Transition from wind pollination to insect pollination in sedges: experimental evidence and functional traits.

PubMed

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.

Synergistic interactions of ecosystem services: florivorous pest control boosts crop yield increase through insect pollination

PubMed Central

Albrecht, Matthias

2016-01-01

Insect pollination and pest control are pivotal functions sustaining global food production. However, they have mostly been studied in isolation and how they interactively shape crop yield remains largely unexplored. Using controlled field experiments, we found strong synergistic effects of insect pollination and simulated pest control on yield quantity and quality. Their joint effect increased yield by 23%, with synergistic effects contributing 10%, while their single contributions were 7% and 6%, respectively. The potential economic benefit for a farmer from the synergistic effects (12%) was 1.8 times greater than their individual contributions (7% each). We show that the principal underlying mechanism was a pronounced pest-induced reduction in flower lifetime, resulting in a strong reduction in the number of pollinator visits a flower receives during its lifetime. Our findings highlight the importance of non-additive interactions among ecosystem services (ES) when valuating, mapping or predicting them and reveal fundamental implications for ecosystem management and policy aimed at maximizing ES for sustainable agriculture. PMID:26865304

Synergistic interactions of ecosystem services: florivorous pest control boosts crop yield increase through insect pollination.

PubMed

Sutter, Louis; Albrecht, Matthias

2016-02-10

Insect pollination and pest control are pivotal functions sustaining global food production. However, they have mostly been studied in isolation and how they interactively shape crop yield remains largely unexplored. Using controlled field experiments, we found strong synergistic effects of insect pollination and simulated pest control on yield quantity and quality. Their joint effect increased yield by 23%, with synergistic effects contributing 10%, while their single contributions were 7% and 6%, respectively. The potential economic benefit for a farmer from the synergistic effects (12%) was 1.8 times greater than their individual contributions (7% each). We show that the principal underlying mechanism was a pronounced pest-induced reduction in flower lifetime, resulting in a strong reduction in the number of pollinator visits a flower receives during its lifetime. Our findings highlight the importance of non-additive interactions among ecosystem services (ES) when valuating, mapping or predicting them and reveal fundamental implications for ecosystem management and policy aimed at maximizing ES for sustainable agriculture. © 2016 The Author(s).

Examining the Potential for Agricultural Benefits from Pollinator Habitat at Solar Facilities in the United States

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

Native bees buffer the negative impact of climate warming on honey bee pollination of watermelon crops.

PubMed

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.

Scarcity of ecosystem services: an experimental manipulation of declining pollination rates and its economic consequences for agriculture.

PubMed

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.

Scarcity of ecosystem services: an experimental manipulation of declining pollination rates and its economic consequences for agriculture

PubMed Central

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

Competition with wind-pollinated plant species alters floral traits of insect-pollinated plant species

PubMed Central

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

Organic Farming and Landscape Structure: Effects on Insect-Pollinated Plant Diversity in Intensively Managed Grasslands

PubMed Central

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

Railway Embankments as New Habitat for Pollinators in an Agricultural Landscape

PubMed Central

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

Organic farming favours insect-pollinated over non-insect pollinated forbs in meadows and wheat fields.

PubMed

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.

Organic Farming Favours Insect-Pollinated over Non-Insect Pollinated Forbs in Meadows and Wheat Fields

PubMed Central

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

Experimental evidence that wildflower strips increase pollinator visits to crops.

PubMed

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.

Experimental evidence that wildflower strips increase pollinator visits to crops

PubMed Central

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

Growing and marketing woody species to support pollinators: An emerging opportunity for forest, conservation, and native plant nurseries in the Northeastern United States

Treesearch

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....

Exotic plant species receive adequate pollinator service despite variable integration into plant-pollinator networks.

PubMed

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.

Orchid sexual deceit provokes ejaculation.

PubMed

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.

Advances in pollination ecology from tropical plantation crops.

PubMed

Klein, Alexandra-Maria; Cunningham, Saul A; Bos, Merijn; Steffan-Dewenter, Ingolf

2008-04-01

Although ecologists traditionally focus on natural ecosystems, there is growing awareness that mixed landscapes of managed and unmanaged systems provide a research environment for understanding basic ecological relationships on a large scale. Here, we show how tropical agroforestry systems can be used to develop ideas about the mechanisms that influence species diversity and subsequent biotic interactions at different spatial scales. Our focus is on tropical plantation crops, mainly coffee and cacao, and their pollinators, which are of basic ecological interest as partners in an important mutualistic interaction. We review how insect-mediated pollination services depend on local agroforest and natural habitats in surrounding landscapes. Further, we evaluate the functional significance of pollinator diversity and the explanatory value of species traits, and we provide an intercontinental comparison of pollinator assemblages. We found that optimal pollination success might be best understood as a consequence of niche complementarities among pollinators in landscapes harboring various species. We further show that small cavity-nesting bees and small generalist beetles were especially affected by isolation from forest and that larger-bodied insects in the same landscapes were not similarly affected. We suggest that mixed tropical landscapes with agroforestry systems have great potential for future research on the interactions between plants and pollinators.

Pollination Services of Mango Flower Pollinators

PubMed Central

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

Neither insects nor wind: ambophily in dioecious Chamaedorea palms (Arecaceae).

PubMed

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.

Pollinator-prey conflicts in carnivorous plants: When flower and trap properties mean life or death

PubMed Central

El-Sayed, Ashraf M.; Byers, John A.; Suckling, David M.

2016-01-01

Insect-pollinated carnivorous plants are expected to have higher fitness if they resolve pollinator-prey conflicts by sparing insects pollinating their flowers while trapping prey insects. We examined whether separation between flowers and traps of the carnivorous sundew species or pollinator preferences for colours of flowers enable these plants to spare pollinators. In addition, we collected odours from flowers and traps of each carnivorous species in order to identify volatile chemicals that are attractive or repellent to pollinators and prey insects. In Drosera spatulata and D. arcturi, no volatiles were detected from either their flowers or traps that could serve as kairomone attractants for insects. However, behavioural experiments indicated white colour and spatial separation between flowers and traps aid in reducing pollinator entrapment while capturing prey. In contrast, D. auriculata have flowers that are adjacent to their traps. In this species we identified chemical signals emanating from flowers that comprised an eight-component blend, while the plant’s traps emitted a unique four-component blend. The floral odour attracted both pollinator and prey insects, while trap odour only attracted prey. This is the first scientific report to demonstrate that carnivorous plants utilize visual, spatial, and chemical signals to spare flower visitors while trapping prey insects. PMID:26888545

Insect Pollinated Crops, Insect Pollinators and US Agriculture: Trend Analysis of Aggregate Data for the Period 1992–2009

PubMed Central

Calderone, Nicholas W.

2012-01-01

In the US, the cultivated area (hectares) and production (tonnes) of crops that require or benefit from insect pollination (directly dependent crops: apples, almonds, blueberries, cucurbits, etc.) increased from 1992, the first year in this study, through 1999 and continued near those levels through 2009; aggregate yield (tonnes/hectare) remained unchanged. The value of directly dependent crops attributed to all insect pollination (2009 USD) decreased from $14.29 billion in 1996, the first year for value data in this study, to $10.69 billion in 2001, but increased thereafter, reaching $15.12 billion by 2009. The values attributed to honey bees and non-Apis pollinators followed similar patterns, reaching $11.68 billion and $3.44 billion, respectively, by 2009. The cultivated area of crops grown from seeds resulting from insect pollination (indirectly dependent crops: legume hays, carrots, onions, etc.) was stable from 1992 through 1999, but has since declined. Production of those crops also declined, albeit not as rapidly as the decline in cultivated area; this asymmetry was due to increases in aggregate yield. The value of indirectly dependent crops attributed to insect pollination declined from $15.45 billion in 1996 to $12.00 billion in 2004, but has since trended upward. The value of indirectly dependent crops attributed to honey bees and non-Apis pollinators, exclusive of alfalfa leafcutter bees, has declined since 1996 to $5.39 billion and $1.15 billion, respectively in 2009. The value of alfalfa hay attributed to alfalfa leafcutter bees ranged between $4.99 and $7.04 billion. Trend analysis demonstrates that US producers have a continued and significant need for insect pollinators and that a diminution in managed or wild pollinator populations could seriously threaten the continued production of insect pollinated crops and crops grown from seeds resulting from insect pollination. PMID:22629374

Ants contribute to pollination but not to reproduction in a rare calcareous grassland forb

PubMed Central

Bollmann, Felix; Saville, David; Riedel, Michael

2018-01-01

The number of plants pollinated by ants is surprisingly low given the abundance of ants and the fact that they are common visitors of angiosperms. Generally ants are considered as nectar robbers that do not provide pollination service. We studied the pollination system of the endangered dry grassland forb Euphorbia seguieriana and found two ant species to be the most frequent visitors of its flowers. Workers of Formica cunicularia carried five times more pollen than smaller Tapinoma erraticum individuals, but significantly more viable pollen was recovered from the latter. Overall, the viability of pollen on ant cuticles was significantly lower (p < 0.001)—presumably an antibiotic effect of the metapleural gland secretion. A marking experiment suggested that ants were unlikely to facilitate outcrossing as workers repeatedly returned to the same individual plant. In open pollinated plants and when access was given exclusively to flying insects, fruit set was nearly 100%. In plants visited by ants only, roughly one third of flowers set fruit, and almost none set fruit when all insects were excluded. The germination rate of seeds from flowers pollinated by flying insects was 31 ± 7% in contrast to 1 ± 1% resulting from ant pollination. We conclude that inbreeding depression may be responsible for the very low germination rate in ant pollinated flowers and that ants, although the most frequent visitors, play a negligible or even deleterious role in the reproduction of E. seguieriana. Our study reiterates the need to investigate plant fitness effects beyond seed set in order to confirm ant-plant mutualisms. PMID:29479496

Parallel declines in pollinators and insect-pollinated plants in Britain and the Netherlands.

PubMed

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.

Effects of heterospecific pollen from a wind-pollinated and pesticide-treated plant on reproductive success of an insect-pollinated species.

PubMed

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.

Breeding system and pollen limitation in the masting tree Sorbus aucuparia L. (Rosaceae) in the NW Iberian Peninsula

NASA Astrophysics Data System (ADS)

Pías, Beatriz; Guitián, Pablo

2006-01-01

Mast seeding or masting is the supra-annual periodic production of a large number of seeds by long-lived plants. It has been suggested that this may be a strategy to increase pollination efficiency. Sorbus aucuparia is a masting tree typically showing rather low fruit set, though with some variation among years and populations, together with marked among-year variation in flower and fruit production. Here we report a study of the reproductive biology and insect-visitor spectrum of S. aucuparia in the NW Iberian Peninsula. Results obtained over a 4-year period indicate marked self-incompatibility, so that fruit set is strongly dependent on pollinator service. Nevertheless, fruit and seed set were not limited by pollen supply in any of the years of study, since fruit and seed set after manual cross-pollination were no higher than after natural pollination. Inflorescences were visited by diverse insect species. There was no significant correlation between fruit set and insect visit frequency. Taken together, these findings indicate that the rather low fruit and seed sets observed in this species, and the spatiotemporal variation in these parameters, must be attributed to other factors, such as abiotic resource availability. We conclude that masting in S. aucuparia is probably not a strategy for increasing pollination efficiency.

Organic Farming Improves Pollination Success in Strawberries

PubMed Central

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

Is floral specialization an evolutionary dead-end? Pollination system transitions in Ruellia (Acanthaceae).

PubMed

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.

Pollination and Plant Resources Change the Nutritional Quality of Almonds for Human Health

PubMed Central

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

Seasonal and annual variations in the pollination efficiency of a pollinator community of Dictamnus albus L.

PubMed

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.

Economic impact of ecosystem services provided by ecologically sustainable roadside right of way vegetation management practices.

DOT National Transportation Integrated Search

2014-03-01

The economic value of runoff prevention, carbon sequestration, pollination and other insect services, air quality, : invasive species resistance, and aesthetics was estimated for Floridas State Highway System roadside right-of-way (ROW) ecosystem ...

Where is the UK's pollinator biodiversity? The importance of urban areas for flower-visiting insects.

PubMed

Baldock, Katherine C R; Goddard, Mark A; Hicks, Damien M; Kunin, William E; Mitschunas, Nadine; Osgathorpe, Lynne M; Potts, Simon G; Robertson, Kirsty M; Scott, Anna V; Stone, Graham N; Vaughan, Ian P; Memmott, Jane

2015-03-22

Insect pollinators provide a crucial ecosystem service, but are under threat. Urban areas could be important for pollinators, though their value relative to other habitats is poorly known. We compared pollinator communities using quantified flower-visitation networks in 36 sites (each 1 km(2)) in three landscapes: urban, farmland and nature reserves. Overall, flower-visitor abundance and species richness did not differ significantly between the three landscape types. Bee abundance did not differ between landscapes, but bee species richness was higher in urban areas than farmland. Hoverfly abundance was higher in farmland and nature reserves than urban sites, but species richness did not differ significantly. While urban pollinator assemblages were more homogeneous across space than those in farmland or nature reserves, there was no significant difference in the numbers of rarer species between the three landscapes. Network-level specialization was higher in farmland than urban sites. Relative to other habitats, urban visitors foraged from a greater number of plant species (higher generality) but also visited a lower proportion of available plant species (higher specialization), both possibly driven by higher urban plant richness. Urban areas are growing, and improving their value for pollinators should be part of any national strategy to conserve and restore pollinators.

Where is the UK's pollinator biodiversity? The importance of urban areas for flower-visiting insects

PubMed Central

Baldock, Katherine C. R.; Goddard, Mark A.; Hicks, Damien M.; Kunin, William E.; Mitschunas, Nadine; Osgathorpe, Lynne M.; Potts, Simon G.; Robertson, Kirsty M.; Scott, Anna V.; Stone, Graham N.; Vaughan, Ian P.; Memmott, Jane

2015-01-01

Insect pollinators provide a crucial ecosystem service, but are under threat. Urban areas could be important for pollinators, though their value relative to other habitats is poorly known. We compared pollinator communities using quantified flower-visitation networks in 36 sites (each 1 km2) in three landscapes: urban, farmland and nature reserves. Overall, flower-visitor abundance and species richness did not differ significantly between the three landscape types. Bee abundance did not differ between landscapes, but bee species richness was higher in urban areas than farmland. Hoverfly abundance was higher in farmland and nature reserves than urban sites, but species richness did not differ significantly. While urban pollinator assemblages were more homogeneous across space than those in farmland or nature reserves, there was no significant difference in the numbers of rarer species between the three landscapes. Network-level specialization was higher in farmland than urban sites. Relative to other habitats, urban visitors foraged from a greater number of plant species (higher generality) but also visited a lower proportion of available plant species (higher specialization), both possibly driven by higher urban plant richness. Urban areas are growing, and improving their value for pollinators should be part of any national strategy to conserve and restore pollinators. PMID:25673686

Forest habitat conservation in Africa using commercially important insects.

PubMed

Raina, Suresh Kumar; Kioko, Esther; Zethner, Ole; Wren, Susie

2011-01-01

African forests, which host some of the world's richest biodiversity, are rapidly diminishing. The loss of flora and fauna includes economically and socially important insects. Honey bees and silk moths, grouped under commercial insects, are the source for insect-based enterprises that provide income to forest-edge communities to manage the ecosystem. However, to date, research output does not adequately quantify the impact of such enterprises on buffering forest ecosystems and communities from climate change effects. Although diseases/pests of honey bees and silk moths in Africa have risen to epidemic levels, there is a dearth of practical research that can be utilized in developing effective control mechanisms that support the proliferation of these commercial insects as pollinators of agricultural and forest ecosystems. This review highlights the critical role of commercial insects within the environmental complexity of African forest ecosystems, in modern agroindustry, and with respect to its potential contribution to poverty alleviation and pollination services. It identifies significant research gaps that exist in understanding how insects can be utilized as ecosystem health indicators and nurtured as integral tools for important socioeconomic and industrial gains.

Twenty-five years of progress in understanding pollination mechanisms in palms (Arecaceae)

PubMed Central

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

Effects of prescribed fire and fire surrogates on floral visiting insects of the blue ridge province in North Carolina

Treesearch

J.W. Campbell; J.L. Hanula; T.A. Waldrop

2007-01-01

Pollination by insects in forests is an extremely important process that should be conserved. Not only do pollinating insects help to maintain a diversity of plants within forests, but they also aid in pollinating crops found near forested land. Currently, the effects of various forest management practices on floral visiting insect abundance or diversity is unknown, so...

Learning in Insect Pollinators and Herbivores.

PubMed

Jones, Patricia L; Agrawal, Anurag A

2017-01-31

The relationship between plants and insects is influenced by insects' behavioral decisions during foraging and oviposition. In mutualistic pollinators and antagonistic herbivores, past experience (learning) affects such decisions, which ultimately can impact plant fitness. The higher levels of dietary generalism in pollinators than in herbivores may be an explanation for the differences in learning seen between these two groups. Generalist pollinators experience a high level of environmental variation, which we suggest favors associative learning. Larval herbivores employ habituation and sensitization-strategies useful in their less variable environments. Exceptions to these patterns based on habitats, mobility, and life history provide critical tests of current theory. Relevant plant traits should be under selection to be easily learned and remembered in pollinators and difficult to learn in herbivores. Insect learning thereby has the potential to have an important, yet largely unexplored, role in plant-insect coevolution.

Contribution of insect pollinators to crop yield and quality varies with agricultural intensification

PubMed Central

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

Contribution of insect pollinators to crop yield and quality varies with agricultural intensification.

PubMed

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.

Beetle pollination of the fruit-scented cones of the South African cycad Stangeria eriopus.

PubMed

Proches, Serban; Johnson, Steven D

2009-09-01

There has been considerable uncertainty about the importance of wind vs. insects in cycad pollination, but recent studies in several cycad genera have indicated that these are pollinated primarily, if not exclusively, by insects. Stangeria represents an isolated southern African cycad lineage previously thought to be wind-pollinated. Unlike in most other cycads, there is no evidence of cone thermogenesis in Stangeria. We found that the scent of both male and female Stangeria cones mimics that of fermented fruit, the main volatiles being esters of acetic acid, ketones, and aldehydes. We found a large variety of insect visitors on the cones, the most common ones being sap and rove beetles (Coleoptera: Nitidulidae, Staphylinidae) and fruit flies (Diptera: Drosophilidae). Of these, only sap beetles (Nitidulidae) were able to effect pollination under experimental conditions. Because sap beetles are also pollinators of Cycas and members of several ancient angiosperm families, their role in the pollination of Stangeria adds interesting details to the role this group of insects has played in the history of plant-pollinator interactions.

Flower color preferences of insects and livestock: effects on Gentiana lutea reproductive success.

PubMed

Sobral, Mar; Losada, María; Veiga, Tania; Guitián, Javier; Guitián, José; Guitián, Pablo

2016-01-01

Angiosperms diversification was primarily driven by pollinator agents, but non-pollinator agents also promoted floral evolution. Gentiana lutea shows pollinator driven flower color variation in NW Spain. We test whether insect herbivores and livestock, which frequently feed in G.lutea, play a role in G. lutea flower color variation, by answering the following questions: (i) Do insect herbivores and grazing livestock show flower color preferences when feeding on G. lutea? (ii) Do mutualists (pollinators) and antagonists (seed predators, insect herbivores and livestock) jointly affect G. lutea reproductive success? Insect herbivores fed more often on yellow flowering individuals but they did not affect seed production, whereas livestock affected seed production but did not show clear color preferences. Our data indicate that flower color variation of G. lutea is not affected by insect herbivores or grazing livestock.

Flower color preferences of insects and livestock: effects on Gentiana lutea reproductive success

PubMed Central

Losada, María; Veiga, Tania; Guitián, Javier; Guitián, José; Guitián, Pablo

2016-01-01

Angiosperms diversification was primarily driven by pollinator agents, but non-pollinator agents also promoted floral evolution. Gentiana lutea shows pollinator driven flower color variation in NW Spain. We test whether insect herbivores and livestock, which frequently feed in G.lutea, play a role in G. lutea flower color variation, by answering the following questions: (i) Do insect herbivores and grazing livestock show flower color preferences when feeding on G. lutea? (ii) Do mutualists (pollinators) and antagonists (seed predators, insect herbivores and livestock) jointly affect G. lutea reproductive success? Insect herbivores fed more often on yellow flowering individuals but they did not affect seed production, whereas livestock affected seed production but did not show clear color preferences. Our data indicate that flower color variation of G. lutea is not affected by insect herbivores or grazing livestock. PMID:27014509

Special Issue: Honey Bee Viruses

PubMed Central

Gisder, Sebastian; Genersch, Elke

2015-01-01

Pollination of flowering plants is an important ecosystem service provided by wild insect pollinators and managed honey bees. Hence, losses and declines of pollinating insect species threaten human food security and are of major concern not only for apiculture or agriculture but for human society in general. Honey bee colony losses and bumblebee declines have attracted intensive research interest over the last decade and although the problem is far from being solved we now know that viruses are among the key players of many of these bee losses and bumblebee declines. With this special issue on bee viruses we, therefore, aimed to collect high quality original papers reflecting the current state of bee virus research. To this end, we focused on newly discovered viruses (Lake Sinai viruses, bee macula-like virus), or a so far neglected virus species (Apis mellifera filamentous virus), and cutting edge technologies (mass spectrometry, RNAi approach) applied in the field. PMID:26702462

Special Issue: Honey Bee Viruses.

PubMed

Gisder, Sebastian; Genersch, Elke

2015-10-01

Pollination of flowering plants is an important ecosystem service provided by wild insect pollinators and managed honey bees. Hence, losses and declines of pollinating insect species threaten human food security and are of major concern not only for apiculture or agriculture but for human society in general. Honey bee colony losses and bumblebee declines have attracted intensive research interest over the last decade and although the problem is far from being solved we now know that viruses are among the key players of many of these bee losses and bumblebee declines. With this special issue on bee viruses we, therefore, aimed to collect high quality original papers reflecting the current state of bee virus research. To this end, we focused on newly discovered viruses (Lake Sinai viruses, bee macula-like virus), or a so far neglected virus species (Apis mellifera filamentous virus), and cutting edge technologies (mass spectrometry, RNAi approach) applied in the field.

Honey bee disease overview

USDA-ARS?s Scientific Manuscript database

Sexual reproduction of many crops and the majority of wild plants is dependent on animal pollination through insects, birds, bats and others, with insects playing the major role. The majority of crops requiring pollination are dependent on managed pollinators, and especially on managed honeybees. Lo...

Evaluation of native bees as pollinators of cucurbit crops under floating row covers.

PubMed

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.

Floral traits mediate the vulnerability of aloes to pollen theft and inefficient pollination by bees

PubMed Central

Hargreaves, Anna L.; Harder, Lawrence D.; Johnson, Steven D.

2012-01-01

Background and Aims Pollen-collecting bees are among the most important pollinators globally, but are also the most common pollen thieves and can significantly reduce plant reproduction. The pollination efficiency of pollen collectors depends on the frequency of their visits to female(-phase) flowers, contact with stigmas and deposition of pollen of sufficient quantity and quality to fertilize ovules. Here we investigate the relative importance of these components, and the hypothesis that floral and inflorescence characteristics mediate the pollination role of pollen collection by bees. Methods For ten Aloe species that differ extensively in floral and inflorescence traits, we experimentally excluded potential bird pollinators to quantify the contributions of insect visitors to pollen removal, pollen deposition and seed production. We measured corolla width and depth to determine nectar accessibility, and the phenology of anther dehiscence and stigma receptivity to quantify herkogamy and dichogamy. Further, we compiled all published bird-exclusion studies of aloes, and compared insect pollination success with floral morphology. Key Results Species varied from exclusively insect pollinated, to exclusively bird pollinated but subject to extensive pollen theft by insects. Nectar inaccessibility and strong dichogamy inhibited pollination by pollen-collecting bees by discouraging visits to female-phase (i.e. pollenless) flowers. For species with large inflorescences of pollen-rich flowers, pollen collectors successfully deposited pollen, but of such low quality (probably self-pollen) that they made almost no contribution to seed set. Indeed, considering all published bird-exclusion studies (17 species in total), insect pollination efficiency varied significantly with floral shape. Conclusions Species-specific floral and inflorescence characteristics, especially nectar accessibility and dichogamy, control the efficiency of pollen-collecting bees as pollinators of aloes. PMID:22278414

Floral trait evolution associated with shifts between insect and wind pollination in the dioecious genus Leucadendron (Proteaceae).

PubMed

Welsford, Megan R; Hobbhahn, Nina; Midgley, Jeremy J; Johnson, Steven D

2016-01-01

Transitions between animal and wind pollination have occurred in many lineages and have been linked to various floral modifications, but these have seldom been assessed in a phylogenetic framework. In the dioecious genus Leucadendron (Proteaceae), transitions from insect to wind pollination have occurred at least four times. Using analyses that controlled for relatedness among Leucadendron species, we investigated how these transitions shaped the evolution of floral structural and signaling traits, including the degree of sexual dimorphism in these traits. Pollen grains of wind-pollinated species were found to be smaller, more numerous, and dispersed more efficiently in wind than were those of insect-pollinated species. Wind-pollinated species also exhibited a reduction in spectral contrast between showy subtending leaves and background foliage, reduced volatile emissions, and a greater degree of sexual dimorphism in color and scent. Uniovulate flowers and inflorescence condensation are conserved ancestral features in Leucadendron and likely served as exaptations in shifts to wind pollination. These results offer insights into the key modifications of male and female floral traits involved in transitions between insect and wind pollination. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Pollinator decline - an ecological calamity in the making?

PubMed

Rhodes, Christopher J

2018-06-01

Since pollination by insects is vitally important for much of global crop production, and to provide pollination services more widely throughout the planetary ecosystems, the prospect of an imminent 'pollination crisis', due to a die-off of flying insects, is most disquieting, to say the least. Indeed, the term 'ecological Armageddon' has been used in the media. However, to know whether or not a wholesale decline in flying pollinators (including non-bee species) is occurring across the world is very difficult, due to an insufficiency of geographically widespread and long-term data. Bees, as the best documented species, can be seen to be suffering from chronic exposure to a range of stressors, which include: a loss of abundance and diversity of flowers, and a decline in suitable habitat for them to build nests; long-term exposure to agrochemicals, including pesticides such as neonicotinoids; and infection by parasites and pathogens, many inadvertently spread by the actions of humans. It is likely that climate change may impact further on particular pollinators, for example bumble bees, which are cool-climate specialists. Moreover, the co-operative element of various different stress factors should be noted; thus, for example, exposure to pesticides is known to diminish detoxification mechanisms and also immune responses, hence lowering the resistance of bees to parasitic infections. It is further conspicuous that for those wild non-bee insects - principally moths and butterflies - where data are available, the picture is also one of significant population losses. Alarmingly, a recent study in Germany indicated that a decline in the biomass of flying insects had occurred by 76% in less than three decades, as sampled in nature reserves across the country. Accordingly, to fully answer the question posed in the title of this article 'pollinator decline - an ecological calamity in the making?' will require many more detailed, more geographically encompassing, more species-inclusive, and longer-term studies, but the available evidence points to a clear 'probably', and the precautionary principle would suggest this is not a prospect we can afford to ignore.

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...

Insects, birds and lizards as pollinators of the largest-flowered Scrophularia of Europe and Macaronesia.

PubMed

Ortega-Olivencia, Ana; Rodríguez-Riaño, Tomás; Pérez-Bote, José L; López, Josefa; Mayo, Carlos; Valtueña, Francisco J; Navarro-Pérez, Marisa

2012-01-01

It has traditionally been considered that the flowers of Scrophularia are mainly pollinated by wasps. We studied the pollination system of four species which stand out for their large and showy flowers: S. sambucifolia and S. grandiflora (endemics of the western Mediterranean region), S. trifoliata (an endemic of the Tyrrhenian islands) and S. calliantha (an endemic of the Canary Islands). Our principal aim was to test whether these species were pollinated by birds or showed a mixed pollination system between insects and birds. Censuses and captures of insects and birds were performed to obtain pollen load transported and deposited on the stigmas. Also, a qualitative and quantitative analysis of the flowers and inflorescences was carried out. Flowers were visited by Hymenoptera and by passerine birds. The Canarian species was the most visited by birds, especially by Phylloscopus canariensis, and its flowers were also accessed by juveniles of the lizard Gallotia stehlini. The most important birds in the other three species were Sylvia melanocephala and S. atricapilla. The most important insect-functional groups in the mixed pollination system were: honey-bees and wasps in S. sambucifolia; bumble-bees and wasps in S. grandiflora; wasps in S. trifoliata; and a small bee in S. calliantha. The species studied show a mixed pollination system between insects and passerine birds. In S. calliantha there is, in addition, a third agent (juveniles of Gallotia stehlini). The participation of birds in this mixed pollination system presents varying degrees of importance because, while in S. calliantha they are the main pollinators, in the other species they interact to complement the insects which are the main pollinators. A review of different florae showed that the large showy floral morphotypes of Scrophularia are concentrated in the western and central Mediterranean region, Macaronesia and USA (New Mexico).

Insects, birds and lizards as pollinators of the largest-flowered Scrophularia of Europe and Macaronesia

PubMed Central

Ortega-Olivencia, Ana; Rodríguez-Riaño, Tomás; Pérez-Bote, José L.; López, Josefa; Mayo, Carlos; Valtueña, Francisco J.; Navarro-Pérez, Marisa

2012-01-01

Background and Aims It has traditionally been considered that the flowers of Scrophularia are mainly pollinated by wasps. We studied the pollination system of four species which stand out for their large and showy flowers: S. sambucifolia and S. grandiflora (endemics of the western Mediterranean region), S. trifoliata (an endemic of the Tyrrhenian islands) and S. calliantha (an endemic of the Canary Islands). Our principal aim was to test whether these species were pollinated by birds or showed a mixed pollination system between insects and birds. Methods Censuses and captures of insects and birds were performed to obtain pollen load transported and deposited on the stigmas. Also, a qualitative and quantitative analysis of the flowers and inflorescences was carried out. Key Results Flowers were visited by Hymenoptera and by passerine birds. The Canarian species was the most visited by birds, especially by Phylloscopus canariensis, and its flowers were also accessed by juveniles of the lizard Gallotia stehlini. The most important birds in the other three species were Sylvia melanocephala and S. atricapilla. The most important insect-functional groups in the mixed pollination system were: honey-bees and wasps in S. sambucifolia; bumble-bees and wasps in S. grandiflora; wasps in S. trifoliata; and a small bee in S. calliantha. Conclusions The species studied show a mixed pollination system between insects and passerine birds. In S. calliantha there is, in addition, a third agent (juveniles of Gallotia stehlini). The participation of birds in this mixed pollination system presents varying degrees of importance because, while in S. calliantha they are the main pollinators, in the other species they interact to complement the insects which are the main pollinators. A review of different florae showed that the large showy floral morphotypes of Scrophularia are concentrated in the western and central Mediterranean region, Macaronesia and USA (New Mexico). PMID:22021816

Long-Proboscid Flies as Pollinators of Cretaceous Gymnosperms.

PubMed

Peñalver, Enrique; Arillo, Antonio; Pérez-de la Fuente, Ricardo; Riccio, Mark L; Delclòs, Xavier; Barrón, Eduardo; Grimaldi, David A

2015-07-20

The great evolutionary success of angiosperms has traditionally been explained, in part, by the partnership of these plants with insect pollinators. The main approach to understanding the origins of this pervasive relationship has been study of the pollinators of living cycads, gnetaleans, and basal angiosperms. Among the most morphologically specialized living pollinators are diverse, long-proboscid flies. Early such flies include the brachyceran family Zhangsolvidae, previously known only as compression fossils from the Early Cretaceous of China and Brazil. It belongs to the infraorder Stratiomyomorpha, a group that includes the flower-visiting families Xylomyidae and Stratiomyidae. New zhangsolvid specimens in amber from Spain (ca. 105 mega-annum [Ma]) and Myanmar (100 Ma) reveal a detailed proboscis structure adapted to nectivory. Pollen clumped on a specimen from Spain is Exesipollenites, attributed to a Mesozoic gymnosperm, most likely the Bennettitales. Late Mesozoic scorpionflies with a long proboscis have been proposed as specialized pollinators of various extinct gymnosperms, but pollen has never been observed on or in their bodies. The new discovery is a very rare co-occurrence of pollen with its insect vector and provides substantiating evidence that other long-proboscid Mesozoic insects were gymnosperm pollinators. Evidence is thus now gathering that visitors and probable pollinators of early anthophytes, or seed plants, involved some insects with highly specialized morphological adaptations, which has consequences for interpreting the reproductive modes of Mesozoic gymnosperms and the significance of insect pollination in angiosperm success. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effective prey attraction in the rare Drosophyllum lusitanicum, a flypaper-trap carnivorous plant.

PubMed

Bertol, Nils; Paniw, Maria; Ojeda, Fernando

2015-05-01

Carnivorous plants have unusually modified leaves to trap insects as an adaptation to low-nutrient environments. Disparate mechanisms have been suggested as luring traits to attract prey insects into their deadly leaves, ranging from very elaborate to none at all. Drosophyllum lusitanicum is a rare carnivorous plant with a common flypaper-trap mechanism. Here we tested whether Drosophyllum plants lure prey insects into their leaves or they act just as passive traps. We compared prey capture between live, potted plants and Drosophyllum-shaped artificial mimics coated with odorless glue. Since this species is insect-pollinated, we also explored the possible existence of a pollinator-prey conflict by quantifying the similarity between the pollination and prey guilds in a natural population. All experiments were done in southern Spain. The sticky leaves of Drosophyllum captured significantly more prey than mimics, particularly small dipterans. Prey attraction, likely exerted by scent or visual cues, seems to be unrelated to pollinator attraction by flowers, as inferred from the low similarity between pollinator and prey insect faunas found in this species. Our results illustrate the effectiveness of this carnivorous species at attracting insects to their flypaper-trap leaves. © 2015 Botanical Society of America, Inc.

Defining the Insect Pollinator Community Found in Iowa Corn and Soybean Fields: Implications for Pollinator Conservation.

PubMed

Wheelock, M J; Rey, K P; O'Neal, M E

2016-10-01

Although corn (Zea mays L.) and soybeans (Glycine max L.) do not require pollination, they offer floral resources used by insect pollinators. We asked if a similar community of insect pollinators visits these crops in central Iowa, a landscape dominated by corn and soybean production. We used modified pan traps (i.e., bee bowls) in both corn and soybean fields during anthesis and used nonmetric multidimensional scaling (NMS) to compare the communities found in the two crops. Summed across both crops, 6,704 individual insects were captured representing at least 60 species, morphospecies, or higher-level taxa. Thirty-four species were collected in both crops, 19 collected only in corn and seven were collected only in soybean. The most abundant taxa were Lasioglossum [Dialictus] spp., Agapostemon virescens Cresson, Melissodes bimaculata (Lepeletier), and Toxomerus marginatus (Say), which accounted for 65% of the insect pollinators collected from both crops. Although social bees (Apis mellifera L. and Bombus spp.) were found in both crops, they accounted for only 0.5% of all insects captured. The NMS analysis revealed a shared community of pollinators composed of mostly solitary, ground nesting bees. Many of these species have been found in other crop fields throughout North America. Although corn and soybean are grown in landscapes that are often highly disturbed, these data suggest that a community of pollinators can persist within them. We suggest approaches to conserving this community based on partnering with activities that aim to lessen the environmental impact of annual crop production. © 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.

Pollination of Granadilla (Passiflora ligularis) Benefits From Large Wild Insects.

PubMed

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.

Pollinator-mediated competition between two co-flowering Neotropical mangrove species, Avicennia germinans (Avicenniaceae) and Laguncularia racemosa (Combretaceae)

PubMed Central

Landry, C. L.

2013-01-01

Background and Aims Three ecological relationships are possible between co-flowering plant species; they may have no effect on one another, compete for pollination services, or facilitate one another by attracting more pollinators to the area. In this study, the pollinator-mediated relationship between two mangrove species with overlapping flowering phenologies was investigated in one south Florida community. Methods Pollinator observations were recorded between 0900 h and 1700 h during June and July, 2008–2010. Insect visitation rates to Avicennia germinans and Laguncularia racemosa were estimated from 522 observation intervals of 10 min during three phenological time periods, when each species flowered alone and when they co-flowered. The number of timed intervals varied between years due to differences in flowering phenology, from four to 42 for A. germinans and from nine to 94 for L. racemosa. Key Results Avicennia germinans began flowering first in all years, and insect visitation rates were significantly greater to A. germinans than to L. racemosa (P<0·001). Flowers of both species received visits from bees, wasps, flies and butterflies; Apis mellifera was the most common floral visitor to both species. Visitation rates to L. racemosa increased significantly when A. germinans stopped flowering (P<0·001). However, there was no significant change in visitation rates to A. germinans after L. racemosa began flowering (P=0·628). Conclusions When they co-flowered, A. germinans outcompeted L. racemosa for pollinators. Laguncularia racemosa hermaphrodites self-pollinate autogamously when not visited by insects, so reduced visitation to L. racemosa flowers reduced the frequency of outcrossing and increased the frequency of selfing. Reduced outcrossing limits male reproductive success in this androdioecious species, which could lead to changes in the breeding system. The degree of overlap in flowering phenologies varied between years, so the effect on the mating and breeding system may differ between years. PMID:23235696

Asynchronous diversification in a specialized plant-pollinator mutualism.

PubMed

Ramírez, Santiago R; Eltz, Thomas; Fujiwara, Mikiko K; Gerlach, Günter; Goldman-Huertas, Benjamin; Tsutsui, Neil D; Pierce, Naomi E

2011-09-23

Most flowering plants establish mutualistic associations with insect pollinators to facilitate sexual reproduction. However, the evolutionary processes that gave rise to these associations remain poorly understood. We reconstructed the times of divergence, diversification patterns, and interaction networks of a diverse group of specialized orchids and their bee pollinators. In contrast to a scenario of coevolution by race formation, we show that fragrance-producing orchids originated at least three times independently after their fragrance-collecting bee mutualists. Whereas orchid diversification has apparently tracked the diversification of orchids' bee pollinators, bees appear to have depended on the diverse chemical environment of neotropical forests. We corroborated this apparent asymmetrical dependency by simulating co-extinction cascades in real interaction networks that lacked reciprocal specialization. These results suggest that the diversification of insect-pollinated angiosperms may have been facilitated by the exploitation of preexisting sensory biases of insect pollinators.

The role of native flower visitors in pollinating Opuntia ficus-indica (L.) Mill., naturalized in Sicily

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.

Elevated temperature drives a shift from selfing to outcrossing in the insect-pollinated legume, faba bean (Vicia faba).

PubMed

Bishop, Jacob; Jones, Hannah E; O'Sullivan, Donal M; Potts, Simon G

2017-04-01

Climate change can threaten the reproductive success of plants, both directly, through physiological damage during increasingly extreme weather events, and indirectly, through disruption of plant-pollinator interactions. To explore how plant-pollinator interactions are modified by extreme weather, we exposed faba bean (Vicia faba) plants to elevated temperature for 5 d during flowering, simulating a heatwave. We then moved the plants to flight cages with either bumblebees or no pollinators, or to two field sites, where plants were enclosed in mesh bags or pollinated by wild insect communities. We used a morphological marker to quantify pollen movement between experimental plants. There was a substantial increase in the level of outcrossing by insect pollinators following heat stress. Proportion outcrossed seed increased from 17 % at control temperature, to 33 % following heat stress in the flight cages, and from 31 % to 80 % at one field site, but not at the other (33 % to 32 %). Abiotic stress can dramatically shift the relative contributions of cross- and self-pollination to reproduction in an insect pollinated plant. The resulting increases in gene flow have broad implications for genetic diversity and functioning of ecosystems, and may increase resilience by accelerating the selection of more stress-tolerant genotypes. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Melittofauna and Other Potential Pollinators in Wetland and Uplands in South Central Nebraska (Insecta: Apoidea).

PubMed

Park, Cynthia N; Overall, Lisa M; Smith, Loren M; Lagrange, Ted; McMurry, Scott

2017-03-10

Our objective was to document potential wild pollinating insects in south central Nebraska. This intensively cultivated region is known as the Rainwater Basin and contains some of the most endangered wetland systems in North America. We used blue vane traps to passively collect insects and insect nets to actively collect on flowering plants from April through October in 2014 and 2015. Habitat types included playa wetlands, adjacent mixed and tallgrass prairies, and agricultural fields. Over 112,000 insects were collected; Hymenoptera represented 78% of the total, and the families Apidae and Halictidae comprised 99% of the total melittofauna. Insects from 13 orders were collected, but Hymenoptera, Diptera, and Coleoptera were the most abundant potential pollinators.

Insect community responses to climate and weather across elevation gradients in the Sagebrush Steppe, eastern Oregon

USGS Publications Warehouse

Pilliod, David S.; Rohde, Ashley T.

2016-11-17

Executive SummaryIn this study, the U.S. Geological Survey investigated the use of insects as bioindicators of climate change in sagebrush steppe shrublands and grasslands in the Upper Columbia Basin. The research was conducted in the Stinkingwater and Pueblo mountain ranges in eastern Oregon on lands administered by the Bureau of Land Management.We used a “space-for-time” sampling design that related insect communities to climate and weather along elevation gradients. We analyzed our insect dataset at three levels of organization: (1) whole-community, (2) feeding guilds (detritivores, herbivores, nectarivores, parasites, and predators), and (3) orders within nectarivores (i.e., pollinators). We captured 59,517 insects from 176 families and 10 orders at the Pueblo Mountains study area and 112,305 insects from 185 families and 11 orders at the Stinkingwater Mountains study area in 2012 and 2013. Of all the individuals captured at the Stinkingwater Mountains study area, 77,688 were from the family Cecidomyiidae (Diptera, gall gnats).We found that the composition of insect communities was associated with variability in long-term (30-yr) temperature and interannual fluctuations in temperature. We found that captures of certain fly, bee, moth, and butterfly pollinators were more strongly associated with some climate and vegetation variables than others. We found that timing of emergence, as measured by first detection of families, was associated with elevation. When analyzed by feeding guilds, we found that all guilds emerged later at high elevations except for detritivores, which emerged earlier at high elevations. The abundance of most taxa varied through time, mostly in response to temperature and precipitation. Of the pollinators, bees (particularly, Halictidae and Megachilidae) peaked in abundance in late June and early July, whereas butterflies and moths peaked in August. Flies peaked in abundance in July.Overall, our interpretation of these patterns is that insect communities respond positively and negatively to weather and local vegetation more than to long-term climate. Given increasing variability in weather and high probability of extreme weather events, insect communities in sagebrush steppe also may experience considerable fluctuations in composition and abundance, as well as phenology. These findings have implications for many ecosystem services, including pollination, decomposition, and food resources for predatory birds and other vertebrates.

Milkweed: A resource for increasing stink bug parasitism and aiding insect pollinator and monarch butterfly conservation

USDA-ARS?s Scientific Manuscript database

The flowers of milkweed species can produce a rich supply of nectar, and therefore, planting an insecticide-free milkweed habitat in agricultural farmscapes could possibly conserve monarch butterflies, bees and other insect pollinators, as well as enhance parasitism of insect pests. In peanut-cotton...

Logging legacies affect insect pollinator communities in southern Appalachian forests

Treesearch

Michelle M. Jackson; Monica G. Turner; Scott M. Pearson

2014-01-01

Many temperate deciduous forests are recovering from past logging, but the effects of logging legacies and environmental gradients on forest insect pollinators have not been well studied. In this study, we asked how pollinator abundance and community composition varied with distance from logging roads and elevation in old (logged >90 years ago) and young (logged 20–...

A Study of Insect Pollinators Associated With DoD TER-S Flowering Plants, Including Identification of Habitat Types Where They Co-Occur by Military Installation in the Southeastern United States

DTIC Science & Technology

2010-12-01

html. Keywords: Lists plant - pollinator interactions for 456 plant species in Illinois obtained by direct observation. Sahapiro, A. M., J...00-2010 4. TITLE AND SUBTITLE A Study Of Insect Pollinators Associated With DoD TER-S Flowering Plants , Including Identification Of Habitat Types...information on new biological and pollination ecology for military natural resource managers to employ when managing their natural resources in

Generalisation and specialisation in hoverfly (Syrphidae) grassland pollen transport networks revealed by DNA metabarcoding.

PubMed

Lucas, Andrew; Bodger, Owen; Brosi, Berry J; Ford, Col R; Forman, Dan W; Greig, Carolyn; Hegarty, Matthew; Neyland, Penelope J; de Vere, Natasha

2018-04-16

Pollination by insects is a key ecosystem service and important to wider ecosystem function. Most species-level pollination networks studied have a generalised structure, with plants having several potential pollinators, and pollinators in turn visiting a number of different plant species. This is in apparent contrast to a plant's need for efficient conspecific pollen transfer. The aim of this study was to investigate the structure of pollen transport networks at three levels of biological hierarchy: community, species and individual. We did this using hoverflies in the genus Eristalis, a key group of non-Hymenopteran pollinators. We constructed pollen transport networks using DNA metabarcoding to identify pollen. We captured hoverflies in conservation grasslands in west Wales, UK, removed external pollen loads, sequenced the pollen DNA on the Illumina MiSeq platform using the standard plant barcode rbcL, and matched sequences using a pre-existing plant DNA barcode reference library. We found that Eristalis hoverflies transport pollen from 65 plant taxa, more than previously appreciated. Networks were generalised at the site and species level, suggesting some degree of functional redundancy, and were more generalised in late summer compared to early summer. In contrast, pollen transport at the individual level showed some degree of specialisation. Hoverflies defined as "single-plant visitors" varied from 40% of those captured in early summer to 24% in late summer. Individual hoverflies became more generalised in late summer, possibly in response to an increase in floral resources. Rubus fruticosus agg. and Succisa pratensis were key plant species for hoverflies at our sites Our results contribute to resolving the apparent paradox of how generalised pollinator networks can provide efficient pollination to plant species. Generalised hoverfly pollen transport networks may result from a varied range of short-term specialised feeding bouts by individual insects. The generalisation and functional redundancy of Eristalis pollen transport networks may increase the stability of the pollination service they deliver. © 2018 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Virus Infection of Plants Alters Pollinator Preference: A Payback for Susceptible Hosts?

PubMed Central

Davey, Matthew P.; Bruce, Toby J. A.; Caulfield, John C.; Furzer, Oliver J.; Reed, Alison; Robinson, Sophie I.; Miller, Elizabeth; Davis, Christopher N.; Pickett, John A.; Whitney, Heather M.; Glover, Beverley J.; Carr, John P.

2016-01-01

Plant volatiles play important roles in attraction of certain pollinators and in host location by herbivorous insects. Virus infection induces changes in plant volatile emission profiles, and this can make plants more attractive to insect herbivores, such as aphids, that act as viral vectors. However, it is unknown if virus-induced alterations in volatile production affect plant-pollinator interactions. We found that volatiles emitted by cucumber mosaic virus (CMV)-infected tomato (Solanum lycopersicum) and Arabidopsis thaliana plants altered the foraging behaviour of bumblebees (Bombus terrestris). Virus-induced quantitative and qualitative changes in blends of volatile organic compounds emitted by tomato plants were identified by gas chromatography-coupled mass spectrometry. Experiments with a CMV mutant unable to express the 2b RNA silencing suppressor protein and with Arabidopsis silencing mutants implicate microRNAs in regulating emission of pollinator-perceivable volatiles. In tomato, CMV infection made plants emit volatiles attractive to bumblebees. Bumblebees pollinate tomato by ‘buzzing’ (sonicating) the flowers, which releases pollen and enhances self-fertilization and seed production as well as pollen export. Without buzz-pollination, CMV infection decreased seed yield, but when flowers of mock-inoculated and CMV-infected plants were buzz-pollinated, the increased seed yield for CMV-infected plants was similar to that for mock-inoculated plants. Increased pollinator preference can potentially increase plant reproductive success in two ways: i) as female parents, by increasing the probability that ovules are fertilized; ii) as male parents, by increasing pollen export. Mathematical modeling suggested that over a wide range of conditions in the wild, these increases to the number of offspring of infected susceptible plants resulting from increased pollinator preference could outweigh underlying strong selection pressures favoring pathogen resistance, allowing genes for disease susceptibility to persist in plant populations. We speculate that enhanced pollinator service for infected individuals in wild plant populations might provide mutual benefits to the virus and its susceptible hosts. PMID:27513727

Attract them anyway: benefits of large, showy flowers in a highly autogamous, carnivorous plant species

PubMed Central

Salces-Castellano, A.; Paniw, M.; Casimiro-Soriguer, R.; Ojeda, F.

2016-01-01

Reproductive biology of carnivorous plants has largely been studied on species that rely on insects as pollinators and prey, creating potential conflicts. Autogamous pollination, although present in some carnivorous species, has received less attention. In angiosperms, autogamous self-fertilization is expected to lead to a reduction in flower size, thereby reducing resource allocation to structures that attract pollinators. A notable exception is the carnivorous pyrophyte Drosophyllum lusitanicum (Drosophyllaceae), which has been described as an autogamous selfing species but produces large, yellow flowers. Using a flower removal and a pollination experiment, we assessed, respectively, whether large flowers in this species may serve as an attracting device to prey insects or whether previously reported high selfing rates for this species in peripheral populations may be lower in more central, less isolated populations. We found no differences between flower-removed plants and intact, flowering plants in numbers of prey insects trapped. We also found no indication of reduced potential for autogamous reproduction, in terms of either seed set or seed size. However, our results showed significant increases in seed set of bagged, hand-pollinated flowers and unbagged flowers exposed to insect visitation compared with bagged, non-manipulated flowers that could only self-pollinate autonomously. Considering that the key life-history strategy of this pyrophytic species is to maintain a viable seed bank, any increase in seed set through insect pollinator activity would increase plant fitness. This in turn would explain the maintenance of large, conspicuous flowers in a highly autogamous, carnivorous plant. PMID:26977052

Viruses of commercialized insect pollinators.

PubMed

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.

Pollination by brood-site deception.

PubMed

Urru, Isabella; Stensmyr, Marcus C; Hansson, Bill S

2011-09-01

Pollination is often regarded as a mutualistic relationship between flowering plants and insects. In such a relationship, both partners gain a fitness benefit as a result of their interaction. The flower gets pollinated and the insect typically gets a food-related reward. However, flower-insect communication is not always a mutualistic system, as some flowers emit deceitful signals. Insects are thus fooled by irresistible stimuli and pollination is accomplished. Such deception requires very fine tuning, as insects in their typically short life span, try to find mating/feeding breeding sites as efficiently as possible, and following deceitful signals thus is both costly and time-consuming. Deceptive flowers have thus evolved the ability to emit signals that trigger obligate innate or learned responses in the targeted insects. The behavior, and thus the signals, exploited are typically involved in reproduction, from attracting pheromones to brood/food-site cues. Chemical mimicry is one of the main modalities through which flowers trick their pollen vectors, as olfaction plays a pivotal role in insect-insect and insect-plant interactions. Here we focus on floral odors that specifically mimic an oviposition substrate, i.e., brood-site mimicry. The phenomenon is wide spread across unrelated plant lineages of Angiosperm, Splachnaceae and Phallaceae. Targeted insects are mainly beetles and flies, and flowers accordingly often emit, to the human nose, highly powerful and fetid smells that are conversely extremely attractive to the duped insects. Brood-site deceptive plants often display highly elaborate flowers and have evolved a trap-release mechanism. Chemical cues often act in unison with other sensory cues to refine the imitation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Pollen resources for pollinators in specialty oilseed crops

USDA-ARS?s Scientific Manuscript database

Simplified agroecosystems have depleted habitats for beneficial insects throughout the Midwest and Northern Great Plains of the USA. Beneficial insects include pollinators and natural enemies of crop pests, and both rely heavily on floral resources and habitat diversity to maintain healthy populatio...

Context-dependency of arbuscular mycorrhizal fungi on plant-insect interactions in an agroecosystem

PubMed Central

Barber, Nicholas A.; Kiers, E. Toby; Hazzard, Ruth V.; Adler, Lynn S.

2013-01-01

Plants interact with a variety of other community members that have the potential to indirectly influence each other through a shared host plant. Arbuscular mycorrhizal fungi (AMF) are generally considered plant mutualists because of their generally positive effects on plant nutrient status and growth. AMF may also have important indirect effects on plants by altering interactions with other community members. By influencing plant traits, AMF can modify aboveground interactions with both mutualists, such as pollinators, and antagonists, such as herbivores. Because herbivory and pollination can dramatically influence plant fitness, comprehensive assessment of plant–AMF interactions should include these indirect effects. To determine how AMF affect plant–insect interactions, we grew Cucumis sativus (Cucurbitaceae) under five AMF inoculum treatments and control. We measured plant growth, floral production, flower size, and foliar nutrient content of half the plants, and transferred the other half to a field setting to measure pollinator and herbivore preference of wild insects. Mycorrhizal treatment had no effect on plant biomass or floral traits but significantly affected leaf nutrients, pollinator behavior, and herbivore attack. Although total pollinator visitation did not vary with AMF treatment, pollinators exhibited taxon-specific responses, with honey bees, bumble bees, and Lepidoptera all responding differently to AMF treatments. Flower number and size were unaffected by treatments, suggesting that differences in pollinator preference were driven by other floral traits. Mycorrhizae influenced leaf K and Na, but these differences in leaf nutrients did not correspond to variation in herbivore attack. Overall, we found that AMF indirectly influence both antagonistic and mutualistic insects, but impacts depend on the identity of both the fungal partner and the interacting insect, underscoring the context-dependency of plant–AMF interactions. PMID:24046771

Comparative Phylogeography in a Specific and Obligate Pollination Antagonism

PubMed Central

Espíndola, Anahí; Alvarez, Nadir

2011-01-01

In specific and obligate interactions the nature and abundance of a given species can have important effects on the survival and population dynamics of associated organisms. In a phylogeographic framework, we therefore expect that the fates of organisms interacting specifically are also tightly interrelated. Here we investigate such a scenario by analyzing the genetic structures of species interacting in an obligate plant-insect pollination lure-and-trap antagonism, involving Arum maculatum (Araceae) and its specific psychodid (Diptera) visitors Psychoda phalaenoides and Psycha grisescens. Because the interaction is asymmetric (i.e., only the plant depends on the insect), we expect the genetic structure of the plant to be related with the historical pollinator availability, yielding incongruent phylogeographic patterns between the interacting organisms. Using insect mtDNA sequences and plant AFLP genome fingerprinting, we inferred the large-scale phylogeographies of each species and the distribution of genetic diversities throughout the sampled range, and evaluated the congruence in their respective genetic structures using hierarchical analyses of molecular variances (AMOVA). Because the composition of pollinator species varies in Europe, we also examined its association with the spatial genetic structure of the plant. Our findings indicate that while the plant presents a spatially well-defined genetic structure, this is not the case in the insects. Patterns of genetic diversities also show dissimilar distributions among the three interacting species. Phylogeographic histories of the plant and its pollinating insects are thus not congruent, a result that would indicate that plant and insect lineages do not share the same glacial and postglacial histories. However, the genetic structure of the plant can, at least partially, be explained by the type of pollinators available at a regional scale. Differences in life-history traits of available pollinators might therefore have influenced the genetic structure of the plant, the dependent organism, in this antagonistic interaction. PMID:22216104

Efficiency of malaise traps and colored pan traps for collecting flower visiting insects from three forested ecosystems

Treesearch

Joshua W. Campbell; J.L. Hanula

2007-01-01

Pan and Malaise traps have been used widely to sample insect abundance and diversity, but no studies have compared their performance for sampling pollinators in forested ecosystems. Malaise trap design and color of pan traps are important parameters that influence insect pollinator catches. We compared pan trap (blue, yellow, white, and red) and Malaise trap catches...

Hawkmoths evaluate scenting flowers with the tip of their proboscis

PubMed Central

Haverkamp, Alexander; Yon, Felipe; Keesey, Ian W; Mißbach, Christine; Koenig, Christopher; Hansson, Bill S; Baldwin, Ian T

2016-01-01

Pollination by insects is essential to many ecosystems. Previously, we have shown that floral scent is important to mediate pollen transfer between plants (Kessler et al., 2015). Yet, the mechanisms by which pollinators evaluate volatiles of single flowers remained unclear. Here, Nicotiana attenuata plants, in which floral volatiles have been genetically silenced and its hawkmoth pollinator, Manduca sexta, were used in semi-natural tent and wind-tunnel assays to explore the function of floral scent. We found that floral scent functions to increase the fitness of individual flowers not only by increasing detectability but also by enhancing the pollinator's foraging efforts. Combining proboscis choice tests with neurophysiological, anatomical and molecular analyses we show that this effect is governed by newly discovered olfactory neurons on the tip of the moth's proboscis. With the tip of their tongue, pollinators assess the advertisement of individual flowers, an ability essential for maintaining this important ecosystem service. DOI: http://dx.doi.org/10.7554/eLife.15039.001 PMID:27146894

Nectar production in oilseeds: Food for pollinators in an agriculture dominated landscape

USDA-ARS?s Scientific Manuscript database

Simplified agroecosystems have degraded habitats for beneficial insects throughout the Midwest and Northern Great Plains of the USA. Beneficial insects include pollinators and natural enemies of crop pests, and both rely heavily on floral resources and habitat diversity to maintain healthy populatio...

The habitat disruption induces immune-suppression and oxidative stress in honey bees

PubMed Central

Morimoto, Tomomi; Kojima, Yuriko; Toki, Taku; Komeda, Yayoi; Yoshiyama, Mikio; Kimura, Kiyoshi; Nirasawa, Keijiro; Kadowaki, Tatsuhiko

2011-01-01

The honey bee is a major insect used for pollination of many commercial crops worldwide. Although the use of honey bees for pollination can disrupt the habitat, the effects on their physiology have never been determined. Recently, honey bee colonies have often collapsed when introduced in greenhouses for pollination in Japan. Thus, suppressing colony collapses and maintaining the number of worker bees in the colonies is essential for successful long-term pollination in greenhouses and recycling of honey bee colonies. To understand the physiological states of honey bees used for long-term pollination in greenhouses, we characterized their gene expression profiles by microarray. We found that the greenhouse environment changes the gene expression profiles and induces immune-suppression and oxidative stress in honey bees. In fact, the increase of the number of Nosema microsporidia and protein carbonyl content was observed in honey bees during pollination in greenhouses. Thus, honey bee colonies are likely to collapse during pollination in greenhouses when heavily infested with pathogens. Degradation of honey bee habitat by changing the outside environment of the colony, during pollination services for example, imposes negative impacts on honey bees. Thus, worldwide use of honey bees for crop pollination in general could be one of reasons for the decline of managed honey bee colonies. PMID:22393496

Bee pollination increases yield quantity and quality of cash crops in Burkina Faso, West Africa.

PubMed

Stein, Katharina; Coulibaly, Drissa; Stenchly, Kathrin; Goetze, Dethardt; Porembski, Stefan; Lindner, André; Konaté, Souleymane; Linsenmair, Eduard K

2017-12-18

Mutualistic biotic interactions as among flowering plants and their animal pollinators are a key component of biodiversity. Pollination, especially by insects, is a key element in ecosystem functioning, and hence constitutes an ecosystem service of global importance. Not only sexual reproduction of plants is ensured, but also yields are stabilized and genetic variability of crops is maintained, counteracting inbreeding depression and facilitating system resilience. While experiencing rapid environmental change, there is an increased demand for food and income security, especially in sub-Saharan communities, which are highly dependent on small scale agriculture. By combining exclusion experiments, pollinator surveys and field manipulations, this study for the first time quantifies the contribution of bee pollinators to smallholders' production of the major cash crops, cotton and sesame, in Burkina Faso. Pollination by honeybees and wild bees significantly increased yield quantity and quality on average up to 62%, while exclusion of pollinators caused an average yield gap of 37% in cotton and 59% in sesame. Self-pollination revealed inbreeding depression effects on fruit set and low germination rates in the F1-generation. Our results highlight potential negative consequences of any pollinator decline, provoking risks to agriculture and compromising crop yields in sub-Saharan West Africa.

Orchid pollination by sexual deception: pollinator perspectives.

PubMed

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.

Experimental evidence that honeybees depress wild insect densities in a flowering crop

PubMed Central

Herbertsson, Lina; Rundlöf, Maj; Bommarco, Riccardo; Smith, Henrik G.

2016-01-01

While addition of managed honeybees (Apis mellifera) improves pollination of many entomophilous crops, it is unknown if it simultaneously suppresses the densities of wild insects through competition. To investigate this, we added 624 honeybee hives to 23 fields of oilseed rape (Brassica napus L.) over 2 years and made sure that the areas around 21 other fields were free from honeybee hives. We demonstrate that honeybee addition depresses the densities of wild insects (bumblebees, solitary bees, hoverflies, marchflies, other flies, and other flying and flower-visiting insects) even in a massive flower resource such as oilseed rape. The effect was independent of the complexity of the surrounding landscape, but increased with the size of the crop field, which suggests that the effect was caused by spatial displacement of wild insects. Our results have potential implications both for the pollination of crops (if displacement of wild pollinators offsets benefits achieved by adding honeybees) and for conservation of wild insects (if displacement results in negative fitness consequences). PMID:27881750

Experimental evidence that honeybees depress wild insect densities in a flowering crop.

PubMed

Lindström, Sandra A M; Herbertsson, Lina; Rundlöf, Maj; Bommarco, Riccardo; Smith, Henrik G

2016-11-30

While addition of managed honeybees (Apis mellifera) improves pollination of many entomophilous crops, it is unknown if it simultaneously suppresses the densities of wild insects through competition. To investigate this, we added 624 honeybee hives to 23 fields of oilseed rape (Brassica napus L.) over 2 years and made sure that the areas around 21 other fields were free from honeybee hives. We demonstrate that honeybee addition depresses the densities of wild insects (bumblebees, solitary bees, hoverflies, marchflies, other flies, and other flying and flower-visiting insects) even in a massive flower resource such as oilseed rape. The effect was independent of the complexity of the surrounding landscape, but increased with the size of the crop field, which suggests that the effect was caused by spatial displacement of wild insects. Our results have potential implications both for the pollination of crops (if displacement of wild pollinators offsets benefits achieved by adding honeybees) and for conservation of wild insects (if displacement results in negative fitness consequences). © 2016 The Author(s).

Diel Patterns of Activity for Insect Pollinators of Two Oil Palm Species (Arecales : Arecaceae)

PubMed Central

Frérot, Brigitte; Poveda, Roberto; Louise, Claude; Beaudoin-Ollivier, Laurence

2017-01-01

The pollination of two oil palm species, Elaeis guineensis Jacquin and Elaeis oleifera Cortés (Arecales: Arecaceae), depends on a mutualistic relation with insects, which use male inflorescences as a brood site, and visits female inflorescences lured by the emitted odor, which is similar to that of males. Although the activity of visiting the inflorescences by these insects is critical for the adequate natural pollination of the host plant, their activity is poorly documented. In the present study, we determine the diel activity of two specialized pollinator weevils (Coleoptera: Curculionidae) on inflorescences of their respective host-palm: Elaeidobius kamerunicus Faust specialized on E. guineensis, and Grasidius hybridus O’Brien and Beserra specialized on E. oleifera. The average timing of activity was studied by using passive interception traps. Then the pattern and the duration were refined by using aspiration trapping within the active period for each insect species at the male and female inflorescences. All the experiments were conducted in an Ecuadorian oil palm plantation, located close to Amazonian forest. El. kamerunicus and G. hybridus were found to be the pollinators of E. guineensis and E. oleifera, respectively. The two species differed in their diel pattern of activity: E. kamerunicus was active in the morning and G. hybridus during a short period at dusk. For both palm species, insect visits were synchronous on both male and female inflorescences. The synchronicity is discussed as a strategy to maintain the relation mutualistic between partners. These findings increase our understanding of the oil palm pollination system. PMID:28365767

The evolution of floral scent and insect chemical communication.

PubMed

Schiestl, Florian P

2010-05-01

Plants have evolved a range of strategies to manipulate the behaviour of their insect partners. One powerful strategy is to produce signals that already have a role in the animals' own communication systems. To investigate to what extent the evolution of floral scents is correlated with chemical communication in insects, I analyse the occurrence, commonness, and evolutionary patterns of the 71 most common 'floral' volatile organic compounds (VOCs) in 96 plant families and 87 insect families. I found an overlap of 87% in VOCs produced by plants and insects. 'Floral' monoterpenes showed strong positive correlation in commonness between plants (both gymnosperms and angiosperms) and herbivores, whereas the commonness of 'floral' aromatics was positively correlated between angiosperms and both pollinators and herbivores. According to a multivariate regression analysis the commonness of 'floral' aromatics was best explained by their commonness in pollinators, whereas monoterpenes were best explained by herbivores. Among pollinator orders, aromatics were significantly more common in Lepidoptera than in Hymenoptera, whereas monoterpenes showed no difference among the two orders. Collectively, these patterns suggest that plants and insects converge in overall patterns of volatile production, both for attraction and defence. Monoterpenes seem to have evolved primarily for defence under selection by herbivores, whereas aromatics evolved signalling functions in angiosperms, primarily for pollinator attraction.

Risks of large-scale use of systemic insecticides to ecosystem functioning and services.

PubMed

Chagnon, Madeleine; Kreutzweiser, David; Mitchell, Edward A D; Morrissey, Christy A; Noome, Dominique A; Van der Sluijs, Jeroen P

2015-01-01

Large-scale use of the persistent and potent neonicotinoid and fipronil insecticides has raised concerns about risks to ecosystem functions provided by a wide range of species and environments affected by these insecticides. The concept of ecosystem services is widely used in decision making in the context of valuing the service potentials, benefits, and use values that well-functioning ecosystems provide to humans and the biosphere and, as an endpoint (value to be protected), in ecological risk assessment of chemicals. Neonicotinoid insecticides are frequently detected in soil and water and are also found in air, as dust particles during sowing of crops and aerosols during spraying. These environmental media provide essential resources to support biodiversity, but are known to be threatened by long-term or repeated contamination by neonicotinoids and fipronil. We review the state of knowledge regarding the potential impacts of these insecticides on ecosystem functioning and services provided by terrestrial and aquatic ecosystems including soil and freshwater functions, fisheries, biological pest control, and pollination services. Empirical studies examining the specific impacts of neonicotinoids and fipronil to ecosystem services have focused largely on the negative impacts to beneficial insect species (honeybees) and the impact on pollination service of food crops. However, here we document broader evidence of the effects on ecosystem functions regulating soil and water quality, pest control, pollination, ecosystem resilience, and community diversity. In particular, microbes, invertebrates, and fish play critical roles as decomposers, pollinators, consumers, and predators, which collectively maintain healthy communities and ecosystem integrity. Several examples in this review demonstrate evidence of the negative impacts of systemic insecticides on decomposition, nutrient cycling, soil respiration, and invertebrate populations valued by humans. Invertebrates, particularly earthworms that are important for soil processes, wild and domestic insect pollinators which are important for plant and crop production, and several freshwater taxa which are involved in aquatic nutrient cycling, were all found to be highly susceptible to lethal and sublethal effects of neonicotinoids and/or fipronil at environmentally relevant concentrations. By contrast, most microbes and fish do not appear to be as sensitive under normal exposure scenarios, though the effects on fish may be important in certain realms such as combined fish-rice farming systems and through food chain effects. We highlight the economic and cultural concerns around agriculture and aquaculture production and the role these insecticides may have in threatening food security. Overall, we recommend improved sustainable agricultural practices that restrict systemic insecticide use to maintain and support several ecosystem services that humans fundamentally depend on.

Different pollinator assemblages ensure reproductive success of Cleisostoma linearilobatum (Orchidaceae) in fragmented holy hill forest and traditional tea garden.

PubMed

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.

Different pollinator assemblages ensure reproductive success of Cleisostoma linearilobatum (Orchidaceae) in fragmented holy hill forest and traditional tea garden

PubMed Central

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

Pollinator directionality as a response to nectar gradient: promoting outcrossing while avoiding geitonogamy.

PubMed

Fisogni, A; Cristofolini, G; Rossi, M; Galloni, M

2011-11-01

Plants with multiple flowers could be prone to autonomous self-pollination and insect-mediated geitonogamy, but physiological and ecological features have evolved preventing costs related to autogamy. We studied the rare perennial herb Dictamnus albus as a model plant, with the aim of describing the plant-pollinator system from both plant and pollinator perspectives and analysing features that promote outcrossing in an entomophilous species. The breeding system and reproductive success of D. albus were investigated in experimental and natural conditions, showing that it is potentially self-compatible, but only intra-inflorescence insect-mediated selfing is possible. Nectar analysis showed gender-biased production towards the female phase, which follows the male phase, and during flowering, full blooming is found in flowers at the bottom of the raceme. Among a wide spectrum of insect visitors, three genera (Bombus, Apis, Megachile) were found to be principal pollinators. A study of insect behaviour showed a tendency towards bottom-to-top flights for the most important pollinators Bombus spp. and Apis mellifera: upward movements on the racemes could be explained by foraging behaviour, from more to less rewarding flowers. In accordance with the 'declining reward hypothesis', bumblebees and honeybees leave the plant when gain of reward is low, after which few flowers are visited, reducing the chance of self-pollen transfer among flowers. Intra-flower self-pollination is prevented in D. albus by protandry and herkogamy, while the nectar-induced sequential pattern of pollinator visits avoids geitonogamy and tends to maximise pollen export, promoting outcrossing. All these features for preventing selfing benefit plant fitness and population genetic structure. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

Using metabarcoding to reveal and quantify plant-pollinator interactions

PubMed Central

Pornon, André; Escaravage, Nathalie; Burrus, Monique; Holota, Hélène; Khimoun, Aurélie; Mariette, Jérome; Pellizzari, Charlène; Iribar, Amaia; Etienne, Roselyne; Taberlet, Pierre; Vidal, Marie; Winterton, Peter; Zinger, Lucie; Andalo, Christophe

2016-01-01

Given the ongoing decline of both pollinators and plants, it is crucial to implement effective methods to describe complex pollination networks across time and space in a comprehensive and high-throughput way. Here we tested if metabarcoding may circumvent the limits of conventional methodologies in detecting and quantifying plant-pollinator interactions. Metabarcoding experiments on pollen DNA mixtures described a positive relationship between the amounts of DNA from focal species and the number of trnL and ITS1 sequences yielded. The study of pollen loads of insects captured in plant communities revealed that as compared to the observation of visits, metabarcoding revealed 2.5 times more plant species involved in plant-pollinator interactions. We further observed a tight positive relationship between the pollen-carrying capacities of insect taxa and the number of trnL and ITS1 sequences. The number of visits received per plant species also positively correlated to the number of their ITS1 and trnL sequences in insect pollen loads. By revealing interactions hard to observe otherwise, metabarcoding significantly enlarges the spatiotemporal observation window of pollination interactions. By providing new qualitative and quantitative information, metabarcoding holds great promise for investigating diverse facets of interactions and will provide a new perception of pollination networks as a whole. PMID:27255732

Dark Matters: Challenges of Nocturnal Communication Between Plants and Animals in Delivery of Pollination Services

PubMed Central

Borges, Renee M.

2018-01-01

The night is a special niche characterized by dim light, lower temperatures, and higher humidity compared to the day. Several animals have made the transition from the day into the night and have acquired unique adaptations to cope with the challenges of performing nocturnal activities. Several plant species have opted to bloom at night, possibly as a response to aridity to prevent excessive water loss through evapotranspiration since flowering is often a water-demanding process, or to protect pollen from heat stress. Nocturnal pollinators have visual adaptations to function under dim light conditions but may also trade off vision against olfaction when they are dependent on nectar-rewarding and scented flowers. Nocturnal pollinators may use CO2 and humidity cues emanating from freshly-opened flowers as indicators of nectar-rich resources. Some endothermic nocturnal insect pollinators are attracted to thermogenic flowers within which they remain to obtain heat as a reward to increase their energy budget. This review focuses on mechanisms that pollinators use to find flowers at night, and the signals that nocturnally blooming flowers may employ to attract pollinators under dim light conditions. It also indicates gaps in our knowledge. While millions of years of evolutionary time have given pollinators and plants solutions to the delivery of pollination services and to the offering of appropriate rewards, this history of successful evolution is being threatened by artificial light at night. Excessive and inappropriate illumination associated with anthropogenic activities has resulted in significant light pollution which serves to undermine life processes governed by dim light. PMID:29599655

Dark Matters: Challenges of Nocturnal Communication Between Plants and Animals in Delivery of Pollination Services.

PubMed

Borges, Renee M

2018-03-01

The night is a special niche characterized by dim light, lower temperatures, and higher humidity compared to the day. Several animals have made the transition from the day into the night and have acquired unique adaptations to cope with the challenges of performing nocturnal activities. Several plant species have opted to bloom at night, possibly as a response to aridity to prevent excessive water loss through evapotranspiration since flowering is often a water-demanding process, or to protect pollen from heat stress. Nocturnal pollinators have visual adaptations to function under dim light conditions but may also trade off vision against olfaction when they are dependent on nectar-rewarding and scented flowers. Nocturnal pollinators may use CO 2 and humidity cues emanating from freshly-opened flowers as indicators of nectar-rich resources. Some endothermic nocturnal insect pollinators are attracted to thermogenic flowers within which they remain to obtain heat as a reward to increase their energy budget. This review focuses on mechanisms that pollinators use to find flowers at night, and the signals that nocturnally blooming flowers may employ to attract pollinators under dim light conditions. It also indicates gaps in our knowledge. While millions of years of evolutionary time have given pollinators and plants solutions to the delivery of pollination services and to the offering of appropriate rewards, this history of successful evolution is being threatened by artificial light at night. Excessive and inappropriate illumination associated with anthropogenic activities has resulted in significant light pollution which serves to undermine life processes governed by dim light.

Why is the lawn buzzing?

PubMed Central

2014-01-01

Abstract Graminoids, including grasses, are frequently described in the botanical literature as being wind-pollinated. This paper offers visual evidence for insect pollination of a grass. Three of the bees involved were found to have 100% grass pollen in their pollen sacs. In reviewing the literature for this paper, it was evident that those working with bees are well aware that these insects often pollinate graminoids. It is not clear why this information has not been incorporated into the botanical literature. PMID:24891835

Evidence for pollinator sharing in Mediterranean nectar-mimic orchids: absence of premating barriers?

PubMed Central

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

Alfalfa (Medicago sativa L.) seed yield in relation to phosphorus fertilization and honeybee pollination.

PubMed

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.

Effects of shelterwood management on flower-visiting insects and their floral resources

Treesearch

Jessica E. Fultz

2005-01-01

Habitat alteration can affect pollinating-insect community structure, decreasing the efficiency of pollinators on which many agricultural and natural ecosystems rely. Within the Tenderfoot Creek Experimental Forest (TCEF), located in the Little Belt Mountains of Central Montana, two different types of silvicultural techniques, even and group shelterwood, were applied...

Could tanoak mortality affect insect biodiversity? Evidence for insect pollination in tanoaks

Treesearch

Jessica W. Wright; Richard S. Dodd

2013-01-01

Tanoaks, Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S. H. Oh, are being killed by sudden oak death, caused by the pathogen Phytophthora ramorum Werres, de Cock & Man in't Veld. However, very little is known about the basic ecology of the species. Here we investigate the pollination ecology of...

Pollination by sexual deception-it takes chemistry to work.

PubMed

Bohman, Björn; Flematti, Gavin R; Barrow, Russell A; Pichersky, Eran; Peakall, Rod

2016-08-01

Semiochemicals are of paramount importance in sexually deceptive plants. These plants sexually lure specific male insects as pollinators by chemical and physical mimicry of the female of the pollinator. The strategy has evolved repeatedly in orchids, with a wide diversity of insect groups exploited. Chemical communication systems confirmed by field bioassays include: alkenes and alkanes in bee pollinated Ophrys species, keto-acid and hydroxy-acids in scoliid wasp pollinated O. speculum, and cyclohexanediones and pyrazines in thynnine wasp pollinated Chiloglottis and Drakaea orchids, respectively. In Ophrys, stearoyl-acyl carrier protein desaturase (SAD) enzymes have been confirmed to control species level variation in alkene double bond position. The production of cyclohexanediones in Chiloglottis unexpectedly depends on UVB light, a phenomenon unknown for other plant specialised metabolites. Potential biosynthetic pathways for other systems are explored, and alternative approaches to further accelerate chemical discovery in sexually deceptive plants are proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Seed set in guayule (Parthenium argentatum, Asteraceae) in relation to insect pollination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mamood, A.N.; Waller, G.D.; Ray, D.T.

Guayule (Parthenium argentatum, Asteraceae) is one of two major plant species grown for natural rubber. Studies were conducted to determine the effect of honey bee (Apis mellifera) pollination and season on seed set and total seed yield/ha. The experiments involved four pollination treatments: plants caged with bees; plants caged without bees; plants open pollinated (uncovered); and plants individually covered. Seeds were harvested monthly July-September 1984, and May-September 1985. Plots with bees produced at least 150% more seeds than plots without bees, and there were no qualitative differences in the seed weights among treatments. Highest seed yield was in May andmore » September. Results indicate that (1) insect pollination in guayule increases seed yield and (2) fewer seeds are produced in the warmest months.« less

[Preliminary study on pollination biology of Tulipa edulis].

PubMed

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.

Comparative study of the floral biology and of the response of productivity to insect visitation in two rapeseed cultivars (Brassica napus L.) in Rio Grande do Sul.

PubMed

Blochtein, B; Nunes-Silva, P; Halinski, R; Lopes, L A; Witter, S

2014-11-01

Planning the artificial pollination of agricultural crops requires knowledge of the floral biology and reproductive system of the crop in question. Many studies have shown that rapeseed (Brassica napus Linnaeus) is self-compatible and self-pollinated, but its productivity may be increased by insect visitation. In the present study, the floral biology and the response of productivity to insect visitation of two rapeseed cultivars (Hyola 420 and Hyola 61) were analyzed and compared in three regions of Rio Grande do Sul, Brazil. The rapeseed flowers presented three stages during anthesis, with the time periods varying between the cultivars. Both cultivars are self-compatible, but free visitation of insects increased productivity by 17% in the Hyola 420 cultivar and by approximately 30% in the Hyola 61 cultivar. Therefore, it is concluded that the cultivar Hyola 61 is more dependent on insect pollination than Hyola 420.

Pollinator diversity and reproductive success of Epipactis helleborine (L.) Crantz (Orchidaceae) in anthropogenic and natural habitats.

PubMed

Rewicz, Agnieszka; Jaskuła, Radomir; Rewicz, Tomasz; Tończyk, Grzegorz

2017-01-01

Epipactis helleborine is an Eurasian orchid species which prefers woodland environments but it may also spontaneously and successfully colonise human-made artificial and disturbed habitats such as roadsides, town parks and gardens. It is suggested that orchids colonising anthropogenic habitats are characterised by a specific set of features (e.g., large plant size, fast flower production). However, as it is not well known how pollinator diversity and reproductive success of E. helleborine differs in populations in anthropogenic habitats compared to populations from natural habitats, we wanted to compare pollinator diversity and reproductive success of this orchid species between natural and anthropogenic habitat types. Pollination biology, reproductive success and autogamy in populations of E. helleborine from anthropogenic (roadside) and natural (forest) habitats were compared. Eight populations (four natural and four human-disturbed ones) in two seasons were studied according to height of plants, length of inflorescences, as well as numbers of juvenile shoots, flowering shoots, flowers, and fruits. The number and diversity of insect pollinators were studied in one natural and two human-disturbed populations. Reproductive success (the ratio of the number of flowers to the number of fruits) in the populations from anthropogenic habitats was significantly higher than in the natural habitats. Moreover, plants from anthropogenic habitats were larger than those from natural ones. In both types of populations, the main insect pollinators were Syrphidae, Culicidae, Vespidae, Apidae and Formicidae. With respect to the type of pollinators' mouth-parts, chewing (39%), sponging (34%) and chewing-sucking (20%) pollinators prevailed in anthropogenic habitats. In natural habitats, pollinators with sponging (55%) and chewing mouth-parts (32%) dominated, while chewing-sucking and piercing-sucking insects accounted for 9% and 4% respectively. We suggest that higher reproductive success of E. helleborine in the populations from anthropogenic habitats than in the populations from natural habitats may result from a higher number of visits by pollinators and their greater species diversity, but also from the larger size of plants growing in such habitats. Moreover, our data clearly show that E. helleborine is an opportunistic species with respect to pollinators, with a wide spectrum of pollinating insects. Summarising, E. helleborine is a rare example of orchid species whose current range is not declining. Its ability to make use of anthropogenically altered habitats has allowed its significant spatial range expansion, and even successful colonisation of North America.

Hummingbird pollination and the diversification of angiosperms: an old and successful association in Gesneriaceae

PubMed Central

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

Hummingbird pollination and the diversification of angiosperms: an old and successful association in Gesneriaceae.

PubMed

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).

New long-proboscid lacewings of the mid-Cretaceous provide insights into ancient plant-pollinator interactions.

PubMed

Lu, Xiu-Mei; Zhang, Wei-Wei; Liu, Xing-Yue

2016-05-05

Many insects with long-proboscid mouthparts are among the pollinators of seed plants. Several cases of the long-proboscid pollination mode are known between fossil insects (e.g., true flies, scorpionflies, and lacewings) and various extinct gymnosperm lineages, beginning in the Early Permian and increasing during the Middle Jurassic to Early Cretaceous. However, details on the morphology of lacewing proboscides and the relevant pollination habit are largely lacking. Here we report on three lacewing species that belong to two new genera and a described genus from mid-Cretaceous (Albian-Cenomanian) amber of Myanmar. All these species possess relatively long proboscides, which are considered to be modified from maxillary and labial elements, probably functioning as a temporary siphon for feeding on nectar. Remarkably, these proboscides range from 0.4-1.0 mm in length and are attributed to the most diminutive ones among the contemporary long-proboscid insect pollinators. Further, they clearly differ from other long-proboscid lacewings which have a much longer siphon. The phylogenetic analysis indicates that these Burmese long-proboscid lacewings belong to the superfamily Psychopsoidea but cannot be placed into any known family. The present findings represent the first description of the mouthparts of long-proboscid lacewings preserved in amber and highlight the evolutionary diversification of the ancient plant-pollinator interactions.

Can alternative sugar sources buffer pollinators from nectar shortages?

PubMed

Gardner-Gee, Robin; Dhami, Manpreet K; Paulin, Katherine J; Beggs, Jacqueline R

2014-12-01

Honeydew is abundant in many ecosystems and may provide an alternative food source (a buffer) for pollinators during periods of food shortage, but the impact of honeydew on pollination systems has received little attention to date. In New Zealand, kānuka trees (Myrtaceae: Kunzea ericoides (A. Rich) Joy Thompson) are often heavily infested by the endemic honeydew-producing scale insect Coelostomidia wairoensis (Maskell) (Hemiptera: Coelostomidiidae) and the period of high honeydew production can overlap with kānuka flowering. In this study, we quantified the sugar resources (honeydew and nectar) available on kānuka and recorded nocturnal insect activity on infested and uninfested kānuka during the flowering period. Insects were abundant on infested trees, but flowers on infested trees received fewer insect visitors than flowers on uninfested trees. There was little evidence that insects had switched directly from nectar-feeding to honeydew-feeding, but it is possible that some omnivores (e.g., cockroaches) were distracted by the other honeydew-associated resources on infested branches (e.g., sooty molds, prey). Additional sampling was carried out after kānuka flowering had finished to determine honeydew usage in the absence of adjacent nectar resources. Moths, which had fed almost exclusively on nectar earlier, were recorded feeding extensively on honeydew after flowering had ceased; hence, honeydew may provide an additional food source for potential pollinators. Our results show that honeydew resources can impact floral visitation patterns and suggest that future pollinator studies should consider the full range of sugar resources present in the study environment.

Flight performance of bumble bee as a possible pollinator in space agriculture under partial gravity

NASA Astrophysics Data System (ADS)

Yamashita, Masamichi; Hashimoto, Hirofumi; Mitsuhata, Masahiro; Sasaki, Masami; Space Agriculture Task Force, J.

Space agriculture is an advanced life support concept for habitation on extraterrestrial bodies based on biological and ecological function. Flowering plant species are core member of space agriculture to produce food and revitalize air and water. Selection of crop plant species is made on the basis of nutritional requirements to maintain healthy life of space crew. Species selected for space agriculture have several mode of reproduction. For some of plant species, insect pollination is effective to increase yield and quality of food. In terrestrial agriculture, bee is widely introduced to pollinate flower. For pollinator insect on Mars, working environment is different from Earth. Magnitude of gravity is 0.38G on Mars surface. In order to confirm feasibility of insect pollination for space agriculture, capability of flying pollinator insect under such exotic condition should be examined. Even bee does not possess evident gravity sensory system, gravity dominates flying performance and behavior. During flight or hovering, lifting force produced by wing beat sustains body weight, which is the product of body mass and gravitational acceleration. Flying behavior of bumble bee, Bombus ignitus, was documented under partial or micro-gravity produced by parabolic flight of jet plane. Flying behavior at absence of gravity differed from that under normal gravity. Ability of bee to fly under partial gravity was examined at the level of Mars, Moon and the less, to determine the threshold level of gravity for bee flying maneuver. Adaptation process of bee flying under different gravity level was evaluated as well by successive documentation of parabolic flight experiment.

DNA barcoding implicates 23 species and four orders as potential pollinators of Chinese knotweed (Persicaria chinensis) in Peninsular Malaysia.

PubMed

Wong, M-M; Lim, C-L; Wilson, J-J

2015-08-01

Chinese knotweed (Persicaria chinensis) is of ecological and economic importance as a high-risk invasive species and a traditional medicinal herb. However, the insects associated with P. chinensis pollination have received scant attention. As a widespread invasive plant we would expect P. chinensis to be associated with a diverse group of insect pollinators, but lack of taxonomic identification capacity is an impediment to confirm this expectation. In the present study we aimed to elucidate the insect pollinators of P. chinensis in peninsular Malaysia using DNA barcoding. Forty flower visitors, representing the range of morphological diversity observed, were captured at flowers at Ulu Kali, Pahang, Malaysia. Using Automated Barcode Gap Discovery, 17 morphospecies were assigned to 23 species representing at least ten families and four orders. Using the DNA barcode library (BOLD) 30% of the species could be assigned a species name, and 70% could be assigned a genus name. The insects visiting P. chinensis were broadly similar to those previously reported as visiting Persicaria japonica, including honey bees (Apis), droneflies (Eristalis), blowflies (Lucilia) and potter wasps (Eumedes), but also included thrips and ants.

High specialisation in the pollination system of Mandevilla tenuifolia (J.C. Mikan) Woodson (Apocynaceae) drives the effectiveness of butterflies as pollinators.

PubMed

de Araújo, L D A; Quirino, Z G M; Machado, I C

2014-09-01

Butterfly pollination in the tropics is considered somewhat effective or solely effective in a few plant species. In the present study, we tested the hypothesis that Mandevilla tenuifolia (Apocynaceae), which has floral attributes associated with psychophily, has strategies adapted to pollination by butterflies, restricting other floral visitors and making these insects act as efficient pollinators. We analysed the floral and reproductive biology of M. tenuifolia, as well as the frequency and efficiency of its flower visitors. M. tenuifolia is an herb whose flowers have strong herkogamy and secondary pollen presentation on the style head, which corresponds to 60.4% of pollen on the anthers. Flower longevity and the long period of receptivity of the stigmatic region associated with the large amount of pollen removed in the first visits suggest that flowers remain functionally female during part of anthesis. Butterflies, mainly of the families Nymphalidae and Pieridae, are the only pollinators of M. tenuifolia. Despite being self-compatible, M. tenuifolia depends on biotic vectors for fruit production. A non-significant difference in fruit set between controlled treatments and natural conditions suggests that the pollinators are efficient. The inclination resulting from the landing of butterflies on flowers, together with flower morphology, guiding the insect proboscis inside the floral tube, as well as the frequency and efficiency of butterfly visits, are evidence of the close relationship between butterflies and M. tenuifolia, and also of the efficiency of these insects as pollinators. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Pollination Research Methods with Apis mellifera

USDA-ARS?s Scientific Manuscript database

This chapter describes field and lab procedures for doing experiments on honey bee pollination. Most of the methods apply to any insect for whom pollen vectoring capacity is the question. What makes honey bee pollination distinctive is its historic emphasis on agricultural applications; hence one fi...

Pollination: sexual mimicry abounds.

PubMed

Schiestl, Florian P

2010-12-07

Why do plants mimic female insects to attract males for pollination? A new study gives insights into the advantages of sexual mimicry and documents this pollination system for the first time outside the orchid family, in a South African daisy. Copyright © 2010 Elsevier Ltd. All rights reserved.

Biocommunication between Plants and Pollinating Insects through Fluorescence of Pollen and Anthers.

PubMed

Mori, Shinnosuke; Fukui, Hiroshi; Oishi, Masanori; Sakuma, Masayuki; Kawakami, Mari; Tsukioka, Junko; Goto, Katsumi; Hirai, Nobuhiro

2018-06-01

Flowering plants attract pollinators via various stimuli such as odor, color, and shape. Factors determining the foraging behavior of pollinators remain a major theme in ecological and evolutionary research, although the floral traits and cognitive ability of pollinators have been investigated for centuries. Here we show that the autofluorescence emitted from pollen and anthers under UV irradiation may act as another attractant for flower-visiting insects. We have identified fluorescent compounds from pollen and anthers of five plant species as hydroxycinnamoyl derivatives. The fluorescent compounds are also shown to quench UV energy and exhibit antioxidant activity, indicating a function as protectants of pollen genes from UV-induced damage. A two-choice assay using honeybees in the field demonstrated that they perceived the blue fluorescence emitted from the fluorescent compounds and were attracted to it. This result suggested that the fluorescence from pollen and anthers serves as a visual cue to attract pollinators under sunlight.

Morphofunctional Traits and Pollination Mechanisms of Coronilla emerus L. Flowers (Fabaceae)

PubMed Central

Aronne, Giovanna; Giovanetti, Manuela; De Micco, Veronica

2012-01-01

It is accepted that the papilionaceous corolla of the Fabaceae evolved under the selective pressure of bee pollinators. Morphology and function of different parts of Coronilla emerus L. flowers were related to their role in the pollination mechanism. The corolla has a vexillum with red nectar lines, a keel hiding stamens and pistil, and two wing petals fasten to the keel with two notched folds. Pollinators land on the complex of keel and wings, trigger the protrusion of pollen and finally of the stigma from the keel tip. Data on pollen viability and stigma receptivity prove that flowers are proterandrous. The results of hand-pollination experiments confirmed that insects are fundamental to set seed. Interaction with pollinators allows not only the transport of pollen but also the rupture of the stigmatic cuticle, necessary to achieve both allogamy and autogamy. Field observations showed that Hymenoptera, Lepidoptera, and Diptera visited the flowers. Only some of the Hymenoptera landed on the flowers from the front and elicited pollination mechanisms. Most of the insects sucked the nectar from the back without any pollen transfer. Finally, morphological and functional characteristics of C. emerus flowers are discussed in terms of floral larceny and reduction in pollination efficiency. PMID:22666114

The pollination biology of a pavement plain: pollinator visitation patterns.

PubMed

O'Brien, Mary H

1980-01-01

The pollination biology of the 20 plant species of a treeless, pavement plain in the San Bernardino Mountains of southern California was studied throughout one flowering season.Several patterns of pollinator activity recorded during the season underline the necessity for noting the activity of all insect pollinators whether specialized, non-specialized, regular, or occasional: 1) Occasional insect visitors were a feature of the visitation to nine of the twelve entomophilous plant species and were the sole pollinators for three of these twelve species. 2) The eight entomophilous plant species which had open, generalized flower morphologies received the heaviest pollinator visitation, while three of the four entomophilous species with specialized flower morphologies received little visitation. 3) Most regular flower visitors, whether bees, flies, or wasps, appeared to be similar with respect to number of plant species visited regularly, purity of pollen load, length of residence and localization of activity on the site. The question is raised as to whether such similarity of behavior as pollen vectors is a function of the low plant diversity or a feature commonly found when the pollen loads and behavior of different pollinator types are actually monitored.

Measuring the inefficiency of allowing self-pollinated alfalfa progeny into breeding nurseries

USDA-ARS?s Scientific Manuscript database

Although alfalfa is generally considered an outcrossing species the incidence of self-pollination during insect pollination can be substantial with an observed average 30% selfing rate. Despite this, alfalfa breeders utilizing space plant evaluation nurseries make no attempt to discriminate self-pol...

Using pennycress, camelina, and canola cash crops to provision pollinators

USDA-ARS?s Scientific Manuscript database

As pollinator decline continues, the need to provide high value forage for insects continues to rise. Finding agricultural crops to diversify the landscape and provide forage is one way to improve pollinator health. Three winter industrial oilseed crops (pennycress, winter camelina, and winter canol...

Beneficial Insect Attraction to Milkweeds (Asclepias speciosa, Asclepias fascicularis) in Washington State, USA

PubMed Central

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

Beneficial Insect Attraction to Milkweeds (Asclepias speciosa, Asclepias fascicularis) in Washington State, USA.

PubMed

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.

New long-proboscid lacewings of the mid-Cretaceous provide insights into ancient plant-pollinator interactions

PubMed Central

Lu, Xiu-Mei; Zhang, Wei-Wei; Liu, Xing-Yue

2016-01-01

Many insects with long-proboscid mouthparts are among the pollinators of seed plants. Several cases of the long-proboscid pollination mode are known between fossil insects (e.g., true flies, scorpionflies, and lacewings) and various extinct gymnosperm lineages, beginning in the Early Permian and increasing during the Middle Jurassic to Early Cretaceous. However, details on the morphology of lacewing proboscides and the relevant pollination habit are largely lacking. Here we report on three lacewing species that belong to two new genera and a described genus from mid-Cretaceous (Albian-Cenomanian) amber of Myanmar. All these species possess relatively long proboscides, which are considered to be modified from maxillary and labial elements, probably functioning as a temporary siphon for feeding on nectar. Remarkably, these proboscides range from 0.4–1.0 mm in length and are attributed to the most diminutive ones among the contemporary long-proboscid insect pollinators. Further, they clearly differ from other long-proboscid lacewings which have a much longer siphon. The phylogenetic analysis indicates that these Burmese long-proboscid lacewings belong to the superfamily Psychopsoidea but cannot be placed into any known family. The present findings represent the first description of the mouthparts of long-proboscid lacewings preserved in amber and highlight the evolutionary diversification of the ancient plant-pollinator interactions. PMID:27149436

The evolution of bat pollination: a phylogenetic perspective

PubMed Central

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

Large-Range Movements of Neotropical Orchid Bees Observed via Radio Telemetry

PubMed Central

Wikelski, Martin; Moxley, Jerry; Eaton-Mordas, Alexander; López-Uribe, Margarita M.; Holland, Richard; Moskowitz, David; Roubik, David W.; Kays, Roland

2010-01-01

Neotropical orchid bees (Euglossini) are often cited as classic examples of trapline-foragers with potentially extensive foraging ranges. If long-distance movements are habitual, rare plants in widely scattered locations may benefit from euglossine pollination services. Here we report the first successful use of micro radio telemetry to track the movement of an insect pollinator in a complex and forested environment. Our results indicate that individual male orchid bees (Exaerete frontalis) habitually use large rainforest areas (at least 42–115 ha) on a daily basis. Aerial telemetry located individuals up to 5 km away from their core areas, and bees were often stationary, for variable periods, between flights to successive localities. These data suggest a higher degree of site fidelity than what may be expected in a free living male bee, and has implications for our understanding of biological activity patterns and the evolution of forest pollinators. PMID:20520813

Benefits of insect pollination to confection sunflowers differ across plant genotypes

USDA-ARS?s Scientific Manuscript database

Sunflowers, Helianthus annuus L., are naturally self-infertile, requiring animal pollination to set seed. While domesticated sunflowers have been bred for self-fertility, reducing the need for pollinators, selfing rates vary across genotypes. The goal of this study was to evaluate the benefits of in...

Social insects: from the lab to the landscape - translational approaches to pollinator health

USDA-ARS?s Scientific Manuscript database

Approximately 90% of flowering plants — corresponding to nearly three quarters of global agricultural crops — use pollinators to set seed and fruit. However, populations of several species of pollinators are in decline throughout the world, threatening the stability of our ecosystems and productivit...

Nectar-inhabiting microorganisms influence nectar volatile composition and attractiveness to a generalist pollinator

USDA-ARS?s Scientific Manuscript database

The microbiome of the phyllosphere and anthosphere plays an important role in many plant-plant, plant-insect, and plant-microbe interactions. A particularly essential interaction is that of the plant pollinator, which is important for ensuring high crop yields, pollinator health and successful plant...

Effects of varroa mites and bee disease on pollination efficacy of honeybees

USDA-ARS?s Scientific Manuscript database

Single-stranded RNA viruses cause disease and behavioral changes in many insects, especially honey bees. Varroa mites and viral diseases are known to affect the efficiency of crop pollination by honey bees by eliminating colonies, but almost no information exists about their influence on pollination...

A conceptual framework that links pollinator foraging behavior to gene flow

USDA-ARS?s Scientific Manuscript database

In insect-pollinated crops such as alfalfa, a better understanding of how pollinator foraging behavior affects gene flow could lead to the development of management strategies to reduce gene flow and facilitate the coexistence of distinct seed-production markets. Here, we introduce a conceptual fram...

The pollination of a self-incompatible, food-mimic orchid, Coelogyne fimbriata (Orchidaceae), by female Vespula wasps

PubMed Central

Cheng, Jin; Shi, Jun; Shangguan, Fa-Zhi; Dafni, Amots; Deng, Zhen-Hai; Luo, Yi-Bo

2009-01-01

Background and Aims The study of specialized interactions between species is crucial to our understanding of processes in evolutionary ecology due to their profound effect on life cycles and diversification. Obligate pollination by a single wasp species is rare in Orchidaceae except in species with sexually deceptive flowers that are pollinated exclusively by male insects. The object of this study was to document pollination of the food-deceptive flowers of Coelogyne fimbriata, a species pollinated exclusively by female wasps. Methods Field observations and experiments were conducted in two populations of C. fimbriata. Floral phenology was recorded, and functional floral architecture was measured. Insect visitors to flowers were observed from 2005 to 2007. Bioassay experiments were conducted to check whether the floral odour attracted pollinators. Natural (insect-mediated) rates of pollinarium removal, pollinium deposition on stigmas, and fruit set were recorded. To determine the importance of cross-pollination, the breeding system was assessed via controlled, hand-pollination experiments. Key Results Two populations of C. fimbriata with fragrant, nectarless flowers are pollinated by females of the same Vespula species (Vespidae, Hymenoptera). Experiments on wasps show that they crawl towards the source of the odour. The flowering period appears to coincide with an annual peak in Vespula colony expansion when additional workers forage for carbohydrates. Rates of pollinarium removal (0·069–0·918) and pollinium deposition on stigmas (0·025–0·695) are extremely variable. However, fruit set in C. fimbriata is always low (0·014–0·069) and appears to be based on self-incompatibility coupled with intraclonal (geitonogamous) deposition of pollinia. Conclusions Coelogyne fimbriata and Steveniella satyrioides are now the only orchid species known to have food-deceptive flowers that are pollinated exclusively by eusocial, worker wasps. In C. fimbriata, floral odour appears to be the major attractant. Sub-populations may go through flowering seasons when pollinators are abundant or infrequent, but fruit set always remains low because the obligate pollinator does not often appear to transfer pollinaria between intercompatible genets. PMID:19218578

Self-pollination rate and floral-display size in Asclepias syriaca (Common Milkweed) with regard to floral-visitor taxa.

PubMed

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.

The city as a refuge for insect pollinators.

PubMed

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.

Pollen limitation of reproductive effort in willows.

PubMed

Fox, John F

1992-05-01

Pollen limitation of seed set differs from resource limitation in its implications for the evolution of floral traits. Willow flowers attract insects, but also abundantly produce wind-dispersed pollen. I demonstrated pollen limitation in single branches bearing 2-4 inflorescences (catkins) in a field experiment with five species by artificially increasing or decreasing the pollen load. Because the responses by single branches might be explained by diversion of resources to better-pollinated branches within a plant, a second experiment with one species tested both pollen limitation of whole plants and the autonomy of catkins. Seed set of single willow catkins is unaffected by experimental alterations of seed set in other catkins on the same plant. Hand-pollination of single catkins and of whole plants increased seed set to the same degree, suggesting there is little or no competition for resources between catkins only 5-10 cm apart. Thus, seed set in willows appears to be pollen limited, favoring insect pollination and the evolution of entomophilous traits. The data support previous views that willows have a dual pollination system utilizing wind and insects.

Pollinator diversity and reproductive success of Epipactis helleborine (L.) Crantz (Orchidaceae) in anthropogenic and natural habitats

PubMed Central

Jaskuła, Radomir; Rewicz, Tomasz; Tończyk, Grzegorz

2017-01-01

Background Epipactis helleborine is an Eurasian orchid species which prefers woodland environments but it may also spontaneously and successfully colonise human-made artificial and disturbed habitats such as roadsides, town parks and gardens. It is suggested that orchids colonising anthropogenic habitats are characterised by a specific set of features (e.g., large plant size, fast flower production). However, as it is not well known how pollinator diversity and reproductive success of E. helleborine differs in populations in anthropogenic habitats compared to populations from natural habitats, we wanted to compare pollinator diversity and reproductive success of this orchid species between natural and anthropogenic habitat types. Methods Pollination biology, reproductive success and autogamy in populations of E. helleborine from anthropogenic (roadside) and natural (forest) habitats were compared. Eight populations (four natural and four human-disturbed ones) in two seasons were studied according to height of plants, length of inflorescences, as well as numbers of juvenile shoots, flowering shoots, flowers, and fruits. The number and diversity of insect pollinators were studied in one natural and two human-disturbed populations. Results Reproductive success (the ratio of the number of flowers to the number of fruits) in the populations from anthropogenic habitats was significantly higher than in the natural habitats. Moreover, plants from anthropogenic habitats were larger than those from natural ones. In both types of populations, the main insect pollinators were Syrphidae, Culicidae, Vespidae, Apidae and Formicidae. With respect to the type of pollinators’ mouth-parts, chewing (39%), sponging (34%) and chewing-sucking (20%) pollinators prevailed in anthropogenic habitats. In natural habitats, pollinators with sponging (55%) and chewing mouth-parts (32%) dominated, while chewing-sucking and piercing-sucking insects accounted for 9% and 4% respectively. Discussion We suggest that higher reproductive success of E. helleborine in the populations from anthropogenic habitats than in the populations from natural habitats may result from a higher number of visits by pollinators and their greater species diversity, but also from the larger size of plants growing in such habitats. Moreover, our data clearly show that E. helleborine is an opportunistic species with respect to pollinators, with a wide spectrum of pollinating insects. Summarising, E. helleborine is a rare example of orchid species whose current range is not declining. Its ability to make use of anthropogenically altered habitats has allowed its significant spatial range expansion, and even successful colonisation of North America. PMID:28439457

Phylogenetic and functional signals in gymnosperm ovular secretions.

PubMed

Nepi, Massimo; Little, Stefan; Guarnieri, Massimo; Nocentini, Daniele; Prior, Natalie; Gill, Julia; Barry Tomlinson, P; Ickert-Bond, Stefanie M; Pirone, Cary; Pacini, Ettore; von Aderkas, Patrick

2017-11-28

Gymnosperms are either wind-pollinated (anemophilous) or both wind- and insect-pollinated (ambophilous). Regardless of pollination mode, ovular secretions play a key role in pollen capture, germination and growth; they are likely also involved in pollinator reward. Little is known about the broad-scale diversity of ovular secretions across gymnosperms, and how these may relate to various reproductive functions. This study analyses the sugar and amino acid profiles of ovular secretions across a range of ambophilous (cycads and Gnetales) and anemophilous gymnosperms (conifers) to place them in an evolutionary context of their possible functions during reproduction. Ovular secretions from 13 species representing all five main lineages of extant gymnosperms were sampled. High-performance liquid chromatography techniques were used to measure sugar and amino acid content. Multivariate statistics were applied to assess whether there are significant differences in the chemical profiles of anemophilous and ambophilous species. Data were compared with published chemical profiles of angiosperm nectar. Chemical profiles were placed in the context of phylogenetic relationships. Total sugar concentrations were significantly higher in ovular secretions of ambophilous species than wind-pollinated taxa such as Pinaceae and Cupressophyta. Ambophilous species had lower amounts of total amino acids, and a higher proportion of non-protein amino acids compared with anemophilous lineages, and were also comparable to angiosperm nectar. Results suggest that early gymnosperms likely had ovular secretion profiles that were a mosaic of those associated with modern anemophilous and ambophilous species. Ginkgo, thought to be anemophilous, had a profile typical of ambophilous taxa, suggesting that insect pollination either exists in Gingko, but is undocumented, or that its ancestral populations were insect-pollinated. Chemical profiles of ovular secretions of ambophilous gymnosperms show a clear signal of pollinator-driven selection, including higher levels of carbohydrates than anemophilous taxa, lower levels of amino acids, and the presence of specific amino acids, such as β-alanine, that are known to influence insect feeding behaviour and physiology. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please email: journals.permissions@oup.com

Pollination ecology of Silene acutifolia (Caryophyllaceae): floral traits variation and pollinator attraction.

PubMed

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.

Floral biology, breeding system and pollination ecology of an endangered tree Tetracentron sinense Oliv. (Trochodendraceae).

PubMed

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.

A deceptive pollination system targeting drosophilids through olfactory mimicry of yeast.

PubMed

Stökl, Johannes; Strutz, Antonia; Dafni, Amots; Svatos, Ales; Doubsky, Jan; Knaden, Markus; Sachse, Silke; Hansson, Bill S; Stensmyr, Marcus C

2010-10-26

In deceptive pollination, insects are bamboozled into performing nonrewarded pollination. A prerequisite for the evolutionary stability in such systems is that the plants manage to generate a perfect sensory impression of a desirable object in the insect nervous system [1]. The study of these plants can provide important insights into sensory preference of their visiting insects. Here, we present the first description of a deceptive pollination system that specifically targets drosophilid flies. We show that the examined plant (Arum palaestinum) accomplishes its deception through olfactory mimicry of fermentation, a strategy that represents a novel pollination syndrome. The lily odor is composed of volatiles characteristic of yeast, and produces in Drosophila melanogaster an antennal detection pattern similar to that elicited by a range of fermentation products. By functional imaging, we show that the lily odors target a specific subset of odorant receptors (ORs), which include the most conserved OR genes in the drosophilid olfactome. Furthermore, seven of eight visiting drosophilid species show a congruent olfactory response pattern to the lily, in spite of comprising species pairs separated by ∼40 million years [2], showing that the lily targets a basal function of the fly nose, shared by species with similar ecological preference. Copyright © 2010 Elsevier Ltd. All rights reserved.

Pollen loads and specificity of native pollinators of lowbush blueberry.

PubMed

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.

Floral scent contributes to interaction specificity in coevolving plants and their insect pollinators.

PubMed

Friberg, Magne; Schwind, Christopher; Roark, Lindsey C; Raguso, Robert A; Thompson, John N

2014-09-01

Chemical defenses, repellents, and attractants are important shapers of species interactions. Chemical attractants could contribute to the divergence of coevolving plant-insect interactions, if pollinators are especially responsive to signals from the local plant species. We experimentally investigated patterns of daily floral scent production in three Lithophragma species (Saxifragaceae) that are geographically isolated and tested how scent divergence affects attraction of their major pollinator-the floral parasitic moth Greya politella (Prodoxidae). These moths oviposit through the corolla while simultaneously pollinating the flower with pollen adhering to the abdomen. The complex and species-specific floral scent profiles were emitted in higher amounts during the day, when these day-flying moths are active. There was minimal divergence found in petal color, which is another potential floral attractant. Female moths responded most strongly to scent from their local host species in olfactometer bioassays, and were more likely to oviposit in, and thereby pollinate, their local host species in no-choice trials. The results suggest that floral scent is an important attractant in this interaction. Local specialization in the pollinator response to a highly specific plant chemistry, thus, has the potential to contribute importantly to patterns of interaction specificity among coevolving plants and highly specialized pollinators.

Fruit production in cranberry (Ericaceae: Vaccinium macrocarpon): a bet-hedging strategy to optimize reproductive effort.

PubMed

Brown, Adam O; McNeil, Jeremy N

2006-06-01

In the cultivated cranberry (Vaccinium macrocarpon), reproductive stems produce 1-3 fruit even though they usually have 5-7 flowers in the spring. We undertook experiments to test the hypothesis that this was an adaptive life history strategy associated with reproductive effort rather than simply the result of insufficient pollination. We compared fruit production on naturally pollinated plants with those that were either manually pollinated or that were caged to exclude insects. Clearly, insects are necessary for the effective pollination of cranberry plants, but hand pollination of all flowers did not result in an increase in fruit number. Most of the upper flowers, which had significantly fewer ovules than did the lower flowers, aborted naturally soon after pollination. However, when the lower flower buds were removed, the upper flowers produced fruit. This suggests that the upper flowers may serve as a backup if the earlier blooming lower ones are lost early in the season. Furthermore, the late-blooming flowers may still contribute to the plant's reproductive success as visiting pollinators remove the pollen, which could serve to sire fruit on other plants. These results are discussed in the context of their possible evolutionary and proximate causes.

Contribution of Pollinators to Seed Production as Revealed by Differential Pollinator Exclusion in Clerodendrum trichotomum (Lamiaceae)

PubMed Central

Sakamoto, Ryota L.; Ito, Motomi; Kawakubo, Nobumitsu

2012-01-01

A diverse assemblage of pollinators, such as bees, beetles, flies, and butterflies, will often visit a single plant species. However, evaluating the effect of several insects on fruit and seed production is difficult in plants visited by a variety of insects. Here, we analyzed the effect of three types of pollinators, Papilio spp., Macroglossum pyrrhosticta, and Xylocopa appendiculata on fruit and seed production in Clerodendrum trichotomum by using a flower visitor barrier experiment with nets of specific mesh sizes. As a result, fruit/flower and seed/ovule ratios were significantly lower under Papilio exclusion than under natural conditions. On the other hand, ratios were not significantly different between Papilio excluded and both Papilio and M. pyrrhosticta excluded treatments. Therefore, Papilio and X. appendiculata are effective pollinators, whereas M. pyrrhosticta, which was the most frequent visitor, of C. trichotomum, is not. From our observations of visiting behaviors, we believe that because M. pyrrhosticta probably promotes self- pollination, this species is a non-effective pollinator. This is the first study to separate and compare the contribution of various visitors to the reproductive success of a plant. PMID:22442724

Crop pollination exposes honey bees to pesticides which alters their susceptibility to the gut pathogen Nosema ceranae

USDA-ARS?s Scientific Manuscript database

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large number...

Pollinator shifts drive petal epidermal evolution on the Macaronesian Islands bird-flowered species.

PubMed

Ojeda, Dario I; Valido, Alfredo; Fernández de Castro, Alejandro G; Ortega-Olivencia, Ana; Fuertes-Aguilar, Javier; Carvalho, José A; Santos-Guerra, Arnoldo

2016-04-01

Pollinator shifts are considered to drive floral trait evolution, yet little is still known about the modifications of petal epidermal surface at a biogeographic region scale. Here we investigated how independent shifts from insects to passerine birds in the Macaronesian Islands consistently modified this floral trait (i.e. absence of papillate cells). Using current phylogenies and extensive evidence from field observations, we selected a total of 81 plant species and subspecies for petal microscopy and comparative analysis, including 19 of the 23 insular species pollinated by opportunistic passerine birds (Macaronesian bird-flowered element). Species relying on passerine birds as the most effective pollinators (bird-pollinated) independently evolved at least five times and in all instances associated with a loss of papillate cells, whereas species with a mixed pollination system (birds plus insects and/or other vertebrates) evolved at least five times in Macaronesia and papillate cells were lost in only 25% of these transitions. Our findings suggest that petal micromorphology is a labile trait during pollinator shifts and that papillate cells tend to be absent on those species where pollinators have limited mechanical interaction with flowers, including opportunistic passerine birds that forage by hovering or from the ground. © 2016 The Author(s).

UV induced visual cues in grasses

PubMed Central

Baby, Sabulal; Johnson, Anil John; Govindan, Balaji; Lukose, Sujith; Gopakumar, Bhaskaran; Koshy, Konnath Chacko

2013-01-01

Grasses are traditionally considered as wind pollinated, however, field observations confirmed frequent insect visits to grass flowers, suggesting insect pollination. Fruit and seed predators inflict heavy losses to cereals and millets during their growth, maturation and storage. The actual factors guiding insects and predators to grass flowers, fruits and seeds are not clear. Here, we report attractive blue fluorescence emissions on grass floral parts such as glumes, lemma, palea, lodicules, staminal filaments, pollens and fruits in ultraviolet (UV) 366 nm, whereas the stigmatic portions were not blue, but red fluorescent. We characterized the blue fluorescent constituent in grass reproductive structures as ferulic acid (FA). Fluorescence spectra of blue-emitting grass floral, seed extracts and isolated FA on excitation at 366 nm showed their emissions at 420–460 nm. We propose these FA-based blue fluorescence emissions in grass reproductive structures as visual cues that attract pollinators, predators and even pests towards them. PMID:24061408

The Biosynthesis of Unusual Floral Volatiles and Blends Involved in Orchid Pollination by Deception: Current Progress and Future Prospects.

PubMed

Wong, Darren C J; Pichersky, Eran; Peakall, Rod

2017-01-01

Flowers have evolved diverse strategies to attract animal pollinators, with visual and olfactory floral cues often crucial for pollinator attraction. While most plants provide reward (e.g., nectar, pollen) in return for the service of pollination, 1000s of plant species, particularly in the orchid family, offer no apparent reward. Instead, they exploit their often specific pollinators (one or few) by mimicking signals of female insects, food source, and oviposition sites, among others. A full understanding of how these deceptive pollination strategies evolve and persist remains an open question. Nonetheless, there is growing evidence that unique blends that often contain unusual compounds in floral volatile constituents are often employed to secure pollination by deception. Thus, the ability of plants to rapidly evolve new pathways for synthesizing floral volatiles may hold the key to the widespread evolution of deceptive pollination. Yet, until now the biosynthesis of these volatile compounds has been largely neglected. While elucidating the biosynthesis in non-model systems is challenging, nonetheless, these cases may also offer untapped potential for biosynthetic breakthroughs given that some of the compounds can be exclusive or dominant components of the floral scent and production is often tissue-specific. In this perspective article, we first highlight the chemical diversity underpinning some of the more widespread deceptive orchid pollination strategies. Next, we explore the potential metabolic pathways and biosynthetic steps that might be involved. Finally, we offer recommendations to accelerate the discovery of the biochemical pathways in these challenging but intriguing systems.

The Biosynthesis of Unusual Floral Volatiles and Blends Involved in Orchid Pollination by Deception: Current Progress and Future Prospects

PubMed Central

Wong, Darren C. J.; Pichersky, Eran; Peakall, Rod

2017-01-01

Flowers have evolved diverse strategies to attract animal pollinators, with visual and olfactory floral cues often crucial for pollinator attraction. While most plants provide reward (e.g., nectar, pollen) in return for the service of pollination, 1000s of plant species, particularly in the orchid family, offer no apparent reward. Instead, they exploit their often specific pollinators (one or few) by mimicking signals of female insects, food source, and oviposition sites, among others. A full understanding of how these deceptive pollination strategies evolve and persist remains an open question. Nonetheless, there is growing evidence that unique blends that often contain unusual compounds in floral volatile constituents are often employed to secure pollination by deception. Thus, the ability of plants to rapidly evolve new pathways for synthesizing floral volatiles may hold the key to the widespread evolution of deceptive pollination. Yet, until now the biosynthesis of these volatile compounds has been largely neglected. While elucidating the biosynthesis in non-model systems is challenging, nonetheless, these cases may also offer untapped potential for biosynthetic breakthroughs given that some of the compounds can be exclusive or dominant components of the floral scent and production is often tissue-specific. In this perspective article, we first highlight the chemical diversity underpinning some of the more widespread deceptive orchid pollination strategies. Next, we explore the potential metabolic pathways and biosynthetic steps that might be involved. Finally, we offer recommendations to accelerate the discovery of the biochemical pathways in these challenging but intriguing systems. PMID:29181016

Pollination of Schisandra henryi (Schisandraceae) by Female, Pollen-eating Megommata Species (Cecidomyiidae, Diptera) in South-central China

PubMed Central

Yuan, Liang-Chen; Luo, Yi-Bo; Thien, Leonard B.; Fan, Jian-Hua; Xu, Huan-Li; Chen, Zhi-Duan

2007-01-01

Background and Aims The mutualistic interaction between insects and flowers is considered to be a major factor in the early evolution of flowering plants. The Schisandraceae were, until now, the only family in the ANITA group lacking information on pollination biology in natural ecosystems. Thus, the objective of this research was to document the pollination biology and breeding system of Schisandra henryi. Methods Field observations were conducted in three populations of S. henryi and the floral phenology, floral characters and insect activities were recorded. Floral fragrances were sampled in the field and analysed using TCT-GC-MS. Floral thermogenesis was measured with a TR-71U Thermo Recorder. Pollen loads and location of pollen grains on insect bodies (including the gut) were checked with a scanning electron microscope and under a light microscope. Key Results Schisandra henryi is strictly dioecious. Male flowers are similar to female flowers in colour, shape, and size, but more abundant than female flowers. The distance between tepals and the androecium or gynoecium is narrow. Neither male nor female flowers are fragrant or thermogenic. Schisandra henryi is pollinated only by adult female Megommata sp. (Cecidomyiidae, Diptera) that eat the pollen grains as extra nutrition for ovary maturation and ovipositing. Both male and female flowers attract the pollinators using similar visual cues and thus the female flowers use deceit as they offer no food. Conclusions Schisandra henryi exhibits a specialized pollination system, which differs from the generalized pollination system documented in other ANITA members. Pollen is the sole food resource for Megommata sp. and the female flowers of S. henryi attract pollinators by deceit. This is the first report of predacious gall midges utilizing pollen grains as a food source. The lack of floral thermogenesis and floral odours further enforces the visual cues by reducing attractants for other potential pollinators. PMID:17237212

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.

Possible mechanisms of pollination failure in hybrid carrot seed and implications for industry in a changing climate.

PubMed

Broussard, Melissa Ann; Mas, Flore; Howlett, Brad; Pattemore, David; Tylianakis, Jason M

2017-01-01

Approximately one-third of our food globally comes from insect-pollinated crops. The dependence on pollinators has been linked to yield instability, which could potentially become worse in a changing climate. Insect-pollinated crops produced via hybrid breeding (20% of fruit and vegetable production globally) are especially at risk as they are even more reliant on pollinators than open-pollinated plants. We already observe a wide range of fruit and seed yields between different cultivars of the same crop species, and it is unknown how existing variation will be affected in a changing climate. In this study, we examined how three hybrid carrot varieties with differential performance in the field responded to three temperature regimes (cooler than the historical average, average, and warmer that the historical average). We tested how temperature affected the plants' ability to set seed (seed set, pollen viability) as well as attract pollinators (nectar composition, floral volatiles). We found that there were significant intrinsic differences in nectar phenolics, pollen viability, and seed set between the carrot varieties, and that higher temperatures did not exaggerate those differences. However, elevated temperature did negatively affect several characteristics relating to the attraction and reward of pollinators (lower volatile production and higher nectar sugar concentration) across all varieties, which may decrease the attractiveness of this already pollinator-limited crop. Given existing predictions of lower pollinator populations in a warmer climate, reduced attractiveness would add yet another challenge to future food production.

Possible mechanisms of pollination failure in hybrid carrot seed and implications for industry in a changing climate

PubMed Central

Mas, Flore; Howlett, Brad; Pattemore, David; Tylianakis, Jason M.

2017-01-01

Approximately one-third of our food globally comes from insect-pollinated crops. The dependence on pollinators has been linked to yield instability, which could potentially become worse in a changing climate. Insect-pollinated crops produced via hybrid breeding (20% of fruit and vegetable production globally) are especially at risk as they are even more reliant on pollinators than open-pollinated plants. We already observe a wide range of fruit and seed yields between different cultivars of the same crop species, and it is unknown how existing variation will be affected in a changing climate. In this study, we examined how three hybrid carrot varieties with differential performance in the field responded to three temperature regimes (cooler than the historical average, average, and warmer that the historical average). We tested how temperature affected the plants' ability to set seed (seed set, pollen viability) as well as attract pollinators (nectar composition, floral volatiles). We found that there were significant intrinsic differences in nectar phenolics, pollen viability, and seed set between the carrot varieties, and that higher temperatures did not exaggerate those differences. However, elevated temperature did negatively affect several characteristics relating to the attraction and reward of pollinators (lower volatile production and higher nectar sugar concentration) across all varieties, which may decrease the attractiveness of this already pollinator-limited crop. Given existing predictions of lower pollinator populations in a warmer climate, reduced attractiveness would add yet another challenge to future food production. PMID:28665949

Bumble bee (Hymenoptera: Apidae) community structure on two sagebrush steppe sites in southern Idaho

Treesearch

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...

Silene latifolia temporal patterns of volatile induction and suppression after floral interaction by the nursery pollinator, Hadena bicruris (Lepidoptera: Noctuidae)

USDA-ARS?s Scientific Manuscript database

1. Plant VOC emission can be induced or suppressed after herbivory, oviposition, or pollination, which may influence other trophic levels. Sometimes, a single insect species has multiple roles when interacting with a plant, e.g. as pollinator and herbivore. 2. Two experiments tested whether 14 selec...

Molecular mechanisms of floral mimicry in orchids.

PubMed

Schlüter, Philipp M; Schiestl, Florian P

2008-05-01

Deceptive plants do not produce floral rewards, but attract pollinators by mimicking signals of other organisms, such as food plants or female insects. Such floral mimicry is particularly common in orchids, in which flower morphology, coloration and odour play key roles in deceiving pollinators. A better understanding of the molecular bases for these traits should provide new insights into the occurrence, mechanisms and evolutionary consequences of floral mimicry. It should also reveal the molecular bases of pollinator-attracting signals, in addition to providing strategies for manipulating insect behaviour in general. Here, we review data on the molecular bases for traits involved in floral mimicry, and we describe methodological advances helpful for the functional evaluation of key genes.

Flower-visiting behavior of male bees is triggered by nectar-feeding insects.

PubMed

Sugiura, Shinji; Abe, Tetsuto; Yamaura, Yuichi; Makino, Shun'ichi

2007-08-01

Bees are important pollinators for many flowering plants. Female bees are thought to be more effective pollinators than male bees because they carry much more pollen than males. Males of some solitary bee species are known to patrol near flowers that females visit. Because patrolling males visit flowers to mate or defend their territories, they may function as pollinators. However, the significance of patrolling males to pollination has not been studied. We studied males of a solitary bee, Heriades fulvohispidus (Megachilidae), patrolling near flowers and visiting flowers that attracted nectar-feeding insects, including conspecifics, on the Ogasawara (Bonin) Islands. To test the hypothesis that patrolling male bees may function as pollen vectors, we compared the frequency of visits by H. fulvohispidus to flowers of an endemic plant, Schima mertensiana (Theaceae); comparisons were made among flowers with a dead H. fulvohispidus, a dead beetle, a piece of plastic, and nothing (control flowers). Patrolling H. fulvohispidus more frequently visited flowers with a dead conspecific, a dead beetle, or a piece of plastic than the control flowers. Our experiment demonstrates that nectar-feeding insects (including conspecifics and other insects) enhance the flower-visiting frequency of patrolling H. fulvohispidus males on S. mertensiana flowers. Furthermore, we observed S. mertensiana pollen on patrolling males as well as females, suggesting that male bees may also function as pollen vectors.

Flower-visiting behavior of male bees is triggered by nectar-feeding insects

NASA Astrophysics Data System (ADS)

Sugiura, Shinji; Abe, Tetsuto; Yamaura, Yuichi; Makino, Shun'ichi

2007-08-01

Bees are important pollinators for many flowering plants. Female bees are thought to be more effective pollinators than male bees because they carry much more pollen than males. Males of some solitary bee species are known to patrol near flowers that females visit. Because patrolling males visit flowers to mate or defend their territories, they may function as pollinators. However, the significance of patrolling males to pollination has not been studied. We studied males of a solitary bee, Heriades fulvohispidus (Megachilidae), patrolling near flowers and visiting flowers that attracted nectar-feeding insects, including conspecifics, on the Ogasawara (Bonin) Islands. To test the hypothesis that patrolling male bees may function as pollen vectors, we compared the frequency of visits by H. fulvohispidus to flowers of an endemic plant, Schima mertensiana (Theaceae); comparisons were made among flowers with a dead H. fulvohispidus, a dead beetle, a piece of plastic, and nothing (control flowers). Patrolling H. fulvohispidus more frequently visited flowers with a dead conspecific, a dead beetle, or a piece of plastic than the control flowers. Our experiment demonstrates that nectar-feeding insects (including conspecifics and other insects) enhance the flower-visiting frequency of patrolling H. fulvohispidus males on S. mertensiana flowers. Furthermore, we observed S. mertensiana pollen on patrolling males as well as females, suggesting that male bees may also function as pollen vectors.

Changes in the Relative Abundance and Movement of Insect Pollinators During the Flowering Cycle of Brassica rapa Crops: Implications for Gene Flow

PubMed Central

Mesa, Laura A.; Howlett, Bradley G.; Grant, Jan E.; Didham, Raphael K.

2013-01-01

The potential movement of transgenes from genetically modified crops to non-genetically modified crops via insect-mediated pollen dispersal has been highlighted as one of the areas of greatest concern in regards to genetically modified crops. Pollen movement depends sensitively on spatial and temporal variation in the movement of insect pollinators between crop fields. This study tested the degree of variation in the diversity and relative abundance of flower-visiting insects entering versus leaving pak choi, Brassica rapa var. chinensis L. (Brassicales: Brassicaceae), crops throughout different stages of the flowering cycle. The relative abundance of flower-visiting insects varied significantly with Brassica crop phenology. Greater numbers of flower-visiting insects were captured inside rather than outside the crop fields, with the highest capture rates of flower-visitors coinciding with the peak of flowering in both spring-flowering and summer-flowering crops. Moreover, the ratio of flower-visiting insects entering versus leaving crop fields also varied considerably with changing crop phenology. Despite high variation in relative capture rates, the data strongly indicate non-random patterns of variation in insect movement in relation to crop phenology, with early-season aggregation of flower-visiting insects entering and remaining in the crop, and then mass emigration of flower-visiting insects leaving the crop late in the flowering season. Although pollen movement late in the flowering cycle might contribute relatively little to total seed set (and hence crop production), the findings here suggest that extensive late-season pollinator redistribution in the landscape could contribute disproportionately to long-distance gene movement between crops. PMID:23937538

Pest Control and Pollination Cost-Benefit Analysis of Hedgerow Restoration in a Simplified Agricultural Landscape.

PubMed

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.

A novel method for assessing risks to pollinators from plant protection products using honeybees as a model species.

PubMed

Barmaz, Stefania; Potts, Simon G; Vighi, Marco

2010-10-01

Pollination is one of the most important ecosystem services in agroecosystems and supports food production. Pollinators are potentially at risk being exposed to pesticides and the main route of exposure is direct contact, in some cases ingestion, of contaminated materials such as pollen, nectar, flowers and foliage. To date there are no suitable methods for predicting pesticide exposure for pollinators, therefore official procedures to assess pesticide risk are based on a Hazard Quotient. Here we develop a procedure to assess exposure and risk for pollinators based on the foraging behaviour of honeybees (Apis mellifera) and using this species as indicator representative of pollinating insects. The method was applied in 13 European field sites with different climatic, landscape and land use characteristics. The level of risk during the crop growing season was evaluated as a function of the active ingredients used and application regime. Risk levels were primarily determined by the agronomic practices employed (i.e. crop type, pest control method, pesticide use), and there was a clear temporal partitioning of risks through time. Generally the risk was higher in sites cultivated with permanent crops, such as vineyard and olive, than in annual crops, such as cereals and oil seed rape. The greatest level of risk is generally found at the beginning of the growing season for annual crops and later in June-July for permanent crops.

Floral polymorphism and the fitness implications of attracting pollinating and florivorous insects.

PubMed

de Jager, Marinus L; Ellis, Allan G

2014-01-01

Floral polymorphism is frequently attributed to pollinator-mediated selection. Multiple studies, however, have revealed the importance of non-pollinating visitors in floral evolution. Using the polymorphic annual daisy Ursinia calenduliflora, this study investigated the importance of different insect visitors, and their effects on fitness, in the maintenance of floral polymorphism. The spatial structure of a discrete floral polymorphism was characterized based on the presence/absence of anthocyanin floret spots in U. calenduliflora. A 3-year observational study was then conducted in polymorphic populations to investigate differences in visitation rates of dominant visitors to floral morphs. Experiments were performed to explore the floral preference of male and female Megapalpus capensis (the dominant insect visitor) and their effectiveness as pollinators. Next, floral damage by antagonistic florivores and the reproductive success of the two floral morphs were surveyed in multiple populations and years. Floral polymorphism in U. calenduliflora was structured spatially, as were insect visitation patterns. Megapalpus capensis males were the dominant visitors and exhibited strong preference for the spotted morph in natural and experimental observations. While this may indicate potential fitness benefits for the spotted morph, female fitness did not differ between floral morphs. However, as M. capensis males are very efficient at exporting U. calenduliflora pollen, their preference may likely increase the reproductive fitness of the spotted morph through male fitness components. The spotted morph, however, also suffered significantly greater costs due to ovule predation by florivores than the spotless morph. The results suggest that pollinators and florivores may potentially exert antagonistic selection that could contribute to the maintenance of floral polymorphism across the range of U. calenduliflora. The relative strength of selection imposed by each agent is potentially determined by insect community composition and abundance at each site, highlighting the importance of community context in the evolution of floral phenotypes.

Particles and Prairies

Science.gov Websites

Century Ecology Biotics Plants Animals Mammals Birds Amphib/Reptiles Insects Abiotics Soil 1 Water Sun Wind Seed Dispersal Pollination Fire Research Bird Research Soil Research Insect Research Prairie

Shades of red: bird-pollinated flowers target the specific colour discrimination abilities of avian vision.

PubMed

Shrestha, Mani; Dyer, Adrian G; Boyd-Gerny, Skye; Wong, Bob B M; Burd, Martin

2013-04-01

Colour signals are a major cue in putative pollination syndromes. There is evidence that the reflectance spectra of many flowers target the distinctive visual discrimination abilities of hymenopteran insects, but far less is known about bird-pollinated flowers. Birds are hypothesized to exert different selective pressures on floral colour compared with hymenopterans because of differences in their visual systems. We measured the floral reflectance spectra of 206 Australian angiosperm species whose floral visitors are known from direct observation rather than inferred from floral characteristics. We quantified the match between these spectra and the hue discrimination abilities of hymenopteran and avian vision, and analysed these metrics in a phylogenetically informed comparison of flowers in different pollination groups. We show that bird-visited flowers and insect-visited flowers differ significantly from each other in the chromatic cues they provide, and that the differences are concentrated near wavelengths of optimal colour discrimination by whichever class of pollinator visits the flowers. Our results indicate that angiosperms have evolved the spectral signals most likely to reinforce their pollinators' floral constancy (the tendency of individual pollinators to visit flowers of the same species) in communities of similarly coloured floral competitors. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

A reassessment of the function of floral nectar in Croton suberosus (Euphorbiaceae): A reward for plant defenders and pollinators.

PubMed

Narbona, Eduardo; Dirzo, Rodolfo

2010-04-01

Typically, plant-pollinator interactions are recognized as mutualistic relationships. Flower visitors, however, can potentially play multiple roles. The floral nectar in Croton suberosus has been proposed to operate as a reward for predators, especially the wasp Polistes instabilis (Vespidae), which kills herbivorous insects, while the plant has been thought to be mainly wind-pollinated. In this study, we reassessed the pollination mode of C. suberosus and the possible role of its flower visitors. Pollinator exclusion experiments demonstrated that C. suberosus should be considered a strictly entomophilous species. Inflorescences of C. suberosus were visited by a diverse entomofauna involving 28 taxa belonging to six orders; however, wasps and bees were the only visitors that carried C. suberosus pollen. The visitation rate of wasps was approximately four times that of bees. This observation, combined with the fact that the small size of bees makes effective contact of their bodies with the stigma difficult, strongly suggests that large wasps are responsible for most of the effective pollination of C. suberosus. Among the wasp visitors, P. instabilis seems to be one of the most important. These findings expose an unusual plant-insect interaction, in which the plant provides nectar and wasps pollinate and defend the plant.

Insights into the structure of plant-insect communities: Specialism and generalism in a regional set of non-pollinating fig wasp communities

NASA Astrophysics Data System (ADS)

Farache, F. H. A.; Cruaud, A.; Rasplus, J.-Y.; Cerezini, M. T.; Rattis, L.; Kjellberg, F.; Pereira, R. A. S.

2018-07-01

Insects show a multitude of symbiotic interactions that may vary in degree of specialization and structure. Gall-inducing insects and their parasitoids are thought to be relatively specialized organisms, but despite their ecological importance, the organization and structure of the interactions they establish with their hosts has seldom been investigated in tropical communities. Non-pollinating fig wasps (NPFW) are particularly interesting organisms for the study of ecological networks because most species strictly develop their offspring within fig inflorescences, and show a multitude of life history strategies. They can be gall-makers, cleptoparasites or parasitoids of pollinating or of other non-pollinating fig wasps. Here we analysed a set of non-pollinating fig wasp communities associated with six species of Ficus section Americanae over a wide area. This allowed us to investigate patterns of specialization in a diverse community composed of monophagous and polyphagous species. We observed that most NPFW species were cleptoparasites and parasitoids, colonizing figs several days after oviposition by pollinators. Most species that occurred in more than one host were much more abundant in a single preferential host, suggesting specialization. The food web established between wasps and figs shows structural properties that are typical of specific antagonistic relationships, especially of endophagous insect networks. Two species that occurred in all available hosts were highly abundant in the network, suggesting that in some cases generalized species can be more competitive than strict specialists. The Neotropical and, to a lesser extent, Afrotropical NPFW communities seem to be more generalized than other NPFW communities. However, evidence of host sharing in the Old World is quite limited, since most studies have focused on particular taxonomic groups (genera) of wasps instead of sampling the whole NPFW community. Moreover, the lack of quantitative information in previous studies prevents us from detecting patterns of host preferences in polyphagous species.

Distribution of calcium oxalate crystals in floral organs of Araceae in relation to pollination strategy.

PubMed

Coté, Gary G; Gibernau, Marc

2012-07-01

Many flowers are pollinated by potentially hungry insects, yet flowers also contain gametes and embryos which must be protected from predation. Microscopic calcium oxalate crystals in plant tissues have been proposed to protect against herbivory. Aroids, which have an unusual diversity of such crystals, also exhibit diverse pollination strategies. Many species have pollinators that do not feed while visiting the flowers, while other species, especially those pollinated by beetles, offer sterile staminodia as food rewards. We examined flowers of 21 aroid species with various pollination strategies to test the hypothesis that crystals protect vital gametes and embryos while allowing consumption of food bribes. Aroid inflorescences collected from the field or from greenhouse material were sectioned, cleared, and examined by bright field and polarization microscopy. All species examined, regardless of pollination strategy, arrayed crystals around unshed pollen and ovules. Less vital tissues, such as odoriferous appendages, had few crystals. Staminodia offered as food to beetle pollinators, however, differed greatly between species in their crystal contents. Some had minimal crystals; some had crystals in patterns suggesting they limit beetle feeding; still others had abundant crystals in no obvious pattern. The results are consistent with crystals protecting against insect predation of gametes and embryos. However, the role of crystals in food-bribe staminodia is unclear. They may limit and direct feeding by beetles in some species, while in others they might have no protective role.

Diversification through multitrait evolution in a coevolving interaction.

PubMed

Thompson, John N; Schwind, Christopher; Guimarães, Paulo R; Friberg, Magne

2013-07-09

Mutualisms between species are interactions in which reciprocal exploitation results in outcomes that are mutually beneficial. This reciprocal exploitation is evident in the more than a thousand plant species that are pollinated exclusively by insects specialized to lay their eggs in the flowers they pollinate. By pollinating each flower in which she lays eggs, an insect guarantees that her larval offspring have developing seeds on which to feed, whereas the plant gains a specialized pollinator at the cost of some seeds. These mutualisms are often reciprocally obligate, potentially driving not only ongoing coadaptation but also diversification. The lack of known intermediate stages in most of these mutualisms, however, makes it difficult to understand whether these interactions could have begun to diversify even before they became reciprocally obligate. Experimental studies of the incompletely obligate interactions between woodland star (Lithophragma; Saxifragaceae) plants and their pollinating floral parasites in the moth genus Greya (Prodoxidae) show that, as these lineages have diversified, the moths and plants have evolved in ways that maintain effective oviposition and pollination. Experimental assessment of pollination in divergent species and quantitative evaluation of time-lapse photographic sequences of pollination viewed on surgically manipulated flowers show that various combinations of traits are possible for maintaining the mutualism. The results suggest that at least some forms of mutualism can persist and even diversify when the interaction is not reciprocally obligate.

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.

Flowers at the border: Plant native flowers around your yard to attract pollinators and other beneficial insects

Treesearch

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...

Detecting insect pollinator declines on regional and global scales

USGS Publications Warehouse

Lubuhn, Gretchen; Droege, Sam; Connor, Edward F.; Gemmill-Herren, Barbara; Potts, Simon G.; Minckley, Robert L.; Griswold, Terry; Jean, Robert; Kula, Emanuel; Roubik, David W.; Cane, Jim; Wright, Karen W.; Frankie, Gordon; Parker, Frank

2013-01-01

Recently there has been considerable concern about declines in bee communities in agricultural and natural habitats. The value of pollination to agriculture, provided primarily by bees, is >$200 billion/year worldwide, and in natural ecosystems it is thought to be even greater. However, no monitoring program exists to accurately detect declines in abundance of insect pollinators; thus, it is difficult to quantify the status of bee communities or estimate the extent of declines. We used data from 11 multiyear studies of bee communities to devise a program to monitor pollinators at regional, national, or international scales. In these studies, 7 different methods for sampling bees were used and bees were sampled on 3 different continents. We estimated that a monitoring program with 200-250 sampling locations each sampled twice over 5 years would provide sufficient power to detect small (2-5%) annual declines in the number of species and in total abundance and would cost U.S.$2,000,000. To detect declines as small as 1% annually over the same period would require >300 sampling locations. Given the role of pollinators in food security and ecosystem function, we recommend establishment of integrated regional and international monitoring programs to detect changes in pollinator communities.

Tracking the elusive history of diversification in plant-herbivorous insect-parasitoid food webs: insights from figs and fig wasps.

PubMed

Kjellberg, Finn; Proffit, Magali

2016-02-01

The food webs consisting of plants, herbivorous insects and their insect parasitoids are a major component of terrestrial biodiversity. They play a central role in the functioning of all terrestrial ecosystems, and the number of species involved is mind-blowing (Nyman et al. 2015). Nevertheless, our understanding of the evolutionary and ecological determinants of their diversity is still in its infancy. In this issue of Molecular Ecology, Sutton et al. (2016) open a window into the comparative analysis of spatial genetic structuring in a set of comparable multitrophic models, involving highly species-specific interactions: figs and fig wasps. This is the first study to compare genetic structure using population genetics tools in a fig-pollinating wasp (Pleistodontes imperialis sp1) and its main parasitoid (Sycoscapter sp.A). The fig-pollinating wasp has a discontinuous spatial distribution that correlates with genetic differentiation, while the parasitoid bridges the discontinuity by parasitizing other pollinator species on the same host fig tree and presents basically no spatial genetic structure. The full implications of these results for our general understanding of plant-herbivorous insect-insect parasitoids diversification become apparent when envisioned within the framework of recent advances in fig and fig wasp biology. © 2016 John Wiley & Sons Ltd.

Self-pollination rate and floral-display size in Asclepias syriaca (Common Milkweed) with regard to floral-visitor taxa

PubMed Central

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

North American pollinosis due to insect-pollinated plants.

PubMed

Lewis, W H; Vinay, P

1979-05-01

In warmer regions of North America many newly introduced plants are cultivated widely and others are becoming aggresive naturalized weeds. A large number are insect-pollinated and shed considerable quantities of airborne pollen. Levels of allergenicity based on skin test data, numbers of patients having immediate hypersensitivity and localities where airborne pollen grains have been identified are presented for each genus of entomophilous plants considered incitants of pollinosis. Among the most relevant are Acacia, Brassica, Citrus, Ligustrum, Olea and Schinus.

Floral nectar of the obligate outcrossing Canavalia gladiata (Jacq.) DC. (Fabaceae) contains only one predominant protein, a class III acidic chitinase.

PubMed

Ma, X L; Milne, R I; Zhou, H X; Fang, J Y; Zha, H G

2017-09-01

Floral nectar can affect the fitness of insect-pollinated plants, through both attraction and manipulation of pollinators. Self-incompatible insect-pollinated plants receive more insect visits than their self-compatible relatives, and the nectar of such species might face increased risk of infestation by pathogens carried by pollinators than self-compatible plants. Proteins in nectar (nectarins) play an important role in protecting the nectar, but little is known regarding nectarins in self-incompatible species. The nectarins from a self-incompatible and insect-pollinated leguminous crop, Canavalia gladiata, were separated using two-dimensional electrophoresis and analysed using mass spectrometry. The predominant nectarin gene was cloned and the gene expression pattern investigated using quantitative real-time PCR. Chitinolytic activity in the nectar was tested with different substrates. The C. gladiata nectar proteome only has one predominant nectarin, an acidic class III chitinase (CaChi3). The full-length CaChi3 gene was cloned, coding for a protein of 298 amino acids with a predicted signal peptide. CaChi3 is very similar to members of the class III chitinase family, whose evolution is dominated by purifying selection. CaChi3 was expressed in both nectary and leaves. CaChi3 has thermostable chitinolytic activity according to glycol-chitin zymography or a fluorogenic substratem but has no lysozyme activity. Chitinase might be a critical protein component in nectar. The extremely simple nectar proteome in C. gladiata disproves the hypothesis that self-incompatible species always have more complex nectar proteomes. Accessibility of nectar might be a significant determinant of the evolutionary pressure to develop nectar defence mechanisms. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Florally rich habitats reduce insect pollination and the reproductive success of isolated plants.

PubMed

Evans, Tracie M; Cavers, Stephen; Ennos, Richard; Vanbergen, Adam J; Heard, Matthew S

2017-08-01

Landscape heterogeneity in floral communities has the potential to modify pollinator behavior. Pollinator foraging varies with the diversity, abundance, and spatial configuration of floral resources. However, the implications of this variation for pollen transfer and ultimately the reproductive success of insect pollinated plants remains unclear, especially for species which are rare or isolated in the landscape. We used a landscape-scale experiment, coupled with microsatellite genotyping, to explore how the floral richness of habitats affected pollinator behavior and pollination effectiveness. Small arrays of the partially self-compatible plant Californian poppy ( Eschscholzia californica) were introduced across a landscape gradient to simulate rare, spatially isolated populations. The effects on pollinator activity, outcrossing, and plant reproduction were measured. In florally rich habitats, we found reduced pollen movement between plants, leading to fewer long-distance pollination events, lower plant outcrossing, and a higher incidence of pollen limitation. This pattern indicates a potential reduction in per capita pollinator visitation, as suggested by the lower activity densities and richness of pollinators observed within florally rich habitats. In addition, seed production reduced by a factor of 1.8 in plants within florally rich habitats and progeny germination reduced by a factor of 1.2. We show this to be a consequence of self-fertilization within the partially self-compatible plant, E. californica . These findings indicate that locally rare plants are at a competitive disadvantage within florally rich habitats because neighboring plant species disrupt conspecific mating by co-opting pollinators. Ultimately, this Allee effect may play an important role in determining the long-term persistence of rarer plants in the landscape, both in terms of seed production and viability. Community context therefore requires consideration when designing and implementing conservation management for plants which are comparatively rare in the landscape.

Identification of Insect-Plant Pollination Networks for a Midwest Installation: Fort McCoy, WI

DTIC Science & Technology

2016-04-01

L. and Ø. Totland. 2009. How does climate warming affect plant ‐ pollinator interactions ? Ecology Letters 12, 2:184-195. Hilty, J. 2015. Flower... ecology and net- work traits. This method can be used by installations to assess the plant - pollinator communities on their lands and their vulnerability...been explored. For the U.S. Department of Defense (DoD) and the Army, information on plant - pollinator interactions can be critical for a number of

A Study of Insect Pollinators Associated with DoD TER-S Flowering Plants, Including Identification of Habitat Types Where They Co-Occur by Military Installation in the Western United States

DTIC Science & Technology

2010-04-01

environmental stewardship division chiefs can interact with contractors and partner land managers and biologists with plant and pollinator information in hand...1979. Pollination of Southwestern Opuntias. Plant Systematics and Evolution 133: 15-28. Keywords: Opuntia sp. Agapostemon angelicus...Parrish, J.A.D and F.A. Bazzaz. 1979. Difference in pollination niche relationships in early and late successional plant communities. Ecology 60

Neonicotinoid insecticides can serve as inadvertent insect contraceptives

PubMed Central

Villamar-Bouza, Laura; Bruckner, Selina; Chantawannakul, Panuwan; Gauthier, Laurent; Khongphinitbunjong, Kitiphong; Retschnig, Gina; Troxler, Aline; Vidondo, Beatriz; Neumann, Peter; Williams, Geoffrey R.

2016-01-01

There is clear evidence for sublethal effects of neonicotinoid insecticides on non-target ecosystem service-providing insects. However, their possible impact on male insect reproduction is currently unknown, despite the key role of sex. Here, we show that two neonicotinoids (4.5 ppb thiamethoxam and 1.5 ppb clothianidin) significantly reduce the reproductive capacity of male honeybees (drones), Apis mellifera. Drones were obtained from colonies exposed to the neonicotinoid insecticides or controls, and subsequently maintained in laboratory cages until they reached sexual maturity. While no significant effects were observed for male teneral (newly emerged adult) body mass and sperm quantity, the data clearly showed reduced drone lifespan, as well as reduced sperm viability (percentage living versus dead) and living sperm quantity by 39%. Our results demonstrate for the first time that neonicotinoid insecticides can negatively affect male insect reproductive capacity, and provide a possible mechanistic explanation for managed honeybee queen failure and wild insect pollinator decline. The widespread prophylactic use of neonicotinoids may have previously overlooked inadvertent contraceptive effects on non-target insects, thereby limiting conservation efforts. PMID:27466446

Neonicotinoid insecticides can serve as inadvertent insect contraceptives.

PubMed

Straub, Lars; Villamar-Bouza, Laura; Bruckner, Selina; Chantawannakul, Panuwan; Gauthier, Laurent; Khongphinitbunjong, Kitiphong; Retschnig, Gina; Troxler, Aline; Vidondo, Beatriz; Neumann, Peter; Williams, Geoffrey R

2016-07-27

There is clear evidence for sublethal effects of neonicotinoid insecticides on non-target ecosystem service-providing insects. However, their possible impact on male insect reproduction is currently unknown, despite the key role of sex. Here, we show that two neonicotinoids (4.5 ppb thiamethoxam and 1.5 ppb clothianidin) significantly reduce the reproductive capacity of male honeybees (drones), Apis mellifera Drones were obtained from colonies exposed to the neonicotinoid insecticides or controls, and subsequently maintained in laboratory cages until they reached sexual maturity. While no significant effects were observed for male teneral (newly emerged adult) body mass and sperm quantity, the data clearly showed reduced drone lifespan, as well as reduced sperm viability (percentage living versus dead) and living sperm quantity by 39%. Our results demonstrate for the first time that neonicotinoid insecticides can negatively affect male insect reproductive capacity, and provide a possible mechanistic explanation for managed honeybee queen failure and wild insect pollinator decline. The widespread prophylactic use of neonicotinoids may have previously overlooked inadvertent contraceptive effects on non-target insects, thereby limiting conservation efforts. © 2016 The Authors.

Variation in pollen-donor composition among pollinators in an entomophilous tree species, Castanea crenata, revealed by single-pollen genotyping.

PubMed

Hasegawa, Yoichi; Suyama, Yoshihisa; Seiwa, Kenji

2015-01-01

In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect taxa are effective outcross-pollen transporters under field conditions. In this study, we explored roles of foraging behavior of insect pollinators on pollen-donor composition and subsequent reproductive success in a woody plant. We performed paternity analyses based on microsatellite genotyping of individual pollen grains found on diurnal pollinators (i.e., bumblebee, small bee, fly, small beetle, and honeybee) visiting Castanea crenata trees. The outcross-pollen rate was highest in bumblebees (66%), followed by small bees (35%), flies (31%), and small beetles (18%). The effective number of pollen donors, representing pollen carryover, was greater in bumblebees (9.71) than in flies (3.40), small bees (3.32), and small beetles (3.06). The high percentages of pollen from outside the plot on bumblebees (65.4%) and flies (71.2%) compared to small bees (35.3%) and small beetles (13.5%) demonstrated their longer pollen dispersal distances. All of the diurnal insects carried outcross-pollen grains for long distances via pollen carryover. This fact suggests that a wide range of insect taxa are potential outcross-pollen transporters for the self-incompatible C. crenata.

Buzz in Paris: flower production and plant-pollinator interactions in plants from contrasted urban and rural origins.

PubMed

Desaegher, James; Nadot, Sophie; Dajoz, Isabelle; Colas, Bruno

2017-12-01

Urbanisation, associated with habitat fragmentation, affects pollinator communities and insect foraging behaviour. These biotic changes are likely to select for modified traits in insect-pollinated plants from urban populations compared to rural populations. To test this hypothesis, we conducted an experiment involving four plant species commonly found in both urban and rural landscapes of the Île-de-France region (France): Cymbalaria muralis, Geranium robertianum, Geum urbanum and Prunella vulgaris. The four species were grown in four urban and four rural experimental sites in 2015. For each species and each experimental site, plants were grown from seeds collected in five urban and five rural locations. During flowering, we observed flower production and insect-flower interactions during 14 weeks and tested for the effects of experimental site location and plant origin on flower production and on the number of floral visits. The study species had various flower morphology and hence were visited by different floral visitors. The effect of experimental sites and seed origin also varied among study species. We found that (1) insect visits on P. vulgaris were more frequent in rural than in urban sites; (2) for C. muralis, the slope relating the number of pollinator visits to the number of flowers per individual was steeper in urban versus rural sites, suggesting a greater benefit in allocating resources to flower production in urban conditions; (3) as a likely consequence, C. muralis tended to produce more flowers in plants from urban versus rural origin.

Pollination effects on antioxidant content of Perilla frutescens seeds analysed by NMR spectroscopy.

PubMed

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.

Colour mimicry and sexual deception by Tongue orchids (Cryptostylis).

PubMed

Gaskett, A C; Herberstein, M E

2010-01-01

Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic (Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids' single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids' bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects' innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background.

Floral Trait Associations in Hawkmoth-Specialized and Mixed Pollination Systems

USDA-ARS?s Scientific Manuscript database

Variation in floral traits including odor, color and morphology, demonstrate the selective pressures imposed by specific pollinator taxa, such as insects and birds. In southern Arizona, Manduca sexta (Sphingidae) hawkmoths are associated with Datura wrightii (Solanaceae) at both the larval (herbivo...

Evidence for behavioral attractiveness of methoxylated aromatics in a dynastid scarab beetle-pollinated araceae.

PubMed

Dötterl, Stefan; David, Anja; Boland, Wilhelm; Silberbauer-Gottsberger, Ilse; Gottsberger, Gerhard

2012-12-01

Many plants attract their pollinators with floral scents, and these olfactory signals are especially important at night, when visual signals become inefficient. Dynastid scarab beetles are a speciose group of night-active pollinators, and several plants pollinated by these insects have methoxylated aromatic compounds in their scents. However, there is a large gap in our knowledge regarding the compounds responsible for beetle attraction. We used chemical analytical analyses to determine temporal patterns of scent emission and the composition of scent released from inflorescences of Philodendron selloum. The attractiveness of the main components in the scent to the dynastid scarab beetle Erioscelis emarginata, the exclusive pollinator of this plant, was assessed in field biotests. The amount of scent increased rapidly in the evening, and large amounts of scent were released during the activity time of the beetle pollinators. Inflorescences emitted a high number of compounds of different biosynthetic origin, among them both uncommon and also widespread flower scents. Methoxylated aromatic compounds dominated the scent, and 4-methoxystyrene, the most abundant compound, attracted E. emarginata beetles. Other compounds, such as (Z)-jasmone and possibly also the methoxylated aromatic compound 3,4-dimethoxystyrene increased the attractiveness of 4-methoxystyrene. Methoxylated aromatics, which are known from other dynastid pollinated plants as well, are important signals in many scarab beetles in a different context (e.g., pheromones), thus suggesting that these plants exploit pre-existing preferences of the beetles for attracting this group of insects as pollinators.

[Mechanisms that limit pollinator range in Ericaceae].

PubMed

Dlusskiĭ, G M; Glazunova, K P; Perfil'eva, K S

2005-01-01

Studies were conducted in 2001-2003 at Valdai National Park (Novgorod region) and at the Zvenigorod biological station of Moscow State University. The morphology of flowers, flowering dynamics and composition of insect visiting flowers of Ericaceae species: Andromeda polifolia, Chamaedaphne calyculata, Ledum palustre, Oxycoccus palustris, Vaccinium myrtillus, V. uliginosum, and V. vitis-idaea L. were studied. Some species of insects visiting flowers were excluded from the list of pollinators on the basis of observation on their behavior. L. palustre was visited mainly by flies where as other investigated species were visited mainly by bumblebees. In some cases bumblebees were the only visitors of the investigated plants. Mechanisms that protect flowers from flies and short-tongued solitary bees visits and ensure a best pollination by bumblebees are various among different species of Ericaceae. Efficiency of nectary protection also differs among different plant species and is defined by particularities of their habitats and flowering phenology. As far as all species of this family during the flowering are dominants in typical habitats, a competition for the pollination with species of other families in most cases is megligible. Flowering periods of V. vitis-idaea and V. myrtillus in forest ecosystems overlapped weakly. Moreover, V. myrtillus is pollinated mainly by bumblebee queens where as pollinators of V. vitis-idaea are bumblebee workers, solitary bees and horse flies. The other investigated plant species inhabit only oligotrophic peat bogs. Thery are pollinated by bumblebees but periods of flowering are not overlapped and consequently follow one after another. L. palustre and V. uliginosum flower simultaneosly but they are pollinated by different pollinators.

Morphological Complexity as a Floral Signal: From Perception by Insect Pollinators to Co-Evolutionary Implications.

PubMed

Krishna, Shivani; Keasar, Tamar

2018-06-06

Morphologically complex flowers are characterized by bilateral symmetry, tube-like shapes, deep corolla tubes, fused petals, and/or poricidal anthers, all of which constrain the access of insect visitors to floral nectar and pollen rewards. Only a subset of potential pollinators, mainly large bees, learn to successfully forage on such flowers. Thus, complexity may comprise a morphological filter that restricts the range of visitors and thereby increases food intake for successful foragers. Such pollinator specialization, in turn, promotes flower constancy and reduces cross-species pollen transfer, providing fitness benefits to plants with complex flowers. Since visual signals associated with floral morphological complexity are generally honest (i.e., indicate food rewards), pollinators need to perceive and process them. Physiological studies show that bees detect distant flowers through long-wavelength sensitive photoreceptors. Bees effectively perceive complex shapes and learn the positions of contours based on their spatial frequencies. Complex flowers require long handling times by naive visitors, and become highly profitable only for experienced foragers. To explore possible pathways towards the evolution of floral complexity, we discuss cognitive mechanisms that potentially allow insects to persist on complex flowers despite low initial foraging gains, suggest experiments to test these mechanisms, and speculate on their adaptive value.

The potential indirect effects among plants via shared hummingbird pollinators are structured by phenotypic similarity.

PubMed

Bergamo, Pedro Joaquim; Wolowski, Marina; Maruyama, Pietro Kiyoshi; Vizentin-Bugoni, Jeferson; Carvalheiro, Luísa G; Sazima, Marlies

2017-07-01

Plant species within communities may overlap in pollinators' use and influence visitation patterns of shared pollinators, potentially engaging in indirect interactions (e.g., facilitation or competition). While several studies have explored the mechanisms regulating insect-pollination networks, there is a lack of studies on bird-pollination systems, particularly in species-rich tropical areas. Here, we evaluated if phenotypic similarity, resource availability (floral abundance), evolutionary relatedness and flowering phenology affect the potential for indirect effects via shared pollinators in hummingbird-pollinated plant species within four communities in the Brazilian Atlantic forest. Among the evaluated factors, phenotypic similarity (corolla length and anther height) was the most important variable, while resource availability (floral abundance) had a secondary importance. On the other hand, evolutionary relatedness and flowering phenology were less important, which altogether highlights the relevance of convergent evolution and that the contribution of a plant to the diet of the pollinators of another plant is independent of the level of temporal overlap in flowering in this tropical system. Interestingly, our findings contrast with results from multiple insect-pollinated plant communities, mostly from temperate regions, in which floral abundance was the most important driver, followed by evolutionary relatedness and phenotypic similarity. We propose that these contrasting results are due to high level of specialization inherent to tropical hummingbird-pollination systems. Moreover, our results demonstrated that factors defining linkage rules of plant-hummingbird networks also determinate plant-plant potential indirect effects. Future studies are needed to test if these findings can be generalized to other highly specialized systems. Overall, our results have important implications for the understanding of ecological processes due resource sharing in mutualistic systems. © 2017 by the Ecological Society of America.

Pollination of Cypripedium plectrochilum (Orchidaceae) by Lasioglossum spp. (Halictidae): the roles of generalist attractants versus restrictive floral architecture.

PubMed

Li, P; Luo, Y; Bernhardt, P; Kou, Y; Perner, H

2008-03-01

The pollination of Cypripedium plectrochilum Franch. was studied in the Huanglong Nature Reserve, Sichuan, China. Although large bees (Bombus, Apis), small bees (Ceratina, Lasioglossum), ants (Formica sp.), true flies (Diptera) and a butterfly were all found to visit the flowers, only small bees, including three Lasioglossum spp. (L. viridiclaucum, L. sichuanense and L. sp.; Halictidae) and one Ceratina sp., carried the flower's pollen and contacted the receptive stigma. Measurements of floral architecture showed that interior floral dimensions best fit the exterior dimensions of Lasioglossum spp., leading to the consistent deposition and stigmatic reception of dorsally-placed, pollen smears. The floral fragrance was dominated by one ketone, 3-methyl-Decen-2-one. The conversion rate of flowers into capsules in open (insect) pollinated flowers at the site was more than 38%. We conclude that, while pigmentation patterns and floral fragrance attracted a wide variety of insect foragers, canalization of interior floral dimensions ultimately determined the spectrum of potential pollinators in this generalist, food-mimic flower. A review of the literature showed that the specialised mode of pollination-by-deceit in C. plectrochilum, limiting pollinators to a narrow and closely related guild of 'dupes' is typical for other members of this genus.

Enhancing resource availability in agro-ecosystems for beneficial arthropods through floral provisioning

USDA-ARS?s Scientific Manuscript database

There has been a decline in beneficial arthropods (insects and spiders) including pollinators because of habitat destruction and intense management practices. Enhancing landscapes with additional floral and other non-crop habitats has the potential to attract pollinators, and predatory arthropods wh...

Abundance and Diversity of Wild Bees (Hymenoptera: Apoidea) Found in Lowbush Blueberry Growing Regions of Downeast Maine.

PubMed

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.

Use of video surveillance to measure the influences of habitat management and landscape composition on pollinator visitation and pollen deposition in pumpkin (Cucurbita pepo) agroecosystems

PubMed Central

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

Use of video surveillance to measure the influences of habitat management and landscape composition on pollinator visitation and pollen deposition in pumpkin (Cucurbita pepo) agroecosystems.

PubMed

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.

Pollen limitation and Allee effect related to population size and sex ratio in the endangered Ottelia acuminata (Hydrocharitaceae): implications for conservation and reintroduction.

PubMed

Xia, J; Lu, J; Wang, Z X; Hao, B B; Wang, H B; Liu, G H

2013-03-01

Small populations may suffer more severe pollen limitation and result in Allee effects. Sex ratio may also affect pollination and reproduction success in dioecious species, which is always overlooked when performing conservation and reintroduction tasks. In this study, we investigated whether and how population size and sex ratio affected pollen limitation and reproduction in the endangered Ottelia acuminata, a dioecious submerged species. We established experimental plots with increasing population size and male sex ratio. We observed insect visitation, estimated pollen limitation by hand-pollinations and counted fruit set and seed production per fruit. Fruit set and seed production decreased significantly in small populations due to pollinator scarcity and thus suffered more severe pollen limitation. Although frequently visited, female-biased larger populations also suffered severe pollen limitation due to few effective visits and insufficient pollen availability. Rising male ratio enhanced pollination service and hence reproduction. Unexpectedly, pollinator preferences did not cause reduced reproduction in male-biased populations because of high pollen availability. However, reproductive outputs showed more variability in severe male-biased populations. Our results revealed two component Allee effects in fruit set and seed production, mediated by pollen limitation in O. acuminata. Moreover, reproduction decreased significantly in larger female-biased populations, increasing the risk of an Allee effect. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Nectar production in oilseeds: Food for pollinators in an agricultural landscape

USDA-ARS?s Scientific Manuscript database

Pollinating insects are in decline throughout the world, driven by a combination of factors including the loss of forage resources. The corn- and soybean-dominated agriculture of the Central and Midwestern US produces a landscape relatively devoid of nectar and pollen resources. Introducing specialt...

Two gut community enterotypes recur in diverse bumblebee species

USDA-ARS?s Scientific Manuscript database

Pollinating insects are key to the evolutionary and ecological success of flowering plants and enable much of the diversity in the human diet. Gut microbial communities likely impact pollinators in diverse ways, from nutrition to defense against disease. Honeybees and bumblebees harbor a simple yet ...

Biological pattern and transcriptomic exploration and phylogenetic analysis in the odd floral architecture tree: Helwingia willd.

PubMed

Sun, Cheng; Yu, Guoliang; Bao, Manzhu; Zheng, Bo; Ning, Guogui

2014-06-27

Odd traits in few of plant species usually implicate potential biology significances in plant evolutions. The genus Helwingia Willd, a dioecious medical shrub in Aquifoliales order, has an odd floral architecture-epiphyllous inflorescence. The potential significances and possible evolutionary origin of this specie are not well understood due to poorly available data of biological and genetic studies. In addition, the advent of genomics-based technologies has widely revolutionized plant species with unknown genomic information. Morphological and biological pattern were detailed via anatomical and pollination analyses. An RNA sequencing based transcriptomic analysis were undertaken and a high-resolution phylogenetic analysis was conducted based on single-copy genes in more than 80 species of seed plants, including H. japonica. It is verified that a potential fusion of rachis to the leaf midvein facilitates insect pollination. RNA sequencing yielded a total of 111450 unigenes; half of them had significant similarity with proteins in the public database, and 20281 unigenes were mapped to 119 pathways. Deduced from the phylogenetic analysis based on single-copy genes, the group of Helwingia is closer with Euasterids II and rather than Euasterids, congruent with previous reports using plastid sequences. The odd flower architecture make H. Willd adapt to insect pollination by hosting those insects larger than the flower in size via leave, which has little common character that other insect pollination plants hold. Further the present transcriptome greatly riches genomics information of Helwingia species and nucleus genes based phylogenetic analysis also greatly improve the resolution and robustness of phylogenetic reconstruction in H. japonica.

Variation in Pollen-Donor Composition among Pollinators in an Entomophilous Tree Species, Castanea crenata, Revealed by Single-Pollen Genotyping

PubMed Central

Hasegawa, Yoichi; Suyama, Yoshihisa; Seiwa, Kenji

2015-01-01

Background In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect taxa are effective outcross-pollen transporters under field conditions. In this study, we explored roles of foraging behavior of insect pollinators on pollen-donor composition and subsequent reproductive success in a woody plant. Methods We performed paternity analyses based on microsatellite genotyping of individual pollen grains found on diurnal pollinators (i.e., bumblebee, small bee, fly, small beetle, and honeybee) visiting Castanea crenata trees. Results The outcross-pollen rate was highest in bumblebees (66%), followed by small bees (35%), flies (31%), and small beetles (18%). The effective number of pollen donors, representing pollen carryover, was greater in bumblebees (9.71) than in flies (3.40), small bees (3.32), and small beetles (3.06). The high percentages of pollen from outside the plot on bumblebees (65.4%) and flies (71.2%) compared to small bees (35.3%) and small beetles (13.5%) demonstrated their longer pollen dispersal distances. Conclusions All of the diurnal insects carried outcross-pollen grains for long distances via pollen carryover. This fact suggests that a wide range of insect taxa are potential outcross-pollen transporters for the self-incompatible C. crenata. PMID:25793619

Milkweed (Gentianales: Apocynaceae): a farmscape resource for increasing parasitism of stink bugs (Hemiptera: Pentatomidae) and providing nectar to insect pollinators and monarch butterflies.

PubMed

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.

Flower constancy in insect pollinators

PubMed Central

Ratnieks, Francis L.W.

2011-01-01

As first noted by Aristotle in honeybee workers, many insect pollinators show a preference to visit flowers of just one species during a foraging trip. This “flower constancy” probably benefits plants, because pollen is more likely to be deposited on conspecific stigmas. But it is less clear why insects should ignore rewarding alternative flowers. Many researchers have argued that flower constancy is caused by constraints imposed by insect nervous systems rather than because flower constancy is itself an efficient foraging method. We argue that this view is unsatisfactory because it both fails to explain why foragers flexibly adjust the degree of flower constancy and does not explain why foragers of closely related species show different degrees of constancy. While limitations of the nervous system exist and are likely to influence flower constancy to some degree, the observed behavioural flexibility suggests that flower constancy is a successful foraging strategy given the insect’s own information about different foraging options. PMID:22446521

Reproductive success in varying light environments: direct and indirect effects of light on plants and pollinators.

PubMed

Kilkenny, Francis F; Galloway, Laura F

2008-03-01

Plant populations often exist in spatially heterogeneous environments. Light level can directly affect plant reproductive success through resource availability or by altering pollinator behavior. It can also indirectly influence reproductive success by determining floral display size which may in turn influence pollinator attraction. We evaluated direct and indirect effects of light availability and measured phenotypic selection on phenological traits that may enhance pollen receipt in the insect-pollinated herb Campanulastrum americanum. In a natural population, plants in the sun had larger displays and received 7 times more visits than plants in the shade. Using experimental arrays to separate the direct effects of irradiance on insects from their response to display size, we found more visits to plants in the sun than in the shade, but no association between number of visits each flower received and display size. Plants in the sun were not pollen limited but pollen-augmented shade flowers produced 50% more seeds than open-pollinated flowers. Phenological traits, which may influence pollen receipt, were not under direct selection in the sun. However, earlier initiation and a longer duration of flowering were favored in the shade, which may enhance visitation in this pollen-limited habitat.

Frequent Insect Visitors Are Not Always Pollen Carriers in Hybrid Carrot Pollination.

PubMed

Gaffney, Ann; Bohman, Björn; Quarrell, Stephen R; Brown, Philip H; Allen, Geoff R

2018-06-07

Insect crop visitations do not necessarily translate to carriage or transfer of pollen. To evaluate the potential of the various insects visiting hybrid carrot flowers to facilitate pollen transfer, this study examines insect visitation rates to hybrid carrot seed crops in relation to weather, time of day and season, pollen carrying capacity, inter-row movement, and visitation frequency to male-fertile and male-sterile umbels. The highest pollen loads were carried by nectar scarabs, honey bees, and the hover fly Eristalis tenax (Linnaeus). Honey bees and muscoid flies were observed to forage mostly within the male fertile carrot row while nectar scarabs and E. tenax foraged across rows, carrying equal pollen loads regardless of their distance from the pollen source. All observed insect taxa were more frequently seen visiting male-fertile than male-sterile umbels. In contrast to other visiting insects, honey bees were abundant and frequent visitors and were observed carrying high pollen loads. Consequently, we suggest both optimizing honey bee management and improving the attraction of carrot lines to honey bees to improve pollination rates for hybrid carrot seed crops.

Thrips pollination of Mesozoic gymnosperms.

PubMed

Peñalver, Enrique; Labandeira, Conrad C; Barrón, Eduardo; Delclòs, Xavier; Nel, Patricia; Nel, André; Tafforeau, Paul; Soriano, Carmen

2012-05-29

Within modern gymnosperms, conifers and Ginkgo are exclusively wind pollinated whereas many gnetaleans and cycads are insect pollinated. For cycads, thrips are specialized pollinators. We report such a specialized pollination mode from Early Cretaceous amber of Spain, wherein four female thrips representing a genus and two species in the family Melanthripidae were covered by abundant Cycadopites pollen grains. These females bear unique ring setae interpreted as specialized structures for pollen grain collection, functionally equivalent to the hook-tipped sensilla and plumose setae on the bodies of bees. The most parsimonious explanation for this structure is parental food provisioning for larvae, indicating subsociality. This association provides direct evidence of specialized collection and transportation of pollen grains and likely gymnosperm pollination by 110-105 million years ago, possibly considerably earlier.

Do pollinator distributions underlie the evolution of pollination ecotypes in the Cape shrub Erica plukenetii?

PubMed Central

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

Ecosystems effects 25 years after Chernobyl: pollinators, fruit set and recruitment.

PubMed

Møller, Anders Pape; Barnier, Florian; Mousseau, Timothy A

2012-12-01

Animals are assumed to play a key role in ecosystem functioning through their effects on seed set, seed consumption, seed dispersal, and maintenance of plant communities. However, there are no studies investigating the consequences of animal scarcity on seed set, seed consumption and seed dispersal at large geographical scales. We exploited the unprecedented scarcity of pollinating bumblebees and butterflies in the vicinity of Chernobyl, Ukraine, linked to the effects of radiation on pollinator abundance, to test for effects of pollinator abundance on the ecosystem. There were considerably fewer pollinating insects in areas with high levels of radiation. Fruit trees and bushes (apple Malus domestica, pear Pyrus communis, rowan Sorbus aucuparia, wild rose Rosa rugosa, twistingwood Viburnum lantana, and European cranberry bush Viburnum opulus) that are all pollinated by insects produced fewer fruit in highly radioactively contaminated areas, partly linked to the local reduction in abundance of pollinators. This was the case even when controlling for the fact that fruit trees were generally smaller in more contaminated areas. Fruit-eating birds like thrushes and warblers that are known seed dispersers were less numerous in areas with lower fruit abundance, even after controlling for the effects of radiation, providing a direct link between radiation, pollinator abundance, fruit abundance and abundance of frugivores. Given that the Chernobyl disaster happened 25 years ago, one would predict reduced local recruitment of fruit trees if fruit set has been persistently depressed during that period; indeed, local recruitment was negatively related to the level of radiation and positively to the local level of fruit set. The patterns at the level of trees were replicated at the level of villages across the study site. This study provides the first large-scale study of the effects of a suppressed pollinator community on ecosystem functioning.

Heterotic Patterns of Soybean Lines from 3-Way, 4-Way and 5-way Crosses, and Backcross Populations

USDA-ARS?s Scientific Manuscript database

Identifying heterotic patterns in self-pollinated crops such as soybean [Glycine max (L.) Merr.], requires, among other items, development of different populations types. Male-sterility systems combined with insect-mediated cross-pollination in soybean have been shown to produce large quantities of...

Bee visitation rates to cultivated sunflowers increase with the amount and accessibility of nectar sugars

USDA-ARS?s Scientific Manuscript database

Pollinators make foraging decisions based on numerous floral traits, including nectar and pollen rewards, and associated visual and olfactory cues. For insect-pollinated crops, identifying and breeding for attractive floral traits may increase yields. In this study, we examined floral trait variatio...

Restoring arid western habitats: Native plants maximize wildlife conservation effectiveness

Treesearch

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...

Spatial and temporal patterns of floral scent emission in Dianthus inoxianus and electroantennographic responses of its hawkmoth pollinator.

PubMed

Balao, Francisco; Herrera, Javier; Talavera, Salvador; Dötterl, Stefan

2011-05-01

Scent emission is important in nocturnal pollination systems, and plant species pollinated by nocturnal insects often present characteristic odor compositions and temporal patterns of emission. We investigated the temporal (day/night; flower lifetime) and spatial (different flower parts, nectar) pattern of flower scent emission in nocturnally pollinated Dianthusinoxianus, and determined which compounds elicit physiological responses on the antennae of the sphingid pollinator Hyles livornica. The scent of D.inoxianus comprises 68 volatile compounds, but is dominated by aliphatic 2-ketones and sesquiterpenoids, which altogether make up 82% of collected volatiles. Several major and minor compounds elicit electrophysiological responses in the antennae of H. livornica. Total odor emission does not vary along day and night hours, and neither does along the life of the flower. However, the proportion of compounds eliciting physiological responses varies between day and night. All flower parts as well as nectar release volatiles. The scent of isolated flower parts is dominated by fatty acid derivatives, whereas nectar is dominated by benzenoids. Dissection (= damage) of flowers induced a ca. 20-fold increase in the rate of emission of EAD-active volatiles, especially aliphatic 2-ketones. We suggest that aliphatic 2-ketones might contribute to pollinator attraction in D. inoxianus, even though they have been attributed an insect repellent function in other plant species. We also hypothesize that the benzenoids in nectar may act as an honest signal ('nectar guide') for pollinators. Copyright © 2011 Elsevier Ltd. All rights reserved.

Competitive impacts of an invasive nectar thief on plant-pollinator mutualisms

USGS Publications Warehouse

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.

The United States Army Medical Department Journal. July-September 2012

DTIC Science & Technology

2012-01-01

Baker HG. Bat activity and 20. pollination of Bauhinia Pauletia: plant - pollinator coevolution. Ecology . 1974;55(2):412-419. Venters HD, Hoffert WR...insects, while many plants depend on the pollinating activities of fruit bats.20 BAT RABIES IN THE UNITED STATES Bat rabies was recognized for the fi rst...who may have interacted with the patient.3 Any individual that was identifi ed as meeting the exposure criteria set by the Advisory Committee on

The Keystone Dame Site and other Archaic and Formative Sites in Northwest El Paso, Texas.

DTIC Science & Technology

1980-10-01

an insect pollinated plant , could be the product of water movement and pollen and the finding of such a large percentage in Sample transport through...the contemporary ecolog - below along with some preliminary comments on ical distribution of these same plants . In this respect the kinds of features... pollinated plant , characterized by production of fewer, *0 larger, pollen grains than a wind pollinated plant , finding mre than a very small

Fluctuating selection across years and phenotypic variation in food-deceptive orchids.

PubMed

Scopece, Giovanni; Juillet, Nicolas; Lexer, Christian; Cozzolino, Salvatore

2017-01-01

Nectarless flowers that deceive pollinators offer an opportunity to study asymmetric plant-insect interactions. Orchids are a widely used model for studying these interactions because they encompass several thousand species adopting deceptive pollination systems. High levels of intra-specific phenotypic variation have been reported in deceptive orchids, suggesting a reduced consistency of pollinator-mediated selection on their floral traits. Nevertheless, several studies report on widespread directional selection mediated by pollinators even in these deceptive orchids. In this study we test the hypothesis that the observed selection can fluctuate across years in strength and direction thus likely contributing to the phenotypic variability of this orchid group. We performed a three-year study estimating selection differentials and selection gradients for nine phenotypic traits involved in insect attraction in two Mediterranean orchid species, namely Orchis mascula and O. pauciflora , both relying on a well-described food-deceptive pollination strategy. We found weak directional selection and marginally significant selection gradients in the two investigated species with significant intra-specific differences in selection differentials across years. Our data do not link this variation with a specific environmental cause, but our results suggest that pollinator-mediated selection in food-deceptive orchids can change in strength and in direction over time. In perennial plants, such as orchids, different selection differentials in the same populations in different flowering seasons can contribute to the maintenance of phenotypic variation often reported in deceptive orchids.

Promoting Pollinating Insects in Intensive Agricultural Matrices: Field-Scale Experimental Manipulation of Hay-Meadow Mowing Regimes and Its Effects on Bees

PubMed Central

Buri, Pierrick; Humbert, Jean-Yves; Arlettaz, Raphaël

2014-01-01

Bees are a key component of biodiversity as they ensure a crucial ecosystem service: pollination. This ecosystem service is nowadays threatened, because bees suffer from agricultural intensification. Yet, bees rarely benefit from the measures established to promote biodiversity in farmland, such as agri-environment schemes (AES). We experimentally tested if the spatio-temporal modification of mowing regimes within extensively managed hay meadows, a widespread AES, can promote bees. We applied a randomized block design, replicated 12 times across the Swiss lowlands, that consisted of three different mowing treatments: 1) first cut not before 15 June (conventional regime for meadows within Swiss AES); 2) first cut not before 15 June, as treatment 1 but with 15% of area left uncut serving as a refuge; 3) first cut not before 15 July. Bees were collected with pan traps, twice during the vegetation season (before and after mowing). Wild bee abundance and species richness significantly increased in meadows where uncut refuges were left, in comparison to meadows without refuges: there was both an immediate (within year) and cumulative (from one year to the following) positive effect of the uncut refuge treatment. An immediate positive effect of delayed mowing was also evidenced in both wild bees and honey bees. Conventional AES could easily accommodate such a simple management prescription that promotes farmland biodiversity and is likely to enhance pollination services. PMID:24416434

Thrips pollination of Mesozoic gymnosperms

PubMed Central

Peñalver, Enrique; Labandeira, Conrad C.; Barrón, Eduardo; Delclòs, Xavier; Nel, Patricia; Nel, André; Tafforeau, Paul; Soriano, Carmen

2012-01-01

Within modern gymnosperms, conifers and Ginkgo are exclusively wind pollinated whereas many gnetaleans and cycads are insect pollinated. For cycads, thrips are specialized pollinators. We report such a specialized pollination mode from Early Cretaceous amber of Spain, wherein four female thrips representing a genus and two species in the family Melanthripidae were covered by abundant Cycadopites pollen grains. These females bear unique ring setae interpreted as specialized structures for pollen grain collection, functionally equivalent to the hook-tipped sensilla and plumose setae on the bodies of bees. The most parsimonious explanation for this structure is parental food provisioning for larvae, indicating subsociality. This association provides direct evidence of specialized collection and transportation of pollen grains and likely gymnosperm pollination by 110–105 million years ago, possibly considerably earlier. PMID:22615414

Insect-Flower Interaction Network Structure Is Resilient to a Temporary Pulse of Floral Resources from Invasive Rhododendron ponticum

PubMed Central

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

Floral traits influencing plant attractiveness to three bee species: Consequences for plant reproductive success

USDA-ARS?s Scientific Manuscript database

The ability to attract pollinators is crucial to plants that rely on insects for pollination. We examined and contrasted the role of floral display size and flower color in attracting three bee species to Medicago sativa and determined the relationships between plant attractiveness and seed set for ...

Dissecting the 'bacon and eggs' phenotype: transcriptomics of post-anthesis colour change in Lotus.

PubMed

Boehm, Mannfred M A; Ojeda, Dario I; Cronk, Quentin C B

2017-10-17

Post-anthesis colour change (PACC) is widely thought to be an adaptation to signal floral suitability to pollinators. Lotus filicaulis and Lotus sessilifolius are insect-pollinated herbaceous legumes with flowers that open yellow, shift to orange and finally red. This study examines the molecular basis for floral colour change in these Lotus species. Lotus filicaulis was cultivated in a glasshouse from which pollinating insects (bees) were excluded, and the rate of colour change was recorded in both unpollinated and manually pollinated flowers. Unpollinated flowers from both the yellow stage and the red stage were sampled for sequencing. The transcriptomes of L. filicaulis and L. sessilifolius of both colour stages were analysed for differentially expressed genes and enriched ontologies. The rate of progression through PACC doubled when L. filicaulis was hand-pollinated. De novo assembly of RNA-Seq reads from non-model Lotus species outperformed heterologous alignment of reads to the L. japonicus genome. Differential expression analysis suggested that the carotenoid biosynthetic pathway is upregulated at anthesis while the flavonoid biosynthetic pathway is upregulated with the onset of PACC in L. filicaulis and L. sessilifolius . Pollination significantly accelerates PACC in L. filicaulis , consistent with the hypothesis that PACC increases pollination efficiency by directing pollinators to unpollinated flowers. RNA-Seq results show the synchronized upregulation of the entire cyanidin biosynthesis pathway in the red stage of PACC in L. filicaulis and L. sessilifolius . The genes implicated offer the basis for further investigations into how gene families, transcription factors and related pathways are likely to be involved in PACC. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Effective pollinators of Asian sacred lotus (Nelumbo nucifera): contemporary pollinators may not reflect the historical pollination syndrome

PubMed Central

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

Courgette Production: Pollination Demand, Supply, and Value.

PubMed

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.

Chemical and morphological filters in a specialized floral mimicry system.

PubMed

Martos, Florent; Cariou, Marie-Louise; Pailler, Thierry; Fournel, Jacques; Bytebier, Benny; Johnson, Steven D

2015-07-01

Many plant species attract insect pollinators through chemical mimicry of their oviposition sites, often detaining them in a trap chamber that ensures pollen transfer. These plant mimics are considered to be unspecialized at the pollinator species level, yet field observations of a mycoheterotrophic rainforest orchid (Gastrodia similis), which emits an odour reminiscent of rotting fruit, indicate that it is pollinated by a single drosophilid fly species (Scaptodrosophila bangi). We investigated the roles of floral volatiles and the dimensions of the trap chamber in enforcing this specialization, using gas chromatography-mass spectrometry analyses, bioassays and scanning electron microscopy. We showed that G. similis flowers predominantly emit three fatty-acid esters (ethyl acetate, ethyl isobutyrate and methyl isobutyrate) that were shown in experiments to attract only Scaptodrosophila flies. We additionally showed that the trap chamber, which flies enter into via a touch-sensitive 'trapdoor', closely matches the body size of the pollinator species S. bangi and plays a key role in pollen transfer. Our study demonstrates that specialization in oviposition site mimicry is due primarily to volatile chemistry and is reflected in the dimensions of the trapping apparatus. It also indicates that mycoheterotrophic plants can be specialized both on mycorrhizal fungi and insect pollinators. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Amino Acid Change in an Orchid Desaturase Enables Mimicry of the Pollinator's Sex Pheromone.

PubMed

Sedeek, Khalid E M; Whittle, Edward; Guthörl, Daniela; Grossniklaus, Ueli; Shanklin, John; Schlüter, Philipp M

2016-06-06

Mimicry illustrates the power of selection to produce phenotypic convergence in biology [1]. A striking example is the imitation of female insects by plants that are pollinated by sexual deception of males of the same insect species [2-4]. This involves mimicry of visual, tactile, and chemical signals of females [2-7], especially their sex pheromones [8-11]. The Mediterranean orchid Ophrys exaltata employs chemical mimicry of cuticular hydrocarbons, particularly the 7-alkenes, in an insect sex pheromone to attract and elicit mating behavior in its pollinators, males of the cellophane bee Colletes cunicularius [11-13]. A difference in alkene double-bond positions is responsible for reproductive isolation between O. exaltata and closely related species, such as O. sphegodes [13-16]. We show that these 7-alkenes are likely determined by the action of the stearoyl-acyl-carrier-protein desaturase (SAD) homolog SAD5. After gene duplication, changes in subcellular localization relative to the ancestral housekeeping desaturase may have allowed proto-SAD5's reaction products to undergo further biosynthesis to both 7- and 9-alkenes. Such ancestral coproduction of two alkene classes may have led to pollinator-mediated deleterious pleiotropy. Despite possible evolutionary intermediates with reduced activity, amino acid changes at the bottom of the substrate-binding cavity have conferred enzyme specificity for 7-alkene biosynthesis by preventing the binding of longer-chained fatty acid (FA) precursors by the enzyme. This change in desaturase function enabled the orchid to perfect its chemical mimicry of pollinator sex pheromones by escape from deleterious pleiotropy, supporting a role of pleiotropy in determining the possible trajectories of adaptive evolution. Copyright © 2016 Elsevier Ltd. All rights reserved.

A heterogeneous landscape does not guarantee high crop pollination

PubMed Central

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

Chemical mimicry of insect oviposition sites: a global analysis of convergence in angiosperms.

PubMed

Jürgens, Andreas; Wee, Suk-Ling; Shuttleworth, Adam; Johnson, Steven D

2013-09-01

Floral mimicry of decaying plant or animal material has evolved in many plant lineages and exploits, for the purpose of pollination, insects seeking oviposition sites. Existing studies suggest that volatile signals play a particularly important role in these mimicry systems. Here, we present the first large-scale phylogenetically informed study of patterns of evolution in the volatile emissions of plants that mimic insect oviposition sites. Multivariate analyses showed strong convergent evolution, represented by distinct clusters in chemical phenotype space of plants that mimic animal carrion, decaying plant material, herbivore dung and omnivore/carnivore faeces respectively. These plants deploy universal infochemicals that serve as indicators for the main nutrients utilised by saprophagous, coprophagous and necrophagous insects. The emission of oligosulphide-dominated volatile blends very similar to those emitted by carrion has evolved independently in at least five plant families (Annonaceae, Apocynaceae, Araceae, Orchidaceae and Rafflesiaceae) and characterises plants associated mainly with pollination by necrophagous flies and beetles. © 2013 John Wiley & Sons Ltd/CNRS.

Spatial and Temporal Trends of Global Pollination Benefit

PubMed Central

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

Pollinators of the invasive plant, yellow starthistle (Centaurea solstitialis), in north-eastern Oregon, USA

Treesearch

James McIver; Robbin Thorp; Karen Erickson

2009-01-01

The potential pollinators of yellow starthistle (Centaurea solstitialis) were surveyed at six sites in north-eastern Oregon, USA, between May and September from 2000 to 2002. The objective of the study was to determine the species composition and relative abundance of the insects that visited yellow starthistle throughout the flowering season and...

Habitat choice of multiple pollinators in almond trees and its potential effect on pollen movement and productivity: A theoretical approach using the Shigesada-Kawasaki-Teramoto model.

PubMed

Yong, Kamuela E; Li, Yi; Hendrix, Stephen D

2012-07-21

California's almond industry, valued at $2.3 billion per year, depends on the pollinator services of honey bees, although pollination by other insects, mainly solitary wild bees, is being investigated as an alternative because of recent declines in the number of honey bee colonies. Our objective is to model the movements of honey bees and determine the conditions under which they will forage in less favorable areas of a tree and its surroundings when other pollinators are present. We hypothesize that foraging in less favorable areas leads to increased movement between trees and increased cross pollination between varieties which is required for successful nut production. We use the Shigesada-Kawasaki-Teramoto model (1979) which describes the density of two species in a two-dimensional environment of variable favorableness with respect to intrinsic diffusions and intra and interspecific interactions of species. The model is applied to almond pollination by honey bees and other pollinators with environmental favorableness based on the distribution of flowers in trees. Using the spectral-Galerkin method in a rectangular domain, we numerically approximated the two-dimensional nonlinear parabolic partial differential system arising in the model. When cross-diffusion or interspecific effects of other pollinators was high, honey bees foraged in less favorable areas of the tree. In the model, high cross-diffusion also resulted in increased activity in honey bees which manifested itself in the field in terms of accelerations, decelerations, and changes in direction, indicating rapid redistribution of densities to an equilibrium state. Empirical analysis of the number of honey bees and other visitors in 2-min intervals to almond trees shows a negative relationship, indicating cross-diffusion effects in nature with the potential to increase movement to a different tree with a more favorable environment, potentially increasing nut production. Copyright © 2012 Elsevier Ltd. All rights reserved.

Air pollutants degrade floral scents and increase insect foraging times

NASA Astrophysics Data System (ADS)

Fuentes, Jose D.; Chamecki, Marcelo; Roulston, T.'ai; Chen, Bicheng; Pratt, Kenneth R.

2016-09-01

Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.

Mating patterns and pollinator mobility are critical traits in forest fragmentation genetics

PubMed Central

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

Global change effects on plant-insect interactions: The role of phytochemistry

Treesearch

Mary A. Jamieson; Laura A. Burkle; Jessamyn S. Manson; Justin B. Runyon; Amy M. Trowbridge; Joseph Zientek

2017-01-01

Natural and managed ecosystems are undergoing rapid environmental change due to a growing human population and associated increases in industrial and agricultural activity. Global environmental change directly and indirectly impacts insect herbivores and pollinators. In this review, we highlight recent research examining how environmental change factors affect plant...

Two Ways of Acquiring Environmental Knowledge: By Encountering Living Animals at a Beehive and by Observing Bees via Digital Tools

ERIC Educational Resources Information Center

Schönfelder, Mona L.; Bogner, Franz X.

2017-01-01

Pollinating animals are profoundly affected by the current loss of biodiversity, a problem that is of concern to science, policy-makers and the public. One possibility to raise awareness for pollinator conservation is education. Unfortunately, insects such as bees are often perceived as frightening creatures; a negative emotion that may hinder…

Bees as Biosensors: Chemosensory Ability, Honey Bee Monitoring Systems, and Emergent Sensor Technologies Derived from the Pollinator Syndrome

PubMed Central

Bromenshenk, Jerry J.; Henderson, Colin B.; Seccomb, Robert A.; Welch, Phillip M.; Debnam, Scott E.; Firth, David R.

2015-01-01

This review focuses on critical milestones in the development path for the use of bees, mainly honey bees and bumble bees, as sentinels and biosensors. These keystone species comprise the most abundant pollinators of agro-ecosystems. Pollinating 70%–80% of flowering terrestrial plants, bees and other insects propel the reproduction and survival of plants and themselves, as well as improve the quantity and quality of seeds, nuts, and fruits that feed birds, wildlife, and us. Flowers provide insects with energy, nutrients, and shelter, while pollinators are essential to global ecosystem productivity and stability. A rich and diverse milieu of chemical signals establishes and maintains this intimate partnership. Observations of bee odor search behavior extend back to Aristotle. In the past two decades great strides have been made in methods and instrumentation for the study and exploitation of bee search behavior and for examining intra-organismal chemical communication signals. In particular, bees can be trained to search for and localize sources for a variety of chemicals, which when coupled with emerging tracking and mapping technologies create novel potential for research, as well as bee and crop management. PMID:26529030

Pollen-mediated gene flow from transgenic cotton under greenhouse conditions is dependent on different pollinators

PubMed Central

Yan, Shuo; Zhu, Jialin; Zhu, Weilong; Li, Zhen; Shelton, Anthony M.; Luo, Junyu; Cui, Jinjie; Zhang, Qingwen; Liu, Xiaoxia

2015-01-01

With the large-scale release of genetically modified (GM) crops, there are ecological concerns on transgene movement from GM crops to non-GM counterparts and wild relatives. In this research, we conducted greenhouse experiments to measure pollen-mediated gene flow (PGF) in the absence and presence of pollinators (Bombus ignitus, Apis mellifera and Pieris rapae) in one GM cotton (resistant to the insect Helicoverpa armigera and the herbicide glyphosate) and two non-GM lines (Shiyuan321 and Hai7124) during 2012 and 2013. Our results revealed that: (1) PGF varied depending on the pollinator species, and was highest with B. ignitus (10.83%) and lowest with P. rapae (2.71%); (2) PGF with B. ignitus depended on the distance between GM and non-GM cottons; (3) total PGF to Shiyuan321 (8.61%) was higher than to Hai7124 (4.10%). To confirm gene flow, we tested hybrids carrying transgenes for their resistance to glyphosate and H. armigera, and most hybrids showed strong resistance to the herbicide and insect. Our research confirmed that PGF depended on pollinator species, distance between plants and the receptor plant. PMID:26525573

Bees as Biosensors: Chemosensory Ability, Honey Bee Monitoring Systems, and Emergent Sensor Technologies Derived from the Pollinator Syndrome.

PubMed

Bromenshenk, Jerry J; Henderson, Colin B; Seccomb, Robert A; Welch, Phillip M; Debnam, Scott E; Firth, David R

2015-10-30

This review focuses on critical milestones in the development path for the use of bees, mainly honey bees and bumble bees, as sentinels and biosensors. These keystone species comprise the most abundant pollinators of agro-ecosystems. Pollinating 70%-80% of flowering terrestrial plants, bees and other insects propel the reproduction and survival of plants and themselves, as well as improve the quantity and quality of seeds, nuts, and fruits that feed birds, wildlife, and us. Flowers provide insects with energy, nutrients, and shelter, while pollinators are essential to global ecosystem productivity and stability. A rich and diverse milieu of chemical signals establishes and maintains this intimate partnership. Observations of bee odor search behavior extend back to Aristotle. In the past two decades great strides have been made in methods and instrumentation for the study and exploitation of bee search behavior and for examining intra-organismal chemical communication signals. In particular, bees can be trained to search for and localize sources for a variety of chemicals, which when coupled with emerging tracking and mapping technologies create novel potential for research, as well as bee and crop management.

Time-Dependent Trapping of Pollinators Driven by the Alignment of Floral Phenology with Insect Circadian Rhythms

PubMed Central

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

Specific attraction of fig-pollinating wasps: role of volatile compounds released by tropical figs.

PubMed

Grison-Pigé, Laure; Bessière, Jean-Marie; Hossaert-McKey, Martine

2002-02-01

Floral scents often act as pollinator attractants. In the case of obligate and specific plant-pollinator relationships, the role of floral signals may be crucial in allowing the encounter of the partners. About 750 Ficus species (Moraceae) are involved in such interactions, each with a distinct species of pollinating wasp (Chalcidoidea, Agaonidae). Several species have been shown to release volatile compounds, but their role in pollinator attraction has rarely been simultaneously tested. We investigated the floral scents of four tropical fig species and combined chemical analysis with biological tests of stimulation of insects. Pollinators of three species were stimulated by the odor of their associated fig species and generally not by the odor of another species. The fourth actually comprised two distinct varieties. The main compound was often a different one in each species. Floral blends of different species always shared compounds, but ratios of these compounds varied among species.

Sensitivity of commercial pumpkin yield to potential decline among different groups of pollinating bees.

PubMed

Pfister, Sonja C; Eckerter, Philipp W; Schirmel, Jens; Cresswell, James E; Entling, Martin H

2017-05-01

The yield of animal-pollinated crops is threatened by bee declines, but its precise sensitivity is poorly known. We therefore determined the yield dependence of Hokkaido pumpkin in Germany on insect pollination by quantifying: (i) the relationship between pollen receipt and fruit set and (ii) the cumulative pollen deposition of each pollinator group. We found that approximately 2500 pollen grains per flower were needed to maximize fruit set. At the measured rates of flower visitation, we estimated that bumblebees (21 visits/flower lifetime, 864 grains/visit) or honeybees (123 visits, 260 grains) could individually achieve maximum crop yield, whereas halictid bees are ineffective (11 visits, 16 grains). The pollinator fauna was capable of delivering 20 times the necessary amount of pollen. We therefore estimate that pumpkin yield was not pollination-limited in our study region and that it is currently fairly resilient to single declines of honeybees or wild bumblebees.

Sensitivity of commercial pumpkin yield to potential decline among different groups of pollinating bees

PubMed Central

Eckerter, Philipp W.; Schirmel, Jens; Cresswell, James E.; Entling, Martin H.

2017-01-01

The yield of animal-pollinated crops is threatened by bee declines, but its precise sensitivity is poorly known. We therefore determined the yield dependence of Hokkaido pumpkin in Germany on insect pollination by quantifying: (i) the relationship between pollen receipt and fruit set and (ii) the cumulative pollen deposition of each pollinator group. We found that approximately 2500 pollen grains per flower were needed to maximize fruit set. At the measured rates of flower visitation, we estimated that bumblebees (21 visits/flower lifetime, 864 grains/visit) or honeybees (123 visits, 260 grains) could individually achieve maximum crop yield, whereas halictid bees are ineffective (11 visits, 16 grains). The pollinator fauna was capable of delivering 20 times the necessary amount of pollen. We therefore estimate that pumpkin yield was not pollination-limited in our study region and that it is currently fairly resilient to single declines of honeybees or wild bumblebees. PMID:28573019

Seasonal cycles, phylogenetic assembly, and functional diversity of orchid bee communities.

PubMed

Ramírez, Santiago R; Hernández, Carlos; Link, Andres; López-Uribe, Margarita M

2015-05-01

Neotropical rainforests sustain some of the most diverse terrestrial communities on Earth. Euglossine (or orchid) bees are a diverse lineage of insect pollinators distributed throughout the American tropics, where they provide pollination services to a staggering diversity of flowering plant taxa. Elucidating the seasonal patterns of phylogenetic assembly and functional trait diversity of bee communities can shed new light into the mechanisms that govern the assembly of bee pollinator communities and the potential effects of declining bee populations. Male euglossine bees collect, store, and accumulate odoriferous compounds (perfumes) to subsequently use during courtship display. Thus, synthetic chemical baits can be used to attract and monitor euglossine bee populations. We conducted monthly censuses of orchid bees in three sites in the Magdalena valley of Colombia - a region where Central and South American biotas converge - to investigate the structure, diversity, and assembly of euglossine bee communities through time in relation to seasonal climatic cycles. In particular, we tested the hypothesis that phylogenetic community structure and functional trait diversity changed in response to seasonal rainfall fluctuations. All communities exhibited strong to moderate phylogenetic clustering throughout the year, with few pronounced bursts of phylogenetic overdispersion that coincided with the transition from wet-to-dry seasons. Despite the heterogeneous distribution of functional traits (e.g., body size, body mass, and proboscis length) and the observed seasonal fluctuations in phylogenetic diversity, we found that functional trait diversity, evenness, and divergence remained constant during all seasons in all communities. However, similar to the pattern observed with phylogenetic diversity, functional trait richness fluctuated markedly with rainfall in all sites. These results emphasize the importance of considering seasonal fluctuations in community assembly and provide a glimpse to the potential effects that climatic alterations may have on both pollinator communities and the ecosystem services they provide.

Modelling pollination services across agricultural landscapes

PubMed Central

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

Local shifts in floral biotic interactions in habitat edges and their effect on quantity and quality of plant offspring

PubMed Central

Fenu, Giuseppe; Bernardo, Liliana

2017-01-01

Abstract Spatial shifts in insect fauna due to ecological heterogeneity can severely constrain plant reproduction. Nonetheless, data showing effects of insect visit patterns and intensity of mutualistic and/or antagonistic plant–insect interactions on plant reproduction over structured ecological gradients remain scarce. We investigated how changes in flower-visitor abundance, identity and behaviour over a forest-open habitat gradient affect plant biotic interactions, and quantitative and qualitative fitness in the edge-specialist Dianthus balbisii. Composition and behaviour of the insects visiting flowers of D. balbisii strongly varied over the study gradient, influencing strength and patterns of plant biotic interactions (i.e. herbivory and pollination likelihood). Seed set comparison in free- and manually pollinated flowers suggested spatial variations in the extent of quantitative pollen limitation, which appeared more pronounced at the gradient extremes. Such variations were congruent to patterns of flower visit and plant biotic interactions. The analyses on seed and seedling viability evidenced that spatial variation in amount and type of pollinators, and frequency of herbivory affected qualitative fitness of D. balbisii by influencing selfing and outcrossing rates. Our work emphasizes the role of plant biotic interactions as a fine-scale mediator of plant fitness in ecotones, highlighting that optimal plant reproduction can take place into a restricted interval of the ecological gradients occurring at forest edges. Reducing the habitat complexity typical of such transition contexts can threat edge-adapted plants. PMID:28775831

The betrayed thief – the extraordinary strategy of Aristolochia rotunda to deceive its pollinators

PubMed Central

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

The betrayed thief - the extraordinary strategy of Aristolochia rotunda to deceive its pollinators.

PubMed

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.

[Importance of competition for pollination in formation of the entomophylous plants complex structure].

PubMed

Dlusskiĭ, G M

2013-01-01

Many species of entomophylous plants have a wide range of pollinators, and the same insects visit flowers of many plants. The competition for pollination leads to decreasing in seed production of competing species. However, there exists a variety of adaptations that allow plants to reduce the intensity of competition. A comparative analysis of pollinators spectra has allowed to designate groups (subcomplexes) of plants with regard to dominance of various groups of pollinators: myiophylous (flies from the superfamily Muscomorha dominate), syphidophylous (flies from the family Syrphidae dominate), psychophylous (butterflies dominate), cantharophylous (beetles dominate), nonspecialized and specialized melittophylous (Apidae, mainly bumblebees, dominate). The belonging of plants to a specific subcomplex is defined mainly by the structure of flowers and inflorescences. Modes of mechanical and attractive isolation are discussed that lead to restriction of pollinators composition. Competition abatement between species with similar spectra of pollinators and belonging to the same subcomplex is achieved mainly by spatial (ecological) and temporal (different timing of flowering) isolation.

Pollination and floral ecology of Arundina graminifolia (Orchidaceae) at the northern border of the species' natural distribution.

PubMed

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.

Chronic exposure to a neonicotinoid pesticide alters the interactions between bumblebees and wild plants.

PubMed

Stanley, Dara A; Raine, Nigel E

2016-07-01

Insect pollinators are essential for both the production of a large proportion of world crops and the health of natural ecosystems. As important pollinators, bumblebees must learn to forage on flowers to feed both themselves and provision their colonies.Increased use of pesticides has caused concern over sublethal effects on bees, such as impacts on reproduction or learning ability. However, little is known about how sublethal exposure to field-realistic levels of pesticide might affect the ability of bees to visit and manipulate flowers.We observed the behaviour of individual bumblebees from colonies chronically exposed to a neonicotinoid pesticide (10 ppb thiamethoxam) or control solutions foraging for the first time on an array of morphologically complex wildflowers ( Lotus corniculatus and Trifolium repens ) in an outdoor flight arena.We found that more bees released from pesticide-treated colonies became foragers, and that they visited more L. corniculatus flowers than controls. Interestingly, bees exposed to pesticide collected pollen more often than controls, but control bees learnt to handle flowers efficiently after fewer learning visits than bees exposed to pesticide. There were also different initial floral preferences of our treatment groups; control bees visited a higher proportion of T. repens flowers, and bees exposed to pesticide were more likely to choose L. corniculatus on their first visit.Our results suggest that the foraging behaviour of bumblebees on real flowers can be altered by sublethal exposure to field-realistic levels of pesticide. This has implications for the foraging success and persistence of bumblebee colonies, but perhaps more importantly for the interactions between wild plants and flower-visiting insects and ability of bees to deliver the crucial pollination services to plants necessary for ecosystem functioning.

Economic Dependence of U.S. Industrial Sectors on Animal-Mediated Pollination Service.

PubMed

Chopra, Shauhrat S; Bakshi, Bhavik R; Khanna, Vikas

2015-12-15

Declining animal pollinator health and diversity in the U.S. is a matter of growing concern and has particularly gained attention since the emergence of colony collapse disorder (CCD) in 2006. Failure to maintain adequate animal-mediated pollination service to support increasing demand for pollination-dependent crops poses risks for the U.S. economy. We integrate the Economic Input-Output (EIO) model and network analysis with data on pollinator dependence of crops to understand the economic dependence of U.S. industrial sectors on animal-mediated pollination service. The novelty of this work lies in its ability to identify industrial sectors and industrial communities (groups of closely linked sectors) that are most vulnerable to scarcity of pollination service provided by various animal species. While the economic dependence of agricultural sectors on pollination service is significant (US$14.2-23.8 billion), the higher-order economic dependence of the rest of the U.S. industrial sectors is substantially high as well (US$10.3-21.1 billion). The results are compelling as they highlight the critical importance of animal-induced pollination service for the U.S. economy, and the need to account for the role of ecosystem goods and services in product life cycles.

Plant Secondary Metabolites Modulate Insect Behavior-Steps Toward Addiction?

PubMed

Wink, Michael

2018-01-01

Plants produce a diversity of secondary metabolites (PSMs) that serve as defense compounds against herbivores and microorganisms. In addition, some PSMs attract animals for pollination and seed dispersal. In case of pollinating insects, PSMs with colors or terpenoids with fragrant odors attract pollinators in the first place, but when they arrive at a flower, they are rewarded with nectar, so that the pollinators do not feed on flowers. In order to be effective as defense chemicals, PSMs evolved as bioactive substances, that can interfere with a large number of molecular targets in cells, tissues and organs of animals or of microbes. The known functions of PSMs are summarized in this review. A number of PSMs evolved as agonists or antagonists of neuronal signal transduction. Many of these PSMs are alkaloids. Several of them share structural similarities to neurotransmitters. Evidence for neuroactive and psychoactive PSMs in animals will be reviewed. Some of the neuroactive PSMs can cause addiction in humans and other vertrebrates. Why should a defense compound be addictive and thus attract more herbivores? Some insects are food specialists that can feed on plants that are normally toxic to other herbivores. These specialists can tolerate the toxins and many are stored in the insect body as acquired defense chemicals against predators. A special case are pyrrolizidine alkaloids (PAs) that are neurotoxic and mutagenic in vertebrates. PAs are actively sequestered by moths of the family Arctiidae and a few other groups of arthropods. In arctiids, PAs are not only used for defense, but also serve as morphogens for the induction of male coremata and as precursors for male pheromones. Caterpillars even feed on filter paper impregnated with pure PAs (that modulate serotonin receptors in vertebrates and maybe even in insects) and thus show of behavior with has similarities to addiction in vertebrates. Not only PA specialists, but also many monophagous herbivores select their host plants according to chemical cues i.e., PSMs) and crave for plants with a particular PSMs, again a similarity to addiction in vertebrates.

Reproductive biology of the biofuel plant Jatropha curcas in its center of origin

PubMed Central

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

Diversity of wild bees supports pollination services in an urbanized landscape.

PubMed

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.

Large pollen loads of a South African asclepiad do not interfere with the foraging behaviour or efficiency of pollinating honey bees

NASA Astrophysics Data System (ADS)

Coombs, G.; Dold, A. P.; Brassine, E. I.; Peter, C. I.

2012-07-01

The pollen of asclepiads (Asclepiadoideae, Apocynaceae) and most orchids (Orchidaceae) are packaged as large aggregations known as pollinaria that are removed as entire units by pollinators. In some instances, individual pollinators may accumulate large loads of these pollinaria. We found that the primary pollinator of Cynanchum ellipticum (Apocynaceae—Asclepiadoideae), the honey bee Apis mellifera, accumulate very large agglomerations of pollinaria on their mouthparts when foraging on this species. We tested whether large pollinarium loads negatively affected the foraging behaviour and foraging efficiency of honey bees by slowing foraging speeds or causing honey bees to visit fewer flowers, and found no evidence to suggest that large pollinarium loads altered foraging behaviour. C. ellipticum displayed consistently high levels of pollination success and pollen transfer efficiency (PTE). This may be a consequence of efficiently loading large numbers of pollinaria onto pollinators even when primary points of attachment on pollinators are already occupied and doing so in a manner that does not impact the foraging behaviour of pollinating insects.

Meligethes aeneus pollen-feeding suppresses, and oviposition induces, Brassica napus volatiles: beetle attraction/repellence to lilac aldehydes and veratrole

USDA-ARS?s Scientific Manuscript database

Insect pollination and pollen-feeding can reduce plant volatile emissions and future insect floral attraction, with oviposition having different effects. Meligethes aeneus F. (Coleoptera: Nitidulidae), is a pollen-feeding pest beetle of oilseed rape, Brassica napus L. (Brassicaceae). We measured pla...

Taxonomic description of in situ bee pollen from the middle Eocene of Germany.

PubMed

Grímsson, FriĐgeir; Zetter, Reinhard; Labandeira, Conrad C; Engel, Michael S; Wappler, Torsten

2017-01-02

The middle Eocene Messel and Eckfeld localities are renowned for their excellently preserved faunas and diverse floras. Here we describe for the first time pollen from insect-pollinated plants found in situ on well-preserved ancient bees using light and scanning electron microscopy. There have been 140 pollen types reported from Messel and 162 pollen types from Eckfeld. Here we document 23 pollen types, six from Messel and 18 from Eckfeld (one is shared). The taxa reported here are all pollinated by insects and mostly not recovered in the previously studied dispersed fossil pollen records. Typically, a single or two pollen types are found on each fossil bee specimen, the maximum number of distinct pollen types on a single individual is five. Only five of the 23 pollen types obtained are angiosperms of unknown affinity, the remainder cover a broad taxonomic range of angiosperm trees and include members of several major clades: monocots (1 pollen type), fabids (7), malvids (4), asterids (5) and other core eudicots (1). Seven types each can be assigned to individual genera or infrafamilial clades. Since bees visit only flowers in the relative vicinity of their habitat, the recovered pollen provides a unique insight into the autochthonous palaeo-flora. The coexistence of taxa such as Decodon, Elaeocarpus, Mortoniodendron and other Tilioideae, Mastixoideae, Olax, Pouteria and Nyssa confirms current views that diverse, thermophilic forests thrived at the Messel and Eckfeld localities, probably under a warm subtropical, fully humid climate. Our study calls for increased attention to pollen found in situ on pollen-harvesting insects such as bees, which can provide new insights on insect-pollinated plants and complement even detailed palaeo-palynological knowledge obtained mostly from pollen of wind-pollinated plants in the dispersed pollen record of sediments. In the case of Elaeocarpus, Mortoniodendron, Olax and Pouteria the pollen collected by the middle Eocene bees represent the earliest unambiguous records of their respective genera.

Taxonomic description of in situ bee pollen from the middle Eocene of Germany

PubMed Central

Grímsson, FriĐgeir; Zetter, Reinhard; Labandeira, Conrad C.; Engel, Michael S.; Wappler, Torsten

2017-01-01

Abstract The middle Eocene Messel and Eckfeld localities are renowned for their excellently preserved faunas and diverse floras. Here we describe for the first time pollen from insect-pollinated plants found in situ on well-preserved ancient bees using light and scanning electron microscopy. There have been 140 pollen types reported from Messel and 162 pollen types from Eckfeld. Here we document 23 pollen types, six from Messel and 18 from Eckfeld (one is shared). The taxa reported here are all pollinated by insects and mostly not recovered in the previously studied dispersed fossil pollen records. Typically, a single or two pollen types are found on each fossil bee specimen, the maximum number of distinct pollen types on a single individual is five. Only five of the 23 pollen types obtained are angiosperms of unknown affinity, the remainder cover a broad taxonomic range of angiosperm trees and include members of several major clades: monocots (1 pollen type), fabids (7), malvids (4), asterids (5) and other core eudicots (1). Seven types each can be assigned to individual genera or infrafamilial clades. Since bees visit only flowers in the relative vicinity of their habitat, the recovered pollen provides a unique insight into the autochthonous palaeo-flora. The coexistence of taxa such as Decodon, Elaeocarpus, Mortoniodendron and other Tilioideae, Mastixoideae, Olax, Pouteria and Nyssa confirms current views that diverse, thermophilic forests thrived at the Messel and Eckfeld localities, probably under a warm subtropical, fully humid climate. Our study calls for increased attention to pollen found in situ on pollen-harvesting insects such as bees, which can provide new insights on insect-pollinated plants and complement even detailed palaeo-palynological knowledge obtained mostly from pollen of wind-pollinated plants in the dispersed pollen record of sediments. In the case of Elaeocarpus, Mortoniodendron, Olax and Pouteria the pollen collected by the middle Eocene bees represent the earliest unambiguous records of their respective genera. PMID:28057943

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.

Dispensing Pollen via Catapult: Explosive Pollen Release in Mountain Laurel (Kalmia latifolia).

PubMed

Switzer, Callin M; Combes, Stacey A; Hopkins, Robin

2018-06-01

The astonishing amount of floral diversity has inspired countless assumptions about the function of diverse forms and their adaptive significance, yet many of these hypothesized functions are untested. We investigated an often-repeated adaptive hypothesis about how an extreme floral form functions. In this study, we conducted four investigations to understand the adaptive function of explosive pollination in Kalmia latifolia, the mountain laurel. We first performed a kinematic analysis of anther movement. Second, we constructed a heat map of pollen trajectories in three-dimensional space. Third, we conducted field observations of pollinators and their behaviors while visiting K. latifolia. Finally, we conducted a pollination experiment to investigate the importance of pollinators for fertilization success. Our results suggest that insect visitation dramatically improves fertilization success and that bees are the primary pollinators that trigger explosive pollen release.

Lilies at the limit: Variation in plant-pollinator interactions across an elevational range.

PubMed

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.

Patterns of odour emission, thermogenesis and pollinator activity in cones of an African cycad: what mechanisms apply?

PubMed

Suinyuy, Terence N; Donaldson, John S; Johnson, Steven D

2013-09-01

Ontogenetic patterns of odour emissions and heating associated with plant reproductive structures may have profound effects on insect behaviour, and consequently on pollination. In some cycads, notably Macrozamia, temporal changes in emission of specific odour compounds and temperature have been interpreted as a 'push-pull' interaction in which pollinators are either attracted or repelled according to the concentration of the emitted volatiles. To establish which mechanisms occur in the large Encephalartos cycad clade, the temporal patterns of volatile emissions, heating and pollinator activity of cones of Encephalartos villosus in the Eastern Cape (EC) and KwaZulu Natal (KZN) of South Africa were investigated. Gas chromatography-mass spectrometry (GC-MS) analyses of Encephalartos villosus cone volatiles showed that emissions, dominated by eucalyptol and 2-isopropyl-3-methoxypyrazine in EC populations and (3E)-1,3-octadiene and (3E,5Z)-1,3,5-octatriene in the KZN populations, varied across developmental stages but did not vary significantly on a daily cycle. Heating in male cones was higher at dehiscence than during pre- and post-dehiscence, and reached a maximum at about 1830 h when temperatures were between 7·0 and 12·0 °C above ambient. Daily heating of female cones was less pronounced and reached a maximum at about 1345 h when it was on average between 0·9 and 3·0 °C above ambient. Insect abundance on male cones was higher at dehiscence than at the other stages and significantly higher in the afternoon than in the morning and evening. There are pronounced developmental changes in volatile emissions and heating in E. villosus cones, as well as strong daily changes in thermogenesis. Daily patterns of volatile emissions and pollinator abundance in E. villosus are different from those observed in some Macrozamia cycads and not consistent with the push-pull pattern as periods of peak odour emission do not coincide with mass exodus of insects from male cones.

A flavonoid from Brassica rapa flower as the UV-absorbing nectar guide.

PubMed

Sasaki, Katsunori; Takahashi, Takashi

2002-10-01

The corolla of Brassica rapa has an UV-absorbing zone in its center, known as the nectar guide for attracting pollinating insects. The pigment which plays the role of the nectar guide was isolated from the petals and identified to be isorhamnetin 3,7-O-di-beta-D-glucopyranoside on the basis of MS and NMR spectroscopic data. The D-, L-configurations of the sugar moieties were determined by the fluorometric HPLC method. In plants raised in open field, there was a 13-fold higher content of the compound in the basal parts of the petals compared with the apical parts. This difference in flavonoid content is presumed to contribute to the visual attractiveness of B. rapa flowers to insect pollinators.

Contrasting effects of invasive plants in plant-pollinator networks.

PubMed

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.

Carrion mimicry in a South African orchid: flowers attract a narrow subset of the fly assemblage on animal carcasses.

PubMed

van der Niet, Timotheüs; Hansen, Dennis M; Johnson, Steven D

2011-05-01

Although pollination of plants that attract flies by resembling their carrion brood and food sites has been reported in several angiosperm families, there has been very little work done on the level of specificity in carrion mimicry systems and the importance of plant cues in mediating such specialization. Specificity may be expected, as carrion-frequenting flies often exploit different niches, which has been interpreted as avoidance of interspecific competition. Interactions between the orchid Satyrium pumilum and a local assemblage of carrion flies were investigated, and the functional significance of floral traits, especially scent, tested. Pollination success and the incidence of pollinator-mediated self-pollination were measured and these were compared with values for orchids with sexual- and food-deceptive pollination systems. Observations of insect visitation to animal carcasses and to flowers showed that the local assemblage of carrion flies was dominated by blow flies (Calliphoridae), house flies (Muscidae) and flesh flies (Sarcophagidae), but flowers of the orchid were pollinated exclusively by flesh flies, with a strong bias towards females that sometimes deposited live larvae on flowers. A trend towards similar partitioning of fly taxa was found in an experiment that tested the effect of large versus small carrion quantities on fly attraction. GC-MS analysis showed that floral scent is dominated by oligosulfides, 2-heptanone, p-cresol and indole, compounds that also dominate carrion scent. Flesh flies did not distinguish between floral and carrion scent in a choice experiment using olfactory cues only, which also showed that scent alone is responsible for fly attraction. Pollination success was relatively high (31·5 % of flowers), but tracking of stained pollinia also revealed that a relatively high percentage (46 %) of pollen deposited on stigmas originates from the same plant. Satyrium pumilum selectively attracts flesh flies, probably because its relatively weak scent resembles that of the small carrion on which these flies predominate. In this way, the plants exploit a specific subset of the insect assemblage associated with carrion. Pollination rates and levels of self-pollination were high compared with those in other deceptive orchids and it is therefore unlikely that this mimicry system evolved to promote outcrossing.

Chemical ecology of insect-plant interactions: ecological significance of plant secondary metabolites.

PubMed

Nishida, Ritsuo

2014-01-01

Plants produce a diverse array of secondary metabolites as chemical barriers against herbivores. Many phytophagous insects are highly adapted to these allelochemicals and use such unique substances as the specific host-finding cues, defensive substances of their own, and even as sex pheromones or their precursors by selectively sensing, incorporating, and/or processing these phytochemicals. Insects also serve as pollinators often effectively guided by specific floral fragrances. This review demonstrates the ecological significance of such plant secondary metabolites in the highly diverse interactions between insects and plants.

Colour mimicry and sexual deception by Tongue orchids ( Cryptostylis)

NASA Astrophysics Data System (ADS)

Gaskett, A. C.; Herberstein, M. E.

2010-01-01

Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic ( Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids’ single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids’ bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects’ innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background.

Recent Honey Bee Colony Declines

DTIC Science & Technology

2007-06-20

climate and temperature changes,38 the effects of feed supplements that are produced from transgenic or genetically modified crops, such as high - fructose ... corn syrup ,39 and also the effects of cell phone transmissions and radiation from power lines that may be interfering with a bee’s navigational...podcasts.psu.edu/taxonomy/term/62]. Staple crops such as wheat, corn , and rice do not rely on insect pollination and are mostly wind pollinated

Neonicotinoids decrease sucrose responsiveness of honey bees at first contact.

PubMed

Démares, Fabien J; Pirk, Christian W W; Nicolson, Susan W; Human, Hannelie

2018-07-01

For two decades, neonicotinoid insecticides have been extensively used worldwide. Targeting neuronal receptors, they have deleterious effects on the behaviour and physiology of many insects. Bees are exposed to these insecticides in pollen and nectar while providing pollination services to agricultural crops, and neonicotinoids have been shown to impair navigation and decrease their foraging activity. We have previously reported the effect of dietary thiamethoxam on sucrose responsiveness of young worker bees. Here, we exposed caged foragers to sublethal acute doses of clothianidin, imidacloprid, and thiamethoxam, then tested them individually for sucrose responsiveness using standard methods. In addition, we tested the response to a range of sucrose solutions laced with neonicotinoids on bees previously unexposed to neonicotinoids. This paradigm mimics the situation where foragers would first encounter poisoned nectars varying in sugar concentration. Bees were exposed to the insecticides in the feeding solution for 24 h before testing, or in the test solutions, or both. The three compounds had a detrimental effect on responses to mid-to-high sucrose concentrations under all experimental conditions, and unexposed bees tested with laced sucrose displayed unexpected low responses to the higher sucrose concentrations tested. This attenuation of sucrose response is further evidence that neonicotinoids are multisensory disruptors, with potent actions against pollinators and other beneficial insects at first contact. Copyright © 2018 Elsevier Ltd. All rights reserved.

Shifts in water availability mediate plant-pollinator interactions.

PubMed

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.

Diversity, specificity, co-occurrence and hub taxa of the bacterial-fungal pollen microbiome.

PubMed

Manirajan, Binoy Ambika; Maisinger, Corinna; Ratering, Stefan; Rusch, Volker; Schwiertz, Andreas; Cardinale, Massimiliano; Schnell, Sylvia

2018-06-06

Flower pollen represents a unique microbial habitat, however the factors driving microbial assemblages and microbe-microbe interactions remain largely unexplored. Here we compared the structure and diversity of the bacterial-fungal microbiome between eight different pollen species (four wind-pollinated and four insect-pollinated) from close geographical locations, using high-throughput sequencing of a 16S the rRNA gene fragment (bacteria) and the internal transcribed spacer 2 (ITS2, fungi). Proteobacteria and Ascomycota were the most abundant bacterial and fungal phyla, respectively. Pseudomonas (bacterial) and Cladosporium (fungal) were the most abundant genera. Both bacterial and fungal microbiota were significantly influenced by plant species and pollination type, but showed a core microbiome consisting of 12 bacterial and 33 fungal genera. Co-occurrence analysis highlighted significant inter- and intra-kingdom interactions, and the interaction network was shaped by four bacterial hub taxa: Methylobacterium (two OTUs), Friedmanniella and Rosenbergiella. Rosenbergiella prevailed in insect-pollinated pollen and was negatively correlated with the other hubs, indicating habitat complementarity. Inter-kingdom co-occurrence showed a predominant effect of fungal on bacterial taxa. This study enhances our basic knowledge of pollen microbiota, and poses the basis for further inter- and intra-kingdom interaction studies in the plant reproductive organs.

Altitudinal, temporal and trophic partitioning of flower-visitors in Alpine communities.

PubMed

Lefebvre, Vincent; Villemant, Claire; Fontaine, Colin; Daugeron, Christophe

2018-03-16

The cross-pollination of most alpine plants depends on insects, whose altitudinal distribution is limited by temperature. However, although global warming is causing shifts in temporal and spatial species distribution, we are still largely unaware of how plant-pollinator interactions change with elevation and time along altitudinal gradients. This makes the detection of endangered interactions and species challenging. In this study, we aimed at providing such a reference, and tested if and how the major flower-visiting insect orders and families segregated by altitude, phenology and foraging preferences along an elevational gradient from 970 m to 2700 m in the Alps. Flies were the main potential pollinators from 1500 m, as bees and beetles decreased rapidly above that limit. Diptera, Coleoptera and Hymenoptera differed significantly in the angiosperm assemblages visited. Within Diptera, the predominant group, major families segregated by both phenology and foraging preferences along the gradient. Empidids, muscids and anthomyiids, whose role in pollination has never been investigated, dominated the upper part of the gradient. Our results thus suggest that flies and the peculiar plants they visit might be particularly at risk under global warming, and highlight the blatant lack of studies about critical components of these rich, yet fragile mountain ecosystems.

Caveats to quantifying ecosystem services: fruit abortion blurs benefits from crop pollination.

PubMed

Bos, Merijn M; Veddeler, Dorthe; Bogdanski, Anne K; Klein, Alexandra-Maria; Tscharntke, Teja; Steffan-Dewenter, Ingolf; Tylianakis, Jason M

2007-09-01

The recent trend to place monetary values on ecosystem services has led to studies on the economic importance of pollinators for agricultural crops. Several recent studies indicate regional, long-term pollinator declines, and economic consequences have been derived from declining pollination efficiencies. However, use of pollinator services as economic incentives for conservation must consider environmental factors such as drought, pests, and diseases, which can also limit yields. Moreover, "flower excess" is a well-known reproductive strategy of plants as insurance against unpredictable, external factors that limit reproduction. With three case studies on the importance of pollination levels for amounts of harvested fruits of three tropical crops (passion fruit in Brazil, coffee in Ecuador, and cacao in Indonesia) we illustrate how reproductive strategies and environmental stress can obscure initial benefits from improved pollination. By interpreting these results with findings from evolutionary sciences, agronomy, and studies on wild-plant populations, we argue that studies on economic benefits from pollinators should include the total of ecosystem processes that (1) lead to successful pollination and (2) mobilize nutrients and improve plant quality to the extent that crop yields indeed benefit from enhanced pollinator services. Conservation incentives that use quantifications of nature's services to human welfare will benefit from approaches at the ecosystem level that take into account the broad spectrum of biological processes that limit or deliver the service.

40 CFR 161.590 - Nontarget insect data requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... MP Data to support EP Guidelines reference No. Nontarget insect testing—pollinators Honey bee acute contact LD50 (1) [CR] [CR] [CR] [CR] [CR] [CR] TGAI TGAI 141-1 Honey bee—toxicity of residues on foliage (1), (2) CR CR CR CR CR CR TEP TEP 141-2 Honey bee subacute feeding study (3) 141-4 Field testing for...

40 CFR 161.590 - Nontarget insect data requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... MP Data to support EP Guidelines reference No. Nontarget insect testing—pollinators Honey bee acute contact LD50 (1) [CR] [CR] [CR] [CR] [CR] [CR] TGAI TGAI 141-1 Honey bee—toxicity of residues on foliage (1), (2) CR CR CR CR CR CR TEP TEP 141-2 Honey bee subacute feeding study (3) 141-4 Field testing for...

40 CFR 161.590 - Nontarget insect data requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... MP Data to support EP Guidelines reference No. Nontarget insect testing—pollinators Honey bee acute contact LD50 (1) [CR] [CR] [CR] [CR] [CR] [CR] TGAI TGAI 141-1 Honey bee—toxicity of residues on foliage (1), (2) CR CR CR CR CR CR TEP TEP 141-2 Honey bee subacute feeding study (3) 141-4 Field testing for...

40 CFR 161.590 - Nontarget insect data requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... MP Data to support EP Guidelines reference No. Nontarget insect testing—pollinators Honey bee acute contact LD50 (1) [CR] [CR] [CR] [CR] [CR] [CR] TGAI TGAI 141-1 Honey bee—toxicity of residues on foliage (1), (2) CR CR CR CR CR CR TEP TEP 141-2 Honey bee subacute feeding study (3) 141-4 Field testing for...

The Nuclear and Mitochondrial Genomes of the Facultatively Eusocial Orchid Bee Euglossa dilemma

PubMed Central

Brand, Philipp; Saleh, Nicholas; Pan, Hailin; Li, Cai; Kapheim, Karen M.; Ramírez, Santiago R.

2017-01-01

Bees provide indispensable pollination services to both agricultural crops and wild plant populations, and several species of bees have become important models for the study of learning and memory, plant–insect interactions, and social behavior. Orchid bees (Apidae: Euglossini) are especially important to the fields of pollination ecology, evolution, and species conservation. Here we report the nuclear and mitochondrial genome sequences of the orchid bee Euglossa dilemma Bembé & Eltz. E. dilemma was selected because it is widely distributed, highly abundant, and it was recently naturalized in the southeastern United States. We provide a high-quality assembly of the 3.3 Gb genome, and an official gene set of 15,904 gene annotations. We find high conservation of gene synteny with the honey bee throughout 80 MY of divergence time. This genomic resource represents the first draft genome of the orchid bee genus Euglossa, and the first draft orchid bee mitochondrial genome, thus representing a valuable resource to the research community. PMID:28701376

The Nuclear and Mitochondrial Genomes of the Facultatively Eusocial Orchid Bee Euglossa dilemma.

PubMed

Brand, Philipp; Saleh, Nicholas; Pan, Hailin; Li, Cai; Kapheim, Karen M; Ramírez, Santiago R

2017-09-07

Bees provide indispensable pollination services to both agricultural crops and wild plant populations, and several species of bees have become important models for the study of learning and memory, plant-insect interactions, and social behavior. Orchid bees (Apidae: Euglossini) are especially important to the fields of pollination ecology, evolution, and species conservation. Here we report the nuclear and mitochondrial genome sequences of the orchid bee Euglossa dilemma Bembé & Eltz. E. dilemma was selected because it is widely distributed, highly abundant, and it was recently naturalized in the southeastern United States. We provide a high-quality assembly of the 3.3 Gb genome, and an official gene set of 15,904 gene annotations. We find high conservation of gene synteny with the honey bee throughout 80 MY of divergence time. This genomic resource represents the first draft genome of the orchid bee genus Euglossa , and the first draft orchid bee mitochondrial genome, thus representing a valuable resource to the research community. Copyright © 2017 Brand et al.

Advertising to the enemy: enhanced floral fragrance increases beetle attraction and reduces plant reproduction.

PubMed

Theis, Nina; Adler, Lynn S

2012-02-01

Many organisms face challenges in avoiding predation while searching for mates. For plants, emitting floral fragrances to advertise reproductive structures could increase the attraction of detrimental insects along with pollinators. Very few studies have experimentally evaluated the costs and benefits of fragrance emission with explicit consideration of how plant fitness is affected by both pollinators and florivores. To determine the reproductive consequences of increasing the apparency of reproductive parts, we manipulated fragrance, pollination, and florivores in the wild Texas gourd, Cucurbita pepo var. texana. With enhanced fragrance we found an increase in the attraction of florivores, rather than pollinators, and a decrease in seed production. This study is the first to demonstrate that enhanced floral fragrance can increase the attraction of detrimental florivores and decrease plant reproduction, suggesting that florivory as well as pollination has shaped the evolution of floral scent.

Kin discrimination allows plants to modify investment towards pollinator attraction.

PubMed

Torices, Rubén; Gómez, José M; Pannell, John R

2018-05-22

Pollinators tend to be preferentially attracted to large floral displays that may comprise more than one plant in a patch. Attracting pollinators thus not only benefits individuals investing in advertising, but also other plants in a patch through a 'magnet' effect. Accordingly, there could be an indirect fitness advantage to greater investment in costly floral displays by plants in kin-structured groups than when in groups of unrelated individuals. Here, we seek evidence for this strategy by manipulating relatedness in groups of the plant Moricandia moricandioides, an insect-pollinated herb that typically grows in patches. As predicted, individuals growing with kin, particularly at high density, produced larger floral displays than those growing with non-kin. Investment in attracting pollinators was thus moulded by the presence and relatedness of neighbours, exemplifying the importance of kin recognition in the evolution of plant reproductive strategies.

Selection of trait combinations through bee and fly visitation to flowers of Polemonium foliosissimum.

PubMed

Campbell, D R; Forster, M; Bischoff, M

2014-02-01

Pollinators are known to exert natural selection on floral traits, but the extent to which combinations of floral traits are subject to correlational selection (nonadditive effects of two traits on fitness) is not well understood. Over two years, we used phenotypic manipulations of plant traits to test for effects of flower colour, flower shape and their interaction on rates of pollinator visitation to Polemonium foliosissimum. We also tested for correlational selection based on weighting visitation by the amount of conspecific pollen delivered per visit by each category of insect visitor. Although bumblebees were the presumed pollinators, solitary bees and flies contributed substantially (42%) to pollination. In manipulations of one trait at a time, insects visited flowers presenting the natural colour and shape over flowers manipulated to present artificial mutants with either paler colour or a more open or more tubular flower. When both colour and shape were manipulated in combination, selection on both traits arose, with bumblebees responding mainly to colour and flies responding mainly to shape. Despite selection on both floral traits, in a year with many bumblebees, we saw no evidence for correlational selection of these traits. In a year when flies predominated, fly visitation showed a pattern of correlational selection, but not favouring the natural phenotype, and correlational selection was still not detected for expected pollen receipt. These results show that flower colour and shape are subject to pollinator-mediated selection and that correlational selection can be generated based on pollinator visitation alone, but provide no evidence for correlational selection specifically for the current phenotype. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

The Impact of the Invasive Alien Plant, Impatiens glandulifera, on Pollen Transfer Networks

PubMed Central

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

Focal Plant Observations as a Standardised Method for Pollinator Monitoring: Opportunities and Limitations for Mass Participation Citizen Science.

PubMed

Roy, Helen E; Baxter, Elizabeth; Saunders, Aoine; Pocock, Michael J O

2016-01-01

Recently there has been increasing focus on monitoring pollinating insects, due to concerns about their declines, and interest in the role of volunteers in monitoring pollinators, particularly bumblebees, via citizen science. The Big Bumblebee Discovery was a one-year citizen science project run by a partnership of EDF Energy, the British Science Association and the Centre for Ecology & Hydrology which sought to assess the influence of the landscape at multiple scales on the diversity and abundance of bumblebees. Timed counts of bumblebees (Bombus spp.; identified to six colour groups) visiting focal plants of lavender (Lavendula spp.) were carried out by about 13 000 primary school children (7-11 years old) from over 4000 schools across the UK. 3948 reports were received totalling 26 868 bumblebees. We found that while the wider landscape type had no significant effect on reported bumblebee abundance, the local proximity to flowers had a significant effect (fewer bumblebees where other flowers were reported to be >5m away from the focal plant). However, the rate of mis-identifcation, revealed by photographs uploaded by participants and a photo-based quiz, was high. Our citizen science results support recent research on the importance of local flocal resources on pollinator abundance. Timed counts of insects visiting a lure plant is potentially an effective approach for standardised pollinator monitoring, engaging a large number of participants with a simple protocol. However, the relatively high rate of mis-identifications (compared to reports from previous pollinator citizen science projects) highlights the importance of investing in resources to train volunteers. Also, to be a scientifically valid method for enquiry, citizen science data needs to be sufficiently high quality, so receiving supporting evidence (such as photographs) would allow this to be tested and for records to be verified.

Plant pollinator networks along a gradient of urbanisation.

PubMed

Geslin, Benoît; Gauzens, Benoit; Thébault, Elisa; Dajoz, Isabelle

2013-01-01

Habitat loss is one of the principal causes of the current pollinator decline. With agricultural intensification, increasing urbanisation is among the main drivers of habitat loss. Consequently studies focusing on pollinator community structure along urbanisation gradients have increased in recent years. However, few studies have investigated how urbanisation affects plant-pollinator interaction networks. Here we assessed modifications of plant-pollinator interactions along an urbanisation gradient based on the study of their morphological relationships. Along an urbanisation gradient comprising four types of landscape contexts (semi-natural, agricultural, suburban, urban), we set up experimental plant communities containing two plant functional groups differing in their morphological traits ("open flowers" and "tubular flowers"). Insect visitations on these communities were recorded to build plant-pollinator networks. A total of 17 857 interactions were recorded between experimental plant communities and flower-visitors. The number of interactions performed by flower-visitors was significantly lower in urban landscape context than in semi-natural and agricultural ones. In particular, insects such as Syrphidae and solitary bees that mostly visited the open flower functional group were significantly impacted by urbanisation, which was not the case for bumblebees. Urbanisation also impacted the generalism of flower-visitors and we detected higher interaction evenness in urban landscape context than in agricultural and suburban ones. Finally, in urban context, these modifications lowered the potential reproductive success of the open flowers functional group. Our findings show that open flower plant species and their specific flower-visitors are especially sensitive to increasing urbanisation. These results provide new clues to improve conservation measures within urbanised areas in favour of specialist flower-visitors. To complete this functional approach, studies using networks resolved to the species level along urbanised gradients would be required.

Plant Pollinator Networks along a Gradient of Urbanisation

PubMed Central

Geslin, Benoît; Gauzens, Benoit; Thébault, Elisa; Dajoz, Isabelle

2013-01-01

Background Habitat loss is one of the principal causes of the current pollinator decline. With agricultural intensification, increasing urbanisation is among the main drivers of habitat loss. Consequently studies focusing on pollinator community structure along urbanisation gradients have increased in recent years. However, few studies have investigated how urbanisation affects plant-pollinator interaction networks. Here we assessed modifications of plant-pollinator interactions along an urbanisation gradient based on the study of their morphological relationships. Methodology/Principal Findings Along an urbanisation gradient comprising four types of landscape contexts (semi-natural, agricultural, suburban, urban), we set up experimental plant communities containing two plant functional groups differing in their morphological traits (“open flowers” and “tubular flowers”). Insect visitations on these communities were recorded to build plant-pollinator networks. A total of 17 857 interactions were recorded between experimental plant communities and flower-visitors. The number of interactions performed by flower-visitors was significantly lower in urban landscape context than in semi-natural and agricultural ones. In particular, insects such as Syrphidae and solitary bees that mostly visited the open flower functional group were significantly impacted by urbanisation, which was not the case for bumblebees. Urbanisation also impacted the generalism of flower-visitors and we detected higher interaction evenness in urban landscape context than in agricultural and suburban ones. Finally, in urban context, these modifications lowered the potential reproductive success of the open flowers functional group. Conclusions/Significance Our findings show that open flower plant species and their specific flower-visitors are especially sensitive to increasing urbanisation. These results provide new clues to improve conservation measures within urbanised areas in favour of specialist flower-visitors. To complete this functional approach, studies using networks resolved to the species level along urbanised gradients would be required. PMID:23717421

Floral thermogenesis: An adaptive strategy of pollination biology in Magnoliaceae

PubMed Central

Wang, Ruohan; Zhang, Zhixiang

2015-01-01

Floral thermogenesis plays a crucial role in pollination biology, especially in plant–pollinator interactions. We have recently explored how thermogenesis is related to pollinator activity and odour release in Magnolia sprengeri. By analyzing flower temperatures, emission of volatiles, and insect visitation, we found that floral blends released during pistillate and staminate stages were similar and coincided with sap beetle visitation. Thus, odour mimicry of staminate-stage flowers may occur during the pistillate stage and may be an adaptive strategy of Magnolia species to attract pollinators during both stages, ensuring successful pollination. In addition to the biological significance of floral thermogenesis in Magnolia species, we explored the underlying regulatory mechanisms via profiling miRNA expression in M. denudata flowers during thermogenic and non-thermogenic stages. We identified 17 miRNAs that may play regulatory roles in floral thermogenesis. Functional annotation of their target genes indicated that these miRNAs regulate floral thermogenesis by influencing cellular respiration and light reactions. These findings increase our understanding of plant–pollinator interactions and the regulatory mechanisms in thermogenic plants. PMID:26844867

Oilseed rape (Brassica napus) as a resource for farmland insect pollinators: quantifying floral traits in conventional varieties and breeding systems.

PubMed

Carruthers, Jonathan M; Cook, Samantha M; Wright, Geraldine A; Osborne, Juliet L; Clark, Suzanne J; Swain, Jennifer L; Haughton, Alison J

2017-08-01

Oilseed rape (OSR; Brassica napus L.) is a major crop in temperate regions and provides an important source of nutrition to many of the yield-enhancing insect flower visitors that consume floral nectar. The manipulation of mechanisms that control various crop plant traits for the benefit of pollinators has been suggested in the bid to increase food security, but little is known about inherent floral trait expression in contemporary OSR varieties or the breeding systems used in OSR breeding programmes. We studied a range of floral traits in glasshouse-grown, certified conventional varieties of winter OSR to test for variation among and within breeding systems. We measured 24-h nectar secretion rate, amount, concentration and ratio of nectar sugars per flower, and sizes and number of flowers produced per plant from 24 varieties of OSR representing open-pollinated (OP), genic male sterility (GMS) hybrid and cytoplasmic male sterility (CMS) hybrid breeding systems. Sugar concentration was consistent among and within the breeding systems; however, GMS hybrids produced more nectar and more sugar per flower than CMS hybrid or OP varieties. With the exception of ratio of fructose/glucose in OP varieties, we found that nectar traits were consistent within all the breeding systems. When scaled, GMS hybrids produced 1.73 times more nectar resource per plant than OP varieties. Nectar production and amount of nectar sugar in OSR plants were independent of number and size of flowers. Our data show that floral traits of glasshouse-grown OSR differed among breeding systems, suggesting that manipulation and enhancement of nectar rewards for insect flower visitors, including pollinators, could be included in future OSR breeding programmes.

Amino Acid Change in an Orchid Desaturase Enables Mimicry of the Pollinator’s Sex Pheromone

DOE PAGES

Sedeek, Khalid E. M.; Whittle, Edward; Guthörl, Daniela; ...

2016-05-19

Here, we show that mimicry illustrates the power of selection to produce phenotypic convergence in biology. A striking example is the imitation of female insects by plants that are pollinated by sexual deception of males of the same insect species. This involves mimicry of visual, tactile, and chemical signals of females, especially their sex pheromones. The Mediterranean orchid Ophrys exaltata employs chemical mimicry of cuticular hydrocarbons, particularly the 7-alkenes, in an insect sex pheromone to attract and elicit mating behavior in its pollinators, males of the cellophane bee Colletes cunicularius. A difference in alkene double-bond positions is responsible for reproductivemore » isolation between O. exaltata and closely related species, such as O. sphegodes. We show that these 7-alkenes are likely determined by the action of the stearoyl-acyl-carrier-protein desaturase (SAD) homolog SAD5. After gene duplication, changes in subcellular localization relative to the ancestral housekeeping desaturase may have allowed proto-SAD5’s reaction products to undergo further biosynthesis to both 7- and 9-alkenes. Such ancestral coproduction of two alkene classes may have led to pollinator-mediated deleterious pleiotropy. Despite possible evolutionary intermediates with reduced activity, amino acid changes at the bottom of the substrate-binding cavity have conferred enzyme specificity for 7-alkene biosynthesis by preventing the binding of longer-chained fatty acid (FA) precursors by the enzyme. In conclusion, this change in desaturase function enabled the orchid to perfect its chemical mimicry of pollinator sex pheromones by escape from deleterious pleiotropy, supporting a role of pleiotropy in determining the possible trajectories of adaptive evolution.« less

High Arctic flowering phenology and plant-pollinator interactions in response to delayed snow melt and simulated warming

NASA Astrophysics Data System (ADS)

Gillespie, Mark A. K.; Baggesen, Nanna; Cooper, Elisabeth J.

2016-11-01

The projected alterations to climate in the High Arctic are likely to result in changes to the short growing season, particularly with varying predicted effects on winter snowfall, the timing of summer snowmelt and air temperatures. These changes are likely to affect the phenology of interacting species in a variety of ways, but few studies have investigated the effects of combined climate drivers on plant-pollinator interactions in the High Arctic. In this study, we alter the timing of flowering phenology using a field manipulation experiment in which snow depth is increased using snow fences and temperatures are enhanced by open-top chambers (OTCs). We used this experiment to quantify the combined effects of treatments on the flowering phenology of six dominant plant species (Dryas octopetala, Cassiope tetragona, Bistorta vivipara, Saxifraga oppositifolia, Stellaria crassipes and Pedicularis hirsuita), and to simulate differing responses to climate between plants and pollinators in a subset of plots. Flowers were counted regularly throughout the growing season of 2015, and insect visitors were caught on flowers during standardised observation sessions. As expected, deep snow plots had delayed snow melt timing and this in turn delayed the first and peak flowering dates of the plants and shortened the prefloration period overall. The OTCs counteracted the delay in first and peak flowering to some extent. There was no effect of treatment on length of flowering season, although for all variables there were species-specific responses. The insect flower-visitor community was species poor, and although evidence of disruption to phenological overlaps was not found, the results do highlight the vulnerability of the plant-pollinator network in this system with differing phenological shifts between insects and plants and reduced visitation rates to flowers in plots with deep snow.

Amino Acid Change in an Orchid Desaturase Enables Mimicry of the Pollinator’s Sex Pheromone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sedeek, Khalid E. M.; Whittle, Edward; Guthörl, Daniela

Here, we show that mimicry illustrates the power of selection to produce phenotypic convergence in biology. A striking example is the imitation of female insects by plants that are pollinated by sexual deception of males of the same insect species. This involves mimicry of visual, tactile, and chemical signals of females, especially their sex pheromones. The Mediterranean orchid Ophrys exaltata employs chemical mimicry of cuticular hydrocarbons, particularly the 7-alkenes, in an insect sex pheromone to attract and elicit mating behavior in its pollinators, males of the cellophane bee Colletes cunicularius. A difference in alkene double-bond positions is responsible for reproductivemore » isolation between O. exaltata and closely related species, such as O. sphegodes. We show that these 7-alkenes are likely determined by the action of the stearoyl-acyl-carrier-protein desaturase (SAD) homolog SAD5. After gene duplication, changes in subcellular localization relative to the ancestral housekeeping desaturase may have allowed proto-SAD5’s reaction products to undergo further biosynthesis to both 7- and 9-alkenes. Such ancestral coproduction of two alkene classes may have led to pollinator-mediated deleterious pleiotropy. Despite possible evolutionary intermediates with reduced activity, amino acid changes at the bottom of the substrate-binding cavity have conferred enzyme specificity for 7-alkene biosynthesis by preventing the binding of longer-chained fatty acid (FA) precursors by the enzyme. In conclusion, this change in desaturase function enabled the orchid to perfect its chemical mimicry of pollinator sex pheromones by escape from deleterious pleiotropy, supporting a role of pleiotropy in determining the possible trajectories of adaptive evolution.« less

The pollination ecology of an assemblage of grassland asclepiads in South Africa.

PubMed

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.

The effect of blow flies (Diptera: Calliphoridae) on the size and weight of mangos (Mangifera indica L.)

PubMed Central

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

Floral scent in bird- and beetle-pollinated Protea species (Proteaceae): chemistry, emission rates and function.

PubMed

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.

The Anther Steps onto the Stigma for Self-Fertilization in a Slipper Orchid

PubMed Central

Xiao, Xin-Ju; Tsai, Wen-Chieh; Hsiao, Yu-Yun; Huang, Jie; Liu, Zhong-Jian

2012-01-01

Background Due to the spatial separation between male and female pollen grains from the anther of most flowering plants, including orchids, pollens are transported by wind or animals and deposited onto the receptive surface of the stigma of a different plant. However, self-pollination is common in pollinating animal-scarce habitats. In such habitats, self-pollinations require the assistance of a pollinating agent (e.g., wind, gravity, or floral assembly) to transport the pollen grains from the anther onto its own stigma. Methodology/Principal Findings Based on observations on floral morphology and flowering phenology, tests of the breeding system, and a comparison of pollination mechanisms, a new self-pollination process was discovered in the hermaphroditic (i.e., possessing spatially separated male and female organs) flower of a slipper orchid, Paphiopedilum parishii. The anther changes from a solid to a liquid state and directly steps onto the stigma surface without the aid of any pollinating agent or floral assembly. Conclusions The mode of self-pollination discussed here is a new addition to the broad range of genetic and morphological mechanisms that have evolved in flowering plants to ensure their reproductive success. The present self-contained pollination mechanism is a possible adaptation to the insect-scarce habitat of the orchid. PMID:22649529

Plant-pollinator interactions in tropical monsoon forests in Southeast Asia.

PubMed

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.

Pollination success following loss of a frequent pollinator: the role of compensatory visitation by other effective pollinators

PubMed Central

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

Reconstructing the origin and elaboration of insect-trapping inflorescences in the Araceae1

PubMed Central

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

Pollination ecology and the possible impacts of environmental change in the Southwest Australian Biodiversity Hotspot

PubMed Central

Phillips, Ryan D.; Hopper, Stephen D.; Dixon, Kingsley W.

2010-01-01

The Southwest Australian Biodiversity Hotspot contains an exceptionally diverse flora on an ancient, low-relief but edaphically diverse landscape. Since European colonization, the primary threat to the flora has been habitat clearance, though climate change is an impending threat. Here, we review (i) the ecology of nectarivores and biotic pollination systems in the region, (ii) the evidence that trends in pollination strategies are a consequence of characteristics of the landscape, and (iii) based on these discussions, provide predictions to be tested on the impacts of environmental change on pollination systems. The flora of southwestern Australia has an exceptionally high level of vertebrate pollination, providing the advantage of highly mobile, generalist pollinators. Nectarivorous invertebrates are primarily generalist foragers, though an increasing number of colletid bees are being recognized as being specialized at the level of plant family or more rarely genus. While generalist pollination strategies dominate among insect-pollinated plants, there are some cases of extreme specialization, most notably the multiple evolutions of sexual deception in the Orchidaceae. Preliminary data suggest that bird pollination confers an advantage of greater pollen movement and may represent a mechanism for minimizing inbreeding in naturally fragmented populations. The effects of future environmental change are predicted to result from a combination of the resilience of pollination guilds and changes in their foraging and dispersal behaviour. PMID:20047877

Pollination ecology and the possible impacts of environmental change in the Southwest Australian Biodiversity Hotspot.

PubMed

Phillips, Ryan D; Hopper, Stephen D; Dixon, Kingsley W

2010-02-12

The Southwest Australian Biodiversity Hotspot contains an exceptionally diverse flora on an ancient, low-relief but edaphically diverse landscape. Since European colonization, the primary threat to the flora has been habitat clearance, though climate change is an impending threat. Here, we review (i) the ecology of nectarivores and biotic pollination systems in the region, (ii) the evidence that trends in pollination strategies are a consequence of characteristics of the landscape, and (iii) based on these discussions, provide predictions to be tested on the impacts of environmental change on pollination systems. The flora of southwestern Australia has an exceptionally high level of vertebrate pollination, providing the advantage of highly mobile, generalist pollinators. Nectarivorous invertebrates are primarily generalist foragers, though an increasing number of colletid bees are being recognized as being specialized at the level of plant family or more rarely genus. While generalist pollination strategies dominate among insect-pollinated plants, there are some cases of extreme specialization, most notably the multiple evolutions of sexual deception in the Orchidaceae. Preliminary data suggest that bird pollination confers an advantage of greater pollen movement and may represent a mechanism for minimizing inbreeding in naturally fragmented populations. The effects of future environmental change are predicted to result from a combination of the resilience of pollination guilds and changes in their foraging and dispersal behaviour.

Reproductive biology and pollination of the carnivorous Genlisea violacea (Lentibulariaceae).

PubMed

Aranguren, Y; Płachno, B J; Stpiczyńska, M; Miranda, V F O

2018-05-01

Genlisea violacea is a Brazilian endemic carnivorous plant species distributed in the cerrado biome, mainly in humid environments, on sandy and oligotrophic soil or wet rocks. Studies on reproductive biology or pollination in the Lentibulariaceae are notably scarce; regarding the genus Genlisea, the current study is the first to show systematic and standardised research on reproductive biology from field studies to describe the foraging of visiting insects and determine the effective pollinators of Genlisea. We studied two populations of G. violacea through the observation of flower visitors for 4 months of the rainy and dry seasons. Stigmatic receptivity, pollen viability, and breeding system were evaluated together with histochemistry and morphological analyses of flowers. The flowers showed stigmatic receptivity of 100% in open buds and mature flowers, reducing to 80% for senescent flowers. Nearly 80% of pollen grains are viable, decreasing to 40-45% after 48 h. Nectar is produced by glandular trichomes inside the spur. Two bee species are effective pollinators: one of the genus Lasioglossum (subgenus Dialictus: Halictidae) and the other of the genus Ceratina (subgenus Ceratinula: family Apidae). Moreover, bee-like flies of the Syrphidae family may also be additional pollinators. Genlisea violacea is an allogamous and self-compatible species. The differences in flower-visiting fauna for both populations can be attributed to factors such as climate, anthropogenic effect, seasonal factors related to insects and plants, as well as the morphological variation of flowers in both populations. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

The conservation and restoration of wild bees.

PubMed

Winfree, Rachael

2010-05-01

Bees pollinate most of the world's wild plant species and provide economically valuable pollination services to crops; yet knowledge of bee conservation biology lags far behind other taxa such as vertebrates and plants. There are few long-term data on bee populations, which makes their conservation status difficult to assess. The best-studied groups are the genus Bombus (the bumble bees), and bees in the EU generally; both of these are clearly declining. However, it is not known to what extent these groups represent the approximately 20,000 species of bees globally. As is the case for insects in general, bees are underrepresented in conservation planning and protection efforts. For example, only two bee species are on the global IUCN Red List, and no bee is listed under the U.S. Endangered Species Act, even though many bee species are known to be in steep decline or possibly extinct. At present, bee restoration occurs mainly in agricultural contexts, funded by government programs such as agri-environment schemes (EU) and the Farm Bill (USA). This is a promising approach given that many bee species can use human-disturbed habitats, and bees provide valuable pollination services to crops. However, agricultural restorations only benefit species that persist in agricultural landscapes, and they are more expensive than preserving natural habitat elsewhere. Furthermore, such restorations benefit bees in only about half of studied cases. More research is greatly needed in many areas of bee conservation, including basic population biology, bee restoration in nonagricultural contexts, and the identification of disturbance-sensitive bee species.

Evolutionary relationships among pollinators and repeated pollinator sharing in sexually deceptive orchids.

PubMed

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.

Flower Constancy, Insect Psychology, and Plant Evolution

NASA Astrophysics Data System (ADS)

Chittka, Lars; Thomson, James D.; Waser, Nickolas M.

Individuals of some species of pollinating insects tend to restrict their visits to only a few of the available plant species, in the process bypassing valuable food sources. The question of why this flower constancy exists is a rich and important one with implications for the organization of natural communities of plants, floral evolution, and our understanding of the learning processes involved in finding food. Some scientists have assumed that flower constancy is adaptive per se. Others argued that constancy occurs because memory capacity for floral features in insects is limited, but attempts to identify the limitations often remained rather simplistic. We elucidate now different sensory and motor memories from natural foraging tasks are stored and retrieved, using concepts from modern learning science and visual search, and conclude that flower constancy is likely to have multiple causes. Possible constraints favoring constancy are interference sensitivity of short-term memory, and temporal limitations on retrieving information from long-term memory as rapidly as from short-term memory, but further empirical evidence is needed to substantiate these possibilities. In addition, retrieving memories may be slower and more prone to errors when there are several options than when an insect copes with only a single task. In addition to memory limitations, we also point out alternative explanations for flower constancy. We then consider the way in which floral parameters, such as interplant distances, nectar rewards, flower morphology, and floral color (as seen through bees' eyes) affect constancy. Finally, we discuss the implications of pollinator constancy for plant evolution. To date there is no evidence that flowers have diverged to favor constancy, although the appropriate tests may not have yet been conducted. However, there is good evidence against the notion that pollinator constancy is involved in speciation or maintenance of plant species integrity.

Compilation of 1986 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 2. TABS D-G.

DTIC Science & Technology

1987-07-01

8217. -. , i U ELF ECOLOGICAL MONITORING PROGRAM INDEX OF 1986 ANNUAL REPORTS A. Herbaceous Plant Cover and Tree Studies \\ Michigan Technological University...SUBCONTRACT NUMBER EO 6549-84-C-005 LELF Communications System Ecological Monitoring Program BIOLOGICAL STUDIES ON POLLINATING INSECTS: MEGACHILID...such as those in the vicinity of the ELF antenna because they are pollinators of flowering plants , and are therefore important to the reproductive

Identifying pollination service hotspots and coldspots using citizen science data from the Great Sunflower Project

NASA Astrophysics Data System (ADS)

LeBuhn, G.; Schmucki, R.

2016-12-01

Identifying the spatial patterns of pollinator visitation rates is key to identifying the drivers of differences in pollination service and the areas where pollinator conservation will provide the highest return on investment. However, gathering pollinator abundance data at the appropriate regional and national scales is untenable. As a surrogate, habitat models have been developed to identify areas of pollinator losses but these models have been developed using expert opinion based on foraging and nesting requirements. Thousands of citizen scientists across the United States participating in The Great Sunflower Project (www.GreatSunflower.org) contribute timed counts of pollinator visits to a focal sunflower variety planted in local gardens and green spaces. While these data provide a more direct measure of pollination service to a standardized plant and include a measure of effort, the data are complicated. Each location is sampled at different dates, times and frequencies as well as different points across the local flight season. To overcome this complication, we have used a generalized additive model to generate regional flight curves to calibrate each individual data point and to attain better estimates of pollination service at each site. Using these flight season corrected data, we identify hotspots and cold spots in pollinator service across the United States, evaluate the drivers shaping the spatial patterns and observe how these data align with the results obtained from predictive models that are based on expert knowledge on foraging and nesting habitats.

Yeasts in nectar of an early-blooming herb: sought by bumble bees, detrimental to plant fecundity.

PubMed

Herrera, Carlos M; Pozo, María I; Medrano, Mónica

2013-02-01

Through their effects on physicochemical features of floral nectar, nectar-dwelling yeasts can alter pollinator behavior, but the effect of such changes on pollination success and plant reproduction is unknown. We present results of experiments testing the effects of nectar yeasts on foraging patterns of captive and free-ranging bumble bees, and also on pollination success and fecundity of the early-blooming, bumble bee-pollinated Helleborus foetidus (Ranunculaceae). Under controlled experimental conditions, inexperienced Bombus terrestris workers responded positively to the presence of yeasts in artificial sugar solutions mimicking floral nectar by visiting proportionally more yeast-containing artificial flowers. Free-ranging bumble bees also preferred yeast-containing nectar in the field. Experiments conducted in two different years consistently showed that natural and artificial nectars containing yeasts were more thoroughly removed than nectars without yeasts. Experimental yeast inoculation of the nectar of H. foetidus flowers was significantly associated with reductions in number of pollen tubes in the style, fruit set, seed set, and mass of individual seeds produced. These results provide the first direct evidence to date that nectar yeasts can modify pollinator foraging patterns, pollination success, and the quantity and quality of seeds produced by insect-pollinated plants.

Breeding system and pollination of a narrowly endemic herb of the Lower Florida Keys: impacts of the urban-wildland interface.

PubMed

Liu, Hong; Koptur, Suzanne

2003-08-01

We examined the breeding system and pollination of Chamaecrista keyensis Pennell (Fabaceae: Caesalpinioideae) and the effects of urban edge and mosquito control on reproduction of this rare endemic herb of the Lower Florida Keys. Controlled hand-pollination treatments were applied to plants in the field. Although C. keyensis flowers are self-compatible, they are not capable of automatic selfing. Inbreeding depression was observed in both seed set and percentage seed germination. Bees of seven genera were observed visiting C. keyensis flowers during the peak flowering season (June to July). Only Xylocopa micans and Melissodes spp. may be effective pollinators for C. keyensis, as they were the only bees that "buzz pollinate" this species, which has poricidal anther dehiscence. Chamaecrista keyensis received substantially more visits by X. micans, but fewer visits from Melissodes spp. in urban-edge vs. forest sites. Aerial mosquito spraying may exacerbate the existing pollinator limitation suffered by C. keyensis by reducing the number of visits by the buzz-pollinating bees. Individuals of C. keyensis at urban edges produced fewer seeds per fruit than did individuals in a pristine forest mainly because of greater insect seed predation.

Bee species diversity enhances productivity and stability in a perennial crop.

PubMed

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.

Are pollinating hawk moths declining in the Northeastern United States? An analysis of collection records

PubMed Central

2017-01-01

Increasing attention to pollinators and their role in providing ecosystem services has revealed a paucity of studies on long-term population trends of most insect pollinators in many parts of the world. Because targeted monitoring programs are resource intensive and unlikely to be performed on most insect pollinators, we took advantage of existing collection records to examine long-term trends in northeastern United States populations of 26 species of hawk moths (family Sphingidae) that are presumed to be pollinators. We compiled over 6,600 records from nine museum and 14 private collections that spanned a 112-year period, and used logistic generalized linear mixed models (GLMMs) to examine long-term population trends. We controlled for uneven sampling effort by adding a covariate for list length, the number of species recorded during each sampling event. We found that of the 22 species for which there was sufficient data to assess population trends, eight species declined and four species increased in detection probability (the probability of a species being recorded during each year while accounting for effort, climate, and spatial effects in the GLMMs). Of the four species with too few records to statistically assess, two have disappeared from parts of their ranges. None of the four species with diurnal adults showed a trend in detection probability. Two species that are pests of solanaceous crops declined, consistent with a seven-fold drop in the area planted in tobacco and tomato crops. We found some evidence linking susceptibility to parasitoidism by the introduced fly Compsilura concinnata (Tachinidae) to declines. Moths with larvae that feed on vines and trees, where available evidence indicates that the fly is most likely to attack, had a greater propensity to decline than species that use herbs and shrubs as larval host plants. Species that develop in the spring, before Compsilura populations have increased, did not decline. However, restricting the analysis to hawk moth records from areas outside of a “refuge” area where Compsilura does not occur did not significantly increase the intensity of the declines as would be predicted if Compsilura was the primary cause of declines. Forests have recovered over the study period across most of the northeastern U.S., but this does not appear to have been a major factor because host plants of several of the declining species have increased in abundance with forest expansion and maturation. Climate variables used in the GLMMs were not consistently related to moth detection probability. Hawk moth declines may have ecological effects on both the plants pollinated by these species and vertebrate predators of the moths. PMID:28982152

Habitat and forage associations of a naturally colonising insect pollinator, the tree bumblebee Bombus hypnorum.

PubMed

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.

Patterns of odour emission, thermogenesis and pollinator activity in cones of an African cycad: what mechanisms apply?

PubMed Central

Suinyuy, Terence N.; Donaldson, John S.; Johnson, Steven D.

2013-01-01

Background and Aims Ontogenetic patterns of odour emissions and heating associated with plant reproductive structures may have profound effects on insect behaviour, and consequently on pollination. In some cycads, notably Macrozamia, temporal changes in emission of specific odour compounds and temperature have been interpreted as a ‘push–pull’ interaction in which pollinators are either attracted or repelled according to the concentration of the emitted volatiles. To establish which mechanisms occur in the large Encephalartos cycad clade, the temporal patterns of volatile emissions, heating and pollinator activity of cones of Encephalartos villosus in the Eastern Cape (EC) and KwaZulu Natal (KZN) of South Africa were investigated. Methods and Key Results Gas chromatography–mass spectrometry (GC-MS) analyses of Encephalartos villosus cone volatiles showed that emissions, dominated by eucalyptol and 2-isopropyl-3-methoxypyrazine in EC populations and (3E)-1,3-octadiene and (3E,5Z)-1,3,5-octatriene in the KZN populations, varied across developmental stages but did not vary significantly on a daily cycle. Heating in male cones was higher at dehiscence than during pre- and post-dehiscence, and reached a maximum at about 1830 h when temperatures were between 7·0 and 12·0 °C above ambient. Daily heating of female cones was less pronounced and reached a maximum at about 1345 h when it was on average between 0·9 and 3·0 °C above ambient. Insect abundance on male cones was higher at dehiscence than at the other stages and significantly higher in the afternoon than in the morning and evening. Conclusions There are pronounced developmental changes in volatile emissions and heating in E. villosus cones, as well as strong daily changes in thermogenesis. Daily patterns of volatile emissions and pollinator abundance in E. villosus are different from those observed in some Macrozamia cycads and not consistent with the push–pull pattern as periods of peak odour emission do not coincide with mass exodus of insects from male cones. PMID:23887092

Carrion mimicry in a South African orchid: flowers attract a narrow subset of the fly assemblage on animal carcasses

PubMed Central

van der Niet, Timotheüs; Hansen, Dennis M.; Johnson, Steven D.

2011-01-01

Background and Aims Although pollination of plants that attract flies by resembling their carrion brood and food sites has been reported in several angiosperm families, there has been very little work done on the level of specificity in carrion mimicry systems and the importance of plant cues in mediating such specialization. Specificity may be expected, as carrion-frequenting flies often exploit different niches, which has been interpreted as avoidance of interspecific competition. Interactions between the orchid Satyrium pumilum and a local assemblage of carrion flies were investigated, and the functional significance of floral traits, especially scent, tested. Pollination success and the incidence of pollinator-mediated self-pollination were measured and these were compared with values for orchids with sexual- and food-deceptive pollination systems. Methods and Key Results Observations of insect visitation to animal carcasses and to flowers showed that the local assemblage of carrion flies was dominated by blow flies (Calliphoridae), house flies (Muscidae) and flesh flies (Sarcophagidae), but flowers of the orchid were pollinated exclusively by flesh flies, with a strong bias towards females that sometimes deposited live larvae on flowers. A trend towards similar partitioning of fly taxa was found in an experiment that tested the effect of large versus small carrion quantities on fly attraction. GC-MS analysis showed that floral scent is dominated by oligosulfides, 2-heptanone, p-cresol and indole, compounds that also dominate carrion scent. Flesh flies did not distinguish between floral and carrion scent in a choice experiment using olfactory cues only, which also showed that scent alone is responsible for fly attraction. Pollination success was relatively high (31·5 % of flowers), but tracking of stained pollinia also revealed that a relatively high percentage (46 %) of pollen deposited on stigmas originates from the same plant. Conclusions Satyrium pumilum selectively attracts flesh flies, probably because its relatively weak scent resembles that of the small carrion on which these flies predominate. In this way, the plants exploit a specific subset of the insect assemblage associated with carrion. Pollination rates and levels of self-pollination were high compared with those in other deceptive orchids and it is therefore unlikely that this mimicry system evolved to promote outcrossing. PMID:21402538

The pollination mechanism in Trigonidium obtusum Lindl (Orchidaceae: Maxillariinae): sexual mimicry and trap-flowers.

PubMed

Singer, Rodrigo B

2002-02-01

The pollination process in Trigonidium obtusum Lindl. (Epidendroideae: Maxillariinae) is documented. The flowers are pollinated by sexually excited drones of Plebeia droryana (Meliponinae). When attempting to copulate either with sepals or petals, these bees slip on the waxy perianth surface and become trapped in the funnel-like flower tube. Bees trying to escape from the flowers may instead access the space between the column and lip, fixing the pollinarium on their scutellum. Pollinarium-bearing bees may pollinate the flowers when repeating the above-mentioned steps, leaving pollinia on the concave stigmatic surface, thus effecting pollination. Recently removed pollinaria are too broad to enter the stigma but they begin to dehydrate and within 40 min of removal are small enough to fit the stigmatic cavity. This mechanism prevents insect-mediated self-pollination and promotes cross-pollination. Preliminary evidence based on experiments with cultivated plants suggests that they are self-compatible but that fruit set is pollinator-dependent. The data obtained are discussed in a phylogenetic context. It is suggested that the pseudocopulatory syndrome in Trigonidium could have evolved from rewardless (food advertising) ancestors. Pseudocopulation in the context of the long flowering period of this orchid species (about 7 months) is understandable since the eusocial Plebeia bees produce fertile individuals several times a year.

Pollination niche overlap between a parasitic plant and its host.

PubMed

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.

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.

Stigma Sensitivity and the Duration of Temporary Closure Are Affected by Pollinator Identity in Mazus miquelii (Phrymaceae), a Species with Bilobed Stigma.

PubMed

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.

Synergistic effects of non-Apis bees and honey bees for pollination services

PubMed Central

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

Interactive effects among ecosystem services and management practices on crop production: pollination in coffee agroforestry systems.

PubMed

Boreux, Virginie; Kushalappa, Cheppudira G; Vaast, Philippe; Ghazoul, Jaboury

2013-05-21

Crop productivity is improved by ecosystem services, including pollination, but this should be set in the context of trade-offs among multiple management practices. We investigated the impact of pollination services on coffee production, considering variation in fertilization, irrigation, shade cover, and environmental variables such as rainfall (which stimulates coffee flowering across all plantations), soil pH, and nitrogen availability. After accounting for management interventions, bee abundance improved coffee production (number of berries harvested). Some management interventions, such as irrigation, used once to trigger asynchronous flowering, dramatically increased bee abundance at coffee trees. Others, such as the extent and type of tree cover, revealed interacting effects on pollination and, ultimately, crop production. The effects of management interventions, notably irrigation and addition of lime, had, however, far more substantial positive effects on coffee production than tree cover. These results suggest that pollination services matter, but managing the asynchrony of flowering was a more effective tool for securing good pollination than maintaining high shade tree densities as pollinator habitat. Complex interactions across farm and landscape scales, including both management practices and environmental conditions, shape pollination outcomes. Effective production systems therefore require the integrated consideration of management practices in the context of the surrounding habitat structure. This paper points toward a more strategic use of ecosystem services in agricultural systems, where ecosystem services are shaped by the coupling of management interventions and environmental variables.

Neonicotinoid pesticide exposure impairs crop pollination services provided by bumblebees

NASA Astrophysics Data System (ADS)

Stanley, Dara A.; Garratt, Michael P. D.; Wickens, Jennifer B.; Wickens, Victoria J.; Potts, Simon G.; Raine, Nigel E.

2015-12-01

Recent concern over global pollinator declines has led to considerable research on the effects of pesticides on bees. Although pesticides are typically not encountered at lethal levels in the field, there is growing evidence indicating that exposure to field-realistic levels can have sublethal effects on bees, affecting their foraging behaviour, homing ability and reproductive success. Bees are essential for the pollination of a wide variety of crops and the majority of wild flowering plants, but until now research on pesticide effects has been limited to direct effects on bees themselves and not on the pollination services they provide. Here we show the first evidence to our knowledge that pesticide exposure can reduce the pollination services bumblebees deliver to apples, a crop of global economic importance. Bumblebee colonies exposed to a neonicotinoid pesticide provided lower visitation rates to apple trees and collected pollen less often. Most importantly, these pesticide-exposed colonies produced apples containing fewer seeds, demonstrating a reduced delivery of pollination services. Our results also indicate that reduced pollination service delivery is not due to pesticide-induced changes in individual bee behaviour, but most likely due to effects at the colony level. These findings show that pesticide exposure can impair the ability of bees to provide pollination services, with important implications for both the sustained delivery of stable crop yields and the functioning of natural ecosystems.

In situ modeling of multimodal floral cues attracting wild pollinators across environments

PubMed Central

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

Pollen Foraging Differences Among Three Managed Pollinators in the Highbush Blueberry (Vaccinium corymbosum) Agroecosystem.

PubMed

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.

Land-use change reduces habitat suitability for supporting managed honey bee colonies in the Northern Great Plains

USGS Publications Warehouse

Otto, Clint R.; Roth, Cali; Carlson, Benjamin; Smart, Matthew

2016-01-01

Human reliance on insect pollination services continues to increase even as pollinator populations exhibit global declines. Increased commodity crop prices and federal subsidies for biofuel crops, such as corn and soybeans, have contributed to rapid land-use change in the US Northern Great Plains (NGP), changes that may jeopardize habitat for honey bees in a part of the country that supports >40% of the US colony stock. We investigated changes in biofuel crop production and grassland land covers surrounding ∼18,000 registered commercial apiaries in North and South Dakota from 2006 to 2014. We then developed habitat selection models to identify remotely sensed land-cover and land-use features that influence apiary site selection by Dakota beekeepers. Our study demonstrates a continual increase in biofuel crops, totaling 1.2 Mha, around registered apiary locations in North and South Dakota. Such crops were avoided by commercial beekeepers when selecting apiary sites in this region. Furthermore, our analysis reveals how grasslands that beekeepers target when selecting commercial apiary locations are becoming less common in eastern North and South Dakota, changes that may have lasting impact on pollinator conservation efforts. Our study highlights how land-use change in the NGP is altering the landscape in ways that are seemingly less conducive to beekeeping. Our models can be used to guide future conservation efforts highlighted in the US national pollinator health strategy by identifying areas that support high densities of commercial apiaries and that have exhibited significant land-use changes.

Land-use change reduces habitat suitability for supporting managed honey bee colonies in the Northern Great Plains

PubMed Central

Otto, Clint R. V.; Roth, Cali L.; Carlson, Benjamin L.; Smart, Matthew D.

2016-01-01

Human reliance on insect pollination services continues to increase even as pollinator populations exhibit global declines. Increased commodity crop prices and federal subsidies for biofuel crops, such as corn and soybeans, have contributed to rapid land-use change in the US Northern Great Plains (NGP), changes that may jeopardize habitat for honey bees in a part of the country that supports >40% of the US colony stock. We investigated changes in biofuel crop production and grassland land covers surrounding ∼18,000 registered commercial apiaries in North and South Dakota from 2006 to 2014. We then developed habitat selection models to identify remotely sensed land-cover and land-use features that influence apiary site selection by Dakota beekeepers. Our study demonstrates a continual increase in biofuel crops, totaling 1.2 Mha, around registered apiary locations in North and South Dakota. Such crops were avoided by commercial beekeepers when selecting apiary sites in this region. Furthermore, our analysis reveals how grasslands that beekeepers target when selecting commercial apiary locations are becoming less common in eastern North and South Dakota, changes that may have lasting impact on pollinator conservation efforts. Our study highlights how land-use change in the NGP is altering the landscape in ways that are seemingly less conducive to beekeeping. Our models can be used to guide future conservation efforts highlighted in the US national pollinator health strategy by identifying areas that support high densities of commercial apiaries and that have exhibited significant land-use changes. PMID:27573824

Sunflower (Helianthus annuus) pollination in California's Central Valley is limited by native bee nest site location.

PubMed

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.

Flight of the bumble bee: Buzzes predict pollination services.

PubMed

Miller-Struttmann, Nicole E; Heise, David; Schul, Johannes; Geib, Jennifer C; Galen, Candace

2017-01-01

Multiple interacting factors drive recent declines in wild and managed bees, threatening their pollination services. Widespread and intensive monitoring could lead to more effective management of wild and managed bees. However, tracking their dynamic populations is costly. We tested the effectiveness of an inexpensive, noninvasive and passive acoustic survey technique for monitoring bumble bee behavior and pollination services. First, we assessed the relationship between the first harmonic of the flight buzz (characteristic frequency) and pollinator functional traits that influence pollination success using flight cage experiments and a literature search. We analyzed passive acoustic survey data from three locations on Pennsylvania Mountain, Colorado to estimate bumble bee activity. We developed an algorithm based on Computational Auditory Scene Analysis that identified and quantified the number of buzzes recorded in each location. We then compared visual and acoustic estimates of bumble bee activity. Using pollinator exclusion experiments, we tested the power of buzz density to predict pollination services at the landscape scale for two bumble bee pollinated alpine forbs (Trifolium dasyphyllum and T. parryi). We found that the characteristic frequency was correlated with traits known to affect pollination efficacy, explaining 30-52% of variation in body size and tongue length. Buzz density was highly correlated with visual estimates of bumble bee density (r = 0.97), indicating that acoustic signals are predictive of bumble bee activity. Buzz density predicted seed set in two alpine forbs when bumble bees were permitted access to the flowers, but not when they were excluded from visiting. Our results indicate that acoustic signatures of flight can be deciphered to monitor bee activity and pollination services to bumble bee pollinated plants. We propose that applications of this technique could assist scientists and farmers in rapidly detecting and responding to bee population declines.

Flight of the bumble bee: Buzzes predict pollination services

PubMed Central

Heise, David; Schul, Johannes; Geib, Jennifer C.; Galen, Candace

2017-01-01

Multiple interacting factors drive recent declines in wild and managed bees, threatening their pollination services. Widespread and intensive monitoring could lead to more effective management of wild and managed bees. However, tracking their dynamic populations is costly. We tested the effectiveness of an inexpensive, noninvasive and passive acoustic survey technique for monitoring bumble bee behavior and pollination services. First, we assessed the relationship between the first harmonic of the flight buzz (characteristic frequency) and pollinator functional traits that influence pollination success using flight cage experiments and a literature search. We analyzed passive acoustic survey data from three locations on Pennsylvania Mountain, Colorado to estimate bumble bee activity. We developed an algorithm based on Computational Auditory Scene Analysis that identified and quantified the number of buzzes recorded in each location. We then compared visual and acoustic estimates of bumble bee activity. Using pollinator exclusion experiments, we tested the power of buzz density to predict pollination services at the landscape scale for two bumble bee pollinated alpine forbs (Trifolium dasyphyllum and T. parryi). We found that the characteristic frequency was correlated with traits known to affect pollination efficacy, explaining 30–52% of variation in body size and tongue length. Buzz density was highly correlated with visual estimates of bumble bee density (r = 0.97), indicating that acoustic signals are predictive of bumble bee activity. Buzz density predicted seed set in two alpine forbs when bumble bees were permitted access to the flowers, but not when they were excluded from visiting. Our results indicate that acoustic signatures of flight can be deciphered to monitor bee activity and pollination services to bumble bee pollinated plants. We propose that applications of this technique could assist scientists and farmers in rapidly detecting and responding to bee population declines. PMID:28591213

Firm efficiency and returns-to-scale in the honey bee pollination services industry

USDA-ARS?s Scientific Manuscript database

Honeybees are well-known for producing honey, but they also provide critical ecosystem services through pollination (Goulson, 2003; Potts et al., 2010; Ványi et al., 2012). This pollination service is vital to the production of many cash crops, on which the U.S. agricultural sector depends (Aizen an...

Complementary ecosystem services provided by pest predators and pollinators increase quantity and quality of coffee yields

PubMed Central

Classen, Alice; Peters, Marcell K.; Ferger, Stefan W.; Helbig-Bonitz, Maria; Schmack, Julia M.; Maassen, Genevieve; Schleuning, Matthias; Kalko, Elisabeth K. V.; Böhning-Gaese, Katrin; Steffan-Dewenter, Ingolf

2014-01-01

Wild animals substantially support crop production by providing ecosystem services, such as pollination and natural pest control. However, the strengths of synergies between ecosystem services and their dependencies on land-use management are largely unknown. Here, we took an experimental approach to test the impact of land-use intensification on both individual and combined pollination and pest control services in coffee production systems at Mount Kilimanjaro. We established a full-factorial pollinator and vertebrate exclosure experiment along a land-use gradient from traditional homegardens (agroforestry systems), shaded coffee plantations to sun coffee plantations (total sample size = 180 coffee bushes). The exclusion of vertebrates led to a reduction in fruit set of ca 9%. Pollinators did not affect fruit set, but significantly increased fruit weight of coffee by an average of 7.4%. We found no significant decline of these ecosystem services along the land-use gradient. Pest control and pollination service were thus complementary, contributing to coffee production by affecting the quantity and quality of a major tropical cash crop across different coffee production systems at Mount Kilimanjaro. PMID:24500173

Complementary ecosystem services provided by pest predators and pollinators increase quantity and quality of coffee yields.

PubMed

Classen, Alice; Peters, Marcell K; Ferger, Stefan W; Helbig-Bonitz, Maria; Schmack, Julia M; Maassen, Genevieve; Schleuning, Matthias; Kalko, Elisabeth K V; Böhning-Gaese, Katrin; Steffan-Dewenter, Ingolf

2014-03-22

Wild animals substantially support crop production by providing ecosystem services, such as pollination and natural pest control. However, the strengths of synergies between ecosystem services and their dependencies on land-use management are largely unknown. Here, we took an experimental approach to test the impact of land-use intensification on both individual and combined pollination and pest control services in coffee production systems at Mount Kilimanjaro. We established a full-factorial pollinator and vertebrate exclosure experiment along a land-use gradient from traditional homegardens (agroforestry systems), shaded coffee plantations to sun coffee plantations (total sample size = 180 coffee bushes). The exclusion of vertebrates led to a reduction in fruit set of ca 9%. Pollinators did not affect fruit set, but significantly increased fruit weight of coffee by an average of 7.4%. We found no significant decline of these ecosystem services along the land-use gradient. Pest control and pollination service were thus complementary, contributing to coffee production by affecting the quantity and quality of a major tropical cash crop across different coffee production systems at Mount Kilimanjaro.

Compilation of 1989 Annual Reports of the Navy ELF Communications System Ecological Monitoring Program. Volume 2. Tabs C-F

DTIC Science & Technology

1990-08-01

in ecological communities such as those in the vicinity of the ELF antenna because they are pollinators of flowering plants , and are therefore...I I IITRI E06620-4 Page v I I ELF COMMUNICATIONS SYSTEM ECOLOGICAL MONITORING PROGRAM I INDEX OF 1989 ANNUAL REPORTS I A. Herbaceous Plant Cover and...Communications System Ecological Monitoring Program; BIOLOGICAL STUDIES ON POLLINATING INSECTS: MEGACHILID BEES Reporting year: 11/1/88 - 10/31/89 5 Prepared by

Pollination by sexual mimicry in Mormolyca ringens: a floral chemistry that remarkably matches the pheromones of virgin queens of Scaptotrigona sp.

PubMed

Flach, Adriana; Marsaioli, Anita J; Singer, Rodrigo B; Amaral, Maria do Carmo E; Menezes, Cristiano; Kerr, Warwick Estevam; Batista-Pereira, Luciane G; Corrêa, Arlene G

2006-01-01

The chemical composition of some volatile (2-heptanol) and nonvolatile constituents (a homologous 9-alkene/alkane series) of Mormolyca ringens flowers and Scaptotrigona sp. queen waxes (homologous 9-alkene/alkane series) and cephalic extracts (homologous series of 2-alkanols, including 2-heptanol) involved with the pseudocopulation or sexual mimicry in Orchidaceae pollination is compared. The similarity in chemical composition of flowers and insects is assigned to the chemically induced copulatory activity in Scaptotrigona males.

Pollination Reservoirs in Lowbush Blueberry (Ericales: Ericaceae).

PubMed

Venturini, E M; Drummond, F A; Hoshide, A K; Dibble, A C; Stack, L B

2017-04-01

Pollinator-dependent agriculture heavily relies upon a single pollinator-the honey bee. To diversify pollination strategies, growers are turning to alternatives. Densely planted reservoirs of pollen- and nectar-rich flowers (pollination reservoirs, hereafter "PRs") may improve pollination services provided by wild bees. Our focal agroecosystem, lowbush blueberry (Vaccinium angustifolium Aiton), exists in a simple landscape uniquely positioned to benefit from PRs. First, we contrast bee visitation rates and use of three types of PR. We consider the effects of PRs on wild bee diversity and the composition of bumble bee pollen loads. We contrast field-level crop pollination services between PRs and controls four years postestablishment. Last, we calculate the time to pay for PR investment. Social bees preferentially used clover plantings; solitary bees preferentially used wildflower plantings. On average, bumble bee pollen loads in treatment fields contained 37% PR pollen. PRs significantly increased visitation rates to the crop in year 4, and exerted a marginally significant positive influence on fruit set. The annualized costs of PRs were covered by the fourth year using the measured increase in pollination services. Our findings provide evidence of the positive impact of PRs on crop pollination services. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Honey bee hairs and pollenkitt are essential for pollen capture and removal.

PubMed

Amador, Guillermo J; Matherne, Marguerite; Waller, D'Andre; Mathews, Megha; Gorb, Stanislav N; Hu, David L

2017-03-23

While insect grooming has been observed and documented for over one hundred years, we present the first quantitative analysis of this highly dynamic process. Pollinating insects, like honey bees, purposely cover themselves with millions of pollen particles that, if left ungroomed, would make sensing and controlled flight difficult. How do they get clean? We show that the hairs on insect eyes are tuned to the pollen they collect; namely, the hairs are spaced so that they suspend pollen above the body for easy removal by the forelegs. In turn, hair spacing on the foreleg dictates the leg's ability to store the pollen removed during each swipe. In tests with wax-covered honey bees, we show that hairy forelegs are necessary for pollen removal. Moreover, the viscous fluid found on the surface of pollen grains, or pollenkitt, greatly enhances adhesion. We find that bees accumulate twice as much pollen if pollenkitt is present. This study may help further understand pollination, as well as inform designs for mechanically-sensitive functional surfaces with micro- and nano-structures that are easier to keep clean.

Pollination Requirements of Almond (Prunus dulcis): Combining Laboratory and Field Experiments.

PubMed

Henselek, Yuki; Eilers, Elisabeth J; Kremen, Claire; Hendrix, Stephen D; Klein, Alexandra-Maria

2018-05-28

Almond (Prunus dulcis (Mill.) D. A. Webb; Rosales: Rosaceae) is a cash crop with an estimated global value of over seven billion U.S. dollars annually and commercial varieties are highly dependent on insect pollination. Therefore, the understanding of basic pollination requirements of the main varieties including pollination efficiency of honey bees (Apis mellifera, Linnaeus, Hymenoptera: Apidae) and wild pollinators is essential for almond production. We first conducted two lab experiments to examine the threshold number of pollen grains needed for successful pollination and to determine if varietal identity or diversity promotes fruit set and weight. Further, we examined stigma and ovules of flowers visited by Apis and non-Apis pollinators in the field to study the proportion of almond to non-almond pollen grains deposited, visitation time per flower visit, and tube set. Results indicate that the threshold for successful fertilization is around 60 pollen grains, but pollen can be from any compatible variety as neither pollen varietal identity nor diversity enhanced fruit set or weight. Andrena cerasifolii Cockerell (Hymenoptera: Andrenidae) was a more effective pollinator on a per single visit basis than Apis and syrphid flies. Nevertheless, Apis was more efficient than A. cerasifolii and syrphid flies as they spent less time on a flower during a single visit. Hence, planting with two compatible varieties and managing for both Apis and non-Apis pollinators is likely to be an optimal strategy for farmers to secure high and stable pollination success.

Generalization versus Specialization in Pollination Systems: Visitors, Thieves, and Pollinators of Hypoestes aristata (Acanthaceae)

PubMed Central

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

Generalization versus specialization in pollination systems: visitors, thieves, and pollinators of Hypoestes aristata (Acanthaceae).

PubMed

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.

Wild bees enhance honey bees’ pollination of hybrid sunflower

PubMed Central

Greenleaf, Sarah S.; Kremen, Claire

2006-01-01

Pollinators are required for producing 15–30% of the human food supply, and farmers rely on managed honey bees throughout the world to provide these services. Yet honey bees are not always the most efficient pollinators of all crops and are declining in various parts of the world. Crop pollination shortages are becoming increasingly common. We found that behavioral interactions between wild and honey bees increase the pollination efficiency of honey bees on hybrid sunflower up to 5-fold, effectively doubling honey bee pollination services on the average field. These indirect contributions caused by interspecific interactions between wild and honey bees were more than five times more important than the contributions wild bees make to sunflower pollination directly. Both proximity to natural habitat and crop planting practices were significantly correlated with pollination services provided directly and indirectly by wild bees. Our results suggest that conserving wild habitat at the landscape scale and altering selected farm management techniques could increase hybrid sunflower production. These findings also demonstrate the economic importance of interspecific interactions for ecosystem services and suggest that protecting wild bee populations can help buffer the human food supply from honey bee shortages. PMID:16940358

Wild bees enhance honey bees' pollination of hybrid sunflower.

PubMed

Greenleaf, Sarah S; Kremen, Claire

2006-09-12

Pollinators are required for producing 15-30% of the human food supply, and farmers rely on managed honey bees throughout the world to provide these services. Yet honey bees are not always the most efficient pollinators of all crops and are declining in various parts of the world. Crop pollination shortages are becoming increasingly common. We found that behavioral interactions between wild and honey bees increase the pollination efficiency of honey bees on hybrid sunflower up to 5-fold, effectively doubling honey bee pollination services on the average field. These indirect contributions caused by interspecific interactions between wild and honey bees were more than five times more important than the contributions wild bees make to sunflower pollination directly. Both proximity to natural habitat and crop planting practices were significantly correlated with pollination services provided directly and indirectly by wild bees. Our results suggest that conserving wild habitat at the landscape scale and altering selected farm management techniques could increase hybrid sunflower production. These findings also demonstrate the economic importance of interspecific interactions for ecosystem services and suggest that protecting wild bee populations can help buffer the human food supply from honey bee shortages.

Pollination Reservoirs in Lowbush Blueberry (Ericales: Ericaceae)

PubMed Central

Drummond, F. A.; Hoshide, A. K.; Dibble, A. C.; Stack, L. B.

2017-01-01

Abstract Pollinator-dependent agriculture heavily relies upon a single pollinator—the honey bee. To diversify pollination strategies, growers are turning to alternatives. Densely planted reservoirs of pollen- and nectar-rich flowers (pollination reservoirs, hereafter “PRs”) may improve pollination services provided by wild bees. Our focal agroecosystem, lowbush blueberry (Vaccinium angustifolium Aiton), exists in a simple landscape uniquely positioned to benefit from PRs. First, we contrast bee visitation rates and use of three types of PR. We consider the effects of PRs on wild bee diversity and the composition of bumble bee pollen loads. We contrast field-level crop pollination services between PRs and controls four years postestablishment. Last, we calculate the time to pay for PR investment. Social bees preferentially used clover plantings; solitary bees preferentially used wildflower plantings. On average, bumble bee pollen loads in treatment fields contained 37% PR pollen. PRs significantly increased visitation rates to the crop in year 4, and exerted a marginally significant positive influence on fruit set. The annualized costs of PRs were covered by the fourth year using the measured increase in pollination services. Our findings provide evidence of the positive impact of PRs on crop pollination services. PMID:28069631

Within-Colony Variation in the Immunocompetency of Managed and Feral Honey Bees (Apis mellifera L.) in Different Urban Landscapes

PubMed Central

Appler, R. Holden; Frank, Steven D.; Tarpy, David R.

2015-01-01

Urbanization has the potential to dramatically affect insect populations worldwide, although its effects on pollinator populations are just beginning to be understood. We compared the immunocompetency of honey bees sampled from feral (wild-living) and managed (beekeeper-owned) honey bee colonies. We sampled foragers from feral and managed colonies in rural, suburban, and urban landscapes in and around Raleigh, NC, USA. We then analyzed adult workers using two standard bioassays for insect immune function (encapsulation response and phenoloxidase activity). We found that there was far more variation within colonies for encapsulation response or phenoloxidase activity than among rural to urban landscapes, and we did not observe any significant difference in immune response between feral and managed bees. These findings suggest that social pollinators, like honey bees, may be sufficiently robust or variable in their immune responses to obscure any subtle effects of urbanization. Additional studies of immune physiology and disease ecology of social and solitary bees in urban, suburban, and natural ecosystems will provide insights into the relative effects of changing urban environments on several important factors that influence pollinator productivity and health. PMID:26529020

Within-Colony Variation in the Immunocompetency of Managed and Feral Honey Bees (Apis mellifera L.) in Different Urban Landscapes.

PubMed

Appler, R Holden; Frank, Steven D; Tarpy, David R

2015-10-29

Urbanization has the potential to dramatically affect insect populations worldwide, although its effects on pollinator populations are just beginning to be understood. We compared the immunocompetency of honey bees sampled from feral (wild-living) and managed (beekeeper-owned) honey bee colonies. We sampled foragers from feral and managed colonies in rural, suburban, and urban landscapes in and around Raleigh, NC, USA. We then analyzed adult workers using two standard bioassays for insect immune function (encapsulation response and phenoloxidase activity). We found that there was far more variation within colonies for encapsulation response or phenoloxidase activity than among rural to urban landscapes, and we did not observe any significant difference in immune response between feral and managed bees. These findings suggest that social pollinators, like honey bees, may be sufficiently robust or variable in their immune responses to obscure any subtle effects of urbanization. Additional studies of immune physiology and disease ecology of social and solitary bees in urban, suburban, and natural ecosystems will provide insights into the relative effects of changing urban environments on several important factors that influence pollinator productivity and health.

Focal Plant Observations as a Standardised Method for Pollinator Monitoring: Opportunities and Limitations for Mass Participation Citizen Science

PubMed Central

Roy, Helen E.; Baxter, Elizabeth; Saunders, Aoine; Pocock, Michael J. O.

2016-01-01

Background Recently there has been increasing focus on monitoring pollinating insects, due to concerns about their declines, and interest in the role of volunteers in monitoring pollinators, particularly bumblebees, via citizen science. Methodology / Principal Findings The Big Bumblebee Discovery was a one-year citizen science project run by a partnership of EDF Energy, the British Science Association and the Centre for Ecology & Hydrology which sought to assess the influence of the landscape at multiple scales on the diversity and abundance of bumblebees. Timed counts of bumblebees (Bombus spp.; identified to six colour groups) visiting focal plants of lavender (Lavendula spp.) were carried out by about 13 000 primary school children (7–11 years old) from over 4000 schools across the UK. 3948 reports were received totalling 26 868 bumblebees. We found that while the wider landscape type had no significant effect on reported bumblebee abundance, the local proximity to flowers had a significant effect (fewer bumblebees where other flowers were reported to be >5m away from the focal plant). However, the rate of mis-identifcation, revealed by photographs uploaded by participants and a photo-based quiz, was high. Conclusions / Significance Our citizen science results support recent research on the importance of local flocal resources on pollinator abundance. Timed counts of insects visiting a lure plant is potentially an effective approach for standardised pollinator monitoring, engaging a large number of participants with a simple protocol. However, the relatively high rate of mis-identifications (compared to reports from previous pollinator citizen science projects) highlights the importance of investing in resources to train volunteers. Also, to be a scientifically valid method for enquiry, citizen science data needs to be sufficiently high quality, so receiving supporting evidence (such as photographs) would allow this to be tested and for records to be verified. PMID:26985824

Interactive effects among ecosystem services and management practices on crop production: Pollination in coffee agroforestry systems

PubMed Central

Boreux, Virginie; Kushalappa, Cheppudira G.; Vaast, Philippe; Ghazoul, Jaboury

2013-01-01

Crop productivity is improved by ecosystem services, including pollination, but this should be set in the context of trade-offs among multiple management practices. We investigated the impact of pollination services on coffee production, considering variation in fertilization, irrigation, shade cover, and environmental variables such as rainfall (which stimulates coffee flowering across all plantations), soil pH, and nitrogen availability. After accounting for management interventions, bee abundance improved coffee production (number of berries harvested). Some management interventions, such as irrigation, used once to trigger asynchronous flowering, dramatically increased bee abundance at coffee trees. Others, such as the extent and type of tree cover, revealed interacting effects on pollination and, ultimately, crop production. The effects of management interventions, notably irrigation and addition of lime, had, however, far more substantial positive effects on coffee production than tree cover. These results suggest that pollination services matter, but managing the asynchrony of flowering was a more effective tool for securing good pollination than maintaining high shade tree densities as pollinator habitat. Complex interactions across farm and landscape scales, including both management practices and environmental conditions, shape pollination outcomes. Effective production systems therefore require the integrated consideration of management practices in the context of the surrounding habitat structure. This paper points toward a more strategic use of ecosystem services in agricultural systems, where ecosystem services are shaped by the coupling of management interventions and environmental variables. PMID:23671073

Pollination in Brazilian Syngonanthus (Eriocaulaceae) Species: Evidence for Entomophily Instead of Anemophily

PubMed Central

RAMOS, CARLIANNE O. C.; BORBA, EDUARDO L.; FUNCH, LÍGIA S.

2005-01-01

• Background and Aims The reproductive biology of Syngonanthus mucugensis and S. curralensis (Eriocaulaceae) was studied in areas of ‘campo rupestre’ vegetation in the Chapada Diamantina, north-eastern Brazil. These species are herbaceous and the individuals have a grouped distribution. Their leaves are united in a rosette, and their inflorescence is monoecious, of the capitulum type. The staminate and pistillate rings mature in a centripetal manner on the capitulum. • Methods A field study was conducted, including observations concerning the morphology and biology of the flowers, fruit development, insect visits and anemophily, in both S. mucugensis and S. curralensis. Experimental pollinations were also carried out to study the mating systems of S. mucugensis. • Key Results Both species flower from June to August. The staminate cycle lasts approx. 7 d, and the pistillate cycle from 3 to 4 d, with no temporal overlap between them on the same capitulum. The pollen viability of S. mucugensis was 88·6%, and 92·5% for S. curralensis. The inflorescences of both species demonstrated ultraviolet absorbance, and a sweet odour was detected during both the staminate and pistillate phases. No nectar production was ever noted, although nectaries are present. Both species were visited by numerous groups of insects, with the Diptera being the principal pollinators, especially the species of Syrphidae and Bombyliidae. There were secondary pollinators among species of Coleoptera and Hymenoptera. There was no evidence of wind pollination. Syngonanthus mucugensis is a self-compatible species, and forms fruits by agamospermy at low frequencies. • Conclusions This is apparently the first report for pollination biology and mating systems of Eriocaulaceae. Conversely to that stated by some authors, entomophily, mainly effected by species of Diptera but also by species of Coleoptera and Hymenoptera, is probably the only pollination system in these species. In spite of the monoecious inflorescences without overlap of the staminate and pistillate phases, geitonogamy may occur in S. mucugensis, as the species is self-compatible and different capitula in the same plant at different phases is common. PMID:15967774

The Whereabouts of Flower Visitors: Contrasting Land-Use Preferences Revealed by a Country-Wide Survey Based on Citizen Science

PubMed Central

Deguines, Nicolas; Julliard, Romain; de Flores, Mathieu; Fontaine, Colin

2012-01-01

Background In the past decade, accumulating evidence of pollinator decline has raised concerns regarding the functioning of terrestrial ecosystems and the sustainability of crop production. Although land-use changes have been advanced as the major causes, the affinities of most wild pollinators with the main land-use types remain unknown. Filling this gap in our knowledge is a prerequisite to improving conservation and management programmes. Methodology/Principal Findings We estimated the affinity of flower visitors with urban, agricultural and natural land-uses using data from a country-wide scale monitoring scheme based on citizen science (Spipoll). We tested whether the affinities differed among insect orders and according to insect frequency (frequent or infrequent). Our results indicate that the affinities with the three land-use types differed among insect orders. Apart from Hymenopterans, which appeared tolerant to the different land-uses, all flower visitors presented a negative affinity with urban areas and a positive affinity with agricultural and natural areas. Additionally, infrequent taxa displayed a lower affinity with urban areas and a higher affinity with natural areas than did frequent taxa. Within frequent taxa, Hymenoptera and Coleoptera included specialists of the three land-use types whereas Diptera and Lepidoptera contained specialists of all but urban areas. Conclusions/Significance Our approach allowed the first standardised evaluation of the affinity of flower visitors with the main land-use types across a broad taxonomical range and a wide geographic scope. Our results suggest that the most detrimental land-use change for flower visitor communities is urbanisation. Moreover, our findings highlight the fact that agricultural areas have the potential to host highly diverse pollinator communities. We suggest that policy makers should, therefore, focus on the implementation of pollinator-friendly practices in agricultural lands. This may be a win-win strategy, as both biodiversity and crop production may benefit from healthier communities of flower visitors in these areas. PMID:23029262

The whereabouts of flower visitors: contrasting land-use preferences revealed by a country-wide survey based on citizen science.

PubMed

Deguines, Nicolas; Julliard, Romain; de Flores, Mathieu; Fontaine, Colin

2012-01-01

In the past decade, accumulating evidence of pollinator decline has raised concerns regarding the functioning of terrestrial ecosystems and the sustainability of crop production. Although land-use changes have been advanced as the major causes, the affinities of most wild pollinators with the main land-use types remain unknown. Filling this gap in our knowledge is a prerequisite to improving conservation and management programmes. We estimated the affinity of flower visitors with urban, agricultural and natural land-uses using data from a country-wide scale monitoring scheme based on citizen science (Spipoll). We tested whether the affinities differed among insect orders and according to insect frequency (frequent or infrequent). Our results indicate that the affinities with the three land-use types differed among insect orders. Apart from Hymenopterans, which appeared tolerant to the different land-uses, all flower visitors presented a negative affinity with urban areas and a positive affinity with agricultural and natural areas. Additionally, infrequent taxa displayed a lower affinity with urban areas and a higher affinity with natural areas than did frequent taxa. Within frequent taxa, Hymenoptera and Coleoptera included specialists of the three land-use types whereas Diptera and Lepidoptera contained specialists of all but urban areas. Our approach allowed the first standardised evaluation of the affinity of flower visitors with the main land-use types across a broad taxonomical range and a wide geographic scope. Our results suggest that the most detrimental land-use change for flower visitor communities is urbanisation. Moreover, our findings highlight the fact that agricultural areas have the potential to host highly diverse pollinator communities. We suggest that policy makers should, therefore, focus on the implementation of pollinator-friendly practices in agricultural lands. This may be a win-win strategy, as both biodiversity and crop production may benefit from healthier communities of flower visitors in these areas.

Selenium toxicity to honey bee (Apis mellifera L.) pollinators: effects on behaviors and survival.

PubMed

Hladun, Kristen R; Smith, Brian H; Mustard, Julie A; Morton, Ray R; Trumble, John T

2012-01-01

We know very little about how soil-borne pollutants such as selenium (Se) can impact pollinators, even though Se has contaminated soils and plants in areas where insect pollination can be critical to the functioning of both agricultural and natural ecosystems. Se can be biotransferred throughout the food web, but few studies have examined its effects on the insects that feed on Se-accumulating plants, particularly pollinators. In laboratory bioassays, we used proboscis extension reflex (PER) and taste perception to determine if the presence of Se affected the gustatory response of honey bee (Apis mellifera L., Hymenoptera: Apidae) foragers. Antennae and proboscises were stimulated with both organic (selenomethionine) and inorganic (selenate) forms of Se that commonly occur in Se-accumulating plants. Methionine was also tested. Each compound was dissolved in 1 M sucrose at 5 concentrations, with sucrose alone as a control. Antennal stimulation with selenomethionine and methionine reduced PER at higher concentrations. Selenate did not reduce gustatory behaviors. Two hours after being fed the treatments, bees were tested for sucrose response threshold. Bees fed selenate responded less to sucrose stimulation. Mortality was higher in bees chronically dosed with selenate compared with a single dose. Selenomethionine did not increase mortality except at the highest concentration. Methionine did not significantly impact survival. Our study has shown that bees fed selenate were less responsive to sucrose, which may lead to a reduction in incoming floral resources needed to support coworkers and larvae in the field. If honey bees forage on nectar containing Se (particularly selenate), reductions in population numbers may occur due to direct toxicity. Given that honey bees are willing to consume food resources containing Se and may not avoid Se compounds in the plant tissues on which they are foraging, they may suffer similar adverse effects as seen in other insect guilds.

Selenium Toxicity to Honey Bee (Apis mellifera L.) Pollinators: Effects on Behaviors and Survival

PubMed Central

Hladun, Kristen R.; Smith, Brian H.; Mustard, Julie A.; Morton, Ray R.; Trumble, John T.

2012-01-01

We know very little about how soil-borne pollutants such as selenium (Se) can impact pollinators, even though Se has contaminated soils and plants in areas where insect pollination can be critical to the functioning of both agricultural and natural ecosystems. Se can be biotransferred throughout the food web, but few studies have examined its effects on the insects that feed on Se-accumulating plants, particularly pollinators. In laboratory bioassays, we used proboscis extension reflex (PER) and taste perception to determine if the presence of Se affected the gustatory response of honey bee (Apis mellifera L., Hymenoptera: Apidae) foragers. Antennae and proboscises were stimulated with both organic (selenomethionine) and inorganic (selenate) forms of Se that commonly occur in Se-accumulating plants. Methionine was also tested. Each compound was dissolved in 1 M sucrose at 5 concentrations, with sucrose alone as a control. Antennal stimulation with selenomethionine and methionine reduced PER at higher concentrations. Selenate did not reduce gustatory behaviors. Two hours after being fed the treatments, bees were tested for sucrose response threshold. Bees fed selenate responded less to sucrose stimulation. Mortality was higher in bees chronically dosed with selenate compared with a single dose. Selenomethionine did not increase mortality except at the highest concentration. Methionine did not significantly impact survival. Our study has shown that bees fed selenate were less responsive to sucrose, which may lead to a reduction in incoming floral resources needed to support coworkers and larvae in the field. If honey bees forage on nectar containing Se (particularly selenate), reductions in population numbers may occur due to direct toxicity. Given that honey bees are willing to consume food resources containing Se and may not avoid Se compounds in the plant tissues on which they are foraging, they may suffer similar adverse effects as seen in other insect guilds. PMID:22514621

Floral traits and pollination systems in the Caatinga, a Brazilian tropical dry forest.

PubMed

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.

Repeated Inactivation of the First Committed Enzyme Underlies the Loss of Benzaldehyde Emission after the Selfing Transition in Capsella.

PubMed

Sas, Claudia; Müller, Frank; Kappel, Christian; Kent, Tyler V; Wright, Stephen I; Hilker, Monika; Lenhard, Michael

2016-12-19

The enormous species richness of flowering plants is at least partly due to floral diversification driven by interactions between plants and their animal pollinators [1, 2]. Specific pollinator attraction relies on visual and olfactory floral cues [3-5]; floral scent can not only attract pollinators but also attract or repel herbivorous insects [6-8]. However, despite its central role for plant-animal interactions, the genetic control of floral scent production and its evolutionary modification remain incompletely understood [9-13]. Benzenoids are an important class of floral scent compounds that are generated from phenylalanine via several enzymatic pathways [14-17]. Here we address the genetic basis of the loss of floral scent associated with the transition from outbreeding to selfing in the genus Capsella. While the outbreeding C. grandiflora emits benzaldehyde as a major constituent of its floral scent, this has been lost in the selfing C. rubella. We identify the Capsella CNL1 gene encoding cinnamate:CoA ligase as responsible for this variation. Population genetic analysis indicates that CNL1 has been inactivated twice independently in C. rubella via different novel mutations to its coding sequence. Together with a recent study in Petunia [18], this identifies cinnamate:CoA ligase as an evolutionary hotspot for mutations causing the loss of benzenoid scent compounds in association with a shift in the reproductive strategy of Capsella from pollination by insects to self-fertilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Direct benefits and indirect costs of warm temperatures for high-elevation populations of a solitary bee.

PubMed

Forrest, Jessica R K; Chisholm, Sarah P M

2017-02-01

Warm temperatures are required for insect flight. Consequently, warming could benefit many high-latitude and high-altitude insects by increasing opportunities for foraging or oviposition. However, warming can also alter species interactions, including interactions with natural enemies, making the net effect of rising temperatures on population growth rate difficult to predict. We investigated the temperature-dependence of nesting activity and lifetime reproductive output over 3 yr in subalpine populations of a pollen-specialist bee, Osmia iridis. Rates of nest provisioning increased with ambient temperatures and with availability of floral resources, as expected. However, warmer conditions did not increase lifetime reproductive output. Lifetime offspring production was best explained by rates of brood parasitism (by the wasp Sapyga), which increased with temperature. Direct observations of bee and parasite activity suggest that although activity of both species is favored by warmer temperatures, bees can be active at lower ambient temperatures, while wasps are active only at higher temperatures. Thus, direct benefits to the bees of warmer temperatures were nullified by indirect costs associated with increased parasite activity. To date, most studies of climate-change effects on pollinators have focused on changing interactions between pollinators and their floral host-plants (i.e., bottom-up processes). Our results suggest that natural enemies (i.e., top-down forces) can play a key role in pollinator population regulation and should not be overlooked in forecasts of pollinator responses to climate change. © 2016 by the Ecological Society of America.

Floral advertisement and the competition for pollination services.

PubMed

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.

Enhancing Legume Ecosystem Services through an Understanding of Plant-Pollinator Interplay.

PubMed

Suso, María J; Bebeli, Penelope J; Christmann, Stefanie; Mateus, Célia; Negri, Valeria; Pinheiro de Carvalho, Miguel A A; Torricelli, Renzo; Veloso, Maria M

2016-01-01

Legumes are bee-pollinated, but to a different extent. The importance of the plant-pollinator interplay (PPI), in flowering crops such as legumes lies in a combination of the importance of pollination for the production service and breeding strategies, plus the increasing urgency in mitigating the decline of pollinators through the development and implementation of conservation measures. To realize the full potential of the PPI, a multidisciplinary approach is required. This article assembles an international team of genebank managers, geneticists, plant breeders, experts on environmental governance and agro-ecology, and comprises several sections. The contributions in these sections outline both the state of the art of knowledge in the field and the novel aspects under development, and encompass a range of reviews, opinions and perspectives. The first three sections explore the role of PPI in legume breeding strategies. PPI based approaches to crop improvement can make it possible to adapt and re-design breeding strategies to meet both goals of: (1) optimal productivity, based on an efficient use of pollinators, and (2) biodiversity conservation. The next section deals with entomological aspects and focuses on the protection of the "pest control service" and pollinators in legume crops. The final section addresses general approaches to encourage the synergy between food production and pollination services at farmer field level. Two basic approaches are proposed: (a) Farming with Alternative Pollinators and (b) Crop Design System.

Chemical ecology of obligate pollination mutualisms: testing the 'private channel' hypothesis in the Breynia-Epicephala association.

PubMed

Svensson, Glenn P; Okamoto, Tomoko; Kawakita, Atsushi; Goto, Ryutaro; Kato, Makoto

2010-06-01

*Obligate mutualisms involving actively pollinating seed predators are among the most remarkable insect-plant relationships known, yet almost nothing is known about the chemistry of pollinator attraction in these systems. The extreme species specificity observed in these mutualisms may be maintained by specific chemical compounds through 'private channels'. Here, we tested this hypothesis using the monoecious Breynia vitis-idaea and its host-specific Epicephala pollinator as a model. *Headspace samples were collected from both male and female flowers of the host. Gas chromatography with electroantennographic detection (GC-EAD), coupled gas chromatography-mass spectrometry, and olfactometer bioassays were used to identify the floral compounds acting as the pollinator attractant. *Male and female flowers of B. vitis-idaea produced similar sets of general floral compounds, but in different ratios, and male flowers emitted significantly more scent than female flowers. A mixture of 2-phenylethyl alcohol and 2-phenylacetonitrile, the two most abundant compounds in male flowers, was as attractive to female moths as the male flower sample, although the individual compounds were slightly less attractive when tested separately. *Data on the floral scent signals mediating obligate mutualisms involving active pollination are still very limited. We show that system-specific chemistry is not necessary for efficient host location by exclusive pollinators in these tightly coevolved mutualisms.

Evolution of sexual mimicry in the orchid subtribe orchidinae: the role of preadaptations in the attraction of male bees as pollinators

PubMed Central

2008-01-01

Background Within the astonishing diversity of orchid pollination systems, sexual deception is one of the most stunning. An example is the genus Ophrys, where plants attract male bees as pollinators by mimicking female mating signals. Unsaturated hydrocarbons (alkenes) are often the key signal for this chemical mimicry. Here we investigate the evolution of these key compounds within Orchidinae by mapping their production in flowers of selected species onto their estimated phylogeny. Results We found that alkenes, at least in trace amounts, were present in 18 of 20 investigated species together representing 10 genera. Thus, the reconstruction of ancestral state for alkene-production showed that this is a primitive character state in Ophrys, and can be interpreted as a preadaptation for the evolution of sexual deception. Four of the investigated species, namely Ophrys sphegodes, Serapias lingua, S. cordigera, and Anacamptis papilionacea, that are pollinated primarily by male bees, produced significantly larger amounts and a greater number of different alkenes than the species pollinated either primarily by female bees or other insects. Conclusion We suggest that high amounts of alkenes evolved for the attraction of primarily male bees as pollinators by sensory exploitation, and discuss possible driving forces for the evolution of pollination by male bees. PMID:18226206

Evolution of sexual mimicry in the orchid subtribe orchidinae: the role of preadaptations in the attraction of male bees as pollinators.

PubMed

Schiestl, Florian P; Cozzolino, Salvatore

2008-01-28

Within the astonishing diversity of orchid pollination systems, sexual deception is one of the most stunning. An example is the genus Ophrys, where plants attract male bees as pollinators by mimicking female mating signals. Unsaturated hydrocarbons (alkenes) are often the key signal for this chemical mimicry. Here we investigate the evolution of these key compounds within Orchidinae by mapping their production in flowers of selected species onto their estimated phylogeny. We found that alkenes, at least in trace amounts, were present in 18 of 20 investigated species together representing 10 genera. Thus, the reconstruction of ancestral state for alkene-production showed that this is a primitive character state in Ophrys, and can be interpreted as a preadaptation for the evolution of sexual deception. Four of the investigated species, namely Ophrys sphegodes, Serapias lingua, S. cordigera, and Anacamptis papilionacea, that are pollinated primarily by male bees, produced significantly larger amounts and a greater number of different alkenes than the species pollinated either primarily by female bees or other insects. We suggest that high amounts of alkenes evolved for the attraction of primarily male bees as pollinators by sensory exploitation, and discuss possible driving forces for the evolution of pollination by male bees.

Spatial diversification of agroecosystems to enhance biological control and other regulating services: An agroecological perspective.

PubMed

Hatt, Séverin; Boeraeve, Fanny; Artru, Sidonie; Dufrêne, Marc; Francis, Frédéric

2018-04-15

Spatial diversification of crop and non-crop habitats in farming systems is promising for enhancing natural regulation of insect pests. Nevertheless, results from recent syntheses show variable effects. One explanation is that the abundance and diversity of pests and natural enemies are affected by the composition, design and management of crop and non-crop habitats. Moreover, interactions between both local and landscape elements and practices carried out at different spatial scales may affect the regulation of insect pests. Hence, research is being conducted to understand these interdependencies. However, insects are not the only pests and pests are not the only elements to regulate in agroecosystems. Broadening the scope could allow addressing multiple issues simultaneously, but also solving them together by enhancing synergies. Indeed, spatial diversification of crop and non-crop habitats can allow addressing the issues of weeds and pathogens, along with being beneficial to several other regulating services like pollination, soil conservation and nutrient cycling. Although calls rise to develop multifunctional landscapes that optimize the delivery of multiple ecosystem services, it still represents a scientific challenge today. Enhancing interdisciplinarity in research institutions and building interrelations between scientists and stakeholders may help reach this goal. Despite obstacles, positive results from research based on such innovative approaches are encouraging for engaging science in this path. Hence, the aim of the present paper is to offer an update on these issues by exploring the most recent findings and discussing these results to highlight needs for future research. Copyright © 2017 Elsevier B.V. All rights reserved.

[Preliminary study on breeding system of Prunella vulgaris].

PubMed

Wan, De-Qian; Guo, Qiao-Sheng; Liu, Li; Yang, Wei; Zhou, Man; Li, Yi-Min

2013-03-01

The research was conducted to study the breeding system of Prunella vulgaris L. Flowering dynamics was observed. Pollen viability, stigma receptivity, pollen-ovule ratio (P/O), out-crossing index (OCI) were measured. Bagging experiments were conducted. The results showed that the life span of one single flower was 1-2 days, the flowering span for the inflorescence of stalk was 7-14 days, the P/O was 1 046+/-148. 26, the OCI was 2. Combined with results of bagging experiment, the breeding system of P. vulgaris L. was mixed with cross-polination and self pollination. In the absence of pollination insects, the pollination and fertilization can be accomplished with high seed setting rate, and the seeds have a relatively high germination rate.

Phylogenetic trait-based analyses of ecological networks

PubMed Central

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

Phylogenetic trait-based analyses of ecological networks.

PubMed

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.

Pollination biology of Eulophia alta (Orchidaceae) in Amazonia: effects of pollinator composition on reproductive success in different populations

PubMed Central

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

Floral mimicry enhances pollen export: the evolution of pollination by sexual deceit outside of the orchidaceae.

PubMed

Ellis, Allan G; Johnson, Steven D

2010-11-01

Although the majority of flowering plants achieve pollination by exploiting the food‐seeking behavior of animals, some use alternative ploys that exploit their mate‐seeking behavior. Sexual deception is currently known only from the Orchidaceae and almost always involves pollination by male hymenoptera. An outstanding problem has been to identify the selective factors in plants that favor exploitation of mating versus feeding behaviors in pollinators. Here we show that the insectlike petal ornaments on inflorescences of the daisy Gorteria diffusa elicit copulation attempts from male bombyliid flies and that the intensity of the mating response varies across geographical floral morphotypes, suggesting a continuum in reliance on feeding through mating responses for pollination. Using pollen analogues applied to a morphotype with prominent insectlike petal ornaments, we demonstrate that mate‐seeking male flies are several‐fold more active and export significantly more pollen than females. These results suggest that selection for traits that exploit insect mating behavior can occur through the male component of plant fitness and conclusively demonstrates pollination by sexual deception in Gorteria, making this the first confirmed report of sexual deception outside of the Orchidaceae.

Pollinator-mediated gene flow fosters genetic variability in a narrow alpine endemic, Abronia alpina (Nyctaginaceae).

PubMed

Jabis, Meredith D; Ayers, Tina J; Allan, Gerard J

2011-10-01

For rare and endemic plants that exist in small, isolated habitats, natural selection is expected to favor self-compatibility, which can result in low genetic diversity due to inbreeding and genetic drift. Using Abronia alpina, a rare alpine endemic of the California Floristic Province, we demonstrate that there are exceptions to these predictions. We present the results of both a pollination experiment and a genetic study using AFLPs (amplified fragment length polymorphisms). Using controlled hand-pollination and pollinator observations, we examined the breeding system, pollination ecology, and mechanism for self-incompatibility in A. alpina. Abronia alpina exhibits an allogamous mating system with probable self-incompatibility resulting from limited growth of pollen tubes originating from self-pollination. Only xenogamous crosses and open-pollinated controls produced seed, and only xenogamous crosses produced pollen tubes that reached the ovary. The molecular study shows that A. alpina has substantial genetic diversity for a rare, endemic species, evidenced by the high percentage of polymorphic loci and average expected heterozygosity. Gene flow among subpopulations, as inferred from AFLP markers, appears to be substantial, although the Kern River is an important physical barrier. Our results indicate that A. alpina is dependent on insects for both seed production and the maintenance of genetic diversity. This finding suggests that pollinators may be crucial to the long-term adaptive potential of rare, endemic plants and that conservation of rare endemics is, in part, dependent on community-level interactions such as plant-pollinator mutualisms.

Pre-adaptations and the evolution of pollination by sexual deception: Cope's rule of specialization revisited.

PubMed

Vereecken, Nicolas J; Wilson, Carol A; Hötling, Susann; Schulz, Stefan; Banketov, Sergey A; Mardulyn, Patrick

2012-12-07

Pollination by sexual deception is arguably one of the most unusual liaisons linking plants and insects, and perhaps the most illustrative example of extreme floral specialization in angiosperms. While considerable progress has been made in understanding the floral traits involved in sexual deception, less is known about how this remarkable mimicry system might have arisen, the role of pre-adaptations in promoting its evolution and its extent as a pollination mechanism outside the few groups of plants (primarily orchids) where it has been described to date. In the Euro-Mediterranean region, pollination by sexual deception is traditionally considered to be the hallmark of the orchid genus Ophrys. Here, we introduce two new cases outside of Ophrys, in plant groups dominated by generalized, shelter-mimicking species. On the basis of phylogenetic reconstructions of ancestral pollination strategies, we provide evidence for independent and bidirectional evolutionary transitions between generalized (shelter mimicry) and specialized (sexual deception) pollination strategies in three groups of flowering plants, and suggest that pseudocopulation has evolved from pre-adaptations (floral colours, shapes and odour bouquets) that selectively attract male pollinators through shelter mimicry. These findings, along with comparative analyses of floral traits (colours and scents), shed light on particular phenotypic changes that might have fuelled the parallel evolution of these extraordinary pollination strategies. Collectively, our results provide the first substantive insights into how pollination sexual deception might have evolved in the Euro-Mediterranean region, and demonstrate that even the most extreme cases of pollinator specialization can reverse to more generalized interactions, breaking 'Cope's rule of specialization'.

Pre-adaptations and the evolution of pollination by sexual deception: Cope's rule of specialization revisited

PubMed Central

Vereecken, Nicolas J.; Wilson, Carol A.; Hötling, Susann; Schulz, Stefan; Banketov, Sergey A.; Mardulyn, Patrick

2012-01-01

Pollination by sexual deception is arguably one of the most unusual liaisons linking plants and insects, and perhaps the most illustrative example of extreme floral specialization in angiosperms. While considerable progress has been made in understanding the floral traits involved in sexual deception, less is known about how this remarkable mimicry system might have arisen, the role of pre-adaptations in promoting its evolution and its extent as a pollination mechanism outside the few groups of plants (primarily orchids) where it has been described to date. In the Euro-Mediterranean region, pollination by sexual deception is traditionally considered to be the hallmark of the orchid genus Ophrys. Here, we introduce two new cases outside of Ophrys, in plant groups dominated by generalized, shelter-mimicking species. On the basis of phylogenetic reconstructions of ancestral pollination strategies, we provide evidence for independent and bidirectional evolutionary transitions between generalized (shelter mimicry) and specialized (sexual deception) pollination strategies in three groups of flowering plants, and suggest that pseudocopulation has evolved from pre-adaptations (floral colours, shapes and odour bouquets) that selectively attract male pollinators through shelter mimicry. These findings, along with comparative analyses of floral traits (colours and scents), shed light on particular phenotypic changes that might have fuelled the parallel evolution of these extraordinary pollination strategies. Collectively, our results provide the first substantive insights into how pollination sexual deception might have evolved in the Euro-Mediterranean region, and demonstrate that even the most extreme cases of pollinator specialization can reverse to more generalized interactions, breaking ‘Cope's rule of specialization’. PMID:23055065

Agro-ecological potential of the cup plant (Silphium perfoliatum L.) from a biodiversity perspective

NASA Astrophysics Data System (ADS)

Schrader, Stefan; Schorpp, Quentin; Lena Müller, Anna; Dauber, Jens

2017-04-01

The cup plant (Silphium perfoliatum L.) is an alternative bioenergy crop that may contribute to a more environmentally friendly production of renewable resources. The potential benefits of the cup plant are the perennial cultivation without tillage and its flowering-characteristics. Hence it can be hypothesized that beneficial organisms are promoted which in turn improves the provision of ecosystem services like soil fertility and pollination. To date biomass production in Germany is based mainly on cropping systems like intensive maize cultivation that bear a risk for biodiversity and ecosystem services. The importance to counteract this development increases considering the large land requirements for significant generation of energy from biomass. To what extent cropping of the cup plant meets the expectations of a sustainable biomass production was investigated within a comprehensive assessment of soil fauna communities (earthworms, collembolans, nematodes) including their functional groups as well as pollinating insects (bees and hoverflies) including the quantification of pollen and nectar in cup-plant cultivation systems with a crop management close to agricultural practice. From the results it became obvious that the cup plant as a bioenergy crop has got the necessary potential to mitigate the negative development of biodiversity and ecosystem services, especially in regions with a large share of maize monocultures. This agro-ecological potential can only be reached if certain agronomic requirements are met, i.e. a late harvest and cultivation periods of at least five years. Under these conditions the landscape context has to be considered. Semi-natural habitats in the surrounding landscape are required for nesting and larval development of wild pollinator groups. The development of biological functions in soil is tied to the land use history i.e. previous land use: Positive developments are expected for conversion of intensively managed crop fields to the perennial cup plant. Whereas a conversion of set-aside fields under marginal soil conditions would not result in an improvement of soil biota performance and soil functioning.

Honeybee nutrition is linked to landscape composition

PubMed Central

Donkersley, Philip; Rhodes, Glenn; Pickup, Roger W; Jones, Kevin C; Wilson, Kenneth

2014-01-01

Declines in insect pollinators in Europe have been linked to changes in land use. Pollinator nutrition is dependent on floral resources (i.e., nectar and pollen), which are linked to landscape composition. Here, we present a stratified analysis of the nutritional composition of beebread in managed honeybee hives with a view to examining potential sources of variation in its nutritional composition. Specifically, we tested the hypothesis that beebread composition correlates with local land use and therefore available floral resources. The results demonstrated that the starch, lipid, and moisture contents of beebread are all highly conserved across hives, whereas levels of protein and nonreducing sugar increased as the year progressed, reducing sugars, however, decreased during the first half of the year and then increased toward the end. Local land use around hives was quantified using data from the Countryside Survey 2007 Land Cover Map. Bee-bread protein content was negatively correlated with increasing levels of arable and horticultural farmland surrounding hives and positively correlated with the cover of natural grasslands and broadleaf woodlands. Reducing sugar content was also positively correlated with the amount of broad-leaved woodland in a 3 Km² radius from the hives. Previous studies on a range of invertebrates, including honeybees, indicate that dietary protein intake may have a major impact on correlates of fitness, including longevity and immune function. The finding that beebread protein content correlates with land use suggests that landscape composition may impact on insect pollinator well-being and provides a link between landscape and the nutritional ecology of socially foraging insects in a way not previously considered. PMID:25505544

Large-scale monitoring of effects of clothianidin dressed oilseed rape seeds on pollinating insects in Northern Germany: implementation of the monitoring project and its representativeness.

PubMed

Heimbach, Fred; Russ, Anja; Schimmer, Maren; Born, Katrin

2016-11-01

Monitoring studies at the landscape level are complex, expensive and difficult to conduct. Many aspects have to be considered to avoid confounding effects which is probably the reason why they are not regularly performed in the context of risk assessments of plant protection products to pollinating insects. However, if conducted appropriately their contribution is most valuable. In this paper we identify the requirements of a large-scale monitoring study for the assessment of side-effects of clothianidin seed-treated winter oilseed rape on three species of pollinating insects (Apis mellifera, Bombus terrestris and Osmia bicornis) and present how these requirements were implemented. Two circular study sites were delineated next to each other in northeast Germany and comprised almost 65 km 2 each. At the reference site, study fields were drilled with clothianidin-free OSR seeds while at the test site the oilseed rape seeds contained a coating with 10 g clothianidin and 2 g beta-cyfluthrin per kg seeds (Elado®). The comparison of environmental conditions at the study sites indicated that they are as similar as possible in terms of climate, soil, land use, history and current practice of agriculture as well as in availability of oilseed rape and non-crop bee forage. Accordingly, local environmental conditions were considered not to have had any confounding effect on the results of the monitoring of the bee species. Furthermore, the study area was found to be representative for other oilseed rape cultivation regions in Europe.

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

Pollinators: Downward Trends and Lofty Goals

EPA Science Inventory

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...

Effects of a Possible Pollinator Crisis on Food Crop Production in Brazil

PubMed Central

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

Effects of a Possible Pollinator Crisis on Food Crop Production in Brazil.

PubMed

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.

Response of native insect communities to invasive plants.

PubMed

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.

Stigma Sensitivity and the Duration of Temporary Closure Are Affected by Pollinator Identity in Mazus miquelii (Phrymaceae), a Species with Bilobed Stigma

PubMed Central

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

Minute pollinators: The role of thrips (Thysanoptera) as pollinators of pointleaf manzanita, Arctostaphylos pungens (Ericaceae)

PubMed Central

Eliyahu, Dorit; McCall, Andrew C.; Lauck, Marina; Trakhtenbrot, Ana; Bronstein, Judith L.

2015-01-01

The feeding habits of thrips on plant tissue, and their ability to transmit viral diseases to their host plants, have usually placed these insects in the general category of pests. However, the characteristics that make them economically important, their high abundance and short- and long-distance movement capability, may also make them effective pollinators. We investigated this lesser-known role of thrips in pointleaf manzanita (Arctostaphylos pungens), a Southwestern US shrub. We measured the abundance of three species of thrips (Orothrips kelloggii, Oligothrips oreios, and Frankliniella occidentalis), examined their pollen-carrying capability, and conducted an exclusion experiment in order to determine whether thrips are able to pollinate this species, and if they do, whether they actually contribute to the reproductive success of the plant. Our data suggest that indeed thrips pollinate and do contribute significantly to reproductive success. Flowers exposed to thrips only produced significantly more fruit than did flowers from which all visitors were excluded. The roles of thrips as antagonists/mutualists are examined in the context of the numerous other floral visitors to the plant. PMID:26207155

Minute pollinators: The role of thrips (Thysanoptera) as pollinators of pointleaf manzanita, Arctostaphylos pungens (Ericaceae).

PubMed

Eliyahu, Dorit; McCall, Andrew C; Lauck, Marina; Trakhtenbrot, Ana; Bronstein, Judith L

The feeding habits of thrips on plant tissue, and their ability to transmit viral diseases to their host plants, have usually placed these insects in the general category of pests. However, the characteristics that make them economically important, their high abundance and short- and long-distance movement capability, may also make them effective pollinators. We investigated this lesser-known role of thrips in pointleaf manzanita ( Arctostaphylos pungens ), a Southwestern US shrub. We measured the abundance of three species of thrips ( Orothrips kelloggii, Oligothrips oreios , and Frankliniella occidentalis ), examined their pollen-carrying capability, and conducted an exclusion experiment in order to determine whether thrips are able to pollinate this species, and if they do, whether they actually contribute to the reproductive success of the plant. Our data suggest that indeed thrips pollinate and do contribute significantly to reproductive success. Flowers exposed to thrips only produced significantly more fruit than did flowers from which all visitors were excluded. The roles of thrips as antagonists/mutualists are examined in the context of the numerous other floral visitors to the plant.

The Genetic Basis of Pollinator Adaptation in a Sexually Deceptive Orchid

PubMed Central

Xu, Shuqing; Schlüter, Philipp M.; Grossniklaus, Ueli; Schiestl, Florian P.

2012-01-01

In plants, pollinator adaptation is considered to be a major driving force for floral diversification and speciation. However, the genetic basis of pollinator adaptation is poorly understood. The orchid genus Ophrys mimics its pollinators' mating signals and is pollinated by male insects during mating attempts. In many species of this genus, chemical mimicry of the pollinators' pheromones, especially of alkenes with different double-bond positions, plays a key role for specific pollinator attraction. Thus, different alkenes produced in different species are probably a consequence of pollinator adaptation. In this study, we identify genes that are likely involved in alkene biosynthesis, encoding stearoyl-acyl carrier protein (ACP) desaturases (SAD), in three closely related Ophrys species, O. garganica, O. sphegodes, and O. exaltata. Combining floral odor and gene expression analyses, two SAD homologs (SAD1/2) showed significant association with the production of (Z)-9- and (Z)-12-alkenes that were abundant in O. garganica and O. sphegodes, supporting previous biochemical data. In contrast, two other newly identified homologs (SAD5/6) were significantly associated with (Z)-7-alkenes that were highly abundant only in O. exaltata. Both molecular evolutionary analyses and pollinator preference tests suggest that the alkenes associated with SAD1/2 and SAD5/6 are under pollinator-mediated divergent selection among species. The expression patterns of these genes in F1 hybrids indicate that species-specific expression differences in SAD1/2 are likely due to cis-regulation, while changes in SAD5/6 are likely due to trans-regulation. Taken together, we report a genetic mechanism for pollinator-mediated divergent selection that drives adaptive changes in floral alkene biosynthesis involved in reproductive isolation among Ophrys species. PMID:22916031

Terrigenous fluxes of pollen, insect scale and land plant palynodebris observed by sediment traps deployed in the subarctic Pacific

NASA Astrophysics Data System (ADS)

Tsutsui, H.; Takahashi, K.; Matsuoka, K.; Jordan, R. W.; Yamamoto, S.

2016-02-01

From 1990 to 2009, sediment traps were deployed and recovered in the subarctic Pacific (Station SA; 49°N, 174°W) during each summer, allowing the long-term observation of particle fluxes. As the Pacific Decadal Oscillation index changed in 1999 while air temperatures cooled, this study focused on pollen, land plant debris and insect scale fluxes during 1994 to 2009 at Station SA. The maximum pollen and fern spores flux was 644 grains m2 d-1, with a mean of 74 grains m2 d-1and the following details: 65% of the total pollen counts represented by wind-pollinated trees (e.g., alder, birch and pine), 24% by the herbaceous plants, and 11% by fern spores. Spore, herbaceous and wind-pollinated tree pollen fluxes peaked primarily in May (and sporadically also in April and June) and September-October. The annual flux peaks of insect scales (of unknown origin) and land-plant debris were in May and September, but over the entire study period the maximum insect scale flux of 161 scales m2 d-1 was in August 2002, with a mean of 16 scales m2 d-1. Furthermore, the maximum (in August 2004) and mean land-plant debris fluxes were 107 and 10 plant fragments m2 d-1, respectively. The sediment traps were situated at southern side of the Aleutian Islands, where snow and ice occurred for six months from October to May. The ice-snow season accounts for 25% of the total annual particle flux, with 75% throughout the rest of the year. The correlation coefficient among pollen, insect scales and land plant debris are: 1) 0.58 (probability <1%) between wind-pollinated plant pollen and insect scales, and 2) 0.75 (probability <5%) between herbaceous plant pollen and land plant debris. The production locations, residence time, routes and mode of transport of the particles are important factors. The pollen fluxes observed during April to June appeared to have originated from the Western Alaska, but during the rest of years they appeared to have been from the eastern Russia. That pollen and other organic debris were conveyed by wind over long distance across the ocean.

Combined pesticide exposure severely affects individual- and colony-level traits in bees

PubMed Central

Gill, Richard J.; Ramos-Rodriguez, Oscar; Raine, Nigel E.

2012-01-01

Reported widespread declines of wild and managed insect pollinators have serious consequences for global ecosystem services and agricultural production1-3. Bees contribute around 80% of insect pollination, so it is imperative we understand and mitigate the causes of current declines4-6. Recent studies have implicated the role of pesticides as exposure to these chemicals has been associated with changes in bee behaviour7-11 and reductions in colony queen production12. However the key link between changes in individual behaviour and consequent impact at the colony level has not been shown. Social bee colonies depend on the collective performance of numerous individual workers. So whilst field-level pesticide concentrations can have a subtle/sublethal effect at the individual level8, it is not known whether bee societies can buffer such effects or if it results in a severe cumulative effect at the colony level. Furthermore, widespread agricultural intensification means bees are exposed to numerous pesticides when foraging13-15, yet the possible combinatorial effects of pesticide exposure have rarely been investigated16,17. Here we show that chronic exposure of bumblebees to two pesticides (neonicotinoid and pyrethroid) at concentrations that could approximate field-level exposure impairs natural foraging behaviour and increases worker mortality leading to significant reductions in brood development and colony success. We found worker foraging performance, particularly pollen collecting efficiency, was significantly reduced with observed knock-on effects for forager recruitment, worker losses and overall worker productivity. Moreover, we provide evidence that combinatorial exposure to pesticides increases the propensity of colonies to fail. PMID:23086150

Does Passive Sampling Accurately Reflect the Bee (Apoidea: Anthophila) Communities Pollinating Apple and Sour Cherry Orchards?

PubMed

Gibbs, Jason; Joshi, Neelendra K; Wilson, Julianna K; Rothwell, Nikki L; Powers, Karen; Haas, Mike; Gut, Larry; Biddinger, David J; Isaacs, Rufus

2017-06-01

During bloom of spring orchard crops, bees are the primary providers of pollination service. Monitoring these insects for research projects is often done by timed observations or by direct aerial netting, but there has been increasing interest in blue vane traps as an efficient passive approach to collecting bees. Over multiple spring seasons in Michigan and Pennsylvania, orchards were monitored for wild bees using timed netting from crop flowers and blue vane traps. This revealed a distinctly different community of wild bees captured using the two methods, suggesting that blue vane traps can complement but cannot replace direct aerial netting. The bee community in blue vane traps was generally composed of nonpollinating species, which can be of interest for broader biodiversity studies. In particular, blue vane traps caught Eucera atriventris (Smith), Eucera hamata (Bradley), Bombus fervidus (F.), and Agapostemon virescens (F.) that were never collected from the orchard crop flowers during the study period. Captures of bee species in nets was generally stable across the 3 yr, whereas we observed significant declines in the abundance of Lasioglossum pilosum (Smith) and Eucera spp. trapped using blue vane traps during the project, suggesting local overtrapping of reproductive individuals. We conclude that blue vane traps are a useful tool for expanding insights into bee communities within orchard crop systems, but they should be used with great caution to avoid local extirpation of these important insects. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Thermoregulatory strategy may shape immune investment in Drosophila melanogaster.

PubMed

Kutch, Ian C; Sevgili, Hasan; Wittman, Tyler; Fedorka, Kenneth M

2014-10-15

As temperatures change, insects alter the amount of melanin in their cuticle to improve thermoregulation. However, melanin is also central to insect immunity, suggesting that thermoregulatory strategy may indirectly impact immune defense by altering the abundance of melanin pathway components (a hypothesis we refer to as thermoregulatory-dependent immune investment). This may be the case in the cricket Allonemobius socius, where warm environments (both seasonal and geographical) produced crickets with lighter cuticles and increased pathogen susceptibility. Unfortunately, the potential for thermoregulatory strategy to influence insect immunity has not been widely explored. Here we address the relationships between temperature, thermoregulatory strategy and immunity in the fruit fly Drosophila melanogaster. To this end, flies from two separate Canadian populations were reared in either a summer- or autumn-like environment. Shortly after adult eclosion, flies were moved to a common environment where their cuticle color and susceptibility to a bacterial pathogen (Pseudomonas aeruginosa) were measured. As with A. socius, individuals from summer-like environments exhibited lighter cuticles and increased pathogen susceptibility, suggesting that the thermoregulatory-immunity relationship is evolutionarily conserved across the hemimetabolous and holometabolous clades. If global temperatures continue to rise as expected, then thermoregulation might play an important role in host infection and mortality rates in systems that provide critical ecosystem services (e.g. pollination), or influence the prevalence of insect-vectored disease (e.g. malaria). © 2014. Published by The Company of Biologists Ltd.

Flower evolution of alpine forbs in the open top chambers (OTCs) from the Qinghai-Tibet Plateau.

PubMed

Zhang, Chan; Wang, Lin-Lin; Yang, Yong-Ping; Duan, Yuan-Wen

2015-05-22

Effects of global changes on biodiversity have been paid more and more attention world widely, and the open top chambers (OTCs) are the most common tools to study the effects of climatic warming on plant diversity. However, it remains unclear how flowers evolve under environmental changes, which could help us to understand the changes of plant diversity in the OTCs. We compared the insect diversity and pollen:ovule (P/O) ratio of eight outcrossing species with different life histories inside and outside the OTCs on the Qinghai-Tibet Plateau, to examine the effects induced by OTCs on the evolution of floral traits. In the OTCs, P/O ratio decreased in annuals, but increased in perennials, indicating an overall trend toward selfing in annuals. We found that the insect diversity differed significantly inside and outside the OTCS, with decreases of dipteran insects and bees. We concluded that changes of P/O ratio in the studied plant species might result from pollination failure, which might be the results of mismatch between flowering time and pollinator activities. We also suggested annuals might be in a more extinction risk than perennials in OTCs, if strong inbreeding depression occurs in these annual outcrossing plants.

Climate-driven spatial mismatches between British orchards and their pollinators: increased risks of pollination deficits

PubMed Central

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

HiveScience: A Citizen Science Project for Beekeepers##

EPA Science Inventory

Over the past decade, beekeepers have been experiencing unacceptably high colony losses while the demand for insect-pollinated crops has tripled during the same time period. Underscoring the need to develop reliable methods for predicting colony health, the United States Departme...

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...

Genome-wide single nucleotide polymorphism scan suggests adaptation to urbanization in an important pollinator, the red-tailed bumblebee (Bombus lapidarius L.).

PubMed

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).

Economic benefit of crop pollination by bees: a case of Kakamega small-holder farming in western Kenya.

PubMed

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.

On the roles of colour and scent in a specialized floral mimicry system

PubMed Central

Vereecken, Nicolas J.; Schiestl, Florian P.

2009-01-01

Background and Aims Sexually deceptive orchids achieve cross-pollination by mimicking the mating signals of female insects, generally hymenopterans. This pollination mechanism is often highly specific as it is based primarily on the mimicry of mating signals, especially the female sex pheromones of the targeted pollinator. Like many deceptive orchids, the Mediterranean species Ophrys arachnitiformis shows high levels of floral trait variation, especially in the colour of the perianth, which is either green or white/pinkinsh within populations. The adaptive significance of perianth colour polymorphism and its influence on pollinator visitation rates in sexually deceptive orchids remain obscure. Methods The relative importance of floral scent versus perianth colour in pollinator attraction in this orchid pollinator mimicry system was evaluated by performing floral scent analyses by gas chromatography-mass spectrometry (GC-MS) and behavioural bioassays with the pollinators under natural conditions were performed. Key Results The relative and absolute amounts of behaviourally active compounds are identical in the two colour morphs of O. arachnitiformis. Neither presence/absence nor the colour of the perianth (green versus white) influence attractiveness of the flowers to Colletes cunicularius males, the main pollinator of O. arachnitiformis. Conclusion Chemical signals alone can mediate the interactions in highly specialized mimicry systems. Floral colour polymorphism in O. arachnitiformis is not subjected to selection imposed by C. cunicularius males, and an interplay between different non-adaptive processes may be responsible for the maintenance of floral colour polymorphism both within and among populations. PMID:19692390

Specialized and Generalized Pollen-Collection Strategies in an Ancient Bee Lineage.

PubMed

Wappler, Torsten; Labandeira, Conrad C; Engel, Michael S; Zetter, Reinhard; Grímsson, Friðgeir

2015-12-07

Iconic examples of insect pollination have emphasized narrowly specialized pollinator mutualisms such as figs and fig wasps and yuccas and yucca moths. However, recent attention by pollination ecologists has focused on the broad spectra of pollinated plants by generalist pollinators such as bees. Bees have great impact for formulating hypotheses regarding specialization versus generalization in pollination mutualisms. We report the pollination biology of six northern European species of an extinct tribe of pollen-basket-bearing apine bees, Electrapini, of early-middle Eocene age, examined from two deposits of 48 and 44 million years in age. These bees exhibit a pattern of generalized, incidental pollen occurring randomly on their heads, thoraces, and abdomens, obtained from diverse, nectar-bearing plants. By contrast, a more restricted suite of pollen was acquired for metatibial pollen baskets (corbiculae) of the same bee taxa from a taxonomically much narrower suite of arborescent, evergreen hosts with uniform flower structure. The stereotyped plant sources of the specialist strategy of pollen collection consisted of pentamerous, radially symmetrical flowers with a conspicuous gynoecium surrounded by prominent nectar reward, organized in structurally similar compound inflorescences. Pollen specialization in bees occurs not for efficient pollination but rather in the corbiculate Electrapini as food for bee larvae (brood) and involves packing corbiculae with moistened pollen that rapidly loses viability with age. This specialist strategy was a well-developed preference by the early Eocene, providing a geochronologic midpoint assessment of bee pollen-collection strategies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Delayed selfing ensures reproductive assurance in Utricularia praeterita and Utricularia babui in Western Ghats.

PubMed

Chaudhary, Anjali; Yadav, S R; Tandon, Rajesh

2018-02-19

Numerous bladderwort (Utricularia) species are distributed worldwide, but their reproductive biology is rarely investigated. Bladderworts are known to depend on tiny organisms to meet a significant proportion of their energy requirement by trapping them in bladders. However, information on the extent of their reliance on insects for pollination success is limited. We examined the reproductive strategy of two Utricularia species viz. Utricularia praeterita and U. babui, endemic to Western Ghats, India. The main aspects of the investigation involved floral biology, breeding system, pollination mechanism, and reproductive success. Flowers of both the species are structured for outbreeding through entomophilous floral suites, herkogamy, protandrous dichogamy and sensitive lobes of the stigma. With nearly 65% natural fruit-set, both the species appeared to be sufficiently open-pollinated. However, pollinators failed to show in plants of U. praeterita while in U. babui there was an apparent mismatch between the extent of fruit-set and pollinator visits. The study demonstrated that in the absence/insufficient visits of pollinators, the two species resort to autonomous selfing. In U. babui, denser patches of plants appeared to be crucial for attracting the pollinators. Both species are self-compatible, and reproductive success is predominantly achieved by delayed autonomous selfing. The sensitive stigma in the species fails to prevent selfing due to diminished herkogamy during the late anthetic stages. It is inferred that in the pollinator-limited environment, delayed selfing contributes to absolute natural fecundity in U. praeterita, while it produces a mixed progeny in U. babui.

On the roles of colour and scent in a specialized floral mimicry system.

PubMed

Vereecken, Nicolas J; Schiestl, Florian P

2009-11-01

Sexually deceptive orchids achieve cross-pollination by mimicking the mating signals of female insects, generally hymenopterans. This pollination mechanism is often highly specific as it is based primarily on the mimicry of mating signals, especially the female sex pheromones of the targeted pollinator. Like many deceptive orchids, the Mediterranean species Ophrys arachnitiformis shows high levels of floral trait variation, especially in the colour of the perianth, which is either green or white/pinkinsh within populations. The adaptive significance of perianth colour polymorphism and its influence on pollinator visitation rates in sexually deceptive orchids remain obscure. The relative importance of floral scent versus perianth colour in pollinator attraction in this orchid pollinator mimicry system was evaluated by performing floral scent analyses by gas chromatography-mass spectrometry (GC-MS) and behavioural bioassays with the pollinators under natural conditions were performed. The relative and absolute amounts of behaviourally active compounds are identical in the two colour morphs of O. arachnitiformis. Neither presence/absence nor the colour of the perianth (green versus white) influence attractiveness of the flowers to Colletes cunicularius males, the main pollinator of O. arachnitiformis. Chemical signals alone can mediate the interactions in highly specialized mimicry systems. Floral colour polymorphism in O. arachnitiformis is not subjected to selection imposed by C. cunicularius males, and an interplay between different non-adaptive processes may be responsible for the maintenance of floral colour polymorphism both within and among populations.

Population density of oil palm pollinator weevil Elaeidobius kamerunicus based on seasonal effect and age of oil palm

NASA Astrophysics Data System (ADS)

Daud, Syarifah Nadiah Syed Mat; Ghani, Idris Abd.

2016-11-01

The pollinating weevil, Elaedobius kamerunicus (EK) has been known to be the most efficient insect pollinator of oil palm, and has successfully improved the oil palm pollination and increased the yield. Its introduction has greatly reduced the need for assisted pollination. The purpose of this study was to identify the population density of oil palm pollinator weevil EK using the concept of pollinator force and to relate the population density with the seasonal effect and the age of oil palm at Lekir Oil Palm Plantation Batu 14, Perak, Peninsular Malaysia. The pollinator force of the weevil was sustained at a range between 3095.2 to 19126.1 weevils per ha. The overall mean of weevil per spikelet shows that the range of weevil was between 13.51 and 54.06 per spikelet. There was no correlation between rainfall and population density of EK. However, positive correlation was obtained between weevil density and the number of anthesising female inflorescence of oil palm (r= 0.938, p< 0.05). Results of t-test show that the 6-year old oil palm stands had significantly different population density than that of a 8-year old oil palm stand. The information of this study should be useful as a baseline data to investigate why there is such a wide range of weevils per ha or spikelet. Further study should also be done to relate the number pollinator force per spikelete and the Fresh fruit Bunch (FFB), fruit set or fruit to bunch ratio.

Complex pollination of a tropical Asian rainforest canopy tree by flower-feeding thrips and thrips-feeding predators.

PubMed

Kondo, Toshiaki; Nishimura, Sen; Tani, Naoki; Ng, Kevin Kit Siong; Lee, Soon Leong; Muhammad, Norwati; Okuda, Toshinori; Tsumura, Yoshihiko; Isagi, Yuji

2016-11-01

In tropical rainforests of Southeast Asia, a highly fecund thrips (Thrips spp.) responds rapidly to the mass flowering at multiple-year intervals characteristic of certain species such as the canopy tree studied here, Shorea acuminata, by feeding on flower resources. However, past DNA analyses of pollen adherent to thrips bodies revealed that the thrips promoted a very high level of self-pollination. Here, we identified the pollinator that contributes to cross-pollination and discuss ways that the pollination system has adapted to mass flowering. By comparing the patterns of floral visitation and levels of genetic diversity in adherent pollen loads among floral visitors, we evaluated the contribution of each flower visitor to pollination. The big-eyed bug, Geocoris sp., a major thrips predator, was an inadvertent pollinator, and importantly contributed to cross-pollination. The total outcross pollen adhering to thrips was approximately 30% that on the big-eyed bugs. Similarly, 63% of alleles examined in S. acuminata seeds and seedlings occurred in pollen adhering to big-eyed bugs; about 30% was shared with pollen from thrips. During mass flowering, big-eyed bugs likely travel among flowering S. acuminata trees, attracted by the abundant thrips. Floral visitation patterns of big-eyed bugs vs. other insects suggest that these bugs can maintain their population size between flowering by preying upon another thrips (Haplothrips sp.) that inhabits stipules of S. acuminata throughout the year and quickly respond to mass flowering. Thus, thrips and big-eyed bugs are essential components in the pollination of S. acuminata. © 2016 Botanical Society of America.

Gradual disintegration of the floral symmetry gene network is implicated in the evolution of a wind-pollination syndrome

PubMed Central

Preston, Jill C.; Martinez, Ciera C.; Hileman, Lena C.

2011-01-01

Angiosperms exhibit staggering diversity in floral form, and evolution of floral morphology is often correlated with changes in pollination syndrome. The showy, bilaterally symmetrical flowers of the model species Antirrhinum majus (Plantaginaceae) are highly specialized for bee pollination. In A. majus, CYCLOIDEA (CYC), DICHOTOMA (DICH), RADIALIS (RAD), and DIVARICATA (DIV) specify the development of floral bilateral symmetry. However, it is unclear to what extent evolution of these genes has resulted in flower morphological divergence among closely related members of Plantaginaceae differing in pollination syndrome. We compared floral symmetry genes from insect-pollinated Digitalis purpurea, which has bilaterally symmetrical flowers, with those from closely related Aragoa abietina and wind-pollinated Plantago major, both of which have radially symmetrical flowers. We demonstrate that Plantago, but not Aragoa, species have lost a dorsally expressed CYC-like gene and downstream targets RAD and DIV. Furthermore, the single P. major CYC-like gene is expressed across all regions of the flower, similar to expression of its ortholog in closely related Veronica serpyllifolia. We propose that changes in the expression of duplicated CYC-like genes led to the evolution of radial flower symmetry in Aragoa/Plantago, and that further disintegration of the symmetry gene pathway resulted in the wind-pollination syndrome of Plantago. This model underscores the potential importance of gene loss in the evolution of ecologically important traits. PMID:21282634

Edge effects enhance selfing and seed harvesting efforts in the insect-pollinated Neotropical tree Copaifera langsdorffii (Fabaceae)

PubMed Central

Tarazi, R; Sebbenn, A M; Kageyama, P Y; Vencovsky, R

2013-01-01

Edge effects may affect the mating system of tropical tree species and reduce the genetic diversity and variance effective size of collected seeds at the boundaries of forest fragments because of a reduction in the density of reproductive trees, neighbour size and changes in the behaviour of pollinators. Here, edge effects on the genetic diversity, mating system and pollen pool of the insect-pollinated Neotropical tree Copaifera langsdorffii were investigated using eight microsatellite loci. Open-pollinated seeds were collected from 17 seed trees within continuous savannah woodland (SW) and were compared with seeds from 11 seed trees at the edge of the savannah remnant. Seeds collected from the SW had significantly higher heterozygosity levels (Ho=0.780; He=0.831) than seeds from the edge (Ho=0.702; He=0.800). The multilocus outcrossing rate was significantly higher in the SW (tm=0.859) than in the edge (tm=0.759). Pollen pool differentiation was significant, however, it did not differ between the SW (=0.105) and the edge (=0.135). The variance effective size within the progenies was significantly higher in the SW (Ne=2.65) than at the edge (Ne=2.30). The number of seed trees to retain the reference variance effective size of 500 was 189 at the SW and 217 at the edge. Therefore, it is preferable that seed harvesting for conservation and environmental restoration strategies be conducted in the SW, where genetic diversity and variance effective size within progenies are higher. PMID:23486081

Edge effects enhance selfing and seed harvesting efforts in the insect-pollinated Neotropical tree Copaifera langsdorffii (Fabaceae).

PubMed

Tarazi, R; Sebbenn, A M; Kageyama, P Y; Vencovsky, R

2013-06-01

Edge effects may affect the mating system of tropical tree species and reduce the genetic diversity and variance effective size of collected seeds at the boundaries of forest fragments because of a reduction in the density of reproductive trees, neighbour size and changes in the behaviour of pollinators. Here, edge effects on the genetic diversity, mating system and pollen pool of the insect-pollinated Neotropical tree Copaifera langsdorffii were investigated using eight microsatellite loci. Open-pollinated seeds were collected from 17 seed trees within continuous savannah woodland (SW) and were compared with seeds from 11 seed trees at the edge of the savannah remnant. Seeds collected from the SW had significantly higher heterozygosity levels (Ho=0.780; He=0.831) than seeds from the edge (Ho=0.702; He=0.800). The multilocus outcrossing rate was significantly higher in the SW (tm=0.859) than in the edge (tm=0.759). Pollen pool differentiation was significant, however, it did not differ between the SW (=0.105) and the edge (=0.135). The variance effective size within the progenies was significantly higher in the SW (Ne=2.65) than at the edge (Ne=2.30). The number of seed trees to retain the reference variance effective size of 500 was 189 at the SW and 217 at the edge. Therefore, it is preferable that seed harvesting for conservation and environmental restoration strategies be conducted in the SW, where genetic diversity and variance effective size within progenies are higher.

Prezygotic barriers to gene flow between Taraxacum ceratophorum and the invasive Taraxacum officinale (Asteraceae).

PubMed

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.

Bee Species Diversity Enhances Productivity and Stability in a Perennial Crop

PubMed Central

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

Linking Plant Specialization to Dependence in Interactions for Seed Set in Pollination Networks

PubMed Central

Tur, Cristina; Castro-Urgal, Rocío; Traveset, Anna

2013-01-01

Studies on pollination networks have provided valuable information on the number, frequency, distribution and identity of interactions between plants and pollinators. However, little is still known on the functional effect of these interactions on plant reproductive success. Information on the extent to which plants depend on such interactions will help to make more realistic predictions of the potential impacts of disturbances on plant-pollinator networks. Plant functional dependence on pollinators (all interactions pooled) can be estimated by comparing seed set with and without pollinators (i.e. bagging flowers to exclude them). Our main goal in this study was thus to determine whether plant dependence on current insect interactions is related to plant specialization in a pollination network. We studied two networks from different communities, one in a coastal dune and one in a mountain. For ca. 30% of plant species in each community, we obtained the following specialization measures: (i) linkage level (number of interactions), (ii) diversity of interactions, and (iii) closeness centrality (a measure of how much a species is connected to other plants via shared pollinators). Phylogenetically controlled regression analyses revealed that, for the largest and most diverse coastal community, plants highly dependent on pollinators were the most generalists showing the highest number and diversity of interactions as well as occupying central positions in the network. The mountain community, by contrast, did not show such functional relationship, what might be attributable to their lower flower-resource heterogeneity and diversity of interactions. We conclude that plants with a wide array of pollinator interactions tend to be those that are more strongly dependent upon them for seed production and thus might be those more functionally vulnerable to the loss of network interaction, although these outcomes might be context-dependent. PMID:24205187

Linking plant specialization to dependence in interactions for seed set in pollination networks.

PubMed

Tur, Cristina; Castro-Urgal, Rocío; Traveset, Anna

2013-01-01

Studies on pollination networks have provided valuable information on the number, frequency, distribution and identity of interactions between plants and pollinators. However, little is still known on the functional effect of these interactions on plant reproductive success. Information on the extent to which plants depend on such interactions will help to make more realistic predictions of the potential impacts of disturbances on plant-pollinator networks. Plant functional dependence on pollinators (all interactions pooled) can be estimated by comparing seed set with and without pollinators (i.e. bagging flowers to exclude them). Our main goal in this study was thus to determine whether plant dependence on current insect interactions is related to plant specialization in a pollination network. We studied two networks from different communities, one in a coastal dune and one in a mountain. For ca. 30% of plant species in each community, we obtained the following specialization measures: (i) linkage level (number of interactions), (ii) diversity of interactions, and (iii) closeness centrality (a measure of how much a species is connected to other plants via shared pollinators). Phylogenetically controlled regression analyses revealed that, for the largest and most diverse coastal community, plants highly dependent on pollinators were the most generalists showing the highest number and diversity of interactions as well as occupying central positions in the network. The mountain community, by contrast, did not show such functional relationship, what might be attributable to their lower flower-resource heterogeneity and diversity of interactions. We conclude that plants with a wide array of pollinator interactions tend to be those that are more strongly dependent upon them for seed production and thus might be those more functionally vulnerable to the loss of network interaction, although these outcomes might be context-dependent.

Adaptations for insect-trapping in brood-site pollinated Colocasia (Araceae)

PubMed Central

Bröderbauer, D.; Ulrich, S.; Weber, A.

2016-01-01

The Araceae include both taxa with rewarding and deceptive trap pollination systems. Here we report on a genus in which rewarding and imprisonment of the pollinators co-occur. We studied the pollination of four species of Colocasia in Southwest China and investigated the morpho-anatomical adaptations of the spathe related to the attraction and capture of pollinators. All four species were pollinated by drosophilid flies of the genus Colocasiomyia. The flies are temporally arrested within the inflorescence and departure is only possible after pollen release. Trapping of the flies is accomplished by the closure of the spathe during anthesis. Moreover, in two species the spathe is covered with papillate epidermal cells known to form slippery surfaces in deceptive traps of Araceae. However, in Colocasia the papillae proved not slippery for the flies. The morpho-anatomical properties of the spathe epidermis indicate that it is an elaborate osmophore and serves for the emission of odours only. Despite its similarity to deceptive traps of other aroids, Colocasia and Colocasiomyia have a close symbiotic relationship, as the attracted flies use the inflorescence as a site for mating and breeding. The trap mechanism has presumably evolved independently in Colocasia and is supposed to facilitate more efficient pollen export. PMID:24119060

Same but different: Larval development and gall-inducing process of a non-pollinating fig wasp compared to that of pollinating fig-wasps

NASA Astrophysics Data System (ADS)

Jansen-González, Sergio; Teixeira, Simone de Padua; Kjellberg, Finn; Pereira, Rodrigo A. Santinelo

2014-05-01

The receptacles of fig trees (Ficus spp.) can harbor a highly diversified and complex community of chalcid wasps. Functional groups of fig wasps (e.g. gallers, cleptoparasites and parasitoids) oviposit into the fig at different developmental stages, reflecting different feeding regimes for these insect larvae. There are few direct data available on larval feeding regimes and access to resources. We studied the gall induction and larval feeding strategy of an Idarnes (group flavicollis) species, a non-pollinating fig wasp (NPFW) associated to Ficus citrifolia P. Miller in Brazil. This Idarnes species shares with the pollinator characteristics such as time of oviposition, ovipositor insertion through flower and location of the egg inside plant ovaries. Nevertheless, we show that the gall induction differs considerably from that of the pollinating species. This Idarnes species relies on the induction of nucellus cell proliferation for gall formation and as the main larval resource. This strategy enables it to develop in both pollinated and unpollinated figs. The large differences between this NPFW and other fig wasps in how ovules are galled suggest that there are different ways to be a galler. A functional analysis of NPFW community structure may require descriptions of the histological processes associated with larval development.

Many to flower, few to fruit: the reproductive biology of Hamamelis virginiana (Hamamelidaceae).

PubMed

Anderson, Gregory J; Hill, James D

2002-01-01

Hamamelis virginiana flowers from late September to late November. In 1977, we began studying the reproductive biology of this eastern North American arborescent shrub by examining floral phenology and rewards, pollen-ovule ratios, breeding system, pollination, pollinator and resource limitation, and seed dispersal. The homogamous, self-incompatible flowers emit a faint odor, bear nectar with sucrose ratios typical of bee- and fly-pollinated flowers, and produce abundant sticky pollen. Flowers were visited infrequently by insects representing six orders. Flies were the most common floral visitors, specifically members of the genus Bradysia, but small bees also carried high percentages of Hamamelis pollen. Despite high pollen/ovule ratios (11 445 grains/ovule), bees and flies are likely pollinators, as experiments indicate wind pollination is less likely. Pollen quantity and resource availability did not appear to limit reproductive output, but pollen quality did. Tests of >40 000 flowers showed natural fruit set to be <1%. The flowering time, breeding system, and clumped distribution of plants, likely due in part to limited seed dispersal, combine to yield this remarkably low fruit set. Because all other species of Hamamelis flower from late winter to early summer, it may be that H. virginiana evolved a fall flowering phenology to avoid competition for pollinators with the closely related H. vernalis.

The importance of key floral bioactive compounds to honey bees for the detection and attraction of hybrid vegetable crops and increased seed yield.

PubMed

Mas, Flore; Harper, Aimee; Horner, Rachael; Welsh, Taylor; Jaksons, Peter; Suckling, David M

2018-02-15

Crop breeding programmes generally select for traits for improved yield and human consumption preferences. Yet, they often overlook one fundamental trait essential for insect-pollinated crops: pollinator attraction. This is even more critical for hybrid plants that rely on cross-pollination between the male-fertile line and the male-sterile line to set seeds. This study investigated the role of floral odours for honey bee pollination that could explain the poor seed yield in hybrid crops. The key floral bioactive compounds that honey bees detect were identified for three vegetable hybrid crops. It was found that 30% of the variation in bioactive compound quantities was explained by variety. Differences in quantities of the bioactive compounds triggered different degrees of olfactory response and were also associated with varied appetitive response. Correlating the abundance of each bioactive compound with seed yield, it was found that aldehydes such as nonanal and decanal can have a strong negative influence on seed yield with increasing quantity. Using these methodologies to identify relevant bioactive compounds associated with honey bee pollination, plant breeding programmes should also consider selecting for floral traits attractive to honey bees to improve crop pollination for enhanced seed yield. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

A horizon scan of future threats and opportunities for pollinators and pollination.

PubMed

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.

A horizon scan of future threats and opportunities for pollinators and pollination

PubMed Central

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

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...

Evaluating pollination deficits in pumpkin production in New York.

PubMed

Petersen, J D; Huseth, A S; Nault, B A

2014-10-01

Potential decreases in crop yield from reductions in bee-mediated pollination services threaten food production demands of a growing population. Many fruit and vegetable growers supplement their fields with bee colonies during crop bloom. The extent to which crop production requires supplementary pollination services beyond those provided by wild bees is not well documented. Pumpkin, Cucurbita pepo L., requires bee-mediated pollination for fruit development. Previous research identified the common eastern bumble bee, Bombus impatiens (Cresson), as the most efficient pumpkin pollinator. Two concomitant studies were conducted to examine pollination deficits in New York pumpkin fields from 2011 to 2013. In the first study, fruit weight, seed set, and B. impatiens visits to pumpkin flowers were compared across fields supplemented with B. impatiens colonies at a recommended stocking density of five colonies per hectare, a high density of 15 colonies per hectare, or not supplemented with bees. In the second study, fruit weight and seed set of pumpkins that received supplemental pollen through hand-pollination were compared with those that were open-pollinated by wild bees. Results indicated that supplementing pumpkin fields with B. impatiens colonies, regardless of stocking density, did not increase fruit weight, seed set, or B. impatiens visits to pumpkin flowers. Fruit weight and seed set did not differ between hand- and open-pollinated treatments. In general, we conclude that pumpkin production in central New York is not limited by inadequate pollination services provided by wild bees and that on average, supplementation with B. impatiens colonies did not improve pumpkin yield.

Terrigenous fluxes of pollen, insect scale and land plant palynodebris observed by sediment traps deployed in the subarctic Pacific

NASA Astrophysics Data System (ADS)

Tsutsui, H.; Takahashi, K.; Fowell, S. J.; Matsuoka, K.; Jordan, R. W.; Yamamoto, S.

2014-12-01

From 1990 to 2009, sediment traps in the subarctic Pacific (SA; 49°N, 174°W) were deployed and recovered during each summer, allowing the long-term observation of particle fluxes. As the Pacific Decadal Oscillation index changed in 1999 as air-temp cooled, this study focused on pollen, land plant debris and insect scale fluxes at SA during 1998 to 2006. The max pollen and fern spores flux was a mean of 74 grains m2 d-1, and the following details: 65% of the total pollen counts represented by wind-pollinated trees (e.g., alder, birch and pine), 24% by the herbaceous plants (as herbs), and 11% by fern spores. Spore, herbaceous and wind-pollinated tree pollen (as wind-pollen) fluxes peaked in May and Sep-Oct, but flux peaks of the latter also occurred in April and Jun. The annual flux peaks of insect scales (of unknown origin) and land-plant debris were in May and Sep, but over the entire study period the max insect scale flux of 161 was in Aug 2002, with a mean of 16 scales m2d-1, while the max (in Aug 2004) and mean land-plant debris fluxes were 107 and 10 plant fragments m2d-1, respectively. The sediment traps are situated both side of the Aleutian Is., where snow and ice occurs from Oct to May. The ice-snow season accounts for 25% of the total annual particle flux in SA trap, with 75% throughout the rest of the year. The correlation coefficient among pollen, insect scales and land plant debris are: 1) 0.58 (p<1%) between wind-pollen and insect scales, 2) 0.75 (p<5%) between herb-pollen and land plant debris, 3) but only 0.14 between insect scales and herbaceous pollen. Thus, the production location, residence time, route and mode of transport of the particles are important factors. Normally, the wind-pollinated tree flowering season in the northern part of Alaska and Japan where are an upper stream to the stations is from Apr to Jun, with the pollen usually transported across the ocean by winds. Assuming that the pollen takes several months to arrive SA, the wind speed and direction during the summer months also need to be considered. The debris needs about 1 month to sink to the trap water depth. Accordingly, the pollen transported to the trap area in Apr, Aug and Sep, when local wind speeds are 8 to 13 m s-1, are represented by the fluxes in May, Sep and Oct. In summary, the wind-pollen and insect scales in SA appear to be conveyed by wind over long distances.

A trophic cascade induced by predatory ants in a fig-fig wasp mutualism.

PubMed

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.

Enhancing Legume Ecosystem Services through an Understanding of Plant–Pollinator Interplay

PubMed Central

Suso, María J.; Bebeli, Penelope J.; Christmann, Stefanie; Mateus, Célia; Negri, Valeria; Pinheiro de Carvalho, Miguel A. A.; Torricelli, Renzo; Veloso, Maria M.

2016-01-01

Legumes are bee-pollinated, but to a different extent. The importance of the plant–pollinator interplay (PPI), in flowering crops such as legumes lies in a combination of the importance of pollination for the production service and breeding strategies, plus the increasing urgency in mitigating the decline of pollinators through the development and implementation of conservation measures. To realize the full potential of the PPI, a multidisciplinary approach is required. This article assembles an international team of genebank managers, geneticists, plant breeders, experts on environmental governance and agro-ecology, and comprises several sections. The contributions in these sections outline both the state of the art of knowledge in the field and the novel aspects under development, and encompass a range of reviews, opinions and perspectives. The first three sections explore the role of PPI in legume breeding strategies. PPI based approaches to crop improvement can make it possible to adapt and re-design breeding strategies to meet both goals of: (1) optimal productivity, based on an efficient use of pollinators, and (2) biodiversity conservation. The next section deals with entomological aspects and focuses on the protection of the “pest control service” and pollinators in legume crops. The final section addresses general approaches to encourage the synergy between food production and pollination services at farmer field level. Two basic approaches are proposed: (a) Farming with Alternative Pollinators and (b) Crop Design System. PMID:27047514

Phenological responses to climate change and their trait-induced differences

NASA Astrophysics Data System (ADS)

Ziello, Chiara; Estella, Nicole; Menzel, Annette

2010-05-01

On the basis of an extensive plant phenological dataset which involves phenological stations distributed all over Europe (from Spain to Russia, from the Alps to the Scandinavian Peninsula), we assess those differences in temporal trends related to Plant Functional Types (PFTs, i.e. woodiness), ecological traits (i.e. dates of flowering) and functional traits (i.e. pollination mode). We analyze differences in the sensitivity of different flowering stages to these traits. We focus on different substages such as beginning of flowering, full flowering, end of flowering because flowering seems to be so far one of the stages most affected by climate change. An increasing risk of pollinosis is one of the most likely expected consequences of climate change, and the detection of differences in responses of wind-pollinated plants with respect to other vegetation categories is important also to understand the impact of increasing temperatures on the behavior of allergenic plants. Wind-pollinated plants can be considered as representative of allergenic species because anemophilous species include those ones with the highest capability of causing allergy-related diseases in human subjects (e.g. the birch family, some cultivated and spontaneous grasses). Our main results indicate that, during the last three decades, wind-pollinated plants are advancing more than insect-pollinated ones, moreover showing a significant linear dependence of trends on phenodates. The tendency towards an earlier onset of flowering of anemophilous species could be explained due to the fact that all the considered species are angiosperms. For this plant division, anemophily is a condition derived from entomophily, and likely developed as a response to adverse or changing environmental conditions. So, it could be possible to look at them as species somehow predisposed to a more rapid adaptation process. On the other hand, this behavior could also be caused by the direct dependence on temperature of these species, that can hence more easily react to a warming not being tied to other factors. Insect-pollinated plants depend on temperature as well, but in a more indirect way, with a dependence filtered through the life cycle of their pollinators. A further study is necessary to understand which interpretation could be more reliable, e.g. a comparative study with gymnosperms, for which anemophily is the primary condition.

Floral Traits and Pollination Systems in the Caatinga, a Brazilian Tropical Dry Forest

PubMed Central

Machado, Isabel Cristina; Lopes, Ariadna Valentina

2004-01-01

• Background and aims 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. • Methods 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. • Key Results 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 %. • Conclusions 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. PMID:15286010

Extreme divergence in floral scent among woodland star species (Lithophragma spp.) pollinated by floral parasites

PubMed Central

Friberg, Magne; Schwind, Christopher; Raguso, Robert A.; Thompson, John N.

2013-01-01

Backgrounds and Aims A current challenge in coevolutionary biology is to understand how suites of traits vary as coevolving lineages diverge. Floral scent is often a complex, variable trait that attracts a suite of generalized pollinators, but may be highly specific in plants specialized on attracting coevolved pollinating floral parasites. In this study, floral scent variation was investigated in four species of woodland stars (Lithophragma spp.) that share the same major pollinator (the moth Greya politella, a floral parasite). Three specific hypotheses were tested: (1) sharing the same specific major pollinator favours conservation of floral scent among close relatives; (2) selection favours ‘private channels’ of rare compounds particularly aimed at the specialist pollinator; or (3) selection from rare, less-specialized co-pollinators mitigates the conservation of floral scent and occurrence of private channels. Methods Dynamic headspace sampling and solid-phase microextraction were applied to greenhouse-grown plants from a common garden as well as to field samples from natural populations in a series of experiments aiming to disentangle the genetic and environmental basis of floral scent variation. Key Results Striking floral scent divergence was discovered among species. Only one of 69 compounds was shared among all four species. Scent variation was largely genetically based, because it was consistent across field and greenhouse treatments, and was not affected by visits from the pollinating floral parasite. Conclusions The strong divergence in floral scents among Lithophragma species contrasts with the pattern of conserved floral scent composition found in other plant genera involved in mutualisms with pollinating floral parasites. Unlike some of these other obligate pollination mutualisms, Lithophragma plants in some populations are occasionally visited by generalist pollinators from other insect taxa. This additional complexity may contribute to the diversification in floral scent found among the Lithophragma species pollinated by Greya moths. PMID:23365407

Biomechanics of plant-insect interactions.

PubMed

Whitney, Heather M; Federle, Walter

2013-02-01

Plant-insect interactions are determined by both chemical and physical mechanisms. Biomechanical factors play an important role across many ecological situations, including pollination, herbivory and plant carnivory, and have led to complex adaptations in both plants and insects. However, while mechanical factors involved in some highly specific interactions have been elucidated, more generalised effects may be widespread but are more difficult to isolate, due to the multifunctional properties of the plant surfaces and tissues where interactions occur. Novel methodologies are being developed to investigate the mechanisms of biomechanical interactions and discover to what extent adaptive structures could be exploited via biomimetics. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biomechanics of substrate boring by fig wasps.

PubMed

Kundanati, Lakshminath; Gundiah, Namrata

2014-06-01

Female insects of diverse orders bore into substrates to deposit their eggs. Such insects must overcome several biomechanical challenges to successfully oviposit, which include the selection of suitable substrates through which the ovipositor can penetrate without itself fracturing. In many cases, the insect may also need to steer and manipulate the ovipositor within the substrate to deliver eggs at desired locations before rapidly retracting her ovipositor to avoid predation. In the case of female parasitoid ichneumonid wasps, this process is repeated multiple times during her lifetime, thus testing the ability of the ovipositioning apparatus to endure fracture and fatigue. What specific adaptations does the ovipositioning apparatus of a female ichneumonoid wasp possess to withstand these challenges? We addressed this question using a model system composed of parasitoid and pollinator fig wasps. First, we show that parasitoid ovipositor tips have teeth-like structures, preferentially enriched with zinc, unlike the smooth morphology of pollinator ovipositors. We describe sensillae present on the parasitoid ovipositor tip that are likely to aid in the detection of chemical species and mechanical deformations and sample microenvironments within the substrate. Second, using atomic force microscopy, we show that parasitoid tip regions have a higher modulus compared with regions proximal to the abdomen in parasitoid and pollinator ovipositors. Finally, we use videography to film wasps during substrate boring and analyse buckling of the ovipositor to estimate the forces required for substrate boring. Together, these results allow us to describe the biomechanical principles underlying substrate boring in parasitoid ichneumonid wasps. Such studies may be useful for the biomimetic design of surgical tools and in the use of novel mechanisms to bore through hard substrates. © 2014. Published by The Company of Biologists Ltd.

Importance of pollinators in changing landscapes for world crops

PubMed Central

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

Importance of pollinators in changing landscapes for world crops.

PubMed

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.

Sweat bees on hot chillies: provision of pollination services by native bees in traditional slash-and-burn agriculture in the Yucatán Peninsula of tropical Mexico.

PubMed

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.

Characterization of nuclear microsatellite markers from Agrostis species

EPA Science Inventory

Agrostis stolonifera L. (creeping bentgrass) is a widely distributed, out-crossing, wind-pollinated, perennial grass that has been genetically engineered for a variety of traits including herbicide, disease and insect resistance. This allotetraploid species (A2A2A3A3 genomic comp...

A gravity model for the spread of a pollinator-borne plant pathogen.

PubMed

Ferrari, Matthew J; Bjørnstad, Ottar N; Partain, Jessica L; Antonovics, Janis

2006-09-01

Many pathogens of plants are transmitted by arthropod vectors whose movement between individual hosts is influenced by foraging behavior. Insect foraging has been shown to depend on both the quality of hosts and the distances between hosts. Given the spatial distribution of host plants and individual variation in quality, vector foraging patterns may therefore produce predictable variation in exposure to pathogens. We develop a "gravity" model to describe the spatial spread of a vector-borne plant pathogen from underlying models of insect foraging in response to host quality using the pollinator-borne smut fungus Microbotryum violaceum as a case study. We fit the model to spatially explicit time series of M. violaceum transmission in replicate experimental plots of the white campion Silene latifolia. The gravity model provides a better fit than a mean field model or a model with only distance-dependent transmission. The results highlight the importance of active vector foraging in generating spatial patterns of disease incidence and for pathogen-mediated selection for floral traits.

A Meta-Analysis of Effects of Bt Crops on Honey Bees (Hymenoptera: Apidae)

PubMed Central

Duan, Jian J.; Marvier, Michelle; Huesing, Joseph; Dively, Galen; Huang, Zachary Y.

2008-01-01

Background Honey bees (Apis mellifera L.) are the most important pollinators of many agricultural crops worldwide and are a key test species used in the tiered safety assessment of genetically engineered insect-resistant crops. There is concern that widespread planting of these transgenic crops could harm honey bee populations. Methodology/Principal Findings We conducted a meta-analysis of 25 studies that independently assessed potential effects of Bt Cry proteins on honey bee survival (or mortality). Our results show that Bt Cry proteins used in genetically modified crops commercialized for control of lepidopteran and coleopteran pests do not negatively affect the survival of either honey bee larvae or adults in laboratory settings. Conclusions/Significance Although the additional stresses that honey bees face in the field could, in principle, modify their susceptibility to Cry proteins or lead to indirect effects, our findings support safety assessments that have not detected any direct negative effects of Bt crops for this vital insect pollinator. PMID:18183296

Diversity of the Insect Visitors on Calluna vulgaris (Ericaceae) in Southern France Heathlands.

PubMed

Descamps, Charlotte; Moquet, Laura; Migon, Marc; Jacquemart, Anne-Laure

2015-01-01

As part of an ongoing research project on the pollination networks in European heathlands, the objective of this study was to assess the insect visitor guild on Calluna vulgaris (L.) Hull (Ericaceae). We focused the study on a region renowned for its largely well-preserved heathlands, the Cévennes National Park, Southern France. In 2013, flower visitors were observed over 3 d per site, in four heathland sites at mont Lozère. Honeybees (Apis mellifera L.) were the main visitors (62-88% of total visitors). Besides honeybees, a high diversity of visitors was detected with 57 different species identified (42 Diptera and 15 Hymenoptera). Hoverflies (Syrphidae, Diptera) visitors were abundant and diverse, especially individuals belonging to the genera Eristalis and Episyrphus. The reported diversity of visitors was probably due to the preservation of large heathland areas at mont Lozère and to the generalist pollination system of C. vulgaris. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Delivery of crop pollination services is an insufficient argument for wild pollinator conservation.

PubMed

Kleijn, David; Winfree, Rachael; Bartomeus, Ignasi; Carvalheiro, Luísa G; Henry, Mickaël; Isaacs, Rufus; Klein, Alexandra-Maria; Kremen, Claire; M'Gonigle, Leithen K; Rader, Romina; Ricketts, Taylor H; Williams, Neal M; Lee Adamson, Nancy; Ascher, John S; Báldi, András; Batáry, Péter; Benjamin, Faye; Biesmeijer, Jacobus C; Blitzer, Eleanor J; Bommarco, Riccardo; Brand, Mariëtte R; Bretagnolle, Vincent; Button, Lindsey; Cariveau, Daniel P; Chifflet, Rémy; Colville, Jonathan F; Danforth, Bryan N; Elle, Elizabeth; Garratt, Michael P D; Herzog, Felix; Holzschuh, Andrea; Howlett, Brad G; Jauker, Frank; Jha, Shalene; Knop, Eva; Krewenka, Kristin M; Le Féon, Violette; Mandelik, Yael; May, Emily A; Park, Mia G; Pisanty, Gideon; Reemer, Menno; Riedinger, Verena; Rollin, Orianne; Rundlöf, Maj; Sardiñas, Hillary S; Scheper, Jeroen; Sciligo, Amber R; Smith, Henrik G; Steffan-Dewenter, Ingolf; Thorp, Robbin; Tscharntke, Teja; Verhulst, Jort; Viana, Blandina F; Vaissière, Bernard E; Veldtman, Ruan; Ward, Kimiora L; Westphal, Catrin; Potts, Simon G

2015-06-16

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.

Floral traits influencing plant attractiveness to three bee species: Consequences for plant reproductive success.

PubMed

Bauer, Austin A; Clayton, Murray K; Brunet, Johanne

2017-05-01

The ability to attract pollinators is crucial to plants that rely on insects for pollination. We contrasted the roles of floral display size and flower color in attracting three bee species and determined the relationships between plant attractiveness (number of pollinator visits) and seed set for each bee species. We recorded pollinator visits to plants, measured plant traits, and quantified plant reproductive success. A zero-inflated Poisson regression model indicated plant traits associated with pollinator attraction. It identified traits that increased the number of bee visits and traits that increased the probability of a plant not receiving any visits. Different components of floral display size were examined and two models of flower color contrasted. Relationships between plant attractiveness and seed set were determined using regression analyses. Plants with more racemes received more bee visits from all three bee species. Plants with few racemes were more likely not to receive any bee visits. The role of flower color varied with bee species and was influenced by the choice of the flower color model. Increasing bee visits increased seed set for all three bee species, with the steepest slope for leafcutting bees, followed by bumble bees, and finally honey bees. Floral display size influenced pollinator attraction more consistently than flower color. The same plant traits affected the probability of not being visited and the number of pollinator visits received. The impact of plant attractiveness on female reproductive success varied, together with pollinator effectiveness, by pollinator species. © 2017 Bauer et al. Published by the Botanical Society of America. This work is licensed under a Creative Commons public domain license (CC0 1.0).

Field Margins, Foraging Distances and Their Impacts on Nesting Pollinator Success

PubMed Central

Rands, Sean A.; Whitney, Heather M.

2011-01-01

The areas of wild land around the edges of agricultural fields are a vital resource for many species. These include insect pollinators, to whom field margins provide both nest sites and important resources (especially when adjacent crops are not in flower). Nesting pollinators travel relatively short distances from the nest to forage: most species of bee are known to travel less than two kilometres away. In order to ensure that these pollinators have sufficient areas of wild land within reach of their nests, agricultural landscapes need to be designed to accommodate the limited travelling distances of nesting pollinators. We used a spatially-explicit modelling approach to consider whether increasing the width of wild strips of land within the agricultural landscape will enhance the amount of wild resources available to a nesting pollinator, and if it would impact differently on pollinators with differing foraging strategies. This was done both by creating field structures with a randomised geography, and by using landscape data based upon the British agricultural landscape. These models demonstrate that enhancing field margins should lead to an increase in the availability of forage to pollinators that nest within the landscape. With the exception of species that only forage within a very short range of their nest (less than 125 m), a given amount of field margin manipulation should enhance the proportion of land available to a pollinator for foraging regardless of the distance over which it normally travels to find food. A fixed amount of field edge manipulation should therefore be equally beneficial for both longer-distance nesting foragers such as honeybees, and short-distance foragers such as solitary bees. PMID:21991390

Modeling the two-locus architecture of divergent pollinator adaptation: how variation in SAD paralogs affects fitness and evolutionary divergence in sexually deceptive orchids.

PubMed

Xu, Shuqing; Schlüter, Philipp M

2015-01-01

Divergent selection by pollinators can bring about strong reproductive isolation via changes at few genes of large effect. This has recently been demonstrated in sexually deceptive orchids, where studies (1) quantified the strength of reproductive isolation in the field; (2) identified genes that appear to be causal for reproductive isolation; and (3) demonstrated selection by analysis of natural variation in gene sequence and expression. In a group of closely related Ophrys orchids, specific floral scent components, namely n-alkenes, are the key floral traits that control specific pollinator attraction by chemical mimicry of insect sex pheromones. The genetic basis of species-specific differences in alkene production mainly lies in two biosynthetic genes encoding stearoyl-acyl carrier protein desaturases (SAD) that are associated with floral scent variation and reproductive isolation between closely related species, and evolve under pollinator-mediated selection. However, the implications of this genetic architecture of key floral traits on the evolutionary processes of pollinator adaptation and speciation in this plant group remain unclear. Here, we expand on these recent findings to model scenarios of adaptive evolutionary change at SAD2 and SAD5, their effects on plant fitness (i.e., offspring number), and the dynamics of speciation. Our model suggests that the two-locus architecture of reproductive isolation allows for rapid sympatric speciation by pollinator shift; however, the likelihood of such pollinator-mediated speciation is asymmetric between the two orchid species O. sphegodes and O. exaltata due to different fitness effects of their predominant SAD2 and SAD5 alleles. Our study not only provides insight into pollinator adaptation and speciation mechanisms of sexually deceptive orchids but also demonstrates the power of applying a modeling approach to the study of pollinator-driven ecological speciation.

[Breeding system of Paris polyphylla var. yunnanensis].

PubMed

Wang, Yan-Fang; Li, Ge; Tang, Ling; Li, Rong-Ying; Yang, Chun-Yong; Peng, Jian-Ming

2013-09-01

To provide the basic guidance for seed breeding and cross-breeding of Paris polyphylla var. yunnanensis. The floral behavior and pollinators were observed; 0.5% TTC solution was used for the pollen viability test and benzidine and -H2O2 was used for estimation of the stigma receptivity. The mating systems were tested by out crossing index (OC1), and pollination experiment was carried out by bagged and emasculated test in the field. Commonly, stigma lobes spread slightly, and anthers started presenting the pollen from the outer ring while the flower was just beginning to open. Consequently, the distance between the stigma and its own pollen was relatively far, this "floral behavior" may be conducive to outcrossing. Then the flower entered the later period, while the stigma lobes spread widely, anthers all split, and this "floral behavior" shortened the stigma and its own pollen's distance, which may be conducive to selfing. P. polyphylla was partly protogynous. Stigma life-span was about 10-12 d. After anther dehiscence, the pollen viability maintained about 10% within 2 days, and 20% within 10 days. The value of out crossing index (OC1) was 4. By pollination experiment and pollinators observed, P. polyphylla was self-compatible, but no capacity for autonomous self-fertilization; In natural circumstances, outcrossing fructification rate was low, and mainly anemophilous. Assisted selfing-fertilization fructification rate was higher, spider was the main pollinators. P. polyphylla has a mixed mating system with self-pollination and cross-pollination characteristics. Floral behavior has important adaptive significance in avoiding female and male interference, outcrossing, and delayed selfing. P. polyphylla is ambophily (a combination of both wind and insect pollination), pollinators changes due to environment. Pollen limitation is the main cause of low fructification rate under natural conditions.

The Effects of Crop Intensification on the Diversity of Native Pollinator Communities.

PubMed

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.

Sexual mimicry in Mormolyca ringens (Lindl.) Schltr. (Orchidaceae: Maxillariinae).

PubMed

Singer, Rodrigo B; Flach, Adriana; Koehler, Samantha; Marsaioli, Anita J; Amaral, Maria do Carmo E

2004-06-01

Pollination through sexual mimicry, also known as pseudocopulation, has been suggested to occur in some genera of the Neotropical orchid subtribe Maxillariinae. However, it has been demonstrated so far only for Trigonidium obtusum. This study reports and illustrates pollination through sexual mimicry in Mormolyca ringens. A total of 70 h were dedicated to the observation of flowers and pollinator behaviour, which was photographically recorded. Flower features involved in pollinator attraction were studied using a stereomicroscope and by SEM analyses. Preliminary observations on the plant breeding system were made by manually self-pollinating flowers. The chemical composition of the fragrance volatiles was determined by GC/MS analysis. The flower features of M. ringens parallel those of other pseudocopulatory flowers. The labellum shape and indument are reminiscent of an insect. Sexually excited drones of Nannotrigona testaceicornis and Scaptotrigona sp. (both in the Apidae: Meliponini) attempt copulation with the labellum and pollinate the flower in the process. In both bee species, the pollinarium is attached to the scutellum. Pollinator behaviour may promote some degree of self-pollination, but preliminary observations indicate that M. ringens flowers are self-incompatible. Flowers are produced all the year round, which ties in with the production of bee males several times a year. The phylogenetic relationships of M. ringens are discussed and a number of morphological and phenological features supporting them are reported. It is expected that further research could bring to light whether other Maxillariinae species are also pollinated through sexual mimicry. When a definitive and robust phylogeny of this subtribe is available, it should be possible to determine how many times pseudocopulation evolved and its possible evolutionary history.

Asymmetrical nature of the Trollius-Chiastocheta interaction: insights into the evolution of nursery pollination systems.

PubMed

Suchan, Tomasz; Beauverd, Mélanie; Trim, Naïké; Alvarez, Nadir

2015-11-01

The mutualistic versus antagonistic nature of an interaction is defined by costs and benefits of each partner, which may vary depending on the environment. Contrasting with this dynamic view, several pollination interactions are considered as strictly obligate and mutualistic. Here, we focus on the interaction between Trollius europaeus and Chiastocheta flies, considered as a specialized and obligate nursery pollination system - the flies are thought to be exclusive pollinators of the plant and their larvae develop only in T. europaeus fruits. In this system, features such as the globelike flower shape are claimed to have evolved in a coevolutionary context. We examine the specificity of this pollination system and measure traits related to offspring fitness in isolated T. europaeus populations, in some of which Chiastocheta flies have gone extinct. We hypothesize that if this interaction is specific and obligate, the plant should experience dramatic drop in its relative fitness in the absence of Chiastocheta. Contrasting with this hypothesis, T. europaeus populations without flies demonstrate a similar relative fitness to those with the flies present, contradicting the putative obligatory nature of this pollination system. It also agrees with our observation that many other insects also visit and carry pollen among T. europaeus flowers. We propose that the interaction could have evolved through maximization of by-product benefits of the Chiastocheta visits, through the male flower function, and selection on floral traits by the most effective pollinator. We argue this mechanism is also central in the evolution of other nursery pollination systems.

Choices and consequences of oviposition by a pollinating seed predator, Hadena ectypa (Noctuidae), on its host plant, Silene stellata (Caryophyllaceae).

PubMed

Kula, Abigail A R; Dudash, Michele R; Fenster, Charles B

2013-06-01

Pollinating seed predators are models for the study of mutualisms. These insects have dual effects on host-plant fitness, through pollination as adults and flower and fruit predation as larvae. A rarely examined question is whether pollinating seed-predator oviposition choices are influenced by plant floral and size traits and the potential consequences of oviposition for host-plant reproduction. • We quantified oviposition by a pollinating seed predator, Hadena ectypa, on its host, Silene stellata, to determine if oviposition was associated with specific plant traits and whether oviposition was significantly correlated with fruit initiation or flower and fruit predation over three years. We also quantified whether stigmatic pollen loads of flowers visited by Hadena that both fed on nectar and oviposited were greater than when Hadena only fed on nectar. • Hadena had significant preference for plants having flowers with long corolla tubes in all three years. Moth oviposition was correlated with other traits only in some years. Oviposition did not increase stigmatic pollen loads. We observed significant positive relationships between both oviposition and fruit initiation and oviposition and flower/fruit predation. • Hadena ectypa oviposition choices were based consistently on floral tube length differences among individuals, and the consequences of oviposition include both fruit initiation (due to pollination while feeding on nectar prior to oviposition) and larval flower/fruit predation. The positive association between oviposition and fruit initiation may explain the long-term maintenance of facultative pollinating seed-predator interactions.

Evolution of polyploidy and the diversification of plant-pollinator interactions.

PubMed

Thompson, John N; Merg, Kurt F

2008-08-01

One of the major mechanisms of plant diversification has been the evolution of polyploid populations that differ from their diploid progenitors in morphology, physiology, and environmental tolerances. Recent studies have indicated that polyploidy may also have major effects on ecological interactions with herbivores and pollinators. We evaluated pollination of sympatric diploid and tetraploid plants of the rhizomatous herb Heuchera grossulariifolia (Saxifragaceae) along the Selway and Salmon Rivers of northern Idaho, USA, during four consecutive years. Previous molecular and ecological analyses had indicated that the tetraploid populations along these two river systems are independently derived and differ from each other in multiple traits. In each region, we evaluated floral visitation rate by all insect visitors, pollination efficacy of all major visitors, and relative contribution of all major pollinators to seed set. In both regions, diploid and tetraploid plants attracted different suites of floral visitors. Most pollination was attributable to several bee species and the moth Greya politella. Lasioglossum bees preferentially visited diploid plants at Lower Salmon but not at Upper Selway, queen Bombus centralis preferentially visited tetraploids at both sites, and worker B. centralis differed between sites in their cytotype preference. Hence, diploid and autotetraploid H. grossulariifolia plants act essentially as separate ecological species and may experience partial reproductive isolation through differential visitation and pollination by their major floral visitors. Overall the results, together with recent results from other studies, suggest that the repeated evolution of polyploidy in plants may contribute importantly to the structure and diversification of ecological interactions in terrestrial communities.

Pollination Ecology of Four Epiphytic Orchids of New Zealand

PubMed Central

LEHNEBACH, CARLOS A.; ROBERTSON, ALASTAIR W

2004-01-01

• Background and Aims In New Zealand epiphytic orchids are represented by four genera and eight species. The genera Earina (three species) and Winika (one species) are the most conspicuous and widespread. These are likely to be some of the southernmost distributed genera of epiphytic orchids in the world. • Methods To identify the pollination strategies that have evolved in these orchids, hand‐pollination treatments were done and floral visitors were observed in several wild populations at two areas of southern North Island (approx. 40°S). Pollen : ovule ratio and osmophores were also studied and the total carbohydrate content of the nectar produced by each species was measured. • Key results Earina autumnalis and Earina mucronata are self‐compatible, whereas Earina aestivalis and Winika cunninghamii appear to be partially self‐incompatible. All four orchids are incapable of autonomous selfing and therefore completely dependent on pollinators to set fruits. Floral visitors observed in the genus Earina belong to Diptera, Coleoptera and Hymenoptera and to Diptera and Hymenoptera in W. cunninghamii. • Conclusions Contrary to many epiphytic orchids in the tropics, the orchid–pollinator relationship in these orchids is unspecialized and flowers are visited by a wide range of insects. Putative pollinators are flies of the families Bibionidae, Calliphoridae, Syrphidae and Tachinidae. All four orchids display anthecological adaptations to a myophilous pollination system such as simple flowers, well‐exposed reproductive structures, easily accessed nectar and high pollen : ovule ratios. PMID:15113741

Effects of model-mimic frequency on insect visitation and plant reproduction in a self-mimicry pollination system

PubMed Central

Oleques, Suiane Santos; Marciniak, Brisa; Ribeiro, José Ricardo I

2017-01-01

Abstract The proportion of mimics and models is a key parameter in mimetic systems. In monoecious plants with self-mimicry pollination systems, the mimic-model ratio is determined by the floral sex ratio. While an equal sex ratio (1:1) could provide the perfect balance between pollen donors and stigma surfaces able to receive the pollen, an unequal ratio could increase pollination by production of a greater number of rewarding, model flowers. The aim of the present study is to test the differences in visitation frequency and reproductive rates of different mimic and model flower arrays in order to assess the efficacy of the mimetic system in a Begonia cucullata population. The frequencies of visitors to groups of flowers with three distinctive sex ratio arrays (male-biased, female-biased and equal ratio) were compared using a Bayesian approach. The reproductive outcomes were compared in order to detect advantages of particular sex ratios. Low visitation frequency was recorded in all arrays. Pollinators showed similar behaviour regardless of sex ratio; they tended to avoid female, rewardless flowers. Pollination quality was highest in the equal sex ratio array. The current study shows that sex ratio plays a critical role in the pollination of B. cucullata and that the efficacy of the self-mimicry system appears to be doubtful. Visitation frequency may be associated with visual or chemical cues that allow pollinators to recognize models and mimics, regardless of their frequency in the population. PMID:29255587

Effects of model-mimic frequency on insect visitation and plant reproduction in a self-mimicry pollination system.

PubMed

de Avila, Rubem Samuel; Oleques, Suiane Santos; Marciniak, Brisa; Ribeiro, José Ricardo I

2017-11-01

The proportion of mimics and models is a key parameter in mimetic systems. In monoecious plants with self-mimicry pollination systems, the mimic-model ratio is determined by the floral sex ratio. While an equal sex ratio (1:1) could provide the perfect balance between pollen donors and stigma surfaces able to receive the pollen, an unequal ratio could increase pollination by production of a greater number of rewarding, model flowers. The aim of the present study is to test the differences in visitation frequency and reproductive rates of different mimic and model flower arrays in order to assess the efficacy of the mimetic system in a Begonia cucullata population. The frequencies of visitors to groups of flowers with three distinctive sex ratio arrays (male-biased, female-biased and equal ratio) were compared using a Bayesian approach. The reproductive outcomes were compared in order to detect advantages of particular sex ratios. Low visitation frequency was recorded in all arrays. Pollinators showed similar behaviour regardless of sex ratio; they tended to avoid female, rewardless flowers. Pollination quality was highest in the equal sex ratio array. The current study shows that sex ratio plays a critical role in the pollination of B. cucullata and that the efficacy of the self-mimicry system appears to be doubtful. Visitation frequency may be associated with visual or chemical cues that allow pollinators to recognize models and mimics, regardless of their frequency in the population.

Astylus atromaculatus (Coleoptera: Melyridae): abundance and role in pollen dispersal in Bt and non-Bt cotton in South Africa.

PubMed

Pierre, Jacqueline; Hofs, Jean-Luc

2010-10-01

In South Africa, modified Bt (Cry1 Ac) cotton cultivars and organic ones coexist. This raises the question of the risk of dissemination of genetically modified (GM) pollen to non-GM crops by visiting insects. We inventoried the flower-visiting insects in Bt and non-Bt cotton fields of the South African Highveld region and investigated their role in pollen dispersal. Their diversity and abundance varied slightly among sites, with Astylus atromaculatus as the predominant insect on both Bt and non-Bt cotton flowers. The other major flower-visiting species were Apis mellifera and solitary Apidae. No differences were found in the abundance of each taxum between Bt and non-Bt cotton except for Scoliidae and Nitidulidae, which were scarce overall (<0.5%) but more abundant on the non-Bt flowers in the central area of the field at one site. The pollen load on A. atromaculatus was as high as on Apis mellifera. Cage tests showed that A. atromaculatus can pollinate female cotton plants by transferring pollen from male donor plants. In the field, the flight range of this insect was generally short (25 m), but it can occasionally reach up to 200 m or even more. This study therefore highlights that A. atromaculatus, commonly regarded as a pest, could be an unexpected but efficient pollinator. Because its population density can be high, this species could mediate unwanted cotton pollen flow when distances between coexiting fields are not sufficient.

Global growth and stability of agricultural yield decrease with pollinator dependence

PubMed Central

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

Sub-lethal effects of neonicitinoids on the alfalfa leafcutter bee, Megachile rotundata

USDA-ARS?s Scientific Manuscript database

Neonicotinoids are commonly used pesticides in U.S. agriculture. For many beneficial insect species, lethal effects of neonicotinoids are well-documented; however, much less is known about sublethal exposure. The alfalfa leaf cutter bee Megachile rotundata is a managed pollinator that constructs com...

Genomic analyses of the microsporidian Nosema ceranae, an emergent pathogen of honey bees.

USDA-ARS?s Scientific Manuscript database

Recent steep declines in honey bee health have severely impacted the beekeeping industry, presenting new risks for agricultural commodities that depend on insect pollination. Honey bee declines could reflect increased pressures from parasites and pathogens. The incidence of the microsporidian pathog...

Response diversity to land use occurs but does not consistently stabilise ecosystem services provided by native pollinators.

PubMed

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.

Language of plants: Where is the word?

PubMed

Šimpraga, Maja; Takabayashi, Junji; Holopainen, Jarmo K

2016-04-01

Plants emit biogenic volatile organic compounds (BVOCs) causing transcriptomic, metabolomic and behavioral responses in receiver organisms. Volatiles involved in such responses are often called "plant language". Arthropods having sensitive chemoreceptors can recognize language released by plants. Insect herbivores, pollinators and natural enemies respond to composition of volatiles from plants with specialized receptors responding to different types of compounds. In contrast, the mechanism of how plants "hear" volatiles has remained obscured. In a plant-plant communication, several individually emitted compounds are known to prime defense response in receiver plants with a specific manner according to the chemical structure of each volatile compound. Further, composition and ratio of volatile compounds in the plant-released plume is important in plant-insect and plant-plant interactions mediated by plant volatiles. Studies on volatile-mediated plant-plant signaling indicate that the signaling distances are rather short, usually not longer than one meter. Volatile communication from plants to insects such as pollinators could be across distances of hundreds of meters. As many of the herbivore induced VOCs have rather short atmospheric life times, we suggest that in long-distant communications with plant volatiles, reaction products in the original emitted compounds may have additional information value of the distance to emission source together with the original plant-emitted compounds. © 2015 Institute of Botany, Chinese Academy of Sciences.

Flower evolution of alpine forbs in the open top chambers (OTCs) from the Qinghai-Tibet Plateau

PubMed Central

Zhang, Chan; Wang, Lin-Lin; Yang, Yong-Ping; Duan, Yuan-Wen

2015-01-01

Effects of global changes on biodiversity have been paid more and more attention world widely, and the open top chambers (OTCs) are the most common tools to study the effects of climatic warming on plant diversity. However, it remains unclear how flowers evolve under environmental changes, which could help us to understand the changes of plant diversity in the OTCs. We compared the insect diversity and pollen:ovule (P/O) ratio of eight outcrossing species with different life histories inside and outside the OTCs on the Qinghai-Tibet Plateau, to examine the effects induced by OTCs on the evolution of floral traits. In the OTCs, P/O ratio decreased in annuals, but increased in perennials, indicating an overall trend toward selfing in annuals. We found that the insect diversity differed significantly inside and outside the OTCS, with decreases of dipteran insects and bees. We concluded that changes of P/O ratio in the studied plant species might result from pollination failure, which might be the results of mismatch between flowering time and pollinator activities. We also suggested annuals might be in a more extinction risk than perennials in OTCs, if strong inbreeding depression occurs in these annual outcrossing plants. PMID:25998558

A challenge for the seed mixture refuge strategy in Bt maize: impact of cross-pollination on an ear-feeding pest, corn earworm.

PubMed

Yang, Fei; Kerns, David L; Head, Graham P; Leonard, B Rogers; Levy, Ronnie; Niu, Ying; Huang, Fangneng

2014-01-01

To counter the threat of insect resistance, Bacillus thuringiensis (Bt) maize growers in the U.S. are required to plant structured non-Bt maize refuges. Concerns with refuge compliance led to the introduction of seed mixtures, also called RIB (refuge-in-the-bag), as an alternative approach for implementing refuge for Bt maize products in the U.S. Maize Belt. A major concern in RIB is cross-pollination of maize hybrids that can cause Bt proteins to be present in refuge maize kernels and negatively affect refuge insects. Here we show that a mixed planting of 5% nonBt and 95% Bt maize containing the SmartStax traits expressing Cry1A.105, Cry2Ab2 and Cry1F did not provide an effective refuge for an important above-ground ear-feeding pest, the corn earworm, Helicoverpa zea (Boddie). Cross-pollination in RIB caused a majority (>90%) of refuge kernels to express ≥ one Bt protein. The contamination of Bt proteins in the refuge ears reduced neonate-to-adult survivorship of H. zea to only 4.6%, a reduction of 88.1% relative to larvae feeding on ears of pure non-Bt maize plantings. In addition, the limited survivors on refuge ears had lower pupal mass and took longer to develop to adults.

Biopesticide-induced behavioral and morphological alterations in the stingless bee Melipona quadrifasciata.

PubMed

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.

Artificial light at night as a new threat to pollination.

PubMed

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.

Leaf herbivory imposes fitness costs mediated by hummingbird and insect pollinators

PubMed Central

Whitehead, Susan; Amaya-Márquez, Marisol; Poveda, Katja

2017-01-01

Plant responses induced by herbivore damage can provide fitness benefits, but can also have important costs due to altered interactions with mutualist pollinators. We examined the effects of plant responses to herbivory in a hummingbird-pollinated distylous shrub, Palicourea angustifolia. Through a series of field experiments we investigated whether damage from foliar herbivores leads to a reduction in fruit set, influences floral visitation, or alters floral traits that may influence pollinator preference or pollinator efficiency. Foliar herbivory by a generalist grasshopper led to reduced fruit set in branches that were directly damaged as well as in adjacent undamaged branches on the same plant. Furthermore, herbivory resulted in reduced floral visitation from two common hummingbird species and two bee species. An investigation into the potential mechanisms behind reduced floral visitation in induced plants showed that foliar herbivore damage resulted in shorter styles and lower nectar volumes. This reduction in style length could reduce pollen deposition between different floral morphs that is required for optimal pollination in a distylous plant. We did not detect any differences in the volatile blends released by damaged and undamaged branches, suggesting that foliar herbivore-induced changes in floral morphology and rewards, and not volatile blends, are the primary mechanism mediating changes in visitation. Our results provide novel mechanisms for how plant responses induced by foliar herbivores can lead to ecological costs. PMID:29211805

Insecticide use in hybrid onion seed production affects pre- and postpollination processes.

PubMed

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.

Pollination crisis in the butterfly-pollinated wild carnation Dianthus carthusianorum?

PubMed

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.

Safeguarding pollinators and their values to human well-being.

PubMed

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.

Utah lotus: North American legume for rangeland revegetation in southern Great Basin and Colorado Plateau

USDA-ARS?s Scientific Manuscript database

Utah lotus (Lotus utahensis Ottley) is a North American leguminous forb that may hold promise for rangeland revegetation in the western USA for diversifying planting mixtures, attracting pollinators, providing high quality forage, and expanding habitats for insects needed by sage grouse chicks. We ...

Plant Fact Sheet: Western Prairie Clover [Dalea Ornata (Douglas) Eaton & Wright

USDA-ARS?s Scientific Manuscript database

Dalea L. is a widespread genus of the legume family (Fabaceae), which is comprised of 62 species of prairie clovers in North America. Western prairie clover [Dalea ornata (Douglas) Eaton & Wright] is a perennial, insect-pollinated legume that is non-toxic and palatable to herbivores. It occures in...

Ecology in the Classroom [Complete Kit].

ERIC Educational Resources Information Center

Audubon Naturalist Society of the Central Atlantic States, Inc., Washington, DC.

Designed specifically for use in inner city schools, this ecology project for grades four through six attempts to help children develop an appreciation of the out-of-doors and an awareness of the natural features of their own environment. The eight-week project consists of units about interdependence, plants, pollination, insects and their…

Compilation of 1985 annual reports of the Navy elf (extremely low frequency) communications system ecological monitoring program. Volume 2. Tabs D-G. Annual progress report, January-December 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Band, R.N.; Snider, R.J.; Snider, R.M.

1986-07-01

This volume consists of the following reports: Soil Amoeba; Soil and Litter Arthropoda and Earthworm Studies; Biological Studies on Pollinating Insects: Megachilid Bees; Small Vertebrates: Small Mammals and Nesting Birds.

Evidence for pollinator cost and farming benefits of neonicotinoid seed coatings on oilseed rape.

PubMed

Budge, G E; Garthwaite, D; Crowe, A; Boatman, N D; Delaplane, K S; Brown, M A; Thygesen, H H; Pietravalle, S

2015-08-13

Chronic exposure to neonicotinoid insecticides has been linked to reduced survival of pollinating insects at both the individual and colony level, but so far only experimentally. Analyses of large-scale datasets to investigate the real-world links between the use of neonicotinoids and pollinator mortality are lacking. Moreover, the impacts of neonicotinoid seed coatings in reducing subsequent applications of foliar insecticide sprays and increasing crop yield are not known, despite the supposed benefits of this practice driving widespread use. Here, we combine large-scale pesticide usage and yield observations from oilseed rape with those detailing honey bee colony losses over an 11 year period, and reveal a correlation between honey bee colony losses and national-scale imidacloprid (a neonicotinoid) usage patterns across England and Wales. We also provide the first evidence that farmers who use neonicotinoid seed coatings reduce the number of subsequent applications of foliar insecticide sprays and may derive an economic return. Our results inform the societal discussion on the pollinator costs and farming benefits of prophylactic neonicotinoid usage on a mass flowering crop.

Evidence for pollinator cost and farming benefits of neonicotinoid seed coatings on oilseed rape

NASA Astrophysics Data System (ADS)

Budge, G. E.; Garthwaite, D.; Crowe, A.; Boatman, N. D.; Delaplane, K. S.; Brown, M. A.; Thygesen, H. H.; Pietravalle, S.

2015-08-01

Chronic exposure to neonicotinoid insecticides has been linked to reduced survival of pollinating insects at both the individual and colony level, but so far only experimentally. Analyses of large-scale datasets to investigate the real-world links between the use of neonicotinoids and pollinator mortality are lacking. Moreover, the impacts of neonicotinoid seed coatings in reducing subsequent applications of foliar insecticide sprays and increasing crop yield are not known, despite the supposed benefits of this practice driving widespread use. Here, we combine large-scale pesticide usage and yield observations from oilseed rape with those detailing honey bee colony losses over an 11 year period, and reveal a correlation between honey bee colony losses and national-scale imidacloprid (a neonicotinoid) usage patterns across England and Wales. We also provide the first evidence that farmers who use neonicotinoid seed coatings reduce the number of subsequent applications of foliar insecticide sprays and may derive an economic return. Our results inform the societal discussion on the pollinator costs and farming benefits of prophylactic neonicotinoid usage on a mass flowering crop.

Drought and increased CO2 alter floral visual and olfactory traits with context-dependent effects on pollinator visitation

Treesearch

William R. Glenny; Justin B. Runyon; Laura A. Burkle

2018-01-01

Climate change can alter species interactions essential for maintaining biodiversity and ecosystem function, such as pollination. Understanding the interactive effects of multiple abiotic conditions on floral traits and pollinator visitation are important to anticipate the implications of climate change on pollinator services. Floral visual and olfactory traits were...

The diversity of floral temperature patterns, and their use by pollinators

PubMed Central

Harrap, Michael JM; Hempel de Ibarra, Natalie; Whitney, Heather M

2017-01-01

Pollinating insects utilise various sensory cues to identify and learn rewarding flower species. One such cue is floral temperature, created by captured sunlight or plant thermogenesis. Bumblebees, honeybees and stingless bees can distinguish flowers based on differences in overall temperature between flowers. We report here that floral temperature often differs between different parts of the flower creating a temperature structure or pattern. Temperature patterns are common, with 55% of 118 plant species thermographed, showing within-flower temperature differences greater than the 2°C difference that bees are known to be able to detect. Using differential conditioning techniques, we show that bumblebees can distinguish artificial flowers differing in temperature patterns comparable to those seen in real flowers. Thus, bumblebees are able to perceive the shape of these within-flower temperature patterns. Floral temperature patterns may therefore represent a new floral cue that could assist pollinators in the recognition and learning of rewarding flowers. PMID:29254518

Delivery of crop pollination services is an insufficient argument for wild pollinator conservation

PubMed Central

Kleijn, David; Winfree, Rachael; Bartomeus, Ignasi; Carvalheiro, Luísa G; Henry, Mickaël; Isaacs, Rufus; Klein, Alexandra-Maria; Kremen, Claire; M'Gonigle, Leithen K; Rader, Romina; Ricketts, Taylor H; Williams, Neal M; Lee Adamson, Nancy; Ascher, John S; Báldi, András; Batáry, Péter; Benjamin, Faye; Biesmeijer, Jacobus C; Blitzer, Eleanor J; Bommarco, Riccardo; Brand, Mariëtte R; Bretagnolle, Vincent; Button, Lindsey; Cariveau, Daniel P; Chifflet, Rémy; Colville, Jonathan F; Danforth, Bryan N; Elle, Elizabeth; Garratt, Michael P.D.; Herzog, Felix; Holzschuh, Andrea; Howlett, Brad G; Jauker, Frank; Jha, Shalene; Knop, Eva; Krewenka, Kristin M; Le Féon, Violette; Mandelik, Yael; May, Emily A; Park, Mia G; Pisanty, Gideon; Reemer, Menno; Riedinger, Verena; Rollin, Orianne; Rundlöf, Maj; Sardiñas, Hillary S; Scheper, Jeroen; Sciligo, Amber R; Smith, Henrik G; Steffan-Dewenter, Ingolf; Thorp, Robbin; Tscharntke, Teja; Verhulst, Jort; Viana, Blandina F; Vaissière, Bernard E; Veldtman, Ruan; Westphal, Catrin; Potts, Simon G

2015-01-01

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments. PMID:26079893

Insect visitation and pollen deposition in an invaded prairie plant community

USGS Publications Warehouse

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.

Nectar properties and the role of sunbirds as pollinators of the golden-flowered tea (Camellia petelotii).

PubMed

Sun, Shi-Guo; Huang, Zhi-Huan; Chen, Zhi-Bao; Huang, Shuang-Quan

2017-03-01

Properties of floral nectar have been used to predict if a plant species is pollinated by birds. To see whether winter-flowering plants evolve nectar properties corresponding to bird pollinators, nectar properties of several Camellia species (including the golden-flowered tea), as well as the role of floral visitors as effective pollinators, were examined. Potential pollinators of Camellia petelotii were identified at different times of day and under various weather conditions. A bird exclusion experiment was used to compare the pollination effectiveness of birds and insects. Nectar sugar components (fructose, glucose, and sucrose) from C. petelotii growing wild and another seven Camellia species and 22 additional cultivars (all in cultivation) were examined by high-performance liquid chromatography (HPLC). The sunbird Aethopyga siparaja and honeybees were the most frequent floral visitors to C. petelotii . Honeybee visits were significantly reduced in cloudy/rainy weather. The fruit and seed set of flowers with birds excluded were reduced by 64%, indicating that bird pollination is significant. For the wild populations of C. petelotii , a bagged flower could secrete 157 μL nectar; this nectar has a low sugar concentration (19%) and is sucrose-dominant (87%). The eight Camellia species and 22 cultivars had an average sugar concentration of around 30% and a sucrose concentration of 80%, demonstrating sucrose-dominant nectar in Camellia species. The nectar sugar composition of Camellia species was characterized by sucrose dominance. In addition, the large reduction in seed set when birds are excluded in the golden-flowered tea also supports the suggestion that these winter-flowering plants may have evolved with birds as significant pollinators. © 2017 Botanical Society of America.

Hidden floral adaptation to nocturnal moths in an apparently bee-pollinated flower, Adenophora triphylla var. japonica (Campanulaceae).

PubMed

Funamoto, D; Ohashi, K

2017-09-01

The discrepancy between observed flower visitors and those predicted based on floral phenotype has often cast doubt on the pollination syndrome concept. Here we show that this paradox may be alleviated by gaining better knowledge of the contributions of different flower visitors to pollination and the effects of floral traits that cannot be readily perceived by humans in Adenophora triphylla var. japonica. The blue, bell-shaped and pendant flowers of A. triphylla appear to fit a bee pollination syndrome. In contrast to this expectation, recent studies show that these flowers are frequented by nocturnal moths. We compared the flower visitor fauna, their visitation frequency and their relative contributions to seed set between day and night in two field populations of A. triphylla in Japan. We also determined the floral traits associated with temporal changes in the visitor assemblage, i.e. the timing of anthesis, the timing of changes in the sexual phase and the diel pattern of nectar production. While A. triphylla flowers were visited by both diurnal and nocturnal insects, the results from pollination experiments demonstrate that their primary pollinators are nocturnal settling-moths. Moreover, the flowers opened just after sunset, changed from staminate to pistillate phase in successive evenings and produced nectar only during the night, which all conform to the activity of nocturnal/crepuscular moths. Our study illustrates that the tradition of stereotyping the pollinators of a flower based on its appearance can be misleading and that it should be improved with empirical evidence of pollination performance and sufficient trait matching. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Pollinator visitation in populations of tristylous Eichhornia paniculata in northeastern Brazil.

PubMed

Husband, Brian C; Barrett, Spencer C H

1992-03-01

The frequencies of floral morphs in populations of tristylous Eichhornia paniculata often deviate from the theoretical expectation of equality. This variation is associated with the breakdown of tristyly and the evolution of self-fertilization. Differences in morph frequencies could result from selection pressures due to variable levels of insect visitation to populations and contrasting foraging behavior among the floral morphs. We estimated pollinator densities in 16 populations and quantified visitation sequences to morphs in five populations of E. paniculata in northeastern Brazil. Foraging behavior among floral morphs was measured as the frequency of visits to morphs relative to their frequency in the population (preference) and number of flights between inflorescences of the same versus different morphs (constancy). Pollinator density (number/m 2 /minute) was not correlated with population size, plant density or morph diversity. Pollinator densities varied most among populations of less than 200 plants. Whether pollinators discriminated among the morphs, depended on whether they primarily collected nectar or pollen. In four populations, nectar-feeding bees (Ancyloscelis and Florilegus spp.) and butterflies showed no consistent preference or constancy among the morphs. In contrast, pollen-collecting bees (Trigona sp.) visited a lower proportion of longstyled inflorescences than expected and tended to visit more mid-and short-styled inflorescences in succession, once they were encountered. Pollinator constancy for morphs did not result from differences in inflorescence production or spatial patchiness among the morphs. Although non-random pollinator visitation to morphs in heterostylous populations could potentially affect mating and hence morph frequencies, the observed visitation patterns in this study do not provide evidence that pollinators play a major role in influencing floral morph frequencies.

Understanding Barriers to Participation in Cost-Share Programs For Pollinator Conservation by Wisconsin (USA) Cranberry Growers.

PubMed

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.

Understanding Barriers to Participation in Cost-Share Programs For Pollinator Conservation by Wisconsin (USA) Cranberry Growers

PubMed Central

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

Neither protogynous nor obligatory out-crossed: pollination biology and breeding system of the European Red List Fritillaria meleagris L. (Liliaceae).

PubMed

Zych, M; Stpiczyńska, M

2012-03-01

For 4 years we studied pollination biology and breeding system of the critically endangered, Red List plant Fritillaria meleagris L. (Liliaceae), in the larger of the two remaining populations of the plant in SE Poland. Our observations indicated that, contrary to literature data, the species is not dichogamous nor is it obligatorily out-crossing. Selfing, although rare in natural populations, results in fully developed seeds. Flowers are visited by several insect species, mostly social and solitary bees. In spite of extremely low visitation rates to this early spring-flowering plant, the species is not pollen limited. Although the largest pollen loads are transferred by solitary bees, the key pollinators are bumblebees (mostly the most common species, Bombus terrestris and B. lapidarius) due to their seasonal and floral constancy, and tolerance of bad weather conditions. The current decline of the studied population seems not to be related to the species' pollination or breeding systems but to plant habitat loss. It is suggested, however, that in smaller populations, the species' dependence on generally rare pollinators and largely out-crossed breeding system may accelerate local extinction. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

Temporally dependent pollinator competition and facilitation with mass flowering crops affects yield in co-blooming crops

PubMed Central

Grab, Heather; Blitzer, Eleanor J.; Danforth, Bryan; Loeb, Greg; Poveda, Katja

2017-01-01

One of the greatest challenges in sustainable agricultural production is managing ecosystem services, such as pollination, in ways that maximize crop yields. Most efforts to increase services by wild pollinators focus on management of natural habitats surrounding farms or non-crop habitats within farms. However, mass flowering crops create resource pulses that may be important determinants of pollinator dynamics. Mass bloom attracts pollinators and it is unclear how this affects the pollination and yields of other co-blooming crops. We investigated the effects of mass flowering apple on the pollinator community and yield of co-blooming strawberry on farms spanning a gradient in cover of apple orchards in the landscape. The effect of mass flowering apple on strawberry was dependent on the stage of apple bloom. During early and peak apple bloom, pollinator abundance and yield were reduced in landscapes with high cover of apple orchards. Following peak apple bloom, pollinator abundance was greater on farms with high apple cover and corresponded with increased yields on these farms. Spatial and temporal overlap between mass flowering and co-blooming crops alters the strength and direction of these dynamics and suggests that yields can be optimized by designing agricultural systems that avoid competition while maximizing facilitation. PMID:28345653

Stormwater runoff mitigation and nutrient leaching from a green roof designed to attract native pollinating insects

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.

β-Ocimene, a Key Floral and Foliar Volatile Involved in Multiple Interactions between Plants and Other Organisms.

PubMed

Farré-Armengol, Gerard; Filella, Iolanda; Llusià, Joan; Peñuelas, Josep

2017-07-13

β-Ocimene is a very common plant volatile released in important amounts from the leaves and flowers of many plant species. This acyclic monoterpene can play several biological functions in plants, by potentially affecting floral visitors and also by mediating defensive responses to herbivory. The ubiquity and high relative abundance of β-ocimene in the floral scents of species from most plant families and from different pollination syndromes (ranging from generalism to specialism) strongly suggest that this terpenoid may play an important role in the attraction of pollinators to flowers. We compiled abundant evidence from published studies that supports β-ocimene as a generalist attractant of a wide spectrum of pollinators. We found no studies testing behavioural responses of pollinators to β-ocimene, that could directly demonstrate or deny the function of β-ocimene in pollinator attraction; but several case studies support that the emissions of β-ocimene in flowers of different species follow marked temporal and spatial patterns of emission, which are typical from floral volatile organic compound (VOC) emissions that are involved in pollinator attraction. Furthermore, important β-ocimene emissions are induced from vegetative plant tissues after herbivory in many species, which have relevant functions in the establishment of tritrophic interactions. We thus conclude that β-ocimene is a key plant volatile with multiple relevant functions in plants, depending on the organ and the time of emission. Experimental behavioural studies on pure β-ocimene conducted with pollinating insects will be necessary to prove the assumptions made here.

Insect abundance over Chinese rice fields in relation to environmental parameters, studied with a polarization-sensitive CW near-IR lidar system

NASA Astrophysics Data System (ADS)

Zhu, Shiming; Malmqvist, Elin; Li, Wansha; Jansson, Samuel; Li, Yiyun; Duan, Zheng; Svanberg, Katarina; Feng, Hongqiang; Song, Ziwei; Zhao, Guangyu; Brydegaard, Mikkel; Svanberg, Sune

2017-07-01

Effective monitoring of flying insects is of major societal importance in view of the role of insects as indispensable pollinators, destructive disease vectors and economically devastating agricultural pests. The present paper reports on monitoring of flying agricultural pests using a continuous-wave lidar system in a rice-field location in Southern China. Using a Scheimpflug arrangement, range resolution over several 100 m long observational paths was achieved. The system operates with two perpendicularly polarized near-infrared lasers, which are activated intermittently, and back-scattered radiation from insects was recorded by a linear array detector placed after a linear polarizer. Our polarization sensitive system was used to monitor the flying insect diurnal activity and also the influence of changes in weather conditions, e.g., the occurrence of rain. Activity strongly peaked at dusk and rose again, although to a lower extent, just before dawn. At the onset of rainfall, a strong increase in insect counts occurred which was interpreted as the rain-induced bringing down of high-altitude migrant insects.

The evolution of plant-insect mutualisms.

PubMed

Bronstein, Judith L; Alarcón, Ruben; Geber, Monica

2006-01-01

Mutualisms (cooperative interactions between species) have had a central role in the generation and maintenance of life on earth. Insects and plants are involved in diverse forms of mutualism. Here we review evolutionary features of three prominent insect-plant mutualisms: pollination, protection and seed dispersal. We focus on addressing five central phenomena: evolutionary origins and maintenance of mutualism; the evolution of mutualistic traits; the evolution of specialization and generalization; coevolutionary processes; and the existence of cheating. Several features uniting very diverse insect-plant mutualisms are identified and their evolutionary implications are discussed: the involvement of one mobile and one sedentary partner; natural selection on plant rewards; the existence of a continuum from specialization to generalization; and the ubiquity of cheating, particularly on the part of insects. Plant-insect mutualisms have apparently both arisen and been lost repeatedly. Many adaptive hypotheses have been proposed to explain these transitions, and it is unlikely that any one of them dominates across interactions differing so widely in natural history. Evolutionary theory has a potentially important, but as yet largely unfilled, role to play in explaining the origins, maintenance, breakdown and evolution of insect-plant mutualisms.

Fire Promotes Pollinator Visitation: Implications for Ameliorating Declines of Pollination Services

PubMed Central

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

Weight-of-evidence evaluation of an adverse outcome pathway network linking activation of the nicotinic acetylcholine receptor in bees to colony loss

EPA Science Inventory

Ongoing honey bee colony losses are of significant international concern because of the essential role these insects play in pollinating staple food crops. Chemical and non-chemical stressors both have been implicated as possible contributors to colony failure, however, the pote...

ASSESSING THE INFLUENCE OF PLANT GROWTH REGULATOR HERBICIDE VAPOR DRIFT ON ARTHROPOD COMMUNITIES IN FIELD CROP AGRO-ECOSYSTEMS

EPA Science Inventory

Sub-lethal herbicide damage is likely to have negative consequences for plant health. This in turn could lead to positive or negative effects on insects. Plants that are not healthy may not provide the best floral resources for pollinators, potentially further stressing hon...

Do glyphosate resistant feral plants and hay fields spread the transgene to conventional alfalfa seed fields?

USDA-ARS?s Scientific Manuscript database

In addition to meeting domestic needs, large amounts of alfalfa seed and hay produced in the US are being exported overseas. Because alfalfa is an insect pollinated crop, gene flow is a concern. Adding to this alfalfa readily naturalizes along roadsides, irrigation ditches, and unmanaged habitats; a...

Occurrence of transgenic feral alfalfa (Medicago sativa subsp. sativa L.) in alfalfa seed production areas in the United States

USDA-ARS?s Scientific Manuscript database

Genetically-engineered glyphosate-resistant alfalfa (Medicago sativa subsp. sativa) was commercialized in 2011. The potential risk of transgene dispersal into the environment is not clearly understood for alfalfa, a perennial crop that is cross-pollinated by insects. We gathered data on feral and tr...

Specialty oilseed crops provide an attractive source of pollen for beneficial insects

USDA-ARS?s Scientific Manuscript database

The continuing pollinator crisis is due, in part, to the lack of year-round floral resources. In intensive farming regions, such as the Upper Midwest (UMW) of the USA, natural and pastoral vegetation largely has been replaced by annual crops such as corn, soybean, and wheat. Neither the energy (nect...

The ultraviolet radiation environment of pollen and its effect on pollen germination

NASA Technical Reports Server (NTRS)

1981-01-01

The damage to pollen caused by natural ultraviolet radiation was investigated. Experimental and literature research into the UV radiation environment is reported. Viability and germination of wind and insect pollinated species were determined. Physiological, developmental, and protective factors influencing UV sensitivity of binucleate, advanced binucleate, and trinucleate pollen grains are compared.

Status of Some New Herbicides

Treesearch

W.F. Mann; M.J. Haynes

1978-01-01

If herbicides are handled, applied, or disposed of improperly they may be injurious to humans, domestic animals, desirable plants, and pollinating insects, fish, or other wildlife, and may contaminate water supplies. Use herbicides only when needed and handle them with care. Follow the directions and heed all precautions on the container label. The use of trade, firm,...

Plant guide: Sharpleaf penstemon: Penstemon acuminatus Douglas ex Lindl.

Treesearch

Loren St. John; Dan Ogle; Nancy L. Shaw

2009-01-01

Sharpleaf penstemon is primarily used as a forb component for wildlife habitat enhancement and restoration efforts. Its showy flowers attract numerous pollinators and other insects that provide a food source for birds and other vertebrates. This species is used in xeriscaping and other low-wateruse landscaping. It is suited for roadside and other beautification...

Plant guide: Douglas' dusty-maiden (Chaenactic douglasii)

Treesearch

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...

Natural and cultural history of beargrass (Xerophyllum tenax)

Treesearch

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...

Spatiotemporal variation in the reproductive ecology of two parapatric subspecies of Oenothera cespitosa (Onagraceae).

PubMed

Artz, Derek R; Villagra, Cristian A; Raguso, Robert A

2010-09-01

• Flowering plants that rely on pollinators for most of their reproduction may experience unpredictable and inconsistent availability of effective pollinators throughout their reproductive lifetime. We investigated the reproductive ecology of two subspecies of the tufted evening primrose, Oenothera cespitosa, which occupy geographically and edaphically distinct habitats in western North America: O. cespitosa subsp. navajoensis inhabits sandstone soils on open sites or rocky slopes in the Colorado Plateau and O. cespitosa subsp. cespitosa grows in clay soils on talus slopes and exposed rocky ridges in the western Great Plains and northern Rocky Mountains of the United States. • Pollen augmentation and selfing experiments, floral visitor observations, and single-visit effectiveness experiments were conducted over 4 years to examine the breeding system and spatiotemporal variation in pollinator behavior, assemblage, and abundance at different populations for each subspecies. • Both subspecies of O. cespitosa were self-incompatible and pollen-limited, suggesting that the relative abundance, effectiveness, and movement patterns of different insects as pollinators influenced the quality and quantity of seed production in these plants. Medium-sized vespertine hawkmoths (Hyles lineata, Sphinx vashti) were effective pollinators when present, as were large matinal bees (Anthophora affabilis, A. dammersi, Xylocopa tabaniformis androleuca), whereas small oligolectic Lasioglossum bees primarily functioned as pollen thieves in the evening and morning. • These findings highlight the importance of variability of pollinator composition and abundance in the evolution of plant breeding systems and reproductive success at varying spatial and temporal scales.

Differential pollinator effectiveness and importance in a milkweed (Asclepias, Apocynaceae) hybrid zone.

PubMed

Stoepler, Teresa M; Edge, Andrea; Steel, Anna; O'Quinn, Robin L; Fishbein, Mark

2012-03-01

Exceptions to the ideal of complete reproductive isolation between species are commonly encountered in diverse plant, animal, and fungal groups, but often the causative ecological processes are poorly understood. In flowering plants, the outcome of hybridization depends in part on the effectiveness of pollinators in interspecific pollen transport. In the Asclepias exaltata and A. syriaca (Apocynaceae) hybrid zone in Shenandoah National Park, Virginia, extensive introgression has been documented. The objectives of this study were to (1) determine the extent of pollinator overlap among A. exaltata, A. syriaca, and their hybrids and (2) identify the insect taxa responsible for hybridization and introgression. We observed focal plants of parental species and hybrids to measure visitation rate, visit duration, and per-visit pollinia removal and deposition, and we calculated pollinator effectiveness and importance. Visitation rates varied significantly between the 2 yr of the study. Overall, Apis mellifera, Bombus sp., and Epargyreus clarus were the most important pollinators. However, Bombus sp. was the only visitor that was observed to both remove and insert pollinia for both parent species as well as hybrids. We conclude that Bombus may be a key agent of hybridization and introgression in these sympatric milkweed populations, and hybrids are neither preferred nor selected against by pollinators. Thus, we have identified a potential mechanism for how hybrids act as bridges to gene flow between A. exaltata and A. syriaca. These results provide insights into the breakdown of prezygotic isolating mechanisms.

Evidence for mixed sexual and asexual reproduction in the rare European mycoheterotrophic orchid Epipogium aphyllum, Orchidaceae (ghost orchid)

PubMed Central

Krawczyk, Emilia; Rojek, Joanna; Kowalkowska, Agnieszka K.; Kapusta, Małgorzata; Znaniecka, Joanna; Minasiewicz, Julita

2016-01-01

Background and Aims Despite their significant capacity to propagate vegetatively, most orchids reproduce via seeds. Sexual reproduction via seed is commonly reported, in contrast to apomixis, whereby seeds are clones of the mother. Although insect pollination and autonomous self-pollination exist in mycoheterotrophic plants, the reproductive embryology of these plants remains under-studied. This paper provides evidence for the co-occurrence of both sexual and apomictic reproduction in a population of mycoheterotrophic plants – Epipogium aphyllum. We investigated seed formation via open pollination, induced autogamy, autogamy sensu stricto and autonomous apomixis. Methods The study was performed on a population of E. aphyllum located in northern Poland. The research included studies of the micromorphology, histochemistry and embryology of four types of reproductive systems. Scanning, fluorescence and light microscopy accompanied by graphical and statistical analyses were employed. Key Results We observed gametophyte development, from the one-nucleate stage to maturity, in unpollinated flower buds. The lack of zygotes in flower buds indicated that fertilization did not occur at this stage. Manual self-pollination led to a zygote, followed by embryo formation. Fertilization and embryo development derived from embryogenesis via open pollination is delayed compared with hand pollination. Isolation from external pollination resulted only in structures resembling zygotes that may originate either sexually or independent of fertilization. Parthenogenetic structures that resembled zygotes were observed in flowers that were emasculated and isolated from pollination. Zygotes formed at significantly higher frequencies via open pollination and induced autogamy in comparison to the parthenogenetic structures formed in other treatments. Conclusions We showed the absence of pre-zygotic barriers for autogamy in E. aphyllum. Self-pollination and self-fertilization are possible; however, natural self-pollination is unlikely or rare due to the position of the pollinia. Incidental parthenogenesis in E. aphyllum is very likely, given the biology of ovule development of this mycoheterotrophic orchid. This species therefore has the potential to produce seeds via both sexual and asexual means, although the contribution of apomixis to this process appears largely negligible. PMID:27288512

Evidence for mixed sexual and asexual reproduction in the rare European mycoheterotrophic orchid Epipogium aphyllum, Orchidaceae (ghost orchid).

PubMed

Krawczyk, Emilia; Rojek, Joanna; Kowalkowska, Agnieszka K; Kapusta, Małgorzata; Znaniecka, Joanna; Minasiewicz, Julita

2016-07-01

Despite their significant capacity to propagate vegetatively, most orchids reproduce via seeds. Sexual reproduction via seed is commonly reported, in contrast to apomixis, whereby seeds are clones of the mother. Although insect pollination and autonomous self-pollination exist in mycoheterotrophic plants, the reproductive embryology of these plants remains under-studied. This paper provides evidence for the co-occurrence of both sexual and apomictic reproduction in a population of mycoheterotrophic plants - Epipogium aphyllum We investigated seed formation via open pollination, induced autogamy, autogamy sensu stricto and autonomous apomixis. The study was performed on a population of E. aphyllum located in northern Poland. The research included studies of the micromorphology, histochemistry and embryology of four types of reproductive systems. Scanning, fluorescence and light microscopy accompanied by graphical and statistical analyses were employed. We observed gametophyte development, from the one-nucleate stage to maturity, in unpollinated flower buds. The lack of zygotes in flower buds indicated that fertilization did not occur at this stage. Manual self-pollination led to a zygote, followed by embryo formation. Fertilization and embryo development derived from embryogenesis via open pollination is delayed compared with hand pollination. Isolation from external pollination resulted only in structures resembling zygotes that may originate either sexually or independent of fertilization. Parthenogenetic structures that resembled zygotes were observed in flowers that were emasculated and isolated from pollination. Zygotes formed at significantly higher frequencies via open pollination and induced autogamy in comparison to the parthenogenetic structures formed in other treatments. We showed the absence of pre-zygotic barriers for autogamy in E. aphyllum Self-pollination and self-fertilization are possible; however, natural self-pollination is unlikely or rare due to the position of the pollinia. Incidental parthenogenesis in E. aphyllum is very likely, given the biology of ovule development of this mycoheterotrophic orchid. This species therefore has the potential to produce seeds via both sexual and asexual means, although the contribution of apomixis to this process appears largely negligible. © 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.

Thermogenesis, Flowering and the Association with Variation in Floral Odour Attractants in Magnolia sprengeri (Magnoliaceae)

PubMed Central

Wang, Ruohan; Xu, Sai; Liu, Xiangyu; Zhang, Yiyuan; Wang, Jianzhong; Zhang, Zhixiang

2014-01-01

Magnolia sprengeri Pamp. is an ornamentally and ecologically important tree that blooms at cold temperatures in early spring. In this study, thermogenesis and variation in the chemical compounds of floral odours and insect visitation in relation to flowering cycles were studied to increase our understanding of the role of floral thermogenesis in the pollination biology of M. sprengeri. There were five distinct floral stages across the floral cycle of this species: pre-pistillate, pistillate, pre-staminate, staminate and post-staminate. Floral thermogenesis during anthesis and consisted of two distinct peaks: one at the pistillate stage and the other at the staminate stage. Insects of five families visited M. sprengeri during the floral cycle, and sap beetles (Epuraea sp., Nitidulidae) were determined to be the most effective pollinators, whereas bees (Apis cerana, Apidae) were considered to be occasional pollinators. A strong fragrance was released during thermogenesis, consisting of 18 chemical compounds. Although the relative proportions of these compounds varied at different floral stages across anthesis, linalool, 1-iodo-2-methylundecane and 2,2,6-trimethyl-6-vinyltetrahydro-2H-pyran-3-ol were dominant. Importantly, we found that the floral blends released during the pistillate and staminate stages were very similar, and coincided with flower visitation by sap beetles and the two thermogenic episodes. Based on these results, we propose that odour acts as a signal for a reward (pollen) and that an odour mimicry of staminate-stage flowers occurs during the pistillate stage. PMID:24922537

Community and species-specific responses of wild bees to insect pest control programs applied to a pollinator-dependent crop.

PubMed

Tuell, Julianna K; Isaacs, Rufus

2010-06-01

Wild bee conservation is regarded as essential for sustainable production of pollinator-dependent crops, yet little is known about the effects on wild bee communities of typical insect pest management programs used postbloom. We developed an insecticide program risk (IPR) index to quantify the relative risk to wild bees of insecticide programs applied to blueberry fields. This was used to determine the relationship between IPR and the abundance, diversity, and richness of wild bee communities sampled during three successive flowering seasons. In 2 of 3 yr, bee abundance and species richness declined with increasing IPR. Bee diversity declined with IPR in one of 3 yr. These results indicate that wild bee communities are negatively affected by increasingly intensive chemical pest management activities in crop fields and that interyear variability in bee populations has the potential to mask such effects in short-term studies. When several wild bee species were analyzed separately, two of three solitary and one of three social blueberry-foraging species declined with increasing IPR values, suggesting that different life histories and nesting habits may help some bee populations escape the negative effects of insecticides applied after bloom. Pollinator conservation programs aimed strictly at reducing insecticide use may have varying success, depending on the biology of the target bee species. The IPR index provides a standard method to compare pest management programs for their potential effect on wild bee communities, with broad application for use in other agricultural systems.

Limited mate availability decreases reproductive success of fragmented populations of Linnaea borealis, a rare, clonal self-incompatible plant

PubMed Central

Scobie, A. R.; Wilcock, C. C.

2009-01-01

Background and Aims Small populations of rare plant species are increasingly reported to have high levels of reproductive failure. The objective of this study was to understand the principal constraints on sexual reproduction in small fragmented populations of a rare clonal self-incompatible plant. Methods The pollinator spectrum, diversity of flower colour, natural pollination and fruit-set levels of L. borealis were examined in Scotland. Artificially crossed seed production was compared within and between different flower colour types and patches. Key Results Linnaea borealis was pollinated by a diverse spectrum of insect species and the principal pollinators were muscid, syrphid and empid flies which mostly moved only small distances (<0·25 m) between flowers when foraging. Natural pollination levels were high, indicating high pollinator effectiveness, but fruit set was very low in most patches. Flower colour diversity was low in most patches and only those with a diversity of flower colour types had high fruiting success. Pollination experiments showed L. borealis to be highly self-incompatible and artificial crosses within and between patches and flower colour types confirmed that low fruit success was the result of a lack of compatible mates and limited pollen movement between them. Evidence of isolation from pollen exchange was apparent at as little as 6 m and severe at 30 m and beyond. Conclusions Limited mate availability and isolation from pollen exchange compromise the reproductive success of fragmented populations of L. borealis in Scotland. A diversity of compatible mates situated within close proximity (<6 m) is the key requirement to ensure high natural fruiting success. This study emphasizes that an understanding of the breeding system, pollinator spectrum and potential for interconnectivity via pollinator movement are fundamental to identify isolation distances and to establish when conservation intervention is necessary for rare species. PMID:19181748