remain open longer under cooler temperatures, thereby ameliorating slow pollination, and to close earlier when pollination tends to be faster under warmer conditions. Plastic potential FL provides adaptive advantages in the cold, thermally variable alpine habitat, and has important implications for reproductive success in alpine plants in a warming world. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.
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Pansarin, Emerson R; Ferreira, Alessandro W C
2015-05-01
Spiranthinae orchids are known for being self-compatible and offering nectar as a reward. Although data on their pollinators are scarce, members of this tribe are mostly pollinated by bees, hummingbirds and moths. Some of them even reproduce through facultative self-pollination. Nothing is known about the pollinators and reproduction system in Pteroglossa. Based on records on flowering phenology, floral morphology, reward production, pollinators and breeding system, this paper aims to study the reproductive biology of two Pteroglossa spp. Both species offer nectar as a resource and are pollinated exclusively by diurnal Lepidoptera at the studied areas. Nectar is produced by two glandular nectaries, and is stored in a spur. Pollinaria possess a ventrally adhesive viscidium that is deposited on the basal portion of butterfly proboscides. Both species are self-compatible but pollinator-dependent. The reproductive success is low when compared to other Spiranthinae. Although no evident mechanical barrier to avoid self-pollination or geitonogamy was identified, the erratic behavior of the butterflies, with their infrequent visits to only one flower per inflorescence, contributes to an increased fruit set produced through cross-pollination. The presence of ventrally adhesive viscidia in Spiranthinae is responsible for greater pollinator diversity when compared to bee-pollinated Goodyerinae with dorsally adhesive viscidia, adapted to attach to bee mouthparts.
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Global malnutrition overlaps with pollinator-dependent micronutrient production
Chaplin-Kramer, Rebecca; Dombeck, Emily; Gerber, James; Knuth, Katherine A.; Mueller, Nathaniel D.; Mueller, Megan; Ziv, Guy; Klein, Alexandra-Maria
2014-01-01
Pollinators contribute around 10% of the economic value of crop production globally, but the contribution of these pollinators to human nutrition is potentially much higher. Crops vary in the degree to which they benefit from pollinators, and many of the most pollinator-dependent crops are also among the richest in micronutrients essential to human health. This study examines regional differences in the pollinator dependence of crop micronutrient content and reveals overlaps between this dependency and the severity of micronutrient deficiency in people around the world. As much as 50% of the production of plant-derived sources of vitamin A requires pollination throughout much of Southeast Asia, whereas other essential micronutrients such as iron and folate have lower dependencies, scattered throughout Africa, Asia and Central America. Micronutrient deficiencies are three times as likely to occur in areas of highest pollination dependence for vitamin A and iron, suggesting that disruptions in pollination could have serious implications for the accessibility of micronutrients for public health. These regions of high nutritional vulnerability are understudied in the pollination literature, and should be priority areas for research related to ecosystem services and human well-being. PMID:25232140
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RAPID EVOLUTION CAUSED BY POLLINATOR LOSS IN MIMULUS GUTTATUS
Bodbyl Roels, Sarah A.; Kelly, John K.
2018-01-01
Anthropogenic perturbations including habitat loss and emerging disease are changing pollinator communities and generating novel selection pressures on plant populations. Disruption of plant–pollinator relationships is predicted to cause plant mating system evolution, although this process has not been directly observed. This study demonstrates the immediate evolutionary effects of pollinator loss within experimental populations of a predominately outcrossing wildflower. Initially equivalent populations evolved for five generations within two pollination treatments: abundant bumblebee pollinators versus no pollinators. The populations without pollinators suffered greatly reduced fitness in early generations but rebounded as they evolved an improved ability to self-fertilize. All populations diverged in floral, developmental, and life-history traits, but only a subset of characters showed clear association with pollination treatment. Pronounced treatment effects were noted for anther–stigma separation and autogamous seed set. Dramatic allele frequency changes at two chromosomal polymorphisms occurred in the no pollinator populations, explaining a large fraction of divergence in pollen viability. The pattern of phenotypic and genetic changes in this experiment favors a sequential model for the evolution of the multitrait “selfing syndrome” observed throughout angiosperms. PMID:21884055
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Zhou, Xiang; Liu, Qiang; Han, Jessie Yc; Gao, JiangYun
2016-02-24
Orchids are generally recognized to have specialist pollination systems and low fruit set is often thought to be characteristic of the family. In this study, we investigated the reproductive ecology of Cleisostoma linearilobatum, an epiphytic tropical orchid, in a holy hill forest fragment and a traditional tea garden in SW China using comparable methods. C. linearilobatum is self-compatible and dependent on insects for pollination. Fruit production in natural conditions was both pollinator- and resource-limited. However, the natural fruit set remained stable over multiple years at both sites. Pollination observations showed that C. linearilobatum has a generalized pollination system and seven insect species were observed as legitimate pollinators. Although the visit frequencies of different pollinators were different in the two sites, the pollinator assemblages ensured reproductive success of C. linearilobatum in both study sites over multiple years. The results partly explain why C. linearilobatum is so successful in the area, and also suggest that holy hill forest fragments and traditional tea gardens in Xishuangbanna are important in preserving orchids, especially those with generalist pollination.
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Zhou, Xiang; Liu, Qiang; Han, Jessie Yc; Gao, JiangYun
2016-01-01
Orchids are generally recognized to have specialist pollination systems and low fruit set is often thought to be characteristic of the family. In this study, we investigated the reproductive ecology of Cleisostoma linearilobatum, an epiphytic tropical orchid, in a holy hill forest fragment and a traditional tea garden in SW China using comparable methods. C. linearilobatum is self-compatible and dependent on insects for pollination. Fruit production in natural conditions was both pollinator- and resource-limited. However, the natural fruit set remained stable over multiple years at both sites. Pollination observations showed that C. linearilobatum has a generalized pollination system and seven insect species were observed as legitimate pollinators. Although the visit frequencies of different pollinators were different in the two sites, the pollinator assemblages ensured reproductive success of C. linearilobatum in both study sites over multiple years. The results partly explain why C. linearilobatum is so successful in the area, and also suggest that holy hill forest fragments and traditional tea gardens in Xishuangbanna are important in preserving orchids, especially those with generalist pollination. PMID:26907369
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Pollinators' mating rendezvous and the evolution of floral advertisement.
Fishman, Michael A; Hadany, Lilach
2013-01-07
Successful cross-fertilization in plant species that rely on animal pollinators depends not just on the number of pollinator visits, but also on these visits' duration. Furthermore, in non-deceptive pollination, a visit's duration depends on the magnitude of the reward provided to the pollinator. Accordingly, plants that rely on biotic pollination have to partition their investment in cross-fertilization assurance between attracting pollinator visits - advertisement, and rewarding visitors to assure that the visit is of productive duration. Here we analyze these processes by a combination of optimality methods and game theoretical modeling. Our results indicate that the optimality in such allocation of resources depends on the types of reward offered to the pollinators. More precisely, we show that plants that offer both food reward and mating rendezvous to pollinators will evolve to allocate a higher proportion of their cross-fertilization assurance budget to advertisement than plants that offer only food reward. That is, our results indicate that pollinators' mating habits may play a role in floral evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Collapse of a pollination web in small conservation areas.
Pauw, Anton
2007-07-01
A suspected global decline in pollinators has heightened interest in their ecological significance. In a worst-case scenario, the decline of generalist pollinators is predicted to trigger cascades of linked declines among the multiple specialist plant species to which they are linked, but this has not been documented. I studied a portion of a pollination web involving a generalist pollinator, the oil-collecting bee Rediviva peringueyi, and a community of oil-secreting plants. Across 27 established conservation areas located in the Cape Floral Region, I found substantial variation in the bees' occurrence in relation to soil type and the successional stage of the vegetation. Anthropogenic declines were detectable against this background of naturally occurring variation: R. peringueyi was absent from small conservation areas (< 385 ha) in an urban matrix. In the absence of the bee, seed set failed in six specialist plant species that are pollinated only by R. peringueyi but remained high in a pollination generalist, which had replacement pollinators. The findings are consistent with theoretical predictions of the importance of generalist pollinators in maintaining the structure of pollination webs.
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On ‘various contrivances’: pollination, phylogeny and flower form in the Solanaceae
Knapp, Sandra
2010-01-01
Members of the euasterid angiosperm family Solanaceae have been characterized as remarkably diverse in terms of flower morphology and pollinator type. In order to test the relative contribution of phylogeny to the pattern of distribution of floral characters related to pollination, flower form and pollinators have been mapped onto a molecular phylogeny of the family. Bilateral flower symmetry (zygomorphy) is prevalent in the basal grades of the family, and more derived clades have flowers that are largely radially symmetric, with some parallel evolution of floral bilateralism. Pollinator types (‘syndromes’) are extremely homoplastic in the family, but members of subfamily Solanoideae are exceptional in being largely bee pollinated. Pollinator relationships in those genera where they have been investigated more fully are not as specific as flower morphology and the classical pollinator syndrome models might suggest, and more detailed studies in some particularly variable genera, such as Iochroma and Nicotiana, are key to understanding the role of pollinators in floral evolution and adaptive radiation in the family. More studies of pollinators in the field are a priority. PMID:20047871
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Rapid evolution caused by pollinator loss in Mimulus guttatus.
Roels, Sarah A Bodbyl; Kelly, John K
2011-09-01
Anthropogenic perturbations including habitat loss and emerging disease are changing pollinator communities and generating novel selection pressures on plant populations. Disruption of plant-pollinator relationships is predicted to cause plant mating system evolution, although this process has not been directly observed. This study demonstrates the immediate evolutionary effects of pollinator loss within experimental populations of a predominately outcrossing wildflower. Initially equivalent populations evolved for five generations within two pollination treatments: abundant bumblebee pollinators versus no pollinators. The populations without pollinators suffered greatly reduced fitness in early generations but rebounded as they evolved an improved ability to self-fertilize. All populations diverged in floral, developmental, and life-history traits, but only a subset of characters showed clear association with pollination treatment. Pronounced treatment effects were noted for anther-stigma separation and autogamous seed set. Dramatic allele frequency changes at two chromosomal polymorphisms occurred in the no pollinator populations, explaining a large fraction of divergence in pollen viability. The pattern of phenotypic and genetic changes in this experiment favors a sequential model for the evolution of the multitrait "selfing syndrome" observed throughout angiosperms. © 2011 The Author(s).
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Kasina, J M; Mburu, J; Kraemer, M; Holm-Mueller, K
2009-04-01
In most developing countries, crop production is by small scale farmers, who mainly produce for their own consumption and the extra for market. Pollination in such systems is unmanaged and is usually incidental, supported by nearby ecosystems. One of the reasons of not managing pollination is the lack of understanding of its economic value. The "public-good" nature of pollination in these systems also discourages individual initiatives intended to conserve pollinators. We evaluate the economic returns from bee pollination in small-holder farming systems. To do this we apply the factor of production method, a form of revealed preferences methods available for valuing ecosystem services. Our analyses show that bee pollination enhances the yield of most crops grown in the farmland and improves immensely the quality of produce. Almost 40% of the annual value of crops under consideration represented the net returns derived from bee pollination. More than 99% of this benefit is attributed to pollination by feral bees. We provide in-depth valuation of pollination service and discuss applicability and limitations of the factor of production method in developing countries.
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Population dynamics and the ecological stability of obligate pollination mutualisms
Holland, J. Nathaniel; DeAngelis, Donald L.
2001-01-01
Mutualistic interactions almost always produce both costs and benefits for each of the interacting species. It is the difference between gross benefits and costs that determines the net benefit and the per-capita effect on each of the interacting populations. For example, the net benefit of obligate pollinators, such as yucca and senita moths, to plants is determined by the difference between the number of ovules fertilized from moth pollination and the number of ovules eaten by the pollinator's larvae. It is clear that if pollinator populations are large, then, because many eggs are laid, costs to plants are large, whereas, if pollinator populations are small, gross benefits are low due to lack of pollination. Even though the size and dynamics of the pollinator population are likely to be crucial, their importance has been neglected in the investigation of mechanisms, such as selective fruit abortion, that can limit costs and increase net benefits. Here, we suggest that both the population size and dynamics of pollinators are important in determining the net benefits to plants, and that fruit abortion can significantly affect these. We develop a model of mutualism between populations of plants and their pollinating seed-predators to explore the ecological consequences of fruit abortion on pollinator population dynamics and the net effect on plants. We demonstrate that the benefit to a plant population is unimodal as a function of pollinator abundance, relative to the abundance of flowers. Both selective abortion of fruit with eggs and random abortion of fruit, without reference to whether they have eggs or not, can limit pollinator population size. This can increase the net benefits to the plant population by limiting the number of eggs laid, if the pollination rate remains high. However, fruit abortion can possibly destabilize the pollinator population, with negative consequences for the plant population.
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Fishman, Lila; Wyatt, Robert
1999-12-01
Ecological factors that reduce the effectiveness of cross-pollination are likely to play a role in the frequent evolution of routine self-fertilization in flowering plants. However, we lack empirical evidence linking the reproductive assurance value of selfing in poor pollination environments to evolutionary shifts in mating system. Here, we investigated the adaptive significance of prior selfing in the polymorphic annual plant Arenaria uniflora (Caryophyllaceae), in which selfer populations occur only in areas of range overlap with congener A. glabra. To examine the hypothesis that secondary contact between the two species contributed to the evolution and maintenance of selfing, we used field competition experiments and controlled hand-pollinations to measure the female fitness consequences of pollinator-mediated interspecific interactions. Uniformly high fruit set by selfers in the naturally pollinated field arrays confirmed the reproductive assurance value of selfing, whereas substantial reductions in outcrosser fruit set (15%) and total seed production (20-35%) in the presence of A. glabra demonstrated that pollinator-mediated interactions can provide strong selection for self-pollination. Heterospecific pollen transfer, rather than competition for pollinator service, appears to be the primary mechanism of pollinator-mediated competition in Arenaria. Premating barriers to hybridization between outcrossers and A. glabra are extremely weak. The production of a few inviable hybrid seeds after heterospecific pollination and intermediate seed set after mixed pollinations indicates that A. glabra pollen can usurp A. uniflora ovules. Thus, any visit to A. uniflora by shared pollinators carries a potential female fitness cost. Moreover, patterns of fruit set and seed set in the competition arrays relative to controls were consistent with the receipt of mixed pollen loads, rather than a lack of pollinator visits. Competition through pollen transfer favors preemptive self-pollination and may be responsible for the evolution of a highly reduced floral morphology in A. uniflora selfers as well as their current geographical distribution. © 1999 The Society for the Study of Evolution.
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Phylogenetic trait-based analyses of ecological networks
Rafferty, Nicole E.; Ives, Anthony R.
2013-01-01
Ecological networks of two interacting guilds of species, such as flowering plants and pollinators, are common in nature, and studying their structure can yield insights into their resilience to environmental disturbances. Here we develop analytical methods for exploring the strengths of interactions within bipartite networks consisting of two guilds of phylogenetically related species. We then apply these methods to investigate the resilience of a plant–pollinator community to anticipated climate change. The methods allow the statistical assessment of, for example, whether closely related pollinators are more likely to visit plants with similar relative frequencies, and whether closely related pollinators tend to visit closely related plants. The methods can also incorporate trait information, allowing us to identify which plant traits are likely responsible for attracting different pollinators. These questions are important for our study of 14 prairie plants and their 22 insect pollinators. Over the last 70 years, six of the plants have advanced their flowering, while eight have not. When we experimentally forced earlier flowering times, five of the six advanced-flowering species experienced higher pollinator visitation rates, whereas only one of the eight other species had more visits; this network thus appears resilient to climate change, because those species with advanced flowering have ample pollinators earlier in the season. Using the methods developed here, we show that advanced-flowering plants did not have a distinct pollinator community from the other eight species. Furthermore, pollinator phylogeny did not explain pollinator community composition; closely related pollinators were not more likely to visit the same plant species. However, differences among pollinator communities visiting different plants were explained by plant height, floral color, and symmetry. As a result, closely related plants attracted similar numbers of pollinators. By parsing out characteristics that explain why plants share pollinators, we can identify plant species that likely share a common fate in a changing climate. PMID:24358717
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Phylogenetic trait-based analyses of ecological networks.
Rafferty, Nicole E; Ives, Anthony R
2013-10-01
Ecological networks of two interacting guilds of species, such as flowering plants and pollinators, are common in nature, and studying their structure can yield insights into their resilience to environmental disturbances. Here we develop analytical methods for exploring the strengths of interactions within bipartite networks consisting of two guilds of phylogenetically related species. We then apply these methods to investigate the resilience of a plant-pollinator community to anticipated climate change. The methods allow the statistical assessment of, for example, whether closely related pollinators are more likely to visit plants with similar relative frequencies, and whether closely related pollinators tend to visit closely related plants. The methods can also incorporate trait information, allowing us to identify which plant traits are likely responsible for attracting different pollinators. These questions are important for our study of 14 prairie plants and their 22 insect pollinators. Over the last 70 years, six of the plants have advanced their flowering, while eight have not. When we experimentally forced earlier flowering times, five of the six advanced-flowering species experienced higher pollinator visitation rates, whereas only one of the eight other species had more visits; this network thus appears resilient to climate change, because those species with advanced flowering have ample pollinators earlier in the season. Using the methods developed here, we show that advanced-flowering plants did not have a distinct pollinator community from the other eight species. Furthermore, pollinator phylogeny did not explain pollinator community composition; closely related pollinators were not more likely to visit the same plant species. However, differences among pollinator communities visiting different plants were explained by plant height, floral color, and symmetry. As a result, closely related plants attracted similar numbers of pollinators. By parsing out characteristics that explain why plants share pollinators, we can identify plant species that likely share a common fate in a changing climate.
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Jürgens, Andreas; Bosch, Simone R.; Webber, Antonio C.; Witt, Taina; Frame, Dawn; Gottsberger, Gerhard
2009-01-01
Background and Aims Spatial variation in pollinator composition and abundance is a well-recognized phenomenon. However, a weakness of many studies claiming specificity of plant–pollinator interactions is that they are often restricted to a single locality. The aim of the present study was to investigate pollinator effectiveness of the different flower visitors to the terrestrial orchid Eulophia alta at three different localities and to analyse whether differences in pollinator abundance and composition effect this plant's reproductive success. Methods Natural pollination was observed in vivo, and manipulative experiments were used to study the pollination biology and breeding system of E. alta at three sites near Manaus, Brazil. To gain a better understanding of the underlying mechanisms of pollinator attraction, nectar composition and secretion patterns were also studied, floral scent composition was analysed and a bioassay was conducted. Key Results Flower visitors, pollinator composition, pollinia transfer efficiency of particular pollinator species and natural fruit set differed among the investigated populations of E. alta. Flowers were self-compatible, partially autogamous and effectively pollinated by five bee species (four Centris species and Xylocopa muscaria). Visiting insects appeared to imbibe small amounts of hexose-rich nectar. Nectar sugar content was highest on the third day after flower opening. Floral fragrance analyses revealed 42 compounds, of which monoterpenes and benzenoids predominated. A bioassay using floral parts revealed that only floral tissue from the labellum chamber and labellum tip was attractive to flower visitors. Conclusions The data suggest that observed differences in reproductive success in the three populations cannot be explained by absolute abundance of pollinators alone. Due to behavioural patterns such as disturbance of effective pollinators on flowers by male Centris varia bees defending territory, pollinia transfer efficiencies of particular pollinator species also vary between study sites and result in differing reproductive success. PMID:19666899
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Weak trophic links between a crab-spider and the effective pollinators of a rewardless orchid
NASA Astrophysics Data System (ADS)
Quintero, Carolina; Corley, Juan C.; Aizen, Marcelo A.
2015-01-01
Sit and wait predators hunting on flowers are considered to be exploiters of plant-pollinator mutualisms. Several studies have shown that plant-pollinator interactions can be highly susceptible to the impact of a third trophic level, via consumptive (direct) and non-consumptive (indirect) effects that alter pollinator behavior and, ultimately, plant fitness. However, most flowering plants attract a wide array of flower visitors, from which only a subset will be effective pollinators. Hence, a negative effect of an ambush predator on plant fitness should be expected only when: (i) the effective pollinators are part of the predators' diet and/or (ii) the non-consumptive effects of predator presence (e.g. dead prey) alter the behavior of effective pollinators and pollen movement among individual plants. We analyzed the direct and indirect effects of a crab-spider (Misumenops pallidus), on the pollination and reproductive success of Chloraea alpina, a Patagonian rewardless orchid. Our results indicate that most of the flower visitors do not behave as effective pollinators and most effective pollinators were not observed as prey for the crab-spider. In terms of non-consumptive effects, inflorescences with and without spiders and/or dead-prey did not vary the frequency of flower visitors, nor pollinia removal or deposition. Hence, it is not surprising that M. pallidus has a neutral effect on pollinia removal and deposition as well as on fruit and seed set. Similar to other rewardless orchids, the low reproductive success of C. alpina (∼6% fruit set) was associated with the limited number of visits by effective pollinators. Negative top-down effects of a flower-visitor predator on plant pollination may not be anticipated without studying the direct and indirect effects of this predator on the effective pollinators. In pollination systems where effective pollinators visited flowers erratically, such as in deceptive orchids, we expect weak or no effect of predators on plant fitness.
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What the EPA is doing to protect bees and other pollinators from pesticides; including addressing the issue of Colony Collapse Disorder (CCD), risk assessment, decline in pollinator health in general, and why pollinators are important.
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Holland, J. Nathaniel; DeAngelis, Donald L.
2002-01-01
Coevolved mutualisms, such as those between senita cacti, yuccas, and their respective obligate pollinators, benefit both species involved in the interaction. However, in these pollination mutualisms the pollinator's larvae impose a cost on plants through consumption of developing seeds and fruit. The effects of pollinators on benefits and costs are expected to vary with the abundance of pollinators, because large population sizes result in more eggs and larval seed-eaters. Here, we develop the hypothesis that fruit abortion, which is common in yucca, senita, and plants in general, could in some cases have the function of limiting pollinator abundance and, thereby, increasing fruit production. Using a general steady-state model of fruit production and pollinator dynamics, we demonstrate that plants involved in pollinating seed-eater mutualisms can increase their fecundity by randomly aborting fruit. We show that the ecological conditions under which fruit abortion can improve plants fecundity are not unusual. They are best met when the plant is long-lived, the population dynamics of the pollinator are much faster than those of the plant, the loss of one fruit via abortion kills a larva that would have the expectation of destroying more than one fruit through its future egg laying as an adult moth, and the effects of fruit abortion on pollinator abundance are spatially localized. We then use the approach of adaptive dynamics to find conditions under which a fruit abortion strategy based on regulating the pollinator population could feasibly evolve in this type of plant–pollinator interaction.
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The reproductive strategy of a pollinator-limited Himalayan plant, Incarvillea mairei (Bignoniaceae)
2013-01-01
Background Plants may adapt to alpine habitats by specialization in the reproductive strategy and functional aspects of their flowers and pollination systems. Alpine habitats reduce the opportunities for cross-pollination in a relatively high proportion of alpine plant species, and self-pollination may be favored in these adverse conditions. Here, we investigated the mating system and pollination of Incarvillea mairei, a perennial Himalayan herb typically found at altitudes between 3000 and 4500 m. Results Analyses of floral morphology, observation of plant-pollinator interactions, and hand pollination experiments were conducted in three natural populations. Outcrossing rates and effective numbers of pollen donors were assessed in 45 open-pollinated families by using progeny analysis based on seven microsatellite markers. Incarvillea mairei displayed a set of apparently specialized floral traits, the stigma is sensitive to touch and close immediately and its reopening allows a second opportunity for the receipt of pollen. The species is fully self-compatible but employs a predominantly outcrossing mating system according to parentage analysis (tm > 0.9). Fruit set was low (26.3%), whereas seed set was high (67.2%), indicating that this species suffers pollinator limitation. Its main effective pollinator was Halictus sp., and visitation frequency was low. Conclusions Floral features such as having a sensitive stigma and anther-prongs, in conjunction with pollinator behavior, function together contributing to a set of unique reproductive adaptations that enhance outcrossing success. The increased floral longevity and high pollination efficiency operated as compensatory mechanisms to counteract low pollinator visitation frequency. PMID:24289097
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Jacobs, Jennifer H; Clark, Suzanne J; Denholm, Ian; Goulson, Dave; Stoate, Chris; Osborne, Juliet L
2009-12-01
In the UK, the flowers of fruit-bearing hedgerow plants provide a succession of pollen and nectar for flower-visiting insects for much of the year. The fruits of hedgerow plants are a source of winter food for frugivorous birds on farmland. It is unclear whether recent declines in pollinator populations are likely to threaten fruit-set and hence food supply for birds. The present study investigates the pollination biology of five common hedgerow plants: blackthorn (Prunus spinosa), hawthorn (Crataegus monogyna), dog rose (Rosa canina), bramble (Rubus fruticosus) and ivy (Hedera helix). The requirement for insect pollination was investigated initially by excluding insects from flowers by using mesh bags and comparing immature and mature fruit-set with those of open-pollinated flowers. Those plants that showed a requirement for insect pollination were then tested to compare fruit-set under two additional pollination service scenarios: (1) reduced pollination, with insects excluded from flowers bagged for part of the flowering period, and (2) supplemental pollination, with flowers hand cross-pollinated to test for pollen limitation. The proportions of flowers setting fruit in blackthorn, hawthorn and ivy were significantly reduced when insects were excluded from flowers by using mesh bags, whereas fruit-set in bramble and dog rose were unaffected. Restricting the exposure of flowers to pollinators had no significant effect on fruit-set. However, blackthorn and hawthorn were found to be pollen-limited, suggesting that the pollination service was inadequate in the study area. Ensuring strong populations of insect pollinators may be essential to guarantee a winter fruit supply for birds in UK hedgerows.
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Phillips, R D; Brown, G R; Dixon, K W; Hayes, C; Linde, C C; Peakall, R
2017-09-01
The mechanism of pollinator attraction is predicted to strongly influence both plant diversification and the extent of pollinator sharing between species. Sexually deceptive orchids rely on mimicry of species-specific sex pheromones to attract their insect pollinators. Given that sex pheromones tend to be conserved among related species, we predicted that in sexually deceptive orchids, (i) pollinator sharing is rare, (ii) closely related orchids use closely related pollinators and (iii) there is strong bias in the wasp lineages exploited by orchids. We focused on species that are pollinated by sexual deception of thynnine wasps in the distantly related genera Caladenia and Drakaea, including new field observations for 45 species of Caladenia. Specialization was extreme with most orchids using a single pollinator species. Unexpectedly, seven cases of pollinator sharing were found, including two between Caladenia and Drakaea, which exhibit strikingly different floral morphology. Phylogenetic analysis of pollinators using four nuclear sequence loci demonstrated that although orchids within major clades primarily use closely related pollinator species, up to 17% of orchids within these clades are pollinated by a member of a phylogenetically distant wasp genus. Further, compared to the total diversity of thynnine wasps within the study region, orchids show a strong bias towards exploiting certain genera. Although these patterns may arise through conservatism in the chemical classes used in sex pheromones, apparent switches between wasp clades suggest unexpected flexibility in floral semiochemical production. Alternatively, wasp sex pheromones within lineages may exhibit greater chemical diversity than currently appreciated. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.
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Himler, Anna G; Machado, Carlos A
2009-12-01
Coevolutionary interactions between plants and their associated pollinators and seed dispersers are thought to have promoted the diversification of flowering plants (Raven 1977; Regal 1977; Stebbins 1981). The actual mechanisms by which pollinators could drive species diversification in plants are not fully understood. However, it is thought that pollinator host specialization can influence the evolution of reproductive isolation among plant populations because the pollinator's choice of host is what determines patterns of gene flow in its host plant, and host choice may also have important consequences on pollinator and host fitness (Grant 1949; Bawa 1992). In this issue of Molecular Ecology, Smith et al. (2009) present a very interesting study that addresses how host specialization affects pollinator fitness and patterns of gene flow in a plant host. Several aspects of this study match elements of a seminal mathematical model of plant-pollinator codivergence (Kiester et al. 1984) suggesting that reciprocal selection for matched plant and pollinator reproductive traits may lead to speciation in the host and its pollinator when there is strong host specialization and a pattern of geographic subdivision. Smith et al.'s study represents an important step to fill the gap in our understanding of how reciprocal selection may lead to speciation in coevolved plant-pollinator mutualisms.
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Ecology and evolution of plant–pollinator interactions
Mitchell, Randall J.; Irwin, Rebecca E.; Flanagan, Rebecca J.; Karron, Jeffrey D.
2009-01-01
Background Some of the most exciting advances in pollination biology have resulted from interdisciplinary research combining ecological and evolutionary perspectives. For example, these two approaches have been essential for understanding the functional ecology of floral traits, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant–pollinator interactions. However, as research in these and other areas has progressed, many pollination biologists have become more specialized in their research interests, focusing their attention on either evolutionary or ecological questions. We believe that the continuing vigour of a synthetic and interdisciplinary field like pollination biology depends on renewed connections between ecological and evolutionary approaches. Scope In this Viewpoint paper we highlight the application of ecological and evolutionary approaches to two themes in pollination biology: (1) links between pollinator behaviour and plant mating systems, and (2) generalization and specialization in pollination systems. We also describe how mathematical models and synthetic analyses have broadened our understanding of pollination biology, especially in human-modified landscapes. We conclude with several suggestions that we hope will stimulate future research. This Viewpoint also serves as the introduction to this Special Issue on the Ecology and Evolution of Plant–Pollinator Interactions. These papers provide inspiring examples of the synergy between evolutionary and ecological approaches, and offer glimpses of great accomplishments yet to come. PMID:19482881
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Ecology and evolution of plant-pollinator interactions.
Mitchell, Randall J; Irwin, Rebecca E; Flanagan, Rebecca J; Karron, Jeffrey D
2009-06-01
Some of the most exciting advances in pollination biology have resulted from interdisciplinary research combining ecological and evolutionary perspectives. For example, these two approaches have been essential for understanding the functional ecology of floral traits, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant-pollinator interactions. However, as research in these and other areas has progressed, many pollination biologists have become more specialized in their research interests, focusing their attention on either evolutionary or ecological questions. We believe that the continuing vigour of a synthetic and interdisciplinary field like pollination biology depends on renewed connections between ecological and evolutionary approaches. In this Viewpoint paper we highlight the application of ecological and evolutionary approaches to two themes in pollination biology: (1) links between pollinator behaviour and plant mating systems, and (2) generalization and specialization in pollination systems. We also describe how mathematical models and synthetic analyses have broadened our understanding of pollination biology, especially in human-modified landscapes. We conclude with several suggestions that we hope will stimulate future research. This Viewpoint also serves as the introduction to this Special Issue on the Ecology and Evolution of Plant-Pollinator Interactions. These papers provide inspiring examples of the synergy between evolutionary and ecological approaches, and offer glimpses of great accomplishments yet to come.
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Spatial heterogeneity and the distribution of bromeliad pollinators in the Atlantic Forest
NASA Astrophysics Data System (ADS)
Varassin, Isabela Galarda; Sazima, Marlies
2012-08-01
Interactions between plants and their pollinators are influenced by environmental heterogeneity, resulting in small-scale variations in interactions. This may influence pollinator co-existence and plant reproductive success. This study, conducted at the Estação Biológica de Santa Lúcia (EBSL), a remnant of the Atlantic Forest in southeastern Brazil, investigated the effect of small-scale spatial variations on the interactions between bromeliads and their pollinators. Overall, hummingbirds pollinated 19 of 23 bromeliad species, of which 11 were also pollinated by bees and/or butterflies. However, spatial heterogeneity unrelated to the spatial location of plots or bromeliad species abundance influenced the presence of pollinators. Hummingbirds were the most ubiquitous pollinators at the high-elevation transect, with insect participation clearly declining as transect elevation increased. In the redundancy analysis, the presence of the hummingbird species Phaethornis eurynome, Phaethornis squalidus, Ramphodon naevius, and Thalurania glaucopis, and the butterfly species Heliconius erato and Heliconius nattereri in each plot was correlated with environmental factors such as bromeliad and tree abundance, and was also correlated with horizontal diversity. Since plant-pollinator interactions varied within the environmental mosaics at the study site, this small-scale environmental heterogeneity may relax competition among pollinators, and may explain the high diversity of bromeliads and pollinators generally found in the Atlantic Forest.
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Pollinator-driven ecological speciation in plants: new evidence and future perspectives
Van der Niet, Timotheüs; Peakall, Rod; Johnson, Steven D.
2014-01-01
Background The hypothesis that pollinators have been important drivers of angiosperm diversity dates back to Darwin, and remains an important research topic today. Mounting evidence indicates that pollinators have the potential to drive diversification at several different stages of the evolutionary process. Microevolutionary studies have provided evidence for pollinator-mediated floral adaptation, while macroevolutionary evidence supports a general pattern of pollinator-driven diversification of angiosperms. However, the overarching issue of whether, and how, shifts in pollination system drive plant speciation represents a critical gap in knowledge. Bridging this gap is crucial to fully understand whether pollinator-driven microevolution accounts for the observed macroevolutionary patterns. Testable predictions about pollinator-driven speciation can be derived from the theory of ecological speciation, according to which adaptation (microevolution) and speciation (macroevolution) are directly linked. This theory is a particularly suitable framework for evaluating evidence for the processes underlying shifts in pollination systems and their potential consequences for the evolution of reproductive isolation and speciation. Scope This Viewpoint paper focuses on evidence for the four components of ecological speciation in the context of plant-pollinator interactions, namely (1) the role of pollinators as selective agents, (2) floral trait divergence, including the evolution of ‘pollination ecotypes‘, (3) the geographical context of selection on floral traits, and (4) the role of pollinators in the evolution of reproductive isolation. This Viewpoint also serves as the introduction to a Special Issue on Pollinator-Driven Speciation in Plants. The 13 papers in this Special Issue range from microevolutionary studies of ecotypes to macroevolutionary studies of historical ecological shifts, and span a wide range of geographical areas and plant families. These studies further illustrate innovative experimental approaches, and they employ modern tools in genetics and floral trait quantification. Future advances to the field require better quantification of selection through male fitness and pollinator isolation, for instance by exploiting next-generation sequencing technologies. By combining these new tools with strategically chosen study systems, and smart experimental design, we predict that examples of pollinator-driven speciation will be among the most widespread and compelling of all cases of ecological speciation. PMID:24418954
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Maebe, Kevin; Arbetman, Marina; Morales, Carolina; Graystock, Peter; Hughes, William O. H.; Plischuk, Santiago; Lange, Carlos E.; de Graaf, Dirk C.; Zapata, Nelson; de la Rosa, Jose Javier Perez; Murray, Tomás E.; Brown, Mark J. F.; Smagghe, Guy
2013-01-01
The worldwide spread of diseases is considered a major threat to biodiversity and a possible driver of the decline of pollinator populations, particularly when novel species or strains of parasites emerge. Previous studies have suggested that populations of introduced European honeybee (Apis mellifera) and bumblebee species (Bombus terrestris and Bombus ruderatus) in Argentina share the neogregarine parasite Apicystis bombi with the native bumblebee (Bombus dahlbomii). In this study we investigated whether A. bombi is acting as an emergent parasite in the non-native populations. Specifically, we asked whether A. bombi, recently identified in Argentina, was introduced by European, non-native bees. Using ITS1 and ITS2 to assess the parasite’s intraspecific genetic variation in bees from Argentina and Europe, we found a largely unstructured parasite population, with only 15% of the genetic variation being explained by geographic location. The most abundant haplotype in Argentina (found in all 9 specimens of non-native species) was identical to the most abundant haplotype in Europe (found in 6 out of 8 specimens). Similarly, there was no evidence of structuring by host species, with this factor explaining only 17% of the genetic variation. Interestingly, parasites in native Bombus ephippiatus from Mexico were genetically distant from the Argentine and European samples, suggesting that sufficient variability does exist in the ITS region to identify continent-level genetic structure in the parasite. Thus, the data suggest that A. bombi from Argentina and Europe share a common, relatively recent origin. Although our data did not provide information on the direction of transfer, the absence of genetic structure across space and host species suggests that A. bombi may be acting as an emergent infectious disease across bee taxa and continents. PMID:24324696
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Hadley, Adam S; Betts, Matthew G
2012-08-01
Animal-mediated pollination is essential for both ecosystem services and conservation of global biodiversity, but a growing body of work reveals that it is negatively affected by anthropogenic disturbance. Landscape-scale disturbance results in two often inter-related processes: (1) habitat loss, (2) disruptions of habitat configuration (i.e. fragmentation). Understanding the relative effects of such processes is critical in designing effective management strategies to limit pollination and pollinator decline. We reviewed existing published work from 1989 to 2009 and found that only six of 303 studies considering the influence of landscape context on pollination separated the effects of habitat loss from fragmentation. We provide a synthesis of the current landscape, behavioural, and pollination ecology literature in order to present preliminary multiple working hypotheses explaining how these two landscape processes might independently influence pollination dynamics. Landscape disturbance primarily influences three components of pollination interactions: pollinator density, movement, and plant demography. We argue that effects of habitat loss on each of these components are likely to differ substantially from the effects of fragmentation, which is likely to be more complex and may influence each pollination component in contrasting ways. The interdependency between plants and animals inherent to pollination systems also has the possibility to drive cumulative effects of fragmentation, initiating negative feedback loops between animals and the plants they pollinate. Alternatively, due to their asymmetrical structure, pollination networks may be relatively robust to fragmentation. Despite the potential importance of independent effects of habitat fragmentation, its effects on pollination remain largely untested. We postulate that variation across studies in the effects of 'fragmentation' owes much to artifacts of the sampling regimes adopted, particularly (1) incorrectly separating fragmentation from habitat loss, and (2) mis-matches in spatial scale between landscapes studied and the ecological processes of interest. The field of landscape pollination ecology could be greatly advanced through the consideration and quantification of the matrix, landscape functional connectivity, and pollinator movement behaviour in response to these elements. Studies designed to disentangle the independent effects of habitat loss and fragmentation are essential for gaining insight into landscape-mediated pollination declines, implementing effective conservation measures, and optimizing ecosystem services in complex landscapes. © 2011 The Authors. Biological Reviews © 2011 Cambridge Philosophical Society.
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Barcellos, Silvia Helena; Goldman, Dana P.; Smith, James P.
2013-01-01
Newly arrived Mexican immigrants generally report better health in the United States than do native-born Americans, but this health advantage erodes over time. At issue is whether this advantage is illusory – or a product of disease that goes undiagnosed in Mexico but is discovered after immigration. Using the National Health and Nutrition Survey we compare clinical to self-reported diagnosed disease prevalence. We find that diagnosed prevalence is 47 percent lower among recent Mexican immigrants than among natives for both diabetes and hypertension, and that undiagnosed disease explains one third of this recent immigrant advantage for diabetes and one fifth for hypertension. The remaining health advantage might be explained by immigrant selectivity (how migrants differ from those in Mexico who stayed) or assimilation (the process of integration into the U.S.). Since undiagnosed disease can have adverse health consequences, medical practice should emphasize disease detection among new arrivals as part of routine doctor or hospital visits. PMID:23213157
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The evolution of bat pollination: a phylogenetic perspective
Fleming, Theodore H.; Geiselman, Cullen; Kress, W. John
2009-01-01
Background Most tropical and subtropical plants are biotically pollinated, and insects are the major pollinators. A small but ecologically and economically important group of plants classified in 28 orders, 67 families and about 528 species of angiosperms are pollinated by nectar-feeding bats. From a phylogenetic perspective this is a derived pollination mode involving a relatively large and energetically expensive pollinator. Here its ecological and evolutionary consequences are explored. Scope and Conclusions This review summarizes adaptations in bats and plants that facilitate this interaction and discusses the evolution of bat pollination from a plant phylogenetic perspective. Two families of bats contain specialized flower visitors, one in the Old World and one in the New World. Adaptation to pollination by bats has evolved independently many times from a variety of ancestral conditions, including insect-, bird- and non-volant mammal-pollination. Bat pollination predominates in very few families but is relatively common in certain angiosperm subfamilies and tribes. We propose that flower-visiting bats provide two important benefits to plants: they deposit large amounts of pollen and a variety of pollen genotypes on plant stigmas and, compared with many other pollinators, they are long-distance pollen dispersers. Bat pollination tends to occur in plants that occur in low densities and in lineages producing large flowers. In highly fragmented tropical habitats, nectar bats play an important role in maintaining the genetic continuity of plant populations and thus have considerable conservation value. PMID:19789175
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Reconstructing the origin and elaboration of insect-trapping inflorescences in the Araceae1
Bröderbauer, David; Diaz, Anita; Weber, Anton
2016-01-01
Premise of the study Floral traps are among the most sophisticated devices that have evolved in angiosperms in the context of pollination, but the evolution of trap pollination has not yet been studied in a phylogenetic context. We aim to determine the evolutionary history of morphological traits that facilitate trap pollination and to elucidate the impact of pollinators on the evolution of inflorescence traps in the family Araceae. Methods Inflorescence morphology was investigated to determine the presence of trapping devices and to classify functional types of traps. We inferred phylogenetic relationships in the family using maximum likelihood and Bayesian methods. Character evolution of trapping devices, trap types, and pollinator types was then assessed with maximum parsimony and Bayesian methods. We also tested for an association of trap pollination with specific pollinator types. Key results Inflorescence traps have evolved independently at least 10 times within the Araceae. Trapping devices were found in 27 genera. On the basis of different combinations of trapping devices, six functional types of traps were identified. Trap pollination in Araceae is correlated with pollination by flies. Conclusions Trap pollination in the Araceae is more common than was previously thought. Preadaptations such as papillate cells or elongated sterile flowers facilitated the evolution of inflorescence traps. In some clades, imperfect traps served as a precursor for the evolution of more elaborate traps. Traps that evolved in association with fly pollination were most probably derived from mutualistic ancestors, offering a brood-site to their pollinators. PMID:22965851
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Landscape genetic approaches to guide native plant restoration in the Mojave Desert
Shryock, Daniel F.; Havrilla, Caroline A.; DeFalco, Lesley; Esque, Todd C.; Custer, Nathan; Wood, Troy E.
2016-01-01
Restoring dryland ecosystems is a global challenge due to synergistic drivers of disturbance coupled with unpredictable environmental conditions. Dryland plant species have evolved complex life-history strategies to cope with fluctuating resources and climatic extremes. Although rarely quantified, local adaptation is likely widespread among these species and potentially influences restoration outcomes. The common practice of reintroducing propagules to restore dryland ecosystems, often across large spatial scales, compels evaluation of adaptive divergence within these species. Such evaluations are critical to understanding the consequences of large-scale manipulation of gene flow and to predicting success of restoration efforts. However, genetic information for species of interest can be difficult and expensive to obtain through traditional common garden experiments. Recent advances in landscape genetics offer marker-based approaches for identifying environmental drivers of adaptive genetic variability in non-model species, but tools are still needed to link these approaches with practical aspects of ecological restoration. Here, we combine spatially-explicit landscape genetics models with flexible visualization tools to demonstrate how cost-effective evaluations of adaptive genetic divergence can facilitate implementation of different seed sourcing strategies in ecological restoration. We apply these methods to Amplified Fragment Length Polymorphism (AFLP) markers genotyped in two Mojave Desert shrub species of high restoration importance: the long-lived, wind-pollinated gymnosperm Ephedra nevadensis, and the short-lived, insect-pollinated angiosperm Sphaeralcea ambigua. Mean annual temperature was identified as an important driver of adaptive genetic divergence for both species. Ephedra showed stronger adaptive divergence with respect to precipitation variability, while temperature variability and precipitation averages explained a larger fraction of adaptive divergence in Sphaeralcea. We describe multivariate statistical approaches for interpolating spatial patterns of adaptive divergence while accounting for potential bias due to neutral genetic structure. Through a spatial bootstrapping procedure, we also visualize patterns in the magnitude of model uncertainty. Finally, we introduce an interactive, distance-based mapping approach that explicitly links marker-based models of adaptive divergence with local or admixture seed sourcing strategies, promoting effective native plant restoration.
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McIntyre, N.E.; Thompson, Thomas R.
2003-01-01
The Conservation Reserve Program (CRP) was designed to reduce soil erosion and curb agricultural overproduction by converting highly erodible agricultural land to various forms of perennial habitat. It has had an incidental benefit of providing habitat for wildlife and has been beneficial in reversing population declines of several grassland bird species. However, the mechanisms behind these reversals remain unknown. One such mechanism may be differences in food availability on CRP vs. non-CRP land or between different types of CRP. The influence of CRP habitat type on the abundance of arthropod prey used by grassland birds has not been previously explored. We compared the abundance and diversity of arthropods among four CRP habitat types in Texas [replicated plots of exotic lovegrass (Eragrostis curvula), Old World bluestem (Bothriochloa ischaemum), mixed native grasses with buffalograss (Buchloe?? dactyloides) and mixed native grasses without buffalograss] and native shortgrass prairie. Attention was focused on adult and juvenile spiders (Order Araneae), beetles (Coleoptera), orthopterans (Orthroptera: grasshoppers and crickets) and lepidopterans (Lepidoptera: butterflies and moths), as these taxa are the primary prey items of grassland birds during the breeding season. Arthropod diversity and abundance were higher on indigenous prairie compared to CRP, reflecting differences in vegetative diversity and structure, but there were no differences in arthropod richness or abundance among CRP types. These results indicate that, although CRP is not equivalent to native prairie in terms of vegetation or arthropod diversity, CRP lands do support arthropod prey for grassland birds. More direct assays of the survivorship and fitness of birds on CRP compared to native shortgrass prairie are clearly warranted.
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[Preliminary study on pollination biology of Tulipa edulis].
Wu, Zhengjun; Zhu, Zaibiao; Guo, Qiaosheng; Xu, Hongjian; Ma, Hongliang; Miao, Yuanyuan
2012-02-01
Current study on the pollination biology of Tulipa edulis was conducted to investigate its pollination characteristics and to provide references for artificial domestication and breeding of T. edulis. Flowering dynamics, pollinators, morphology and structure of flower were observed. Different methods were adopted to evaluate the pollen vitality, and benzidine-H2O2 method was used for estimation of the stigma receptivity. Breeding system was evaluated based on out-crossing index (OCI) , pollen-ovule ratio (P/O) and the results of emasculation, bagging and artificial pollination studies. The flower of T. edulis showed typical characteristics of Liliaceae. The pollen remained viable to some extent during all the anthesis and peaked within three days after blossoming. Stigma acceptability peaked in the first day of blossom and dwindled away in the next four days. The type of breeding system of T. edulis was facultative xenogamy, three species of Halictus are the main pollination insects. The type of breeding system of T. edulis was facultative xenogamy, withal cross-pollination give priority to self-pollination, and the insects play a main role on the pollination of T. edulis, further validation are needed to judge if the wind is helpful to pollination.
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Constraints imposed by pollinator behaviour on the ecology and evolution of plant mating systems.
Devaux, C; Lepers, C; Porcher, E
2014-07-01
Most flowering plants rely on pollinators for their reproduction. Plant-pollinator interactions, although mutualistic, involve an inherent conflict of interest between both partners and may constrain plant mating systems at multiple levels: the immediate ecological plant selfing rates, their distribution in and contribution to pollination networks, and their evolution. Here, we review experimental evidence that pollinator behaviour influences plant selfing rates in pairs of interacting species, and that plants can modify pollinator behaviour through plastic and evolutionary changes in floral traits. We also examine how theoretical studies include pollinators, implicitly or explicitly, to investigate the role of their foraging behaviour in plant mating system evolution. In doing so, we call for more evolutionary models combining ecological and genetic factors, and additional experimental data, particularly to describe pollinator foraging behaviour. Finally, we show that recent developments in ecological network theory help clarify the impact of community-level interactions on plant selfing rates and their evolution and suggest new research avenues to expand the study of mating systems of animal-pollinated plant species to the level of the plant-pollinator networks. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.
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Gómez, José María; Perfectti, Francisco; Klingenberg, Christian Peter
2014-01-01
Flowers of animal-pollinated plants are integrated structures shaped by the action of pollinator-mediated selection. It is widely assumed that pollination specialization increases the magnitude of floral integration. However, empirical evidence is still inconclusive. In this study, we explored the role of pollinator diversity in shaping the evolution of corolla-shape integration in Erysimum, a plant genus with generalized pollination systems. We quantified floral integration in Erysimum using geometric morphometrics and explored its evolution using phylogenetic comparative methods. Corolla-shape integration was low but significantly different from zero in all study species. Spatial autocorrelation and phylogenetic signal in corolla-shape integration were not detected. In addition, integration in Erysimum seems to have evolved in a way that is consistent with Brownian motion, but with frequent convergent evolution. Corolla-shape integration was negatively associated with the number of pollinators visiting the flowers of each Erysimum species. That is, it was lower in those species having a more generalized pollination system. This negative association may occur because the co-occurrence of many pollinators imposes conflicting selection and cancels out any consistent selection on specific floral traits, preventing the evolution of highly integrated flowers. PMID:25002702
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How does climate warming affect plant-pollinator interactions?
Hegland, Stein Joar; Nielsen, Anders; Lázaro, Amparo; Bjerknes, Anne-Line; Totland, Ørjan
2009-02-01
Climate warming affects the phenology, local abundance and large-scale distribution of plants and pollinators. Despite this, there is still limited knowledge of how elevated temperatures affect plant-pollinator mutualisms and how changed availability of mutualistic partners influences the persistence of interacting species. Here we review the evidence of climate warming effects on plants and pollinators and discuss how their interactions may be affected by increased temperatures. The onset of flowering in plants and first appearance dates of pollinators in several cases appear to advance linearly in response to recent temperature increases. Phenological responses to climate warming may therefore occur at parallel magnitudes in plants and pollinators, although considerable variation in responses across species should be expected. Despite the overall similarities in responses, a few studies have shown that climate warming may generate temporal mismatches among the mutualistic partners. Mismatches in pollination interactions are still rarely explored and their demographic consequences are largely unknown. Studies on multi-species plant-pollinator assemblages indicate that the overall structure of pollination networks probably are robust against perturbations caused by climate warming. We suggest potential ways of studying warming-caused mismatches and their consequences for plant-pollinator interactions, and highlight the strengths and limitations of such approaches.
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Sugiura, Naoto
2014-01-01
Arundina graminifolia is an early successional plant on Iriomote Island, the Ryukyus, Japan, where it is endangered. Populations flower for more than half a year, and many inflorescences bloom for one to several months. The nectarless gullet flowers, which open for up to six days, are self-compatible but cannot self-pollinate spontaneously; thus they rely on pollinating agents for capsule production. Field observations at two habitats identified at least six species of bees and wasps, primarily mate-seeking males of Megachile yaeyamaensis and Thyreus takaonis, as legitimate pollinators. Thus, this orchid is a pollinator generalist, probably owing to its long blooming period and simple flower morphology. Carpenter bees, which were previously reported to pollinate this orchid, frequently visited flowers but were too large to crawl into the labellum chamber and never pollinated the flowers. Extrafloral nectaries on inflorescences attracted approximately 40 insect taxa but were not involved with pollination. Fruit-set ratios at the population level varied spatiotemporally but were generally low (5.2-12.4 %), presumably owing to infrequent flower visits by mate-seeking pollinators and the lack of food rewards to pollinators.
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Effects of distance from models on the fitness of floral mimics.
Duffy, K J; Johnson, S D
2017-05-01
Rewardless plants can attract pollinators by mimicking floral traits of rewarding heterospecific plants. This should result in the pollination success of floral mimics being dependent on the relative abundance of their models, as pollinator abundance and conditioning on model signals should be higher in the vicinity of the models. However, the attraction of pollinators to signals of the models may be partially innate, such that spatial isolation of mimics from model species may not strongly affect pollination success of mimics. We tested whether pollination rates and fruit set of the rewardless orchid Disa pulchra were influenced by proximity and abundance of its rewarding model species, Watsonia lepida. Pollination success of the orchid increased with proximity to the model species, while fruit set of the orchid increased with local abundance of the model species. Orchids that were experimentally translocated outside the model population experienced reduced pollinaria removal and increased pollinator-mediated self-pollination. These results confirm predictions that the pollination success of floral mimics should be dependent on the proximity and abundance of model taxa, and thus highlight the importance of ecological facilitation among species involved in mimicry systems. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Jacobs, Jennifer H.; Clark, Suzanne J.; Denholm, Ian; Goulson, Dave; Stoate, Chris; Osborne, Juliet L.
2009-01-01
Background and Aims In the UK, the flowers of fruit-bearing hedgerow plants provide a succession of pollen and nectar for flower-visiting insects for much of the year. The fruits of hedgerow plants are a source of winter food for frugivorous birds on farmland. It is unclear whether recent declines in pollinator populations are likely to threaten fruit-set and hence food supply for birds. The present study investigates the pollination biology of five common hedgerow plants: blackthorn (Prunus spinosa), hawthorn (Crataegus monogyna), dog rose (Rosa canina), bramble (Rubus fruticosus) and ivy (Hedera helix). Methods The requirement for insect pollination was investigated initially by excluding insects from flowers by using mesh bags and comparing immature and mature fruit-set with those of open-pollinated flowers. Those plants that showed a requirement for insect pollination were then tested to compare fruit-set under two additional pollination service scenarios: (1) reduced pollination, with insects excluded from flowers bagged for part of the flowering period, and (2) supplemental pollination, with flowers hand cross-pollinated to test for pollen limitation. Key Results The proportions of flowers setting fruit in blackthorn, hawthorn and ivy were significantly reduced when insects were excluded from flowers by using mesh bags, whereas fruit-set in bramble and dog rose were unaffected. Restricting the exposure of flowers to pollinators had no significant effect on fruit-set. However, blackthorn and hawthorn were found to be pollen-limited, suggesting that the pollination service was inadequate in the study area. Conclusions Ensuring strong populations of insect pollinators may be essential to guarantee a winter fruit supply for birds in UK hedgerows. PMID:19770165
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Lázaro, A.; Totland, Ø.
2014-01-01
Background and Aims The pollinator-mediated stabilizing selection hypothesis suggests that the specialized pollination system of zygomorphic flowers might cause stabilizing selection, reducing their flower size variation compared with actinomorphic flowers. However, the degree of ecological generalization and of dependence on pollinators varies greatly among species of both flower symmetry types and this may also affect flower size variation. Methods Data on 43 species from two contrasting communities (one alpine and one lowland community) were used to test the relationships and interactions between flower size phenotypic variation, floral symmetry, ecological pollination generalization and species' dependence on pollinators. Key Results Contrary to what was expected, higher flower size variation was found in zygomorphic than in actinomorphic species in the lowland community, and no difference in flower size variation was found between symmetry types in the alpine community. The relationship between floral symmetry and flower size variation depended on ecological generalization and species' dependence on pollinators, although the influence of ecological generalization was only detected in the alpine community. Zygomorphic species that were highly dependent on pollinators and that were ecologically specialized were less variable in flower size than ecologically generalist and selfing zygomorphic species, supporting the pollinator-mediated stabilizing selection hypothesis. However, these relationships were not found in actinomorphic species, probably because they are not dependent on any particular pollinator for efficient pollination and therefore their flower size always shows moderate levels of variation. Conclusions The study suggests that the relationship between flower size variation and floral symmetry may be influenced by population-dependent factors, such as ecological generalization and species' dependence on pollinators. PMID:24838838
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Lázaro, A; Totland, O
2014-07-01
The pollinator-mediated stabilizing selection hypothesis suggests that the specialized pollination system of zygomorphic flowers might cause stabilizing selection, reducing their flower size variation compared with actinomorphic flowers. However, the degree of ecological generalization and of dependence on pollinators varies greatly among species of both flower symmetry types and this may also affect flower size variation. Data on 43 species from two contrasting communities (one alpine and one lowland community) were used to test the relationships and interactions between flower size phenotypic variation, floral symmetry, ecological pollination generalization and species' dependence on pollinators. Contrary to what was expected, higher flower size variation was found in zygomorphic than in actinomorphic species in the lowland community, and no difference in flower size variation was found between symmetry types in the alpine community. The relationship between floral symmetry and flower size variation depended on ecological generalization and species' dependence on pollinators, although the influence of ecological generalization was only detected in the alpine community. Zygomorphic species that were highly dependent on pollinators and that were ecologically specialized were less variable in flower size than ecologically generalist and selfing zygomorphic species, supporting the pollinator-mediated stabilizing selection hypothesis. However, these relationships were not found in actinomorphic species, probably because they are not dependent on any particular pollinator for efficient pollination and therefore their flower size always shows moderate levels of variation. The study suggests that the relationship between flower size variation and floral symmetry may be influenced by population-dependent factors, such as ecological generalization and species' dependence on pollinators. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Mesquita-Neto, J N; Costa, B K P; Schlindwein, C
2017-11-01
Heteranthery, the presence of feeding and pollinating anthers in the same flower, seems to mediate the evolutionary dilemma for plants to protect their gametes and yet provide food for pollinators. This study aims to elucidate the role of heteranthery in the buzz-pollinated Senna reniformis. The fecundity of pollen from long-, medium- and short-sized anthers was determined by hand cross-pollination experiments, and the quantity, size, ornamentation and viability of pollen of different anthers were compared. Rates of flower rejection by bees were measured in anther removal experiments to assess the preferences of flower visitors for feeding or pollinating anthers. Large bees, which were the effective pollinators of self-incompatible S. reniformis, avoided flowers without short feeding anthers, but not those without medium or long anthers. Illegitimate small and medium-sized bees were unresponsive to anther exclusion experiments. Long anthers deposited pollen on the back and short anthers on the venter of large bees. Pollen from long anthers had higher in vitro viability and higher fruit and seed set after cross-pollination than pollen from other sized anthers. Short anthers produce feeding pollen to effective pollinators and long anthers are related to pollination of S. reniformis. Bee behaviour and size was found to directly influence the role of anthers in the 'division of labour'. Only large bee pollinators that carry the pollinating pollen from long anthers in 'safe sites' associated short anthers with the presence of food. In the absence of these larger bee pollinators, the role of heteranthery in S. reniformis would be strongly compromised and its function would be lost. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.
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Padyšáková, Eliška; Bartoš, Michael; Tropek, Robert; Janeček, Štěpán
2013-01-01
Many recent studies have suggested that the majority of animal-pollinated plants have a higher diversity of pollinators than that expected according to their pollination syndrome. This broad generalization, often based on pollination web data, has been challenged by the fact that some floral visitors recorded in pollination webs are ineffective pollinators. To contribute to this debate, and to obtain a contrast between visitors and pollinators, we studied insect and bird visitors to virgin flowers of Hypoestes aristata in the Bamenda Highlands, Cameroon. We observed the flowers and their visitors for 2-h periods and measured the seed production as a metric of reproductive success. We determined the effects of individual visitors using 2 statistical models, single-visit data that were gathered for more frequent visitor species, and frequency data. This approach enabled us to determine the positive as well as neutral or negative impact of visitors on H. aristata’s reproductive success. We found that (i) this plant is not generalized but rather specialized; although we recorded 15 morphotaxa of visitors, only 3 large bee species seemed to be important pollinators; (ii) the carpenter bee Xylocopa cf. inconstans was both the most frequent and the most effective pollinator; (iii) the honey bee Apis mellifera acted as a nectar thief with apparent negative effects on the plant reproduction; and (iv) the close relationship between H. aristata and carpenter bees was in agreement with the large-bee pollination syndrome of this plant. Our results highlight the need for studies detecting the roles of individual visitors. We showed that such an approach is necessary to evaluate the pollination syndrome hypothesis and create relevant evolutionary and ecological hypotheses. PMID:23593135
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Padyšáková, Eliška; Bartoš, Michael; Tropek, Robert; Janeček, Stěpán
2013-01-01
Many recent studies have suggested that the majority of animal-pollinated plants have a higher diversity of pollinators than that expected according to their pollination syndrome. This broad generalization, often based on pollination web data, has been challenged by the fact that some floral visitors recorded in pollination webs are ineffective pollinators. To contribute to this debate, and to obtain a contrast between visitors and pollinators, we studied insect and bird visitors to virgin flowers of Hypoestes aristata in the Bamenda Highlands, Cameroon. We observed the flowers and their visitors for 2-h periods and measured the seed production as a metric of reproductive success. We determined the effects of individual visitors using 2 statistical models, single-visit data that were gathered for more frequent visitor species, and frequency data. This approach enabled us to determine the positive as well as neutral or negative impact of visitors on H. aristata's reproductive success. We found that (i) this plant is not generalized but rather specialized; although we recorded 15 morphotaxa of visitors, only 3 large bee species seemed to be important pollinators; (ii) the carpenter bee Xylocopa cf. inconstans was both the most frequent and the most effective pollinator; (iii) the honey bee Apis mellifera acted as a nectar thief with apparent negative effects on the plant reproduction; and (iv) the close relationship between H. aristata and carpenter bees was in agreement with the large-bee pollination syndrome of this plant. Our results highlight the need for studies detecting the roles of individual visitors. We showed that such an approach is necessary to evaluate the pollination syndrome hypothesis and create relevant evolutionary and ecological hypotheses.
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Pollinators: Downward Trends and Lofty Goals
Pollinators are essential to natural and managed landscapes. By providing critical pollination services, bees, birds, beetles, butterflies, bats and other animals enhance biodiversity and contribute to production of many nutritious foods. Honey bees alone pollinate 90 commercia...
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Morales, Carolina L.; Traveset, Anna; Harder, Lawrence D.
2013-01-01
Background and Aims Large floral displays have opposing consequences for animal-pollinated angiosperms: they attract more pollinators but also enable elevated among-flower self-pollination (geitonogamy). The presence of sterile flowers as pollinator signals may enhance attraction while allowing displays of fewer open fertile flowers, limiting geitonogamy. The simultaneous contributions of fertile and non-fertile display components to pollinator attraction and reproductive output remain undetermined. Methods The simultaneous effects of the presence of sterile flowers and fertile-flower display size in two populations of Leopoldia comosa were experimentally assessed. Pollinator behaviour, pollen removal and deposition, and fruit and seed production were compared between intact plants and plants with sterile flowers removed. Key Results The presence of sterile flowers almost tripled pollinator attraction, supplementing the positive effect of the number of fertile flowers on the number of bees approaching inflorescences. Although attracted bees visited more flowers on larger inflorescences, the number visited did not additionally depend on the presence of sterile flowers. The presence of sterile flowers improved all aspects of plant performance, the magnitude of plant benefit being context dependent. During weather favourable to pollinators, the presence of sterile flowers increased pollen deposition on stigmas of young flowers, but this difference was not evident in older flowers, probably because of autonomous self-pollination in poorly visited flowers. Total pollen receipt per stigma decreased with increasing fertile display size. In the population with more pollinators, the presence of sterile flowers increased fruit number but not seed set or mass, whereas in the other population sterile flowers enhanced seeds per fruit, but not fruit production. These contrasts are consistent with dissimilar cross-pollination and autonomous self-pollination, coupled with the strong predispersal inbreeding depression exhibited by L. comosa populations. Conclusions Sterile flowers enrich pollination quality by promoting pollen export and import, while limiting the mating costs of geitonogamy associated with large fertile displays. PMID:23131298
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Jin, Xiao-Fang; Ye, Zhong-Ming; Amboka, Grace M.; Wang, Qing-Feng; Yang, Chun-Feng
2017-01-01
A sensitive bilobed stigma is thought to assure reproduction, avoid selfing and promote outcrossing. In addition, it may also play a role in pollinator selection since only pollinators with the appropriate body size can trigger this mechanism. However, no experimental study has investigated how the sensitive stigma responds to different pollinators and its potential effects on pollination. Mazus miquelii (Phrymaceae), a plant with a bilobed stigma was studied to investigate the relationship between stigma behaviors and its multiple insect pollinators. The reaction time of stigma closure after touched, duration of temporary closure, and factors determining permanent closure of the stigma were studied when flowers were exposed to different visitors and conducted with hand pollination. Manual stimulation was also used to detect the potential differences in stigmas when touched with different degrees of external forces. Results indicated that, compared to pollinators with a small body size, larger pollinators transferred more pollen grains to the stigma, causing a rapid stigma response and resulting in a higher percentage of permanent closures. Duration of temporary closure was negatively correlated with the speed of stigma closure; a stigma that closed more rapidly reopened more slowly. Manual stimulation showed that reaction time of stigma closure was likely a response to external mechanical forces. Hand pollination treatments revealed that the permanent closure of a stigma was determined by the size of stigmatic pollen load. For large pollinators, the speedy reaction of the stigma might help to reduce pollen loss, enhance pollen germination and avoid obstructing pollen export. Stigmas showed low sensitivity when touched by inferior pollinators, which may have increased the possibility of pollen deposition by subsequent visits. Therefore, the stigma behavior in M. miquelii is likely a mechanism of pollinator selection to maximize pollination success. PMID:28539934
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Wolowski, Marina; Ashman, Tia-Lynn; Freitas, Leandro
2014-01-01
Despite the extensive knowledge of pollen limitation in angiosperms, its assessment within tropical forests is still limited. Especially lacking are large scale comparisons of species within this biome – one that is highly diverse but also becoming increasingly threatened. In fact, many tropical plant species depend upon pollinators for reproduction but evaluation of the impact of this dependence via different levels of pollination specialization has yet to be made at the biome scale. We assessed the occurrence and magnitude of pollen limitation for species in the Brazilian Atlantic forest and tested the association of pollination specialization, breeding system, and life habit with pollination efficiency. We compiled data from studies published between 1985 and 2012. We calculated species' effect size (d) from data on fruit set after hand cross-pollination and natural pollination and conducted standard and phylogenetically independent meta-analysis. Overall pollen limitation was moderate, with magnitude of 0.50, and 95% confidence interval [0.37, 0.62] for 126 species. Pollen limitation was observed in 39% of species. Pollination specialization was the factor that best explained the occurrence of pollen limitation. Specifically, phenotypic and ecological specialists (plants with zygomorphic flowers and pollinated by one species of pollinator, respectively) had higher pollen limitation than generalist plants (actinomorphic flowers and pollination by two or more species). Functional generalists (plants pollinated by three or more functional groups) were not pollen limited. On the other hand, breeding system and life habit were not associated to pollen limitation. Pollen limitation was observed in the Atlantic forest and its magnitude was comparable to that for angiosperms as a whole. The finding that pollination specialization was the strongest predictor of pollen limitation suggests that specialist plants in this biome may be most prone to the reproductive failure as a result of pollinator loss. PMID:24586827
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Cooley, A M; Carvallo, G; Willis, J H
2008-04-01
Adaptation to different pollinators is thought to drive divergence in flower colour and morphology, and may lead to interspecific reproductive isolation. Floral diversity was tested for association with divergent pollinator preferences in a group of four closely related wildflower species: the yellow-flowered Mimulus luteus var. luteus and the red-pigmented M. l. variegatus, M. naiandinus and M. cupreus. Patterns of pollinator visitation were evaluated in natural plant populations in central Chile, including both single-species and mixed-species sites. Floral anthocyanin pigments were identified, and floral morphology and nectar variation were quantified in a common garden experiment using seeds collected from the study sites. Mimulus l. luteus, M. l. variegatus and M. naiandinus are morphologically similar and share a single generalist bumblebee pollinator, Bombus dahlbomii. Mimulus cupreus differs significantly from the first three taxa in corolla shape as well as nectar characteristics, and had far fewer pollinator visits. This system shows limited potential for pollinator-mediated restriction of gene flow as a function of flower colour, and no evidence of transition to a novel pollinator. Mimulus cupreus may experience reduced interspecific gene flow due to a lack of bumblebee visitation, but not because of its red pigmentation: rare yellow morphs are equally undervisited by pollinators. Overall, the results suggest that factors other than pollinator shifts may contribute to the maintenance of floral diversity in these Chilean Mimulus species.
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Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F; Tscharntke, Teja
2013-01-01
The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators.
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Insecticide use in hybrid onion seed production affects pre- and postpollination processes.
Gillespie, Sandra; Long, Rachael; Seitz, Nicola; Williams, Neal
2014-02-01
Research on threats to pollination service in agro-ecosystems has focused primarily on the negative impacts of land use change and agricultural practices such as insecticide use on pollinator populations. Insecticide use could also affect the pollination process, through nonlethal impacts on pollinator attraction and postpollination processes such as pollen viability or pollen tube growth. Hybrid onion seed (Allium cepa L., Alliaceae) is an important pollinator-dependent crop that has suffered yield declines in California, concurrent with increased insecticide use. Field studies suggest that insecticide use reduces pollination service in this system. We conducted a field experiment manipulating insecticide use to examine the impacts of insecticides on 1) pollinator attraction, 2) pollen/stigma interactions, and 3) seed set and seed quality. Select insecticides had negative impacts on pollinator attraction and pollen/stigma interactions, with certain products dramatically reducing pollen germination and pollen tube growth. Decreased pollen germination was not associated with reduced seed set; however, reduced pollinator attraction was associated with lower seed set and seed quality, for one of the two female lines examined. Our results highlight the importance of pesticide effects on the pollination process. Overuse may lead to yield reductions through impacts on pollinator behavior and postpollination processes. Overall, in hybrid onion seed production, moderation in insecticide use is advised when controlling onion thrips, Thrips tabaci, on commercial fields.
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Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F.; Tscharntke, Teja
2013-01-01
The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators. PMID:23382979
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Contribution of Pollinator-Mediated Crops to Nutrients in the Human Food Supply
Eilers, Elisabeth J.; Kremen, Claire; Smith Greenleaf, Sarah; Garber, Andrea K.; Klein, Alexandra-Maria
2011-01-01
The contribution of nutrients from animal pollinated world crops has not previously been evaluated as a biophysical measure for the value of pollination services. This study evaluates the nutritional composition of animal-pollinated world crops. We calculated pollinator dependent and independent proportions of different nutrients of world crops, employing FAO data for crop production, USDA data for nutritional composition, and pollinator dependency data according to Klein et al. (2007). Crop plants that depend fully or partially on animal pollinators contain more than 90% of vitamin C, the whole quantity of Lycopene and almost the full quantity of the antioxidants β-cryptoxanthin and β-tocopherol, the majority of the lipid, vitamin A and related carotenoids, calcium and fluoride, and a large portion of folic acid. Ongoing pollinator decline may thus exacerbate current difficulties of providing a nutritionally adequate diet for the global human population. PMID:21731717
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Floral advertisement scent in a changing plant-pollinators market.
Filella, Iolanda; Primante, Clara; Llusià, Joan; Martín González, Ana M; Seco, Roger; Farré-Armengol, Gerard; Rodrigo, Anselm; Bosch, Jordi; Peñuelas, Josep
2013-12-05
Plant-pollinator systems may be considered as biological markets in which pollinators choose between different flowers that advertise their nectar/pollen rewards. Although expected to play a major role in structuring plant-pollinator interactions, community-wide patterns of flower scent signals remain largely unexplored. Here we show for the first time that scent advertisement is higher in plant species that bloom early in the flowering period when pollinators are scarce relative to flowers than in species blooming later in the season when there is a surplus of pollinators relative to flowers. We also show that less abundant flowering species that may compete with dominant species for pollinator visitation early in the flowering period emit much higher proportions of the generalist attractant β-ocimene. Overall, we provide a first community-wide description of the key role of seasonal dynamics of plant-specific flower scent emissions, and reveal the coexistence of contrasting plant signaling strategies in a plant-pollinator market.
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A trophic cascade induced by predatory ants in a fig-fig wasp mutualism.
Wang, Bo; Geng, Xiang-Zong; Ma, Li-Bin; Cook, James M; Wang, Rui-Wu
2014-09-01
A trophic cascade occurs when predators directly decrease the densities, or change the behaviour, of herbivores and thus indirectly increase plant productivity. The predator-herbivore-plant context is well known, but some predators attack species beneficial to plants (e.g. pollinators) and/or enemies of herbivores (e.g. parasites), and their role in the dynamics of mutualisms remains largely unexplored. We surveyed the predatory ant species and studied predation by the dominant ant species, the weaver ant Oecophylla smaragdina, associated with the fig tree Ficus racemosa in southwest China. We then tested the effects of weaver ants on the oviposition behaviour of pollinating and non-pollinating fig wasps in an ant-exclusion experiment. The effects of weaver ants on fig wasp community structure and fig seed production were then compared between trees with and without O. smaragdina. Oecophylla smaragdina captured more non-pollinating wasps (Platyneura mayri) than pollinators as the insects arrived to lay eggs. When ants were excluded, more non-pollinators laid eggs into figs and fewer pollinators entered figs. Furthermore, trees with O. smaragdina produced more pollinator offspring and fewer non-pollinator offspring, shifting the community structure significantly. In addition, F. racemosa produced significantly more seeds on trees inhabited by weaver ants. Oecophylla smaragdina predation reverses the dominance of the two commonest wasp species at the egg-laying stage and favours the pollinators. This behavioural pattern is mirrored by wasp offspring production, with pollinators' offspring dominating figs produced by trees inhabited by weaver ants, and offspring of the non-pollinator P. mayri most abundant in figs on trees inhabited by other ants. Overall, our results suggest that predation by weaver ants limits the success of the non-pollinating P. mayri and therefore indirectly benefits the mutualism by increasing the reproductive success of both the pollinators and the plant. Predation is thus a key functional factor that can shape the community structure of a pollinator-plant mutualistic system. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.
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In situ modeling of multimodal floral cues attracting wild pollinators across environments
Dahlbom, Josefin; Ghosh, Suhrid; Olsson, Amadeus; Dyakova, Olga; Suresh, Shravanti Krishna
2017-01-01
With more than 80% of flowering plant species specialized for animal pollination, understanding how wild pollinators utilize resources across environments can encourage efficient planting and maintenance strategies to maximize pollination and establish resilience in the face of environmental change. A fundamental question is how generalist pollinators recognize “flower objects” in vastly different ecologies and environments. On one hand, pollinators could employ a specific set of floral cues regardless of environment. Alternatively, wild pollinators could recognize an exclusive signature of cues unique to each environment or flower species. Hoverflies, which are found across the globe, are one of the most ecologically important alternative pollinators after bees and bumblebees. Here, we have exploited their cosmopolitan status to understand how wild pollinator preferences change across different continents. Without employing any a priori assumptions concerning the floral cues, we measured, predicted, and finally artificially recreated multimodal cues from individual flowers visited by hoverflies in three different environments (hemiboreal, alpine, and tropical) using a field-based methodology. We found that although “flower signatures” were unique for each environment, some multimodal lures were ubiquitously attractive, despite not carrying any reward, or resembling real flowers. While it was unexpected that cue combinations found in real flowers were not necessary, the robustness of our lures across insect species and ecologies could reflect a general strategy of resource identification for generalist pollinators. Our results provide insights into how cosmopolitan pollinators such as hoverflies identify flowers and offer specific ecologically based cues and strategies for attracting pollinators across diverse environments. PMID:29180408
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Bobiwash, Kyle; Uriel, Yonathan; Elle, Elizabeth
2018-02-09
Highbush blueberry, Vaccinium corymbosum (Gray), production in British Columbia is dependent upon insect pollination for fruit yield with particular cultivars demonstrating low yields due to poor pollination. New managed species of pollinators are being developed to provide farmers with managed pollinator options beyond Apis mellifera (Linnaeus). Pollinators in highbush blueberry agricultural systems encounter a variety of nontarget floral resources that may affect the pollination received by the crop. Our study analyzed the differences in pollen foraging of honey bees and two species of managed bumblebees across nine farm sites. Corbicular pollen loads from pollen foraging workers were removed and identified to the lowest taxonomic level possible. Of the three managed pollinators, the corbicular pollen loads of Bombus huntii (Greene) contained the most blueberry pollen (52.1%), three times as much as the two other managed bee species. Fifteen morphotypes of pollen were identified from all foraging workers with Rosaceae being the most frequently gathered overall pollen type (n = 74). The noncrop pollen identified in our samples derived from plant species not common as weedy species in the agroecosystem suggesting that floral resource diversity outside of the farm boundaries is important to pollinators. The three managed species in our blueberry fields utilized floral resources differentially underscoring the importance of pollinator species' characteristics and large-scale floral resource landscape in developing new managed pollinators and pollination strategies. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Rain pollination provides reproductive assurance in a deceptive orchid.
Fan, Xu-Li; Barrett, Spencer C H; Lin, Hua; Chen, Ling-Ling; Zhou, Xiang; Gao, Jiang-Yun
2012-10-01
Abiotic pollination by wind or water is well established in flowering plants. In some species pollination by rain splashes, a condition known as ombrophily, has been proposed as a floral strategy. However, evidence for this type of abiotic pollination has remained controversial and many reported cases have subsequently been shown to be false. This study investigates ombrophily in the deceptive orchid Acampe rigida to determine the mechanism by which this species is able to maintain high fecundity, despite flowering during the rainy season in south-west China when pollinators are scarce. The floral mechanisms promoting rain pollination in A. rigida were observed and described in detail. Controlled pollination experiments and observations of floral visitors were conducted. A field experiment using rain shelters at 14 sites in Guangxi, south-west China, evaluated the contribution of rain pollination to fruit-set. During rainfall, raindrops physically flicked away the anther cap exposing the pollinarium. Raindrops then caused pollinia to be ejected upwards with the strap-like stipe pulling them back and causing them to fall into the stigmatic cavity, resulting in self-pollination. Neither flower nor pollen function were damaged by water. Although A. rigida is self-compatible, it is incapable of autonomous self-pollination without the assistance of rain splashes. The results of the rain-sheltering experiment indicated that rain pollination contributed substantially to increasing fruit-set, although there was variation among sites in the intensity of this effect. A. rigida flowers during the rainy season, when pollinators are scarce, and ombrophily functions to provide reproductive assurance without compromising opportunities for outcrossing.
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Rain pollination provides reproductive assurance in a deceptive orchid
Fan, Xu-Li; Barrett, Spencer C. H.; Lin, Hua; Chen, Ling-Ling; Zhou, Xiang; Gao, Jiang-Yun
2012-01-01
Background and Aims Abiotic pollination by wind or water is well established in flowering plants. In some species pollination by rain splashes, a condition known as ombrophily, has been proposed as a floral strategy. However, evidence for this type of abiotic pollination has remained controversial and many reported cases have subsequently been shown to be false. This study investigates ombrophily in the deceptive orchid Acampe rigida to determine the mechanism by which this species is able to maintain high fecundity, despite flowering during the rainy season in south-west China when pollinators are scarce. Methods The floral mechanisms promoting rain pollination in A. rigida were observed and described in detail. Controlled pollination experiments and observations of floral visitors were conducted. A field experiment using rain shelters at 14 sites in Guangxi, south-west China, evaluated the contribution of rain pollination to fruit-set. Key Results During rainfall, raindrops physically flicked away the anther cap exposing the pollinarium. Raindrops then caused pollinia to be ejected upwards with the strap-like stipe pulling them back and causing them to fall into the stigmatic cavity, resulting in self-pollination. Neither flower nor pollen function were damaged by water. Although A. rigida is self-compatible, it is incapable of autonomous self-pollination without the assistance of rain splashes. The results of the rain-sheltering experiment indicated that rain pollination contributed substantially to increasing fruit-set, although there was variation among sites in the intensity of this effect. Conclusions A. rigida flowers during the rainy season, when pollinators are scarce, and ombrophily functions to provide reproductive assurance without compromising opportunities for outcrossing. PMID:22851311
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Parallel declines in pollinators and insect-pollinated plants in Britain and the Netherlands.
Biesmeijer, J C; Roberts, S P M; Reemer, M; Ohlemüller, R; Edwards, M; Peeters, T; Schaffers, A P; Potts, S G; Kleukers, R; Thomas, C D; Settele, J; Kunin, W E
2006-07-21
Despite widespread concern about declines in pollination services, little is known about the patterns of change in most pollinator assemblages. By studying bee and hoverfly assemblages in Britain and the Netherlands, we found evidence of declines (pre-versus post-1980) in local bee diversity in both countries; however, divergent trends were observed in hoverflies. Depending on the assemblage and location, pollinator declines were most frequent in habitat and flower specialists, in univoltine species, and/or in nonmigrants. In conjunction with this evidence, outcrossing plant species that are reliant on the declining pollinators have themselves declined relative to other plant species. Taken together, these findings strongly suggest a causal connection between local extinctions of functionally linked plant and pollinator species.
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Mating patterns and pollinator mobility are critical traits in forest fragmentation genetics
Breed, M F; Ottewell, K M; Gardner, M G; Marklund, M H K; Dormontt, E E; Lowe, A J
2015-01-01
Most woody plants are animal-pollinated, but the global problem of habitat fragmentation is changing the pollination dynamics. Consequently, the genetic diversity and fitness of the progeny of animal-pollinated woody plants sired in fragmented landscapes tend to decline due to shifts in plant-mating patterns (for example, reduced outcrossing rate, pollen diversity). However, the magnitude of this mating-pattern shift should theoretically be a function of pollinator mobility. We first test this hypothesis by exploring the mating patterns of three ecologically divergent eucalypts sampled across a habitat fragmentation gradient in southern Australia. We demonstrate increased selfing and decreased pollen diversity with increased fragmentation for two small-insect-pollinated eucalypts, but no such relationship for the mobile-bird-pollinated eucalypt. In a meta-analysis, we then show that fragmentation generally does increase selfing rates and decrease pollen diversity, and that more mobile pollinators tended to dampen these mating-pattern shifts. Together, our findings support the premise that variation in pollinator form contributes to the diversity of mating-pattern responses to habitat fragmentation. PMID:24002239
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Private channels in plant-pollinator mutualisms
Chen, Chun; Hossaert-McKey, Martine
2010-01-01
Volatile compounds often mediate plant-pollinator interactions, and may promote specialization in plant-pollinator relationships, notably through private channels of unusual compounds. Nevertheless, the existence of private channels, i.e., the potential for exclusive communication via unique signals and receptors, is still debated in the literature. Interactions between figs and their pollinating wasps offer opportunities for exploring this concept. Several experiments have demonstrated that chemical mediation is crucial in ensuring the encounter between figs and their species-specific pollinators. Indeed, chemical messages emitted by figs are notably species- and developmental stage-specific, making them reliable cues for the pollinator. In most cases, the species-specificity of wasp attraction is unlikely to result from the presence of a single specific compound. Nevertheless, a recent paper on the role of scents in the interaction between Ficus semicordata and its pollinating wasp Ceratosolen gravelyi showed that a single compound, 4-methylanisole, is the main signal compound in the floral scent, and is sufficient by itself to attract the obligate pollinator. Mainly focusing on these results, we propose here that a floral scent can act as a private channel, attracting only the highly specific pollinator. PMID:20484975
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Al-Kahtani, Saad Naser; Taha, El-Kazafy Abdou; Al-Abdulsalam, Mohammed
2017-07-01
This investigation was conducted at the Agricultural and Veterinary Training and Research Station, King Faisal University, Al-Ahsa, Saudi Arabia, during the alfalfa growing season in 2014. The study aimed to evaluate the impact of phosphorus fertilization and honeybee pollination on alfalfa seed production. The experiment was divided into 9 treatments of open pollination, honeybee pollination, and non-pollination with three different levels (0, 300 or 600 kg P 2 O 5 /ha/year) of triple super phosphate. All vegetative growth attributes of Hassawi alfalfa were significantly higher in the non-insect pollination plots, while the yield and yield component traits were significantly higher with either open pollination or honeybee pollination in parallel with the increasing level of phosphorus fertilizer up to 600 kg P 2 O 5 /ha/year in light salt-affected loamy sand soils. There was no seed yield in Hassawi alfalfa without insect pollination. Therefore, placing honeybee colonies near the fields of Hassawi alfalfa and adding 600 kg P 2 O 5 /ha/year can increase seed production.
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Shifts in water availability mediate plant-pollinator interactions.
Gallagher, M Kate; Campbell, Diane R
2017-07-01
Altered precipitation patterns associated with anthropogenic climate change are expected to have many effects on plants and insect pollinators, but it is unknown if effects on pollination are mediated by changes in water availability. We tested the hypothesis that impacts of climate on plant-pollinator interactions operate through changes in water availability, and specifically that such effects occur through alteration of floral attractants. We manipulated water availability in two naturally occurring Mertensia ciliata (Boraginaceae) populations using water addition, water reduction and control plots and measured effects on vegetative and floral traits, pollinator visitation and seed set. While most floral trait values, including corolla size and nectar, increased linearly with increasing water availability, in this bumblebee-pollinated species, pollinator visitation peaked at intermediate water levels. Visitation also peaked at an intermediate corolla length, while its relationship to corolla width varied across sites. Seed set, however, increased linearly with water. These results demonstrate the potential for changes in water availability to impact plant-pollinator interactions through pollinator responses to differences in floral attractants, and that the effects of water on pollinator visitation can be nonlinear. Plant responses to changes in resource availability may be an important mechanism by which climate change will affect species interactions. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.
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Pollination syndromes in African Marantaceae.
Ley, Alexandra C; Classen-Bockhoff, Regine
2009-07-01
The Marantaceae (550 spp.) is the most derived family in the order Zingiberales and exhibits a complex explosive pollination mechanism. To understand the evolutionary significance of this unique process of pollen transfer, comparative morphological and ecological studies were conducted in Gabon. During a total stay of 11 months, 31 species of Marantaceae were investigated at different sites in Gabon. The study included analyses of floral diversity, observations on the pollinator spectrum as well as ecological measurements (e.g. nectar sugar concentration and volume). Analyses reveal five flower types based on flower size and pigmentation, spatial arrangement of the floral tube and presence/absence of nectar guides and conspicuous outer staminodes. Each type is associated with a specific functional pollinator group leading to the description of distinct pollination syndromes. The 'small (horizontal)' flowers are predominantly pollinated by small bees (Thrinchostoma spp., Allodapula ornaticeps), the 'large (horizontal)' and 'medium-sized (horizontal)' flowers by medium-sized bees (Amegilla vivida, Thrinchostoma bicometes), the 'locked (horizontal)' flowers by large bees (Xylocopa nigrita, X. varipes) and the '(large) vertical' flowers by sunbirds. The longevity of Marantaceae individuals and the omnipresence of their pollinators allowed the specialization to a given functional pollinator group. Intermediate ecological values, however, make occasional pollinator overlaps possible, indicating potential pathways of pollinator shifts. Similar radiation tendencies observed on other continents hint at similar selective pressures and evolutionary constraints.
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Pollinator Behaviour on a Food-Deceptive Orchid Calypso bulbosa and Coflowering Species
Tuomi, Juha; Lämsä, Juho; Wannas, Lauri; Abeli, Thomas; Jäkäläniemi, Anne
2015-01-01
Food deception as a pollination strategy has inspired many studies over the last few decades. Pollinator deception has evolved in many orchids possibly to enhance outcrossing. Food-deceptive orchids usually have low pollinator visitation rates as compared to rewarding species. They may benefit in visitations from the presence (magnet-species hypothesis) or, alternatively, absence of coflowering rewarding species (competition hypothesis). We present data on pollinator visitations on a deceptive, terrestrial orchid Calypso bulbosa, a species with a single flower per plant and whose flowering period partly overlaps with rewarding, early flowering willows (Salix sp.) and later-flowering bilberry (Vaccinium myrtillus). When surveying inactive bumblebee queens on willows in cool weather, about 7% of them carried Calypso pollinia. Most common bumblebee species appeared to visit and thus pollinate Calypso. Bumblebees typically visited one to three Calypso flowers before flying away, providing some support for the outcrossing hypothesis. We conclude that, regarding the pollinations strategy, both magnet-species and competition hypotheses have a role in the pollination of Calypso, but on different spatial scales. On a large scale rewarding species are important for attracting pollinators to a given region, but on a small scale absence of competition ensures sufficient pollination rate for the deceptive orchid. PMID:25861675
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Yan, Juan; Wang, Gang; Sui, Yi; Wang, Menglin; Zhang, Ling
2016-04-13
Floral colour change is visual signals for pollinators to avoid old flowers and increase pollination efficiency. Quisqualis indica flowers change colour from white to pink to red may be associated with a shift from moth to butterfly pollination. To test this hypothesis, we investigated Q. indica populations in Southwest China. Flowers secreted nectar continuously from the evening of anthesis until the following morning, then decreased gradually with floral colour change. The scent compounds in the three floral colour stages were similar; however, the scent composition was different, and the scent emission rate decreased from the white to red stage. Dichogamy in Q. indica prevents self-pollination and interference of male and female functions. Controlled pollinations demonstrated that this species is self-incompatible and needs pollinators for seed production. Different pollinators were attracted in each floral colour stage; mainly moths at night and bees and butterflies during the day. Observations of open-pollinated inflorescences showed that white flowers had a higher fruit set than pink or red flowers, indicating the high contribution of moths to reproductive success. We concluded that the nectar and scent secretion are related to floral colour change in Q. indica, in order to attract different pollinators and promote reproductive fitness.
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Gómez, José María; Perfectti, Francisco; Klingenberg, Christian Peter
2014-08-19
Flowers of animal-pollinated plants are integrated structures shaped by the action of pollinator-mediated selection. It is widely assumed that pollination specialization increases the magnitude of floral integration. However, empirical evidence is still inconclusive. In this study, we explored the role of pollinator diversity in shaping the evolution of corolla-shape integration in Erysimum, a plant genus with generalized pollination systems. We quantified floral integration in Erysimum using geometric morphometrics and explored its evolution using phylogenetic comparative methods. Corolla-shape integration was low but significantly different from zero in all study species. Spatial autocorrelation and phylogenetic signal in corolla-shape integration were not detected. In addition, integration in Erysimum seems to have evolved in a way that is consistent with Brownian motion, but with frequent convergent evolution. Corolla-shape integration was negatively associated with the number of pollinators visiting the flowers of each Erysimum species. That is, it was lower in those species having a more generalized pollination system. This negative association may occur because the co-occurrence of many pollinators imposes conflicting selection and cancels out any consistent selection on specific floral traits, preventing the evolution of highly integrated flowers. © 2014 The Author(s) Published by the Royal Society. All rights reserved.
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Bosch, J; Bosch, J; Kemp, W P
2002-02-01
The development of a bee species as a new crop pollinator starts with the identification of a pollination-limited crop production deficit and the selection of one or more candidate pollinator species. The process continues with a series of studies on the developmental biology, pollinating efficacy, nesting behaviour, preference for different nesting substrates, and population dynamics of the candidate pollinator. Parallel studies investigate the biology of parasites, predators and pathogens. The information gained in these studies is combined with information on the reproductive biology of the crop to design a management system. Complete management systems should provide guidelines on rearing and releasing methods, bee densities required for adequate pollination, nesting materials, and control against parasites, predators and pathogens. Management systems should also provide methods to ensure a reliable pollinator supply. Pilot tests on a commercial scale are then conducted to test and eventually refine the management system. The process culminates with the delivery of a viable system to manage and sustain the new pollinator on a commercial scale. The process is illustrated by the development of three mason bees, Osmia cornifrons (Radoszkowski), O. lignaria Say and O. cornuta (Latreille) as orchard pollinators in Japan, the USA and Europe, respectively.
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How common is self-incompatibility across species of the herkogamous genus Ariocarpus?
Martínez-Peralta, Concepción; Márquez-Guzmán, Judith; Mandujano, María C
2014-03-01
Self-incompatibility (SI), the most effective mechanism to prevent selfing, may limit the number of compatible mates in populations. The seven species of Ariocarpus are endangered and predominantly outcrossers but fruit set may reach 1-20% after selfing. We aimed to determine whether SI is the underlying mechanism influencing mating in Ariocarpus species. We characterized the presence/absence of SI using pollination treatments (self-pollination, cross-pollination, natural pollination) in one population per species. We assessed SI using epifluorescence and generalized linear models (GLMs) to compare the presence of pollen tubes in the stigma, stylar transmitting tissue, and ovary among self- and cross-pollinated pistils 48 h after pollination. Following the same treatments, production of fruit set was noted and related to pollen tube growth. Pollen tubes were found more frequently in the ovaries of natural and cross-pollinated flowers than in ovaries of self-pollinated. Stylar rejection of self-pollen indicated gametophytic SI, although pollen tubes reached the ovaries in six species (4-33% of pistils). Fruit set was lower after hand-pollinations than expected from pollen tube observations. The low percentages of self-compatibility in all species in pollen tube growth and pollination experiments indicated that no species had complete self-sterility, suggesting the presence of partial SI. Reduced fruit set relative to pollen tube production could result from a threshold of insufficient pollination, early-acting inbreeding depression, or resource limitation. The origin of partial SI in Ariocarpus could respond to pressures such as pollen limitation and population size.
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Muola, Anne; Weber, Daniela; Malm, Lisa E.; Egan, Paul A.; Glinwood, Robert; Parachnowitsch, Amy L.; Stenberg, Johan A.
2017-01-01
The global decline in pollinators has partly been blamed on pesticides, leading some to propose pesticide-free farming as an option to improve pollination. However, herbivores are likely to be more prevalent in pesticide-free environments, requiring knowledge of their effects on pollinators, and alternative crop protection strategies to mitigate any potential pollination reduction. Strawberry leaf beetles (SLB) Galerucella spp. are important strawberry pests in Northern Europe and Russia. Given that SLB attack both leaf and flower tissue, we hypothesized pollinators would discriminate against SLB-damaged strawberry plants (Fragaria vesca, cultivar ‘Rügen’), leading to lower pollination success and yield. In addition we screened the most common commercial cultivar ‘Rügen’ and wild Swedish F. vesca genotypes for SLB resistance to assess the potential for inverse breeding to restore high SLB resistance in cultivated strawberry. Behavioral observations in a controlled experiment revealed that the local pollinator fauna avoided strawberry flowers with SLB-damaged petals. Low pollination, in turn, resulted in smaller more deformed fruits. Furthermore, SLB-damaged flowers produced smaller fruits even when they were hand pollinated, showing herbivore damage also had direct effects on yield, independent of indirect effects on pollination. We found variable resistance in wild woodland strawberry to SLB and more resistant plant genotypes than the cultivar ‘Rügen’ were identified. Efficient integrated pest management strategies should be employed to mitigate both direct and indirect effects of herbivory for cultivated strawberry, including high intrinsic plant resistance. PMID:28572811
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Pollinator effectiveness varies with experimental shifts in flowering time
Rafferty, Nicole E.; Ives, Anthony R.
2013-01-01
The earlier flowering times exhibited by many plant species are a conspicuous sign of climate change. Altered phenologies have caused concern that species could suffer population declines if they flower at times when effective pollinators are unavailable. For two perennial wildflowers, Tradescantia ohiensis and Asclepias incarnata, we used an experimental approach to explore how changing phenology affects the taxonomic composition of the pollinator assemblage and the effectiveness of individual pollinator taxa. After finding in the previous year that fruit set varied with flowering time, we manipulated flowering onset in greenhouses, placed plants in the field over the span of five weeks, and measured pollinator effectiveness as the number of seeds produced after a single visit to a flower. The average effectiveness of pollinators and the expected rates of pollination success were lower for plants of both species flowering earlier than for plants flowering at historical times, suggesting there could be reproductive costs to earlier flowering. Whereas for A. incarnata, differences in average seed set among weeks were due primarily to changes in the composition of the pollinator assemblage, the differences for T. ohiensis were driven by the combined effects of compositional changes and increases over time in the effectiveness of some pollinator taxa. Both species face the possibility of temporal mismatch between the availability of the most effective pollinators and the onset of flowering, and changes in the effectiveness of individual pollinator taxa through time may add an unexpected element to the reproductive consequences of such mismatches. PMID:22690631
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Buide, María Luisa
2006-02-01
The floral display influences the composition of pollinators interacting with a plant species. Geographic and temporal variation in pollinator composition complicates the understanding of the evolutionary consequences of floral display variation. This paper analyses the relationships between Silene acutifolia, a hermaphroditic perennial herb, and its pollinators, based on field studies in the north-west of Spain. Studies were conducted over three years (1997-1999). Firstly, the main pollinators of this species were determined for two years in one population. Secondly, pollen limitation in fruit and seed production was analysed by supplementary hand pollinations, and counting the pollen grains and tubes growing in styles for two different-sized populations. Finally, the effect of flower size and number on the rate of visitation and total seed number was examined for 15 marked plants. The primary pollinators were long-tongued insects, including Hymenoptera, Lepidoptera and Diptera, but the composition and visitation frequencies differed between years. Pollen limitation occurred in one of the years of study. There was between-population variation in the number of pollen grains and pollen tubes found in styles, suggesting pollen limitation in one population. Overall, pollinators visited plants with more open flowers more frequently, and pollinated more flowers within these plants. Conversely, petal and calyx sizes had no effect on insect visitation. Plants with higher rates of visits produced higher number of seeds, suggesting that pollinator-mediated limitation of seed and fruit production may be important in some years.
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Zhao, Zhi-Gang; Wang, Yi-Ke
2015-01-01
Abundance and visitation of pollinator assemblages tend to decrease with altitude, leading to an increase in pollen limitation. Thus increased competition for pollinators may generate stronger selection on attractive traits of flowers at high elevations and cause floral adaptive evolution. Few studies have related geographically variable selection from pollinators and intraspecific floral differentiation. We investigated the variation of Trollius ranunculoides flowers and its pollinators along an altitudinal gradient on the eastern Qinghai-Tibet Plateau, and measured phenotypic selection by pollinators on floral traits across populations. The results showed significant decline of visitation rate of bees along altitudinal gradients, while flies was unchanged. When fitness is estimated by the visitation rate rather than the seed number per plant, phenotypic selection on the sepal length and width shows a significant correlation between the selection strength and the altitude, with stronger selection at higher altitudes. However, significant decreases in the sepal length and width of T. ranunculoides along the altitudinal gradient did not correspond to stronger selection of pollinators. In contrast to the pollinator visitation, mean annual precipitation negatively affected the sepal length and width, and contributed more to geographical variation in measured floral traits than the visitation rate of pollinators. Therefore, the sepal size may have been influenced by conflicting selection pressures from biotic and abiotic selective agents. This study supports the hypothesis that lower pollinator availability at high altitude can intensify selection on flower attractive traits, but abiotic selection is preventing a response to selection from pollinators.
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Zhao, Zhi-Gang; Wang, Yi-Ke
2015-01-01
Abundance and visitation of pollinator assemblages tend to decrease with altitude, leading to an increase in pollen limitation. Thus increased competition for pollinators may generate stronger selection on attractive traits of flowers at high elevations and cause floral adaptive evolution. Few studies have related geographically variable selection from pollinators and intraspecific floral differentiation. We investigated the variation of Trollius ranunculoides flowers and its pollinators along an altitudinal gradient on the eastern Qinghai-Tibet Plateau, and measured phenotypic selection by pollinators on floral traits across populations. The results showed significant decline of visitation rate of bees along altitudinal gradients, while flies was unchanged. When fitness is estimated by the visitation rate rather than the seed number per plant, phenotypic selection on the sepal length and width shows a significant correlation between the selection strength and the altitude, with stronger selection at higher altitudes. However, significant decreases in the sepal length and width of T. ranunculoides along the altitudinal gradient did not correspond to stronger selection of pollinators. In contrast to the pollinator visitation, mean annual precipitation negatively affected the sepal length and width, and contributed more to geographical variation in measured floral traits than the visitation rate of pollinators. Therefore, the sepal size may have been influenced by conflicting selection pressures from biotic and abiotic selective agents. This study supports the hypothesis that lower pollinator availability at high altitude can intensify selection on flower attractive traits, but abiotic selection is preventing a response to selection from pollinators. PMID:25692295
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Del Sarto, M C L; Peruquetti, R C; Campos, L A O
2005-04-01
The Neotropical stingless bee Melipona quadrifasciata Lepeletier was evaluated for pollinating tomatoes (variety Rodas; long-life hybrid) in greenhouses under plastic and with a hydroponic system and "organic concepts" in Minas Gerais State, Brazil. Flowers not pollinated did not set any fruit. Pollination by bees plus manual pollination did not differ from either bee or manual pollination. Maximum fruit diameter, fruit height, and roundness (quotient between maximum fruit diameter and fruit height) were not significantly different between treatments, but fruit visited by M. quadrifasciata had 10.8% less seeds (dry mass) than manual pollination. This apparently low efficiency of M. quadrifasciata pollination was attributed to the overlap of only 30 min between highest bee foraging activity and highest flower stigma receptivity. Thus, it was concluded that M. quadrifasciata is a feasible pollinator of greenhouse tomatoes because of 1) the observed increase in fruit quality with lower mechanical injury than traditional manual pollination, 2) no significant decrease in fruit size, and 3) high price of such product in the market. Some considerations for sustainable use of M. quadrifasciata as greenhouse pollinator are presented. Although techniques for keeping captive colonies of M. quadrifasciata are currently available, the sole current method for acquiring new colonies is removing them from the forest, and if demand was created for large numbers of colonies for commercial use, techniques for captive rearing must be developed to prevent serious declines in wild populations.
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Volpe, Noelia L.; Robinson, W. Douglas; Frey, Sarah J. K.; Hadley, Adam S.; Betts, Matthew G.
2016-01-01
Habitat loss and fragmentation influence species distributions and therefore ecological processes that depend upon them. Pollination may be particularly susceptible to fragmentation, as it depends on frequent pollinator movement. Unfortunately, most pollinators are too small to track efficiently which has precluded testing the hypothesis that habitat fragmentation reduces or eliminates pollen flow by disrupting pollinator movement. We used radio-telemetry to examine space use of the green hermit hummingbird (Phaethornis guy), an important ‘hub’ pollinator of understory flowering plants across substantial portions of the neotropics and the primary pollinator of a keystone plant which shows reduced pollination success in fragmented landscapes. We found that green hermits strongly avoided crossing large stretches of non-forested matrix and preferred to move along stream corridors. Forest gaps as small as 50 m diminished the odds of movement by 50%. Green hermits occurred almost exclusively inside the forest, with the odds of occurrence being 8 times higher at points with >95% canopy cover compared with points having <5% canopy cover. Nevertheless, surprisingly. the species occurred in fragmented landscapes with low amounts of forest (~30% within a 2 km radius). Our results indicate that although green hermits are present even in landscapes with low amounts of tropical forest, movement within these landscapes ends up strongly constrained by forest gaps. Restricted movement of pollinators may be an underappreciated mechanism for widespread declines in pollination and plant fitness in fragmented landscapes, even when in the presence of appropriate pollinators. PMID:27941984
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Gan, Xiaohong; Cao, Lingling; Zhang, Xia; Li, Huaichun
2013-12-01
Tetracentron sinense Oliv. is an endangered tree mainly distributed in south-central China. The breeding system and pollination ecology of T. sinense are unclear. With a conservation perspective, the floral biology, breeding system and pollination ecology of Tetracentron sinense Oliv. were investigated, in order to discuss the endangered factors related to pollination, and to provide important information for its conservation. Our results revealed four important aspects of the reproductive biology of T. sinense. 1) T. sinense usually flowers by the beginning of June, and the flowering period of the population is about two months, and the florescence of florets lasted for 15 to 24 days with delicate fragrance. 2) The pollen/ovule ratio is 720 ± 28, and the outcrossing index is three. Artificial pollination experiments showed that T. sinense is self-compatible, with facultative xenogamy and no indication of agamospermy. 3) The pollination syndrome is ambophily, and self-pollination plays an important role in fruit production if wind and insect pollination is unavailable. 4) Insect pollinators were predominantly represented by Coleoptera, Diptera and Hymenoptera. Syrphid fly and bees were the main effective pollinators. The results suggested that T. sinense exhibits a mixed-mating system, and autogamy in its breeding system may provide reproductive assurance for the population maintenance. During flowering and pollination in natural population, the decrease of population density and harsh environmental condition might be one of crucial reasons resulting in endanger for this species.
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Pollinator effectiveness varies with experimental shifts in flowering time.
Rafferty, Nicole E; Ives, Anthony R
2012-04-01
The earlier flowering times exhibited by many plant species are a conspicuous sign of climate change. Altered phenologies have caused concern that species could suffer population declines if they flower at times when effective pollinators are unavailable. For two perennial wildflowers, Tradescantia ohiensis and Asclepias incarnata, we used an experimental approach to explore how changing phenology affects the taxonomic composition of the pollinator assemblage and the effectiveness of individual pollinator taxa. After finding in the previous year that fruit set varied with flowering time, we manipulated flowering onset in greenhouses, placed plants in the field over the span of five weeks, and measured pollinator effectiveness as the number of seeds produced after a single visit to a flower. The average effectiveness of pollinators and the expected rates of pollination success were lower for plants of both species flowering earlier than for plants flowering at historical times, suggesting there could be reproductive costs to earlier flowering. Whereas for A. incarnata, differences in average seed set among weeks were due primarily to changes in the composition of the pollinator assemblage, the differences for T. ohiensis were driven by the combined effects of compositional changes and increases over time in the effectiveness of some pollinator taxa. Both species face the possibility of temporal mismatch between the availability of the most effective pollinators and the onset of flowering, and changes in the effectiveness of individual pollinator taxa through time may add an unexpected element to the reproductive consequences of such mismatches.
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Dose-dependent effects of nectar alkaloids in a montane plant-pollinator community
USDA-ARS?s Scientific Manuscript database
Although secondary metabolites are prevalent in floral nectar, the ecological consequences for pollinators and pollination remain relatively unexplored. While often deterrent to pollinators at high concentrations, secondary metabolite concentrations in nectar tend to be much lower than secondary met...
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Pollinator guilds respond differently to urban habitat fragmentation in a oak-savannah ecosystem
USDA-ARS?s Scientific Manuscript database
Habitat fragmentation is widely thought to threaten biodiversity. However, response of pollinators to habitat fragmentation is still poorly understood, as pollinator communities are notoriously spatially variable. We investigated pollinator community structure in a highly fragmented oak-savannah ec...
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Cottrell, J E; Vaughan, S P; Connolly, T; Sing, L; Moodley, D J; Russell, K
2009-08-01
Conversion of lowland woodland to agricultural land and resulting fragmentation in Britain has been ongoing since Neolithic times. To counteract this decline, plantations of native species, often based on non-British planting stock, have been established. This may ultimately be detrimental to the integrity of the native gene pool. We explore the genetic and ecological factors influencing the success of components of the local pollen pool, including the effect of a non-native planting on an ancient woodland population of wild cherry. Wild cherry exhibits gametophytic self-incompatibility (GSI) and vegetative reproduction, both of which may be determinants of paternal success. The majority (61%) of the successful pollen originated from within the study site with a maximum pollen transfer distance of 694 m. There was a distinct departure from random mating, with over half the successful pollen originating from trees which occur within 100 m of the mother tree. Self-incompatibility, clonality, tree size and proximity to the mother tree were all found to influence paternal success. Kinship of pollen gametes within a maternal progeny was highest when a mother tree was surrounded by a large number of ramets of a single, compatible clone consisting of large, adult trees. Although the contribution from the non-native plantation is currently low, it is likely that this will increasingly contribute to the progeny of the adjacent ancient population as it matures. The results clearly show that in self-incompatible species, such as P. avium, close neighbours may be pollinated by very different components of the local pollen pool.
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Tuell, Julianna K; Fiedler, Anna K; Landis, Douglas; Isaacs, Rufus
2008-06-01
Addition of floral resources to agricultural field margins has been shown to increase abundance of beneficial insects in crop fields, but most plants recommended for this use are non-native annuals. Native perennial plants with different bloom periods can provide floral resources for bees throughout the growing season for use in pollinator conservation projects. To identify the most suitable plants for this use, we examined the relative attractiveness to wild and managed bees of 43 eastern U.S. native perennial plants, grown in a common garden setting. Floral characteristics were evaluated for their ability to predict bee abundance and taxa richness. Of the wild bees collected, the most common species (62%) was Bombus impatiens Cresson. Five other wild bee species were present between 3 and 6% of the total: Lasioglossum admirandum (Sandhouse), Hylaeus affinis (Smith), Agapostemon virescens (F.), Halictus ligatus Say, and Ceratina calcarata/dupla Robertson/Say. The remaining wild bee species were present at <2% of the total. Abundance of honey bees (Apis mellifera L.) was nearly identical to that of B. impatiens. All plant species were visited at least once by wild bees; 9 were highly attractive, and 20 were moderately attractive. Honey bees visited 24 of the 43 plant species at least once. Floral area was the only measured factor accounting for variation in abundance and richness of wild bees but did not explain variation in honey bee abundance. Results of this study can be used to guide selection of flowering plants to provide season-long forage for conservation of wild bees.
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Rosianskey, Yogev; Dahan, Yardena; Yadav, Sharawan; Freiman, Zohar E; Milo-Cochavi, Shira; Kerem, Zohar; Eyal, Yoram; Flaishman, Moshe A
2016-08-01
Expression of 13 genes encoding chlorophyll biosynthesis and degradation was evaluated. Chlorophyll degradation was differentially regulated in pollinated and parthenocarpic fig fruits, leading to earlier chlorophyll degradation in parthenocarpic fruits. Varieties of the common fig typically yield a commercial summer crop that requires no pollination, although it can be pollinated. Fig fruit pollination results in larger fruit size, greener skin and darker interior inflorescence color, and slows the ripening process compared to non-pollinated fruits. We evaluated the effect of pollination on chlorophyll content and levels of transcripts encoding enzymes of the chlorophyll metabolism in fruits of the common fig 'Brown Turkey'. We cloned and evaluated the expression of 13 different genes. All 13 genes showed high expression in the fruit skin, inflorescences and leaves, but extremely low expression in roots. Pollination delayed chlorophyll breakdown in the ripening fruit skin and inflorescences. This was correlated with the expression of genes encoding enzymes in the chlorophyll biosynthesis and degradation pathways. Expression of pheophorbide a oxygenase (PAO) was strongly negatively correlated with chlorophyll levels during ripening in pollinated fruits; along with its high expression levels in yellow leaves, this supports a pivotal role for PAO in chlorophyll degradation in figs. Normalizing expression levels of all chlorophyll metabolism genes in the pollinated and parthenocarpic fruit skin and inflorescences showed three synthesis (FcGluTR1, FcGluTR2 and FcCLS1) and three degradation (FcCLH1, FcCLH2 and FcRCCR1) genes with different temporal expression in the pollinated vs. parthenocarpic fruit skin and inflorescences. FcCAO also showed different expressions in the parthenocarpic fruit skin. Thus, chlorophyll degradation is differentially regulated in the pollinated and parthenocarpic fruit skin and inflorescences, leading to earlier and more sustained chlorophyll degradation in the parthenocarpic fruit.
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Xiong, Ying-Ze; Fang, Qiang; Huang, Shuang-Quan
2013-01-01
Recent molecular phylogenetics have indicated that American mayapple (mainly self-incompatible, SI) and Himalayan mayapple, which was considered to be self-compatible (SC), are sister species with disjunct distribution between eastern Asia and eastern North America. We test a hypothesis that the persistence of this early spring flowering herb in the Himalayan region is attributable to the transition from SI to SC, the capacity for selfing in an unpredictable pollination environment. Pollinator observations were conducted in an alpine meadow with hundreds of Himalayan mayapple (Podophyllum hexandrum Royle) individuals over 2 years. To examine autogamy, seed set under different pollination treatments was compared. To clarify whether automatic self-pollination is achieved by movement of the pistil as a previous study suggested, we measured incline angles of the pistil and observed flower movement during anthesis using video. Floral visitors to the nectarless flowers were very rare, but solitary bees and honeybees could be potential pollinators. Seed set of bagged flowers was not significantly different from that of open-pollinated, self- or cross-pollinated flowers. However, removal of petals or stamens lowered seed yield. The angles of inclination of pistils did not change during the process of pollination. Automatic self-pollination was facilitated by petals closing and stamens moving simultaneously to contact the stigma. Stigmatic pollen load increased little during the day time, in contrast to a sharp increase when the flowers closed during the night-time. These observations indicated that Himalayan mayapple was SC and delayed self-pollination was facilitated by the movement of petals rather than the pistil. Compared with SI American mayapple, no obvious inbreeding depression in SC Himalayan mayapple may contribute its existence in the uplifting zone. A scarcity of pollinators may have driven the shift to delayed selfing in P. hexandrum.
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Moeller, David A
2005-01-01
The structure of diverse floral visitor assemblages and the nature of spatial variation in plant-pollinator interactions have important consequences for floral evolution and reproductive interactions among pollinator-sharing plant species. In this study, I use surveys of floral visitor communities across the geographic range of Clarkia xantiana ssp. xantiana (hereafter C. x. xantiana) (Onagraceae) to examine the structure of visitor communities, the specificity of the pollination system, and the role of variation in the abiotic vs. biotic environment in contributing to spatial variation in pollinator abundance and community composition. Although the assemblage of bee visitors to C. x. xantiana is very diverse (49 species), few were regular visitors and likely to act as pollinators. Seventy-four percent of visitor species accounted for only 11% of total visitor abundance and 69% were collected in three or fewer plant populations (of ten). Of the few reliable visitors, Clarkia pollen specialist bees were the most frequent visitors, carried more Clarkia pollen compared to generalist foragers, and were less likely to harbor foreign pollen. Overall, the core group of pollinators was obscured by high numbers of incidental visitors that are unlikely to contribute to pollination. In a geographic context, the composition of specialist pollinator assemblages varied considerably along the abiotic gradient spanning the subspecies' range. However, the overall abundance of specialist pollinators in plant populations was not influenced by the broad-scale abiotic gradient but strongly affected by local plant community associations. C. x. xantiana populations sympatric with pollinator-sharing congeners were visited twice as often by specialists compared to populations occurring alone. These positive indirect interactions among plant species may promote population persistence and species coexistence by enhancing individual reproductive success.
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Vislobokov, Nikolay A; Galinskaya, Tatiana V; Degtjareva, Galina V; Valiejo-Roman, Carmen M; Samigullin, Tahir H; Kuznetsov, Andrey N; Sokoloff, Dmitry D
2014-09-01
• Aspidistra is a species-rich, herbaceous monocot genus of tropical Southeast Asia. Most species are recently discovered and apparently endangered, though virtually nothing is known about their biology. Species of the genus are primarily distinguished using flower morphology, which is enormously diverse. However, the pollination process has not been directly observed in the center of diversity of the genus (N Vietnam and S China). Indirect and partly direct data on the only widely cultivated species of the genus (A. elatior) placed it among angiosperms with the most unusual pollination biology, though these data are highly controversial, suggesting pollen transfer by mollusks, crustaceans, flies, or possibly tiny soil invertebrates such as collembolans.• Pollination of Aspidistra xuansonensis in the center of diversity of the genus was studied using visual observations and videos and light and scanning electron microscopy investigation of flowers and their pollinators. Pollinators and their larvae were molecularly barcoded.• Aspidistra xuansonensis is pollinated by female cecidomyiid flies (gall midges). They oviposit on anthers, and larvae develop among the pollen mass. Molecular barcoding proved taxonomic identity of the larvae and the flies. The larvae neither damage floral parts nor cause gall formation, but feed on pollen grains by sucking out their content. The larvae move out of the flowers before decomposition starts. Carebara ants steal developing larvae from flowers but do not contribute to pollination.• More than one kind of myiophily is present in Aspidistra. Brood site pollination was documented for the first time in Aspidistra. The pollination system of A. xuansonensis differs from other kinds of brood site pollination in the exit of the larvae prior to the decomposition of floral parts. © 2014 Botanical Society of America, Inc.
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Bhattacharya, Samik; Baldwin, Ian T
2012-08-01
The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fires, and produces flowers that remain open for 3 days and are visited by assorted pollinators. To determine whether and when post-pollination non-random mate selection occurs among self and non-self pollen, seed paternity and semi-in vivo pollen tube growth were determined in controlled single/mixed pollinations. Despite all pollen sources being equally proficient in siring seeds in single-genotype pollinations, self pollen was consistently selected in mixed pollinations, irrespective of maternal genotype. However, clear patterns of mate discrimination occurred amongst non-self pollen when mixed pollinations were performed soon after corollas open, including selection against hygromycin B resistance (transformation selectable marker) in wild-type styles and for it in transformed styles. However, mate choice among pollen genotypes was completely shut down in plants transformed to be unable to produce (irACO) or perceive (ETR1) ethylene. The post-pollination ethylene burst, which originates primarily from the stigma and upper style, was strongly correlated with mate selection in single and mixed hand-pollinations using eight pollen donors in two maternal ecotypes. The post-pollination ethylene burst was also negatively correlated with the continuation of emission of benzylacetone, the most abundant pollinator-attracting corolla-derived floral volatile. We conclude that ethylene signaling plays a pivotal role in mate choice, and the post-pollination ethylene burst and the termination of benzylacetone release are accurate predictors, both qualitatively and quantitatively, of pre-zygotic mate selection and seed paternity. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.
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Floral traits and pollination systems in the Caatinga, a Brazilian tropical dry forest.
Machado, Isabel Cristina; Lopes, Ariadna Valentina
2004-09-01
Pollination is a critical stage in plant reproduction and thus in the maintenance and evolution of species and communities. The Caatinga is the fourth largest ecosystem in Brazil, but despite its great extent and its importance few studies providing ecological information are available, with a notable lack of work focusing on pollination biology. Here, general data are presented regarding the frequency of pollination systems within Caatinga communities, with the aim of characterizing patterns related to floral attributes in order to make possible comparisons with data for plant communities in other tropical areas, and to test ideas about the utility of syndromes. This paper also intends to provide a reference point for further studies on pollination ecology in this threatened ecosystem. The floral traits and the pollination systems of 147 species were analysed in three areas of Caatinga vegetation in northeastern Brazil, and compared with world-wide studies focusing on the same subject. For each species, floral attributes were recorded as form, size, colour, rewards and pollination units. The species were grouped into 12 guilds according to the main pollinator vector. Analyses of the frequencies of the floral traits and pollination systems were undertaken. Nectar and pollen were the most common floral resources and insect pollination was the most frequent, occurring in 69.9 % of the studied species. Of the entomophilous species, 61.7 % were considered to be melittophilous (43.1 % of the total). Vertebrate pollination occurred in 28.1 % of the species (ornithophily in 15.0 % and chiropterophily in 13.1 %), and anemophily was recorded in only 2.0 %. The results indicated that the pollination systems in Caatinga, despite climatic restrictions, are diversified, with a low percentage of generalist flowers, and similar to other tropical dry and wet forest communities, including those with high rainfall levels.
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Arceo-Gómez, Gerardo; Jameel, Mohammad I; Ashman, Tia-Lynn
2018-05-01
Studies on the effects of heterospecific pollen (HP) transfer have been focused mainly on insect-pollinated species, despite evidence of insect visitation to wind-pollinated species and transfer of their pollen onto stigmas of insect-pollinated plants. Thus, the potential consequences of HP transfer from wind-pollinated species remain largely unknown. Furthermore, accumulation of pesticide residues in pollen of wind-pollinated crops has been documented, but its potential effects on wild plant species via HP transfer have not been tested. We evaluated the effect of wind-dispersed Zea mays pollen on pollen tube growth of the insect-pollinated Mimulus nudatus via hand pollinations. We further evaluated whether pesticide-contaminated Z. mays pollen has larger effects on M. nudatus pollen success than non-contaminated Z. mays pollen. We found a significant negative effect of Z. mays pollen on M. nudatus pollen tube growth even when deposited in small amounts. However, we did not observe any difference in the magnitude of this effect between pesticide-laden Z. mays pollen and non-contaminated Z. mays pollen. Our results suggest that wind-pollinated species can have negative effects as HP donors on insect-pollinated recipients. Thus, their role in shaping co-flowering interactions for wind- and insect-pollinated species deserves more attention. Although we did not find evidence that pesticide contamination increased HP effects, we cannot fully rule out the existence of such an effect, because pollen load and thus the pesticide dose applied to stigmas was low. This result should be confirmed using other HP donors and across a range of HP loads, pesticide types, and concentrations. © 2018 Botanical Society of America.
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Rodríguez-Oseguera, A G; Casas, A; Herrerías-Diego, Y; Pérez-Negrón, E
2013-05-01
Stenocereus quevedonis ('pitire') is a columnar cactus endemic to central Mexico, grown for its edible fruit. Phenology, pollination biology and behaviour of flower visitors of this species were compared in six conserved and disturbed sites, hypothesising that: (i) pitire pollination is self-incompatible, requiring animal vectors; (ii) higher incidence of radiation on plants in cleared forest may lead to a higher number of flowers per pitire plant and longer blooming season, and disturbing and differential spatial availability of flower resources may determine differential attraction of pollinators to conserved and disturbed areas; (iii) if pitire pollination system is specialised, reproductive success would decrease with pollinator scarcity, or other species may substitute for main pollinators. In all sites, pitire reproduction started in January, flowering peak occurring in April, anthesis duration was 15 h and predominantly nocturnal (9 h), pollen was released at 23:00 h, nectar was produced throughout anthesis, and breeding system was self-incompatible. Flower production per plant was similar in disturbed and conserved sites, but flower availability was higher (because of higher tree density) and longer in disturbed sites. Pollination is nocturnal, the most frequent legitimate pollinator being the bat Leptonycteris yerbabuenae; diurnal pollination is rare but possible, carried out by bee species. Fruit and seed set in control and nocturnal pollination treatments at disturbed sites were higher than in conserved sites. Frequency of L. yerbabuenae visits was similar among site types, but more visits of complementary nocturnal and diurnal pollinators were recorded in disturbed sites, which could explain differences in reproductive success. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.
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Brunet, Johanne
2009-01-01
Background and Aims Pollinators together with other biotic and some abiotic factors can select for floral traits. However, variation in pollinator abundance over time and space can weaken such selection. In the present study, the variation in pollinator abundance over time and space was examined in populations of the Rocky Mountain columbine. The variation in three floral traits is described and correlations between pollinator type, functional pollinator groups or altitude and floral traits are examined. Methods Pollinator observations took place in six Aquilegia coerulea populations over 1–4 years and spur length, flower colour and sepal length were measured in 12 populations. Pollinator abundance, measured as visits per flower per hour, was compared among populations and years. Pollinators were grouped into two functional groups: pollen or nectar collectors. The following associations were examined: annual presence of hawkmoths and whiter flowers with longer spurs; the presence of Sphinx vashti and longer spurs; and higher altitudes and whiter flowers. The study looked at whether an increase in the proportion of hawkmoths in a population was associated with whiter and larger flowers with longer spurs. Key Results The abundance of different pollinator groups varied over time and space. Floral traits varied among populations. Higher altitude was correlated with bluer flowers. Whiter flowers were associated with the annual presence of hawkmoths. Populations visited by Sphinx vashti had longer spurs than populations visited only by Hyles lineata. Populations with greater percentage of nectar-collecting pollinators did not have whiter, larger flowers with longer spurs. Conclusions Despite the large variation in pollinator abundance over time and space, one species of bumble-bee or hawkmoth tended to predominate in each population each year. Future studies of Aquilegia coerulea should examine the specific influences of pollinators and the environment on flower colour and of hawkmoth species on spur length. PMID:19414518
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Queiroz, Joel A.; Quirino, Zelma G. M.; Machado, Isabel C.
2015-01-01
Floral attributes evolve in response to frequent and efficient pollinators, which are potentially important drivers of floral diversification and reproductive isolation. In this context, we asked, how do flowers evolve in a bat–hummingbird pollination system? Hence, we investigated the pollination ecology of two co-flowering Ipomoea taxa (I. marcellia and I. aff. marcellia) pollinated by bats and hummingbirds, and factors favouring reproductive isolation and pollinator sharing in these plants. To identify the most important drivers of reproductive isolation, we compared the flowers of the two Ipomoea taxa in terms of morphometry, anthesis and nectar production. Pollinator services were assessed using frequency of visits, fruit set and the number of seeds per fruit after visits. The studied Ipomoea taxa differed in corolla size and width, beginning and duration of anthesis, and nectar attributes. However, they shared the same diurnal and nocturnal visitors. The hummingbird Heliomaster squamosus was more frequent in I. marcellia (1.90 visits h−1) than in I. aff. marcellia (0.57 visits h−1), whereas glossophagine bats showed similar visit rates in both taxa (I. marcellia: 0.57 visits h−1 and I. aff. marcellia: 0.64 visits h−1). Bat pollination was more efficient in I. aff. marcellia, whereas pollination by hummingbirds was more efficient in I. marcellia. Differences in floral attributes between Ipomoea taxa, especially related to the anthesis period, length of floral parts and floral arrangement in the inflorescence, favour reproductive isolation from congeners through differential pollen placement on pollinators. This bat–hummingbird pollination system seems to be advantageous in the study area, where the availability of pollinators and floral resources changes considerably throughout the year, mainly as a result of rainfall seasonality. This interaction is beneficial for both sides, as it maximizes the number of potential pollen vectors for plants and resource availability for pollinators. PMID:26558704