Species traits and network structure predict the success and impacts of pollinator invasions.

PubMed

Valdovinos, Fernanda S; Berlow, Eric L; Moisset de Espanés, Pablo; Ramos-Jiliberto, Rodrigo; Vázquez, Diego P; Martinez, Neo D

2018-05-31

Species invasions constitute a major and poorly understood threat to plant-pollinator systems. General theory predicting which factors drive species invasion success and subsequent effects on native ecosystems is particularly lacking. We address this problem using a consumer-resource model of adaptive behavior and population dynamics to evaluate the invasion success of alien pollinators into plant-pollinator networks and their impact on native species. We introduce pollinator species with different foraging traits into network models with different levels of species richness, connectance, and nestedness. Among 31 factors tested, including network and alien properties, we find that aliens with high foraging efficiency are the most successful invaders. Networks exhibiting high alien-native diet overlap, fraction of alien-visited plant species, most-generalist plant connectivity, and number of specialist pollinator species are the most impacted by invaders. Our results mimic several disparate observations conducted in the field and potentially elucidate the mechanisms responsible for their variability.

Resource diversity and landscape-level homogeneity drive native bee foraging.

PubMed

Jha, Shalene; Kremen, Claire

2013-01-08

Given widespread declines in pollinator communities and increasing global reliance on pollinator-dependent crops, there is an acute need to develop a mechanistic understanding of native pollinator population and foraging biology. Using a population genetics approach, we determine the impact of habitat and floral resource distributions on nesting and foraging patterns of a critical native pollinator, Bombus vosnesenskii. Our findings demonstrate that native bee foraging is far more plastic and extensive than previously believed and does not follow a simple optimal foraging strategy. Rather, bumble bees forage further in pursuit of species-rich floral patches and in landscapes where patch-to-patch variation in floral resources is less, regardless of habitat composition. Thus, our results reveal extreme foraging plasticity and demonstrate that floral diversity, not density, drives bee foraging distance. Furthermore, we find a negative impact of paved habitat and a positive impact of natural woodland on bumble bee nesting densities. Overall, this study reveals that natural and human-altered landscapes can be managed for increased native bee nesting and extended foraging, dually enhancing biodiversity and the spatial extent of pollination services.

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...

Unsuccessful introduced biocontrol agents can act as pollinators of invasive weeds: Bitou Bush (Chrysanthemoides monilifera ssp. rotundata) as an example.

PubMed

Gross, Caroline L; Whitehead, Joshua D; Silveira de Souza, Camila; Mackay, David

2017-10-01

The extent of self-compatibility and reliance on pollinators for seed set are critical determinants of reproductive success in invasive plant species. Seed herbivores are commonly used as biocontrol agents but may also act as flower visitors, potentially resulting in pollination. However, such contrasting or potentially counterproductive interaction effects are rarely considered or evaluated for biological control programs. We investigated the breeding system and pollinators of Bitou Bush ( Chrysanthemoides monilifera ssp. rotundata ), an invasive species in Australia that has been the subject of biocontrol programs since 1987. We found the species to be obligate outcrossing in all six populations tested. From 150 video hours, we found 21 species of potential pollinators, including Mesoclanis polana , the Bitou Seedfly, native to South Africa and released in Australia as a biocontrol agent in 1996. Mesoclanis polana transferred pollen to stigmas and was the most common pollinator (52% of pollinator visits), followed by the syrphid fly Simosyrphus grandicornis (9%) and introduced honeybee, Apis mellifera (6.5%). Fruit-to-flower ratios ranged from 0.12 to 0.45 and were highest in the population with the greatest proportion of Mesoclanis polana visits. In an experimental trial, outside the naturalized range, the native bee Homalictus sphecodoides and the native syrphid Melangyna viridiceps were the primary pollinators, and fruit-to-flower ratios were 0.35, indicating that Bitou Bush would have ready pollinators if its range expanded inland. Synthesis . Invasive Bitou Bush requires pollinators, and this is effected by a range of generalist pollinators in eastern Australia including the Bitou Seedfly, introduced as a biocontrol agent, and the major pollinator detected in this study. Fruit-to-flower ratios were highest when the Bitou Seedfly was in high abundance. This study underscores the importance of evaluating the pollination biology of invasive species in their native ranges and prior to the introduction of biocontrol agents.

Collapse of a pollination web in small conservation areas.

PubMed

Pauw, Anton

2007-07-01

A suspected global decline in pollinators has heightened interest in their ecological significance. In a worst-case scenario, the decline of generalist pollinators is predicted to trigger cascades of linked declines among the multiple specialist plant species to which they are linked, but this has not been documented. I studied a portion of a pollination web involving a generalist pollinator, the oil-collecting bee Rediviva peringueyi, and a community of oil-secreting plants. Across 27 established conservation areas located in the Cape Floral Region, I found substantial variation in the bees' occurrence in relation to soil type and the successional stage of the vegetation. Anthropogenic declines were detectable against this background of naturally occurring variation: R. peringueyi was absent from small conservation areas (< 385 ha) in an urban matrix. In the absence of the bee, seed set failed in six specialist plant species that are pollinated only by R. peringueyi but remained high in a pollination generalist, which had replacement pollinators. The findings are consistent with theoretical predictions of the importance of generalist pollinators in maintaining the structure of pollination webs.

Create a pollinator garden at your nursery: An emphasis on monarch butterflies

Treesearch

Thomas D. Landis; R. Kasten Dumroese; Matthew E. Horning

2014-01-01

We realize that this type of article is a departure for FNN readers but feel that it is important for forest, conservation, and native plant nurseries to be good environmental stewards. In addition, establishing a pollinator garden at your nursery can be good for business, too. Demonstrating the role and beauty of native plants and their pollinators, particulary in a...

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....

Nectar minerals as regulators of flower visitation in stingless bees and nectar hoarding wasps.

PubMed

Afik, Ohad; Delaplane, Keith S; Shafir, Sharoni; Moo-Valle, Humberto; Quezada-Euán, J Javier G

2014-05-01

Various nectar components have a repellent effect on flower visitors, and their adaptive advantages for the plant are not well understood. Persea americana (avocado) is an example of a plant that secretes nectar with repellent components. It was demonstrated that the mineral constituents of this nectar, mainly potassium and phosphate, are concentrated enough to repel honey bees, Apis mellifera, a pollinator often used for commercial avocado pollination. Honey bees, however, are not the natural pollinator of P. americana, a plant native to Central America. In order to understand the role of nectar minerals in plant-pollinator relationships, it is important to focus on the plant's interactions with its natural pollinators. Two species of stingless bees and one species of social wasp, all native to the Yucatan Peninsula, Mexico, part of the natural range of P. americana, were tested for their sensitivity to sugar solutions enriched with potassium and phosphate, and compared with the sensitivity of honey bees. In choice tests between control and mineral-enriched solutions, all three native species were indifferent for mineral concentrations lower than those naturally occurring in P. americana nectar. Repellence was expressed at concentrations near or exceeding natural concentrations. The threshold point at which native pollinators showed repellence to increasing levels of minerals was higher than that detected for honey bees. The results do not support the hypothesis that high mineral content is attractive for native Hymenopteran pollinators; nevertheless, nectar mineral composition may still have a role in regulating flower visitors through different levels of repellency.

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.

Invasion of a dominant floral resource: effects on the floral community and pollination of native plants.

PubMed

Goodell, Karen; Parker, Ingrid M

2017-01-01

Through competition for pollinators, invasive plants may suppress native flora. Community-level studies provide an integrative assessment of invasion impacts and insights into factors that influence the vulnerability of different native species. We investigated effects of the nonnative herb Lythrum salicaria on pollination of native species in 14 fens of the eastern United States. We compared visitors per flower for 122 native plant species in invaded and uninvaded fens and incorporated a landscape-scale experiment, removing L. salicaria flowers from three of the invaded fens. Total flower densities were more than three times higher in invaded than uninvaded or removal sites when L. salicaria was blooming. Despite an increase in number of visitors with number of flowers per area, visitors per native flower declined with increasing numbers of flowers. Therefore, L. salicaria invasion depressed visitation to native flowers. In removal sites, visitation to native flowers was similar to uninvaded sites, confirming the observational results and also suggesting that invasion had not generated a persistent build-up of visitor populations. To study species-level impacts, we examined effects of invasion on visitors per flower for the 36 plant species flowering in both invaded and uninvaded fens. On average, the effect of invasion represented about a 20% reduction in visits per flower. We measured the influence of plant traits on vulnerability to L. salicaria invasion using meta-analysis. Bilaterally symmetrical flowers experienced stronger impacts on visitation, and similarity in flower color to L. salicaria weakly intensified competition with the invader for visitors. Finally, we assessed the reproductive consequences of competition with the invader in a dominant flowering shrub, Dasiphora fruticosa. Despite the negative effect of invasion on pollinator visitation in this species, pollen limitation of seed production was not stronger in invaded than in uninvaded sites, suggesting little impact of competition for pollinators on its population demography. Negative effects on pollination of native plants by this copiously flowering invader appeared to be mediated by increases in total flower density that were not matched by increases in pollinator density. The strength of impact was modulated across native species by their floral traits and reproductive ecology. © 2016 The Authors. Ecology, published by Wiley Periodicals, Inc., on behalf of the Ecological Society of America.

Indirect competition for pollinators is weak compared to direct resource competition: pollination and performance in the face of an invader.

PubMed

Palladini, Jennifer D; Maron, John L

2013-08-01

Invasive plants have the potential to reduce native plant abundance through both direct and indirect interactions. Direct interactions, such as competition for soil resources, and indirect interactions, such as competition for shared pollinators, have been shown to influence native plant performance; however, we know much less about how these interactions influence native plant abundance in the field. While direct competitive interactions are often assumed to drive declines in native abundance, an evaluation of their influence relative to indirect mechanisms is needed to more fully understand invasive plant impacts. We quantified the direct effects of resource competition by the invasive perennial forb, Euphorbia esula (Euphorbiaceae), on the recruitment, subsequent performance, and ultimate adult abundance of the native annual, Clarkia pulchella (Onagraceae). We contrast these direct effects with those that indirectly resulted from competition for shared pollinators. Although E. esula dramatically reduced pollinator visitation to C. pulchella, plants were only weakly pollen-limited. Pollen supplementation increased the number of seeds per fruit from 41.28 to 46.38. Seed addition experiments revealed that the impacts of ameliorating pollen limitation only increased potential recruitment by 12.3 %. In contrast, seed addition experiments that ameliorated direct competition with E. esula resulted in an increase in potential future recruitment of 574 %. Our results show that, while the indirect effects of competition for pollinators can influence plant abundance, its effects are dwarfed by the magnitude of direct effects of competition for resources.

Considering the unintentional consequences of pollinator gardens for urban native plants: is the road to extinction paved with good intentions?

PubMed

Johnson, Anna L; Fetters, Andrea M; Ashman, Tia-Lynn

2017-09-01

Urban centers are important foci for plant biodiversity and yet widespread planting of wildflower gardens in cities to sustain pollinator biodiversity is on the rise, without full consideration of potential ecological consequences. The impact of intentional wildflower plantings on remnant native plant diversity in urban and peri-urban settings has not received attention, although shared pollinators are likely to mediate several types of biotic interactions between human-introduced plants and remnant native ones. Additionally, if wildflower species escape gardens these indirect effects may be compounded with direct ones. We review the potential positive and negative impacts of wildflower gardens on urban native flowering plants, and we reveal substantial gaps in our knowledge. We present a roadmap for research to address whether wildflower gardens, while benefiting pollinators, could also hasten the extinction of native remnant plants in urban settings, or whether they could have other effects that enrich urban biodiversity. Goals of future wildflower mixes should consider the totality of potential interactions. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Plant-pollinator interactions in New Caledonia influenced by introduced honey bees.

PubMed

Kato, Makoto; Kawakita, Atsushi

2004-11-01

The flora of New Caledonia is characterized by remarkably high species diversity, high endemicity, and an unusual abundance of archaic plant taxa. To investigate community-level pollination mutualism in this endemic ecosystem, we observed flower visitors on 99 plant species in 42 families of various types of vegetation. Among the 95 native plant species, the most dominant pollination system was melittophily (bee-pollinated, 46.3%), followed by phalaenophily (moth-pollinated, 20.0%), ornithophily (bird-pollinated, 11.6%), cantharophily (beetle-pollinated, 8.4%), myophily (fly-pollinated, 3.2%), chiropterophily (bat-pollinated, 3.2%), and anemophily (wind-pollinated, 3.2%). The prevalence of ornithophily by honeyeaters shows an ecological link to pollination mutualism in Australia. The relative dominance of phalaenophily is unique to New Caledonia, and is proposed to be related to the low diversity of the original bee fauna and the absence of long-tongued bees. Although some archaic plants maintain archaic plant-pollinator interactions, e.g., Zygogynum pollinated by micropterigid moths, or Hedycarya pollinated by thrips and staphylinid beetles, the most dominant organism observed on flowers was the introduced honey bee, Apis mellifera. The plant species now visited by honey bees are thought to have originally been pollinated by native solitary short-tongued bees. Our data suggest that the unique systems of pollination mutualism in New Caledonia are now endangered by the establishment of highly invasive honey bees.

The long-tongued hawkmoth pollinator niche for native and invasive plants in Africa

PubMed Central

Johnson, Steven D.; Raguso, Robert A.

2016-01-01

Background and Aims Unrelated organisms that share similar niches often exhibit patterns of convergent evolution in functional traits. Based on bimodal distributions of hawkmoth tongue lengths and tubular white flowers in Africa, this study hypothesized that long-tongued hawkmoths comprise a pollination niche (ecological opportunity) that is distinct from that of shorter-tongued hawkmoths. Methods Field observations, light trapping, camera surveillance and pollen load analysis were used to identify pollinators of plant species with very long-tubed (>8 cm) flowers. The nectar properties and spectral reflectance of these flowers were also measured. The frequency distributions of proboscis length for all captured hawkmoths and floral tube length for a representative sample of night-blooming plant species were determined. The geographical distributions of both native and introduced plant species with very long floral tubes were mapped. Key Results The convolvulus hawkmoth Agrius convolvuli is identified as the most important pollinator of African plants with very long-tubed flowers. Plants pollinated by this hawkmoth species tend to have a very long (approx. 10 cm) and narrow flower tube or spur, white flowers and large volumes of dilute nectar. It is estimated that >70 grassland and savanna plant species in Africa belong to the Agrius pollination guild. In South Africa, at least 23 native species have very long floral tubes, and pollination by A. convolvuli or, rarely, by the closely related hawkmoth Coelonia fulvinotata, has been confirmed for 11 of these species. The guild is strikingly absent from the species-rich Cape floral region and now includes at least four non-native invasive species with long-tubed flowers that are pre-adapted for pollination by A. convolvuli. Conclusions This study highlights the value of a niche perspective on pollination, which provides a framework for making predictions about the ecological importance of keystone pollinators, and for understanding patterns of convergent evolution and the role of floral traits in plant colonization. PMID:26346719

Direct and Indirect Influence of Non-Native Neighbours on Pollination and Fruit Production of a Native Plant.

PubMed

Montero-Castaño, Ana; Vilà, Montserrat

2015-01-01

Entomophilous non-native plants can directly affect the pollination and reproductive success of native plant species and also indirectly, by altering the composition and abundance of floral resources in the invaded community. Separating direct from indirect effects is critical for understanding the mechanisms underlying the impacts of non-native species on recipient communities. Our aims are: (a) to explore both the direct effect of the non-native Hedysarum coronarium and its indirect effect, mediated by the alteration of floral diversity, on the pollinator visitation rate and fructification of the native Leopoldia comosa and (b) to distinguish whether the effects of the non-native species were due to its floral display or to its vegetative interactions. We conducted field observations within a flower removal experimental setup (i.e. non-native species present, absent and with its inflorescences removed) at the neighbourhood scale. Our study illustrates the complexity of mechanisms involved in the impacts of non-native species on native species. Overall, Hedysarum increased pollinator visitation rates to Leopoldia target plants as a result of direct and indirect effects acting in the same direction. Due to its floral display, Hedysarum exerted a direct magnet effect attracting visits to native target plants, especially those made by the honeybee. Indirectly, Hedysarum also increased the visitation rate of native target plants. Due to the competition for resources mediated by its vegetative parts, it decreased floral diversity in the neighbourhoods, which was negatively related to the visitation rate to native target plants. Hedysarum overall also increased the fructification of Leopoldia target plants, even though such an increase was the result of other indirect effects compensating for the observed negative indirect effect mediated by the decrease of floral diversity.

Direct and Indirect Influence of Non-Native Neighbours on Pollination and Fruit Production of a Native Plant

PubMed Central

Montero-Castaño, Ana; Vilà, Montserrat

2015-01-01

Background Entomophilous non-native plants can directly affect the pollination and reproductive success of native plant species and also indirectly, by altering the composition and abundance of floral resources in the invaded community. Separating direct from indirect effects is critical for understanding the mechanisms underlying the impacts of non-native species on recipient communities. Objectives Our aims are: (a) to explore both the direct effect of the non-native Hedysarum coronarium and its indirect effect, mediated by the alteration of floral diversity, on the pollinator visitation rate and fructification of the native Leopoldia comosa and (b) to distinguish whether the effects of the non-native species were due to its floral display or to its vegetative interactions. Methods We conducted field observations within a flower removal experimental setup (i.e. non-native species present, absent and with its inflorescences removed) at the neighbourhood scale. Results Our study illustrates the complexity of mechanisms involved in the impacts of non-native species on native species. Overall, Hedysarum increased pollinator visitation rates to Leopoldia target plants as a result of direct and indirect effects acting in the same direction. Due to its floral display, Hedysarum exerted a direct magnet effect attracting visits to native target plants, especially those made by the honeybee. Indirectly, Hedysarum also increased the visitation rate of native target plants. Due to the competition for resources mediated by its vegetative parts, it decreased floral diversity in the neighbourhoods, which was negatively related to the visitation rate to native target plants. Hedysarum overall also increased the fructification of Leopoldia target plants, even though such an increase was the result of other indirect effects compensating for the observed negative indirect effect mediated by the decrease of floral diversity. PMID:26110630

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.

Pollination of a native plant changes with distance and density of invasive plants in a simulated biological invasion.

PubMed

Bruckman, Daniela; Campbell, Diane R

2016-08-01

Effects of an exotic plant on pollination may change as the invasive increases in density. Quantity of pollinator visits to a native may increase, decrease, or change nonlinearly, while visit quality is likely to decrease with greater interspecific pollen movement. How visit quantity and quality contribute to the effect on reproductive success at each invasion stage has not been measured. We simulated four stages of invasion by Brassica nigra by manipulating the neighborhood of potted plants of the native Phacelia parryi in a field experiment. Stages were far from the invasion, near the invasion, intermixed with the invasive at low density, and intermixed at high density. We measured pollinator visitation, conspecific and invasive pollen deposition, and seed set for P. parryi at each stage. Native individuals near invasive plants and within areas of low invasive density showed greatest seed production, as expected from concurrent changes in conspecific and invasive pollen deposition. Those plants experienced facilitation of visits and received more conspecific pollen relative to plants farther from invasives. Native individuals within high invasive density also received frequent visits by many pollinators (although not honeybees), but the larger receipt of invasive pollen predicted interference with pollen tubes that matched patterns in seed set. Pollinator visitation was highest when exotic plants were nearby. Detrimental effects of heterospecific pollen deposition were highest at high exotic density. Our study quantified how reproduction benefits from near proximity to a showy invasive, but is still vulnerable when the invasive reaches high density. © 2016 Botanical Society of America.

Bumble bee nest abundance, foraging distance, and host-plant reproduction: implications for management and conservation

USDA-ARS?s Scientific Manuscript database

Recent reports of global declines in pollinator species imply an urgent need to assess native pollinator population sizes and density dependent benefits for linked plants. Here, we estimated effective population sizes (Ne) of four native bumblebee species, Bombus balteatus, B. flavifrons, B. bifariu...

Ecology and economics of using native managed bees for almond pollination

USDA-ARS?s Scientific Manuscript database

Evidence of the efficacy of using managed native bees, rather than or concurrently with honey bees, in crop pollination is increasing. However, a broader ecological economic framework for evaluating the costs and benefits of using these bees has not been developed. We conducted a cost-benefit analy...

The long-tongued hawkmoth pollinator niche for native and invasive plants in Africa.

PubMed

Johnson, Steven D; Raguso, Robert A

2016-01-01

Unrelated organisms that share similar niches often exhibit patterns of convergent evolution in functional traits. Based on bimodal distributions of hawkmoth tongue lengths and tubular white flowers in Africa, this study hypothesized that long-tongued hawkmoths comprise a pollination niche (ecological opportunity) that is distinct from that of shorter-tongued hawkmoths. Field observations, light trapping, camera surveillance and pollen load analysis were used to identify pollinators of plant species with very long-tubed (>8 cm) flowers. The nectar properties and spectral reflectance of these flowers were also measured. The frequency distributions of proboscis length for all captured hawkmoths and floral tube length for a representative sample of night-blooming plant species were determined. The geographical distributions of both native and introduced plant species with very long floral tubes were mapped. The convolvulus hawkmoth Agrius convolvuli is identified as the most important pollinator of African plants with very long-tubed flowers. Plants pollinated by this hawkmoth species tend to have a very long (approx. 10 cm) and narrow flower tube or spur, white flowers and large volumes of dilute nectar. It is estimated that >70 grassland and savanna plant species in Africa belong to the Agrius pollination guild. In South Africa, at least 23 native species have very long floral tubes, and pollination by A. convolvuli or, rarely, by the closely related hawkmoth Coelonia fulvinotata, has been confirmed for 11 of these species. The guild is strikingly absent from the species-rich Cape floral region and now includes at least four non-native invasive species with long-tubed flowers that are pre-adapted for pollination by A. convolvuli. This study highlights the value of a niche perspective on pollination, which provides a framework for making predictions about the ecological importance of keystone pollinators, and for understanding patterns of convergent evolution and the role of floral traits in plant colonization. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Invasive species management restores a plant-pollinator mutualism in Hawaii

USGS Publications Warehouse

Hanna, Cause; Foote, David; Kremen, Claire

2013-01-01

1.The management and removal of invasive species may give rise to unanticipated changes in plant–pollinator mutualisms because they can alter the composition and functioning of plant–pollinator interactions in a variety of ways. To utilize a functional approach for invasive species management, we examined the restoration of plant–pollinator mutualisms following the large-scale removal of an invasive nectar thief and arthropod predator, Vespula pensylvanica. 2.We reduced V. pensylvanica populations in large plots managed over multiple years to examine the response of plant–pollinator mutualisms and the fruit production of a functionally important endemic Hawaiian tree species, Metrosideros polymorpha. To integrate knowledge of the invader's behaviour and the plant's mating system, we determined the efficacy of V. pensylvanica as a pollinator of M. polymorpha and quantified the dependence of M. polymorpha on animal pollination (e.g. level of self-compatibility and pollen limitation). 3.The reduction of V. pensylvanica in managed sites, when compared to unmanaged sites, resulted in a significant increase in the visitation rates of effective bee pollinators (e.g. introduced Apis mellifera and native Hylaeus spp.) and in the fruit production of M. polymorpha. 4.Apis mellifera, following the management of V. pensylvanica, appears to be acting as a substitute pollinator for M. polymorpha, replacing extinct or threatened bird and bee species in our study system. 5.Synthesis and applications. Fruit production of the native M. polymorpha was increased after management of the invasive pollinator predator V. pensylvanica; however, the main pollinators were no longer native but introduced. This research thus demonstrates the diverse impacts of introduced species on ecological function and the ambiguous role they play in restoration. We recommend incorporating ecological function and context into invasive species management as this approach may enable conservation managers to simultaneously minimize the negative and maximize the positive impacts (e.g. taxon substitution) of introduced species. Such novel restoration approaches are needed, especially in highly degraded ecosystems.

Diet overlap of mammalian herbivores and native bees: implications for managing co-occurring grazers and pollinators

Treesearch

Sandra J. DeBano; Samantha M. Roof; Mary M. Rowland; Lauren A. Smith

2016-01-01

Many federal, state, and tribal agencies, as well as nonprofit organizations, have recently increased efforts to understand how natural areas can be managed to enhance native pollinators and the ecosystem services they provide. However, managing this important group must be balanced with other services that natural areas provide including hunting, timber production,...

An enigmatic Hawaiian moth is a missing link in the adaptive radiation of Schiedea.

PubMed

Weller, Stephen G; Sakai, Ann K; Campbell, Diane R; Powers, John M; Peña, Sean R; Keir, Matthew J; Loomis, Alexander K; Heintzman, Scott M; Weisenberger, Lauren

2017-02-01

Shifts in pollination may drive adaptive diversification of reproductive systems within plant lineages. The monophyletic genus Schiedea is a Hawaiian lineage of 32 extant species, with spectacular diversity in reproductive systems. Biotic pollination is the presumed ancestral condition, but this key element of the life history and its role in shaping reproductive systems has remained undocumented. We observed floral visitors to two species of Schiedea and conducted field experiments to test pollinator effectiveness. We used choice tests to compare attraction of pollinators to species hypothesized to be biotically vs wind-pollinated. Pseudoschrankia brevipalpis (Erebidae), a recently described moth species known only from O'ahu, visited hermaphroditic Schiedea kaalae and S. hookeri and removed nectar from their unique tubular nectary extensions. Pseudoschrankia brevipalpis effectively pollinates S. kaalae; single visits to emasculated flowers resulted in pollen transfer. In choice tests, P. brevipalpis strongly preferred these hermaphroditic species over two subdioecious species capable of wind pollination. A shift from biotic to abiotic pollination is clearly implicated in the diversification of reproductive systems within Schiedea. Abundant pollination by a previously unknown native moth in experimental and restored populations suggests the potential for restoration to re-establish native plant-pollinator interactions critical for production of outcrossed individuals with high fitness. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

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.

Cage-Fighting Bees: Can Aggressive Competition Increase Pollination Efficacy for an Oligolectic Native Bee?

USDA-ARS?s Scientific Manuscript database

Pollination efficacy of the oligolectic bee Ptilothrix bombiformis was measured as the number of pollen grains delivered to virgin Hibiscus stigmas. Such specialized bee foragers are often assumed to be highly efficient pollinators. Intriguingly, however, we discovered females fight over host blooms...

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.

Native Honey Bees Outperform Adventive Honey Bees in Increasing Pyrus bretschneideri (Rosales: Rosaceae) Pollination.

PubMed

Gemeda, Tolera Kumsa; Shao, Youquan; Wu, Wenqin; Yang, Huipeng; Huang, Jiaxing; Wu, Jie

2017-12-05

The foraging behavior of different bee species is a key factor influencing the pollination efficiency of different crops. Most pear species exhibit full self-incompatibility and thus depend entirely on cross-pollination. However, as little is known about the pear visitation preferences of native Apis cerana (Fabricius; Hymenoptera: Apidae) and adventive Apis mellifera (L.; Hymenoptera: Apidae) in China. A comparative analysis was performed to explore the pear-foraging differences of these species under the natural conditions of pear growing areas. The results show significant variability in the pollen-gathering tendency of these honey bees. Compared to A. mellifera, A. cerana begins foraging at an earlier time of day and gathers a larger amount of pollen in the morning. Based on pollen collection data, A. mellifera shows variable preferences: vigorously foraging on pear on the first day of observation but collecting pollen from non-target floral resources on other experimental days. Conversely, A. cerana persists in pear pollen collection, without shifting preference to other competitive flowers. Therefore, A. cerana outperforms adventive A. mellifera with regard to pear pollen collection under natural conditions, which may lead to increased pear pollination. This study supports arguments in favor of further multiplication and maintenance of A. cerana for pear and other native crop pollination. Moreover, it is essential to develop alternative pollination management techniques to utilize A. mellifera for pear pollination. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Bombus huntii, Bombus impatiens and Bombus vosnesenskii (Hymenoptera: Apidae) pollinate greenhouse-grown tomatoes in western North America

USDA-ARS?s Scientific Manuscript database

Bumble bees (Bombus) are the primary pollinators of tomatoes grown in greenhouses and can significantly increase fruit weight compared to tomatoes that receive no supplemental pollination. Due to mounting concerns over the transportation of bumble bees outside of their native ranges, several specie...

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.

Nonrandom Composition of Flower Colors in a Plant Community: Mutually Different Co-Flowering Natives and Disturbance by Aliens

PubMed Central

Makino, Takashi T.; Yokoyama, Jun

2015-01-01

When pollinators use flower color to locate food sources, a distinct color can serve as a reproductive barrier against co-flowering species. This anti-interference function of flower color may result in a community assembly of plant species displaying mutually different flower colors. However, such color dispersion is not ubiquitous, suggesting a variable selection across communities and existence of some opposing factors. We conducted a 30-week study in a plant community and measured the floral reflectances of 244 species. The reflectances were evaluated in insect color spaces (bees, swallowtails, and flies), and the dispersion was compared with random expectations. We found that co-existing colors were overdispersed for each analyzed pollinator type, and this overdispersion was statistically significant for bees. Furthermore, we showed that exclusion of 32 aliens from the analysis significantly increased the color dispersion of native flowers in every color space. This result indicated that aliens disturbed a native plant–pollinator network via similarly colored flowers. Our results demonstrate the masking effects of aliens in the detection of color dispersion of native flowers and that variations in pollinator vision yield different outcomes. Our results also support the hypothesis that co-flowering species are one of the drivers of color diversification and affect the community assembly. PMID:26650121

Native Bees Effectively Pollinate New World Cucurbita (C. pepo and C. maxima): An Internet Collaboration

USDA-ARS?s Scientific Manuscript database

Wild squash bees have all five traits ascribed to the most effective crop pollinators. They are abundant, competitive, efficient, faithful to a specific crop and fast. Shared pollinator surveys covering 2,700 ha of US squash and pumpkin (n = 50 farms) show strong parallels among Cucurbita’s bee gui...

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

How scent and nectar influence floral antagonists and mutualists.

PubMed

Kessler, Danny; Kallenbach, Mario; Diezel, Celia; Rothe, Eva; Murdock, Mark; Baldwin, Ian T

2015-07-01

Many plants attract and reward pollinators with floral scents and nectar, respectively, but these traits can also incur fitness costs as they also attract herbivores. This dilemma, common to most flowering plants, could be solved by not producing nectar and/or scent, thereby cheating pollinators. Both nectar and scent are highly variable in native populations of coyote tobacco, Nicotiana attenuata, with some producing no nectar at all, uncorrelated with the tobacco's main floral attractant, benzylacetone. By silencing benzylacetone biosynthesis and nectar production in all combinations by RNAi, we experimentally uncouple these floral rewards/attractrants and measure their costs/benefits in the plant's native habitat and experimental tents. Both scent and nectar increase outcrossing rates for three, separately tested, pollinators and both traits increase oviposition by a hawkmoth herbivore, with nectar being more influential than scent. These results underscore that it makes little sense to study floral traits as if they only mediated pollination services.

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...

Spinosad in the native stingless bee Melipona quadrifasciata: regrettable non-target toxicity of a bioinsecticide.

PubMed

Tomé, Hudson Vaner V; Barbosa, Wagner F; Martins, Gustavo F; Guedes, Raul Narciso C

2015-04-01

The risks imposed by novel insecticides, mainly bioinsecticides, are largely unknown despite their increased use and their perceived environmental safety, which is based on their natural origin. Furthermore, unlike honeybees, native pollinator species have received little attention. In the present study, the lethal and sublethal effects of the neonicotinoid imidacloprid and the bioinsecticide spinosad were assessed in the stingless bee species Meliponaquadrifasciata, an important native pollinator in the Neotropical region. The adult stingless bee workers exhibited high oral insecticide susceptibility, with LD50s of 23.54 and 12.07 ng a.i./bee for imidacloprid and spinosad, respectively. Imidacloprid also impaired worker respiration and overall group activity and flight, while spinosad significantly impaired only worker flight despite exhibiting higher oral toxicity to adult workers than imidacloprid. These findings indicate the hazardous nature not only of imidacloprid but also the bioinsecticide spinosad to adult workers of the native pollinator M. quadrifasciata. Therefore, bioinsecticides should not be exempted from risk assessment analysis due to their lethal and sublethal components. Copyright © 2014 Elsevier Ltd. All rights reserved.

Solitary invasive orchid bee outperforms co-occurring native bees to promote fruit set of an invasive Solanum.

PubMed

Liu, Hong; Pemberton, Robert W

2009-03-01

Our understanding of the effects of introduced invasive pollinators on plants has been exclusively drawn from studies on introduced social bees. One might expect, however, that the impacts of introduced solitary bees, with much lower population densities and fewer foragers, would be small. Yet little is known about the potential effects of naturalized solitary bees on the environment. We took advantage of the recent naturalization of an orchid bee, Euglossa viridissima, in southern Florida to study the effects of this solitary bee on reproduction of Solanum torvum, an invasive shrub. Flowers of S. torvum require specialized buzz pollination. Through timed floral visitor watches and two pollination treatments (control and pollen supplementation) at three forest edge and three open area sites, we found that the fruit set of S. torvum was pollen limited at the open sites where the native bees dominate, but was not pollen limited at the forest sites where the invasive orchid bees dominate. The orchid bee's pollination efficiency was nearly double that of the native halictid bees, and was also slightly higher than that of the native carpenter bee. Experiments using small and large mesh cages (to deny or allow E. viridissima access, respectively) at one forest site indicated that when the orchid bee was excluded, the flowers set one-quarter as many fruit as when the bee was allowed access. The orchid bee was the most important pollinator of the weed at the forest sites, which could pose additional challenges to the management of this weed in the fragmented, endangered tropical hardwood forests in the region. This specialized invasive mutualism may promote populations of both the orchid bee and this noxious weed. Invasive solitary bees, particularly species that are specialized pollinators, appear to have more importance than has previously been recognized.

Habitat management utilizing native wildflowers to foster pollinator abundance

USDA-ARS?s Scientific Manuscript database

Pollinators provide essential ecosystem services to agricultural crops, however their population has come under threat globally as a result of intensive agricultural practices and landscape simplification. Designing diverse heterogeneous agricultural landscapes to provide optimal resources serves as...

Using Nonmetric Multidimensional Scaling to Analyze Bee Visitation in East Tennessee Crops as an Indicator of Pollination Services Provided by Honey Bees (Apis mellifera L.) and Native Bees.

PubMed

Wilson, Michael E; Skinner, John A; Wszelaki, Annette L; Drummond, Frank

2016-04-01

This study investigated bee visitation on 10 agricultural crops grown on diverse small farms in Tennessee to determine the abundance of native bees and honey bees and the partitioning of visitation among crops. Summaries for each crop are used to generate mean proportions of bee visitation by categories of bees. This shows that native bee visits often occur as frequently, or in greater proportions than non-native honey bee visits. Visitation across multiple crops is then analyzed together with nonmetric multidimensional scaling to show how communities of bees that provide crop pollination change depending on the crop. Within squash and pumpkin plantings, continuous and discrete factors, such as "time of day" and "organic practices," further explain shifts in the community composition of flower visitors. Results from this study show that native bees frequently visit flowers on various crops, indicating that they are likely contributing to pollination services in addition to honey bees. Furthermore, the community of bees visiting flowers changes based on crop type, phenology, and spatial-temporal factors. Results suggest that developing pollinator conservation for farms that grow a wide variety of crops will likely require multiple conservation strategies. Farms that concentrate on a single crop may be able to tailor conservation practices toward the most important bees in their system and geographic locale. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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.

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.

Pollination ecology and floral function of Brown's peony (Paeonia brownii) in the Blue Mountains of northeastern Oregon

Treesearch

Peter Bernhardt; Retha Meier; Nan Vance

2013-01-01

Brown’s peony, Paeonia brownie (Paeoniaceae), is one of only two peony species native to the Western Hemisphere, yet its pollination ecology and breeding system have never been documented. Using flowering individuals of an endemic colony in the Blue Mountains of Oregon, U.S., we investigated the peony’s pollination system and floral function. We...

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.

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.

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...

Aging and body size in solitary bees

USDA-ARS?s Scientific Manuscript database

Solitary bees are important pollinators of crops and non-domestic plants. Osmia lignaria is a native, commercially-reared solitary bee used to maximize pollination in orchard crops. In solitary bees, adult body size is extremely variable depending on the nutritional resources available to the develo...

How scent and nectar influence floral antagonists and mutualists

PubMed Central

Kessler, Danny; Kallenbach, Mario; Diezel, Celia; Rothe, Eva; Murdock, Mark; Baldwin, Ian T

2015-01-01

Many plants attract and reward pollinators with floral scents and nectar, respectively, but these traits can also incur fitness costs as they also attract herbivores. This dilemma, common to most flowering plants, could be solved by not producing nectar and/or scent, thereby cheating pollinators. Both nectar and scent are highly variable in native populations of coyote tobacco, Nicotiana attenuata, with some producing no nectar at all, uncorrelated with the tobacco's main floral attractant, benzylacetone. By silencing benzylacetone biosynthesis and nectar production in all combinations by RNAi, we experimentally uncouple these floral rewards/attractrants and measure their costs/benefits in the plant's native habitat and experimental tents. Both scent and nectar increase outcrossing rates for three, separately tested, pollinators and both traits increase oviposition by a hawkmoth herbivore, with nectar being more influential than scent. These results underscore that it makes little sense to study floral traits as if they only mediated pollination services. DOI: http://dx.doi.org/10.7554/eLife.07641.001 PMID:26132861

Native bees and plant pollination

USGS Publications Warehouse

Ginsberg, H.S.

2004-01-01

Bees are important pollinators, but evidence suggests that numbers of some species are declining. Decreases have been documented in the honey bee, Apis mellifera (which was introduced to North America), but there are no monitoring programs for the vast majority of native species, so we cannot be sure about the extent of this problem. Recent efforts to develop standardized protocols for bee sampling will help us collect the data needed to assess trends in bee populations. Unfortunately, diversity of bee life cycles and phenologies, and the large number of rare species, make it difficult to assess trends in bee faunas. Changes in bee populations can affect plant reproduction, which can influence plant population density and cover, thus potentially modifying horizontal and vertical structure of a community, microclimate near the ground, patterns of nitrogen deposition, etc. These potential effects of changes in pollination patterns have not been assessed in natural communities. Effects of management actions on bees and other pollinators should be considered in conservation planning.

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.

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.

Sugar and organic acid content of astringent, non-astringent, and pollination variant persimmons (abstract)

USDA-ARS?s Scientific Manuscript database

Although persimmons are native (Diospyros virginiana) to the United States, commercial production consists almost exclusively of the Asian persimmon, Diospyros kaki. Cultivars within this species are classified by their astringency type; non-astringent, astringent, and pollination variant. In the U...

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

Corridors restore animal-mediated pollination in fragmented tropical forest landscapes

PubMed Central

Kormann, Urs; Scherber, Christoph; Tscharntke, Teja; Klein, Nadja; Larbig, Manuel; Valente, Jonathon J.; Hadley, Adam S.; Betts, Matthew G.

2016-01-01

Tropical biodiversity and associated ecosystem functions have become heavily eroded through habitat loss. Animal-mediated pollination is required in more than 94% of higher tropical plant species and 75% of the world's leading food crops, but it remains unclear if corridors avert deforestation-driven pollination breakdown in fragmented tropical landscapes. Here, we used manipulative resource experiments and field observations to show that corridors functionally connect neotropical forest fragments for forest-associated hummingbirds and increase pollen transfer. Further, corridors boosted forest-associated pollinator availability in fragments by 14.3 times compared with unconnected equivalents, increasing overall pollination success. Plants in patches without corridors showed pollination rates equal to bagged control flowers, indicating pollination failure in isolated fragments. This indicates, for the first time, that corridors benefit tropical forest ecosystems beyond boosting local species richness, by functionally connecting mutualistic network partners. We conclude that small-scale adjustments to landscape configuration safeguard native pollinators and associated pollination services in tropical forest landscapes. PMID:26817765

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...

Floral visitation by the Argentine ant reduces pollinator visitation and seed set in the coast barrel cactus, Ferocactus viridescens.

PubMed

LeVan, Katherine E; Hung, Keng-Lou James; McCann, Kyle R; Ludka, John T; Holway, David A

2014-01-01

Mounting evidence indicates that trade-offs between plant defense and reproduction arise not only from resource allocation but also from interactions among mutualists. Indirect costs of plant defense by ants, for example, can outweigh benefits if ants deter pollinators. Plants can dissuade ants from occupying flowers, but such arrangements may break down when novel ant partners infiltrate mutualisms. Here, we examine how floral visitation by ants affects pollination services when the invasive Argentine ant (Linepithema humile) replaces a native ant species in a food-for-protection mutualism with the coast barrel cactus (Ferocactus viridescens), which, like certain other barrel cacti, produces extrafloral nectar. We compared the effects of floral visitation by the Argentine ant with those of the most prevalent native ant species (Crematogaster californica). Compared to C. californica, the Argentine ant was present in higher numbers in flowers. Cactus bees (Diadasia spp.), the key pollinators in this system, spent less time in flowers when cacti were occupied by the Argentine ant compared to when cacti were occupied by C. californica. Presumably as a consequence of decreased duration of floral visits by Diadasia, cacti occupied by L. humile set fewer seeds per fruit and produced fewer seeds overall compared to cacti occupied by C. californica. These data illustrate the importance of mutualist identity in cases where plants balance multiple mutualisms. Moreover, as habitats become increasingly infiltrated by introduced species, the loss of native mutualists and their replacement by non-native species may alter the shape of trade-offs between plant defense and reproduction.

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.

Biodiversity ensures plant-pollinator phenological synchrony against climate change.

PubMed

Bartomeus, Ignasi; Park, Mia G; Gibbs, Jason; Danforth, Bryan N; Lakso, Alan N; Winfree, Rachael

2013-11-01

Climate change has the potential to alter the phenological synchrony between interacting mutualists, such as plants and their pollinators. However, high levels of biodiversity might buffer the negative effects of species-specific phenological shifts and maintain synchrony at the community level, as predicted by the biodiversity insurance hypothesis. Here, we explore how biodiversity might enhance and stabilise phenological synchrony between a valuable crop, apple and its native pollinators. We combine 46 years of data on apple flowering phenology with historical records of bee pollinators over the same period. When the key apple pollinators are considered altogether, we found extensive synchrony between bee activity and apple peak bloom due to complementarity among bee species' activity periods, and also a stable trend over time due to differential responses to warming climate among bee species. A simulation model confirms that high biodiversity levels can ensure plant-pollinator phenological synchrony and thus pollination function. © 2013 John Wiley & Sons Ltd/CNRS.

Conserving pollinators in North American forests: A review

Treesearch

James L. Hanula; Michael D. Ulyshen; Scott Horn

2016-01-01

Bees and butterflies generally favor open forest habitats regardless of forest type, geographic region, or methods used to create these habitats. Dense shrub layers of native or nonnative species beneath forest canopies negatively impact herbaceous plant cover and diversity, and pollinators. The presence of nonnative flowers as a source of nectar, pollen, or larval...

Orchard Pollination in Capitol Reef National Park, Utah, USA. Honey Bees or Native Bees?

USDA-ARS?s Scientific Manuscript database

Unlike most National Parks in the United States, Capitol Reef National Park in central Utah includes an agricultural component. The Park surrounds 22 rosaceous fruit orchards started over a century ago by Mormon pioneers. During bloom, hives of the alien honey bee are imported to pollinate the flow...

Effects of landscape composition and configuration on pollination in a native herb: a field experiment.

PubMed

Ekroos, Johan; Jakobsson, Anna; Wideen, Joel; Herbertsson, Lina; Rundlöf, Maj; Smith, Henrik G

2015-10-01

Bumble bee abundance in agricultural landscapes is known to decrease with increasing distance from seminatural grasslands, but whether the pollination of bumble-bee-pollinated wild plants shows a similar pattern is less well known. In addition, the relative effects of landscape composition (landscape heterogeneity) and landscape configuration (distance from seminatural grassland) on wild plant pollination, and the interaction between these landscape effects, have not been studied using landscape-level replication. We performed a field experiment to disentangle these landscape effects on the pollination of a native herb, the sticky catchfly (Lychnis viscaria), while accounting for the proportion of oilseed rape across landscapes and the local abundance of bee forage flowers. We measured pollen limitation (the degree to which seed set is pollen-limited), seed set, and seed set stability using potted plants placed in landscapes that differed in heterogeneity (composition) and distance from seminatural grassland (configuration). Pollen limitation and seed set in individual plants did not respond to landscape composition, landscape configuration, or proportion of oilseed rape. Instead, seed set increased with increasing local bee forage flower cover. However, we found within-plant variability in pollen limitation and seed set to increase with increasing distance from seminatural pasture. Our results suggest that average within-plant levels of pollen limitation and seed set respond less swiftly than the within-plant variability in pollen limitation and seed set to changes in landscape configuration. Although landscape effects on pollination were less important than predicted, we conclude that landscape configuration and local habitat characteristics play larger roles than landscape composition in the pollination of L. viscaria.

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

Consequences of plant invasions on compartmentalization and species’ roles in plant–pollinator networks

PubMed Central

Albrecht, Matthias; Padrón, Benigno; Bartomeus, Ignasi; Traveset, Anna

2014-01-01

Compartmentalization—the organization of ecological interaction networks into subsets of species that do not interact with other subsets (true compartments) or interact more frequently among themselves than with other species (modules)—has been identified as a key property for the functioning, stability and evolution of ecological communities. Invasions by entomophilous invasive plants may profoundly alter the way interaction networks are compartmentalized. We analysed a comprehensive dataset of 40 paired plant–pollinator networks (invaded versus uninvaded) to test this hypothesis. We show that invasive plants have higher generalization levels with respect to their pollinators than natives. The consequences for network topology are that—rather than displacing native species from the network—plant invaders attracting pollinators into invaded modules tend to play new important topological roles (i.e. network hubs, module hubs and connectors) and cause role shifts in native species, creating larger modules that are more connected among each other. While the number of true compartments was lower in invaded compared with uninvaded networks, the effect of invasion on modularity was contingent on the study system. Interestingly, the generalization level of the invasive plants partially explains this pattern, with more generalized invaders contributing to a lower modularity. Our findings indicate that the altered interaction structure of invaded networks makes them more robust against simulated random secondary species extinctions, but more vulnerable when the typically highly connected invasive plants go extinct first. The consequences and pathways by which biological invasions alter the interaction structure of plant–pollinator communities highlighted in this study may have important dynamical and functional implications, for example, by influencing multi-species reciprocal selection regimes and coevolutionary processes. PMID:24943368

High species richness of native pollinators in Brazilian tomato crops.

PubMed

Silva-Neto, C M; Bergamini, L L; Elias, M A S; Moreira, G L; Morais, J M; Bergamini, B A R; Franceschinelli, E V

2017-01-01

Pollinators provide an essential service to natural ecosystems and agriculture. In tomatoes flowers, anthers are poricidal, pollen may drop from their pore when flowers are shaken by the wind. However, bees that vibrate these anthers increase pollen load on the stigma and in fruit production. The present study aimed to identify the pollinator richness of tomato flowers and investigate their morphological and functional traits related to the plant-pollinator interaction in plantations of Central Brazil. The time of anthesis, flower duration, and the number and viability of pollen grains and ovules were recorded. Floral visitors were observed and collected. Flower buds opened around 6h30 and closed around 18h00. They reopened on the following day at the same time in the morning, lasting on average 48 hours. The highest pollen availability occurred during the first hours of anthesis. Afterwards, the number of pollen grains declined, especially between 10h00 to 12h00, which is consistent with the pollinator visitation pattern. Forty bee species were found in the tomato fields, 30 of which were considered pollinators. We found that during the flowering period, plants offered an enormous amount of pollen to their visitors. These may explain the high richness and amount of bees that visit the tomato flowers in the study areas. The period of pollen availability and depletion throughout the day overlapped with the bees foraging period, suggesting that bees are highly effective in removing pollen grains from anthers. Many of these grains probably land on the stigma of the same flower, leading to self-pollination and subsequent fruit development. Native bees (Exomalopsis spp.) are effective pollinators of tomato flowers and are likely to contribute to increasing crop productivity. On the other hand, here tomato flowers offer large amounts of pollen resource to a high richness and amount of bees, showing a strong plant-pollinator interaction in the study agroecosystem.

Pollination patterns and plant breeding systems in the Galapagos: a review.

PubMed

Chamorro, Susana; Heleno, Ruben; Olesen, Jens M; McMullen, Conley K; Traveset, Anna

2012-11-01

Despite the importance of the Galápagos Islands for the development of central concepts in ecology and evolution, the understanding of many ecological processes in this archipelago is still very basic. One such process is pollination, which provides an important service to both plants and their pollinators. The rather modest level of knowledge on this subject has so far limited our predictive power on the consequences of the increasing threat of introduced plants and pollinators to this unique archipelago. As a first step toward building a unified view of the state of pollination in the Galápagos, a thorough literature search was conducted on the breeding systems of the archipelago's flora and compiled all documented flower-visitor interactions. Based on 38 studies from the last 100 years, we retrieved 329 unique interactions between 123 flowering plant species (50 endemics, 39 non-endemic natives, 26 introduced and eight of unknown origin) from 41 families and 120 animal species from 13 orders. We discuss the emergent patterns and identify promising research avenues in the field. Although breeding systems are known for <20 % of the flora, most species in our database were self-compatible. Moreover, the incidence of autogamy among endemics, non-endemic natives and alien species did not differ significantly, being high in all groups, which suggests that a poor pollinator fauna does not represent a constraint to the integration of new plant species into the native communities. Most interactions detected (approx. 90 %) come from a single island (most of them from Santa Cruz). Hymenopterans (mainly the endemic carpenter bee Xylocopa darwinii and ants), followed by lepidopterans, were the most important flower visitors. Dipterans were much more important flower visitors in the humid zone than in the dry zone. Bird and lizard pollination has been occasionally reported in the dry zone. Strong biases were detected in the sampling effort dedicated to different islands, time of day, focal plants and functional groups of visitors. Thus, the existing patterns need to be confronted with new and less biased data. The implementation of a community-level approach could greatly increase our understanding of pollination on the islands and our ability to predict the consequences of plant invasions for the natural ecosystems of the Galápagos.

Pollination patterns and plant breeding systems in the Galápagos: a review

PubMed Central

Chamorro, Susana; Heleno, Ruben; Olesen, Jens M.; McMullen, Conley K.; Traveset, Anna

2012-01-01

Background Despite the importance of the Galápagos Islands for the development of central concepts in ecology and evolution, the understanding of many ecological processes in this archipelago is still very basic. One such process is pollination, which provides an important service to both plants and their pollinators. The rather modest level of knowledge on this subject has so far limited our predictive power on the consequences of the increasing threat of introduced plants and pollinators to this unique archipelago. Scope As a first step toward building a unified view of the state of pollination in the Galápagos, a thorough literature search was conducted on the breeding systems of the archipelago's flora and compiled all documented flower–visitor interactions. Based on 38 studies from the last 100 years, we retrieved 329 unique interactions between 123 flowering plant species (50 endemics, 39 non-endemic natives, 26 introduced and eight of unknown origin) from 41 families and 120 animal species from 13 orders. We discuss the emergent patterns and identify promising research avenues in the field. Conclusions Although breeding systems are known for <20 % of the flora, most species in our database were self-compatible. Moreover, the incidence of autogamy among endemics, non-endemic natives and alien species did not differ significantly, being high in all groups, which suggests that a poor pollinator fauna does not represent a constraint to the integration of new plant species into the native communities. Most interactions detected (approx. 90 %) come from a single island (most of them from Santa Cruz). Hymenopterans (mainly the endemic carpenter bee Xylocopa darwinii and ants), followed by lepidopterans, were the most important flower visitors. Dipterans were much more important flower visitors in the humid zone than in the dry zone. Bird and lizard pollination has been occasionally reported in the dry zone. Strong biases were detected in the sampling effort dedicated to different islands, time of day, focal plants and functional groups of visitors. Thus, the existing patterns need to be confronted with new and less biased data. The implementation of a community-level approach could greatly increase our understanding of pollination on the islands and our ability to predict the consequences of plant invasions for the natural ecosystems of the Galápagos. PMID:22691541

Honey bees are the dominant diurnal pollinator of native milkweed in a large urban park.

PubMed

MacIvor, James Scott; Roberto, Adriano N; Sodhi, Darwin S; Onuferko, Thomas M; Cadotte, Marc W

2017-10-01

In eastern North America, the field milkweed, Asclepias syriaca L. (Asclepiadaceae), is used in planting schemes to promote biodiversity conservation for numerous insects including the endangered monarch butterfly, Danaus plexippus (Linnaeus) (Nymphalidae). Less is known about its pollinators, and especially in urban habitats where it is planted often despite being under increasing pressure from invasive plant species, such as the related milkweed, the dog-strangling vine (DSV), Vincetoxicum rossicum (Kleopow) Barbar. (Asclepiadaceae). During the A. syriaca flowering period in July 2016, we surveyed bees in open habitats along a DSV invasion gradient and inspected 433 individuals of 25 bee species in 12 genera for pollinia: these were affixed to bees that visited A. syriaca for nectar and contain pollen packets that are vectored (e.g., transferred) between flowers. Of all bees sampled, pollinia were found only on the nonindigenous honeybee, Apis mellifera (43% of all bees identified), as well as one individual bumblebee, Bombus impatiens Cresson. Pollinia were recorded from 45.2% of all honeybees collected. We found no relationship between biomass of DSV and biomass of A. syriaca per site. There was a significant positive correlation between A. syriaca biomass and the number of pollinia, and the proportion vectored. No relationship with DSV biomass was detected for the number of pollinia collected by bees but the proportion of vectored pollinia declined with increasing DSV biomass. Although we find no evidence of DSV flowers attracting potential pollinators away from A. syriaca and other flowering plants, the impacts on native plant-pollinator mutualisms relate to its ability to outcompete native plants. As wild bees do not appear to visit DSV flowers, it could be altering the landscape to one which honeybees are more tolerant than native wild bees.

The most effective pollinator principle applies to new invasive pollinators.

PubMed

Medel, Rodrigo; González-Browne, Catalina; Salazar, Daniela; Ferrer, Pedro; Ehrenfeld, Mildred

2018-06-01

G. L. Stebbins' most effective pollinator principle states that when pollinators are not limiting, plants are expected to specialize and adapt to the most abundant and effective pollinator species available. In this study, we quantify the effectiveness of bees, hummingbirds and hawkmoths in a Chilean population of Erythranthe lutea (Phrymaceae), and examine whether flower traits are subject to pollinator-mediated selection by the most effective pollinator species during two consecutive years. Unlike most species in the pollinator community, the visitation rate of the recently arrived Bombus terrestris did not change substantially between years, which together with its high and stable pollen delivery to flower stigmas made this species the most important in the pollinator assemblage, followed by the solitary bee Centris nigerrima Flower traits were under significant selection in the direction expected for short-tongue bees, suggesting that E. lutea is in the initial steps of adaptation to the highly effective exotic bumblebee . Our results illustrate the applicability of Stebbins' principle for new invasive pollinators, and stress their importance in driving flower adaptation of native plant species, a critical issue in the face of biotic exchange and homogenization. © 2018 The Author(s).

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.

The phylogenetic structure of plant-pollinator networks increases with habitat size and isolation.

PubMed

Aizen, Marcelo A; Gleiser, Gabriela; Sabatino, Malena; Gilarranz, Luis J; Bascompte, Jordi; Verdú, Miguel

2016-01-01

Similarity among species in traits related to ecological interactions is frequently associated with common ancestry. Thus, closely related species usually interact with ecologically similar partners, which can be reinforced by diverse co-evolutionary processes. The effect of habitat fragmentation on the phylogenetic signal in interspecific interactions and correspondence between plant and animal phylogenies is, however, unknown. Here, we address to what extent phylogenetic signal and co-phylogenetic congruence of plant-animal interactions depend on habitat size and isolation by analysing the phylogenetic structure of 12 pollination webs from isolated Pampean hills. Phylogenetic signal in interspecific interactions differed among webs, being stronger for flower-visiting insects than plants. Phylogenetic signal and overall co-phylogenetic congruence increased independently with hill size and isolation. We propose that habitat fragmentation would erode the phylogenetic structure of interaction webs. A decrease in phylogenetic signal and co-phylogenetic correspondence in plant-pollinator interactions could be associated with less reliable mutualism and erratic co-evolutionary change. © 2015 John Wiley & Sons Ltd/CNRS.

First report of downy mildew disease caused by Plasmopara halstedii on the native Rudbeckia fulgida Aiton var. speciosa (Wender.)

USDA-ARS?s Scientific Manuscript database

The showy black-eyed Susan Rudbeckia fulgida Aiton var. speciosa (Wender.) is an important perennial wildflower native to the Northeast and Midwest regions of the United States. Besides its aesthetic value in the landscape, this native plant attracts pollinators and provides seeds for birds during t...

Interactive Effects of Large- and Small-Scale Sources of Feral Honey-Bees for Sunflower in the Argentine Pampas

PubMed Central

Sáez, Agustín; Sabatino, Malena; Aizen, Marcelo A.

2012-01-01

Pollinators for animal pollinated crops can be provided by natural and semi-natural habitats, ranging from large vegetation remnants to small areas of non-crop land in an otherwise highly modified landscape. It is unknown, however, how different small- and large-scale habitat patches interact as pollinator sources. In the intensively managed Argentine Pampas, we studied the additive and interactive effects of large expanses (up to 2200 ha) of natural habitat, represented by untilled isolated “sierras”, and narrow (3–7 m wide) strips of semi-natural habitat, represented by field margins, as pollinator sources for sunflower (Helianthus annus). We estimated visitation rates by feral honey-bees, Apis mellifera, and native flower visitors (as a group) at 1, 5, 25, 50 and 100 m from a field margin in 17 sunflower fields 0–10 km distant from the nearest sierra. Honey-bees dominated the pollinator assemblage accounting for >90% of all visits to sunflower inflorescences. Honey-bee visitation was strongly affected by proximity to the sierras decreasing by about 70% in the most isolated fields. There was also a decline in honey-bee visitation with distance from the field margin, which was apparent with increasing field isolation, but undetected in fields nearby large expanses of natural habitat. The probability of observing a native visitor decreased with isolation from the sierras, but in other respects visitation by flower visitors other than honey-bees was mostly unaffected by the habitat factors assessed in this study. Overall, we found strong hierarchical and interactive effects between the study large and small-scale pollinator sources. These results emphasize the importance of preserving natural habitats and managing actively field verges in the absence of large remnants of natural habitat for improving pollinator services. PMID:22303477

Interactive effects of large- and small-scale sources of feral honey-bees for sunflower in the Argentine Pampas.

PubMed

Sáez, Agustín; Sabatino, Malena; Aizen, Marcelo A

2012-01-01

Pollinators for animal pollinated crops can be provided by natural and semi-natural habitats, ranging from large vegetation remnants to small areas of non-crop land in an otherwise highly modified landscape. It is unknown, however, how different small- and large-scale habitat patches interact as pollinator sources. In the intensively managed Argentine Pampas, we studied the additive and interactive effects of large expanses (up to 2200 ha) of natural habitat, represented by untilled isolated "sierras", and narrow (3-7 m wide) strips of semi-natural habitat, represented by field margins, as pollinator sources for sunflower (Helianthus annus). We estimated visitation rates by feral honey-bees, Apis mellifera, and native flower visitors (as a group) at 1, 5, 25, 50 and 100 m from a field margin in 17 sunflower fields 0-10 km distant from the nearest sierra. Honey-bees dominated the pollinator assemblage accounting for >90% of all visits to sunflower inflorescences. Honey-bee visitation was strongly affected by proximity to the sierras decreasing by about 70% in the most isolated fields. There was also a decline in honey-bee visitation with distance from the field margin, which was apparent with increasing field isolation, but undetected in fields nearby large expanses of natural habitat. The probability of observing a native visitor decreased with isolation from the sierras, but in other respects visitation by flower visitors other than honey-bees was mostly unaffected by the habitat factors assessed in this study. Overall, we found strong hierarchical and interactive effects between the study large and small-scale pollinator sources. These results emphasize the importance of preserving natural habitats and managing actively field verges in the absence of large remnants of natural habitat for improving pollinator services.

Sex-biased oviposition by a nursery pollinator on a gynodioecious host plant: Implications for breeding system evolution and evolution of mutualism.

PubMed

Doubleday, Laura A D; Adler, Lynn S

2017-07-01

Dioecy, a breeding system where individual plants are exclusively male or female, has evolved repeatedly. Extensive theory describes when dioecy should arise from hermaphroditism, frequently through gynodioecy, where females and hermaphrodites coexist, and when gynodioecy should be stable. Both pollinators and herbivores often prefer the pollen-bearing sex, with sex-specific fitness effects that can affect breeding system evolution. Nursery pollination, where adult insects pollinate flowers but their larvae feed on plant reproductive tissues, is a model for understanding mutualism evolution but could also yield insights into plant breeding system evolution. We studied a recently established nursery pollination interaction between native Hadena ectypa moths and introduced gynodioecious Silene vulgaris plants in North America to assess whether oviposition was biased toward females or hermaphrodites, which traits were associated with oviposition, and the effect of oviposition on host plant fitness. Oviposition was hermaphrodite-biased and associated with deeper flowers and more stems. Sexual dimorphism in flower depth, a trait also associated with oviposition on the native host plant ( Silene stellata ), explained the hermaphrodite bias. Egg-receiving plants experienced more fruit predation than plants that received no eggs, but relatively few fruits were lost, and egg receipt did not significantly alter total fruit production at the plant level. Oviposition did not enhance pollination; egg-receiving flowers usually failed to expand and produce seeds. Together, our results suggest that H. ectypa oviposition does not exert a large fitness cost on host plants, sex-biased interactions can emerge from preferences developed on a hermaphroditic host species, and new nursery pollination interactions can arise as negative or neutral rather than as mutualistic for the plant.

Indirect Effects of Field Management on Pollination Service and Seed Set in Hybrid Onion Seed Production.

PubMed

Gillespie, Sandra; Long, Rachael; Williams, Neal

2015-12-01

Pollination in crops, as in native ecosystems, is a stepwise process that can be disrupted at any stage. Healthy pollinator populations are critical for adequate visitation, but pollination still might fail if crop management interferes with the attraction and retention of pollinators. Farmers must balance the direct benefits of applying insecticide and managing irrigation rates against their potential to indirectly interfere with the pollination process. We investigated these issues in hybrid onion seed production, where previous research has shown that high insecticide use reduces pollinator attraction. We conducted field surveys of soil moisture, nectar production, pollinator visitation, pollen-stigma interactions, and seed set at multiple commercial fields across 2 yr. We then examined how management actions, such as irrigation rate (approximated by soil moisture), or insecticide use could affect the pollination process. Onions produced maximum nectar at intermediate soil moisture, and high nectar production attracted more pollinators. Insecticide use weakly affected pollinator visitation, but when applied close to bloom reduced pollen germination and pollen tube growth. Ultimately, neither soil moisture nor insecticide use directly affected seed set, but the high correlation between pollinator visitation and seed set suggests that crop management will ultimately affect yields via indirect effects on the pollination process. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Pollinator-independent orchid attracts biotic pollinators due the production of lipoidal substances.

PubMed

Pansarin, E R; Bergamo, P J; Ferreira-Caliman, M J

2018-03-01

Flowering plants often depend on the attraction of biotic pollinators for sexual reproduction. Consequently, the emergence and maintenance of selected floral attributes related to pollinator attraction and rewarding are driven by pollinator pressure. In this paper we explore the effect of pollinators, rainfall, temperature and air humidity on the reproduction of a Brazilian terrestrial orchid, Cranichis candida based on data of phenology, flower resources, olfactory and visual attraction cues, pollinators and breeding system. The flowers of C. candida are strongly protandrous and pollinated by workers of the social native bee Tetragonisca angustula. The bees collect labellar lipoidal substances (wax scales), which are transported to the nest. The lipoidal substance is composed of sterols, hydrocarbons and terpenes. The last presumably protects the bees and their nests against pathogens and other arthropods. C. candida sets fruits through biotic self- and cross-pollination, and spontaneously due the action of raindrops on flowers. Our results indicate that in C. candida, although rain-mediated spontaneous self-pollination happens, fructification mediated by biotic pollinations also occurs, which may result in fruit set by cross-pollination. A mixed pollination system must result in higher genetic variability when compared to species whose fruits are produced entirely by self-pollination. On the other hand, autogamy is a form of reproductive assurance, and has commonly evolved where pollination services are rare or absent. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Historical changes in northeastern US bee pollinators related to shared ecological traits.

PubMed

Bartomeus, Ignasi; Ascher, John S; Gibbs, Jason; Danforth, Bryan N; Wagner, David L; Hedtke, Shannon M; Winfree, Rachael

2013-03-19

Pollinators such as bees are essential to the functioning of terrestrial ecosystems. However, despite concerns about a global pollinator crisis, long-term data on the status of bee species are limited. We present a long-term study of relative rates of change for an entire regional bee fauna in the northeastern United States, based on >30,000 museum records representing 438 species. Over a 140-y period, aggregate native species richness weakly decreased, but richness declines were significant only for the genus Bombus. Of 187 native species analyzed individually, only three declined steeply, all of these in the genus Bombus. However, there were large shifts in community composition, as indicated by 56% of species showing significant changes in relative abundance over time. Traits associated with a declining relative abundance include small dietary and phenological breadth and large body size. In addition, species with lower latitudinal range boundaries are increasing in relative abundance, a finding that may represent a response to climate change. We show that despite marked increases in human population density and large changes in anthropogenic land use, aggregate native species richness declines were modest outside of the genus Bombus. At the same time, we find that certain ecological traits are associated with declines in relative abundance. These results should help target conservation efforts focused on maintaining native bee abundance and diversity and therefore the important ecosystems services that they provide.

Honeybees Increase Fruit Set in Native Plant Species Important for Wildlife Conservation

NASA Astrophysics Data System (ADS)

Cayuela, Luis; Ruiz-Arriaga, Sarah; Ozers, Christian P.

2011-11-01

Honeybee colonies are declining in some parts of the world. This may have important consequences for the pollination of crops and native plant species. In Spain, as in other parts of Europe, land abandonment has led to a decrease in the number of non professional beekeepers, which aggravates the problem of honeybee decline as a result of bee diseases In this study, we investigated the effects of honeybees on the pollination of three native plant species in northern Spain, namely wildcherry Prunus avium L., hawthorn Crataegus monogyna Jacq., and bilberry Vaccinium myrtillus L. We quantified fruit set of individuals from the target species along transects established from an apiary outwards. Half the samples were bagged in a nylon mesh to avoid insect pollination. Mixed-effects models were used to test the effect of distance to the apiary on fruit set in non-bagged samples. The results showed a negative significant effect of distance from the apiary on fruit set for hawthorn and bilberry, but no significant effects were detected for wildcherry. This suggests that the use of honeybees under traditional farming practices might be a good instrument to increase fruit production of some native plants. This may have important consequences for wildlife conservation, since fruits, and bilberries in particular, constitute an important feeding resource for endangered species, such as the brown bear Ursus arctos L. or the capercaillie Tetrao urogallus cantabricus L.

Honeybees increase fruit set in native plant species important for wildlife conservation.

PubMed

Cayuela, Luis; Ruiz-Arriaga, Sarah; Ozers, Christian P

2011-11-01

Honeybee colonies are declining in some parts of the world. This may have important consequences for the pollination of crops and native plant species. In Spain, as in other parts of Europe, land abandonment has led to a decrease in the number of non professional beekeepers, which aggravates the problem of honeybee decline as a result of bee diseases In this study, we investigated the effects of honeybees on the pollination of three native plant species in northern Spain, namely wildcherry Prunus avium L., hawthorn Crataegus monogyna Jacq., and bilberry Vaccinium myrtillus L. We quantified fruit set of individuals from the target species along transects established from an apiary outwards. Half the samples were bagged in a nylon mesh to avoid insect pollination. Mixed-effects models were used to test the effect of distance to the apiary on fruit set in non-bagged samples. The results showed a negative significant effect of distance from the apiary on fruit set for hawthorn and bilberry, but no significant effects were detected for wild cherry. This suggests that the use of honeybees under traditional farming practices might be a good instrument to increase fruit production of some native plants. This may have important consequences for wildlife conservation, since fruits, and bilberries in particular, constitute an important feeding resource for endangered species, such as the brown bear Ursus arctos L. or the capercaillie Tetrao urogallus cantabricus L.

Experimental studies of adaptation in Clarkia xantiana. III. Phenotypic selection across a subspecies border.

PubMed

Anderson, Jill T; Eckhart, Vincent M; Geber, Monica A

2015-09-01

Sister taxa with distinct phenotypes often occupy contrasting environments in parapatric ranges, yet we generally do not know whether trait divergence reflects spatially varying selection. We conducted a reciprocal transplant experiment to test whether selection favors "native phenotypes" in two subspecies of Clarkia xantiana (Onagraceae), an annual plant in California. For four quantitative traits that differ between subspecies, we estimated phenotypic selection in subspecies' exclusive ranges and their contact zone in two consecutive years. We predicted that in the arid, pollinator-scarce eastern region, selection favors phenotypes of the native subspecies parviflora: small leaves, slow leaf growth, early flowering, and diminutive flowers. In the wetter, pollinator-rich, western range of subspecies xantiana, we expected selection for opposite phenotypes. We investigated pollinator contributions to selection by comparing naturally pollinated and pollen-supplemented individuals. For reproductive traits and for subspecies xantiana, selection generally matched expectations. The contact zone sometimes showed distinctive selection, and in ssp. parviflora selection sometimes favored nonnative phenotypes. Pollinators influenced selection on flowering time but not on flower size. Little temporal variation in selection occurred, possibly because of plastic trait responses across years. Though there were exceptions and some causes of selection remain obscure, phenotypic differentiation between subspecies appears to reflect spatially variable selection. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

The effect of nest box distribution on sustainable propagation of Osmia lignaria (Hymenoptera: Megachilidae) in commercial tart cherry orchards

USDA-ARS?s Scientific Manuscript database

The blue orchard bee, Osmia lignaria Say, is a solitary, native bee that is an excellent pollinator of tree fruit orchards. Due to the annual rising costs of honey bee hive rentals, many orchardists are eager to develop management tools and practices to support O. lignaria as alternative pollinator...

Habitat restoration promotes pollinator persistence and colonization in intensively managed agriculture.

PubMed

M'Gonigle, Leithen K; Ponisio, Lauren C; Cutler, Kerry; Kremen, Claire

2015-09-01

Widespread evidence of pollinator declines has led to policies supporting habitat restoration including in agricultural landscapes. Yet, little is yet known about the effectiveness of these restoration techniques for promoting stable populations and communities of pollinators, especially in intensively managed agricultural landscapes. Introducing floral resources, such as flowering hedgerows, to enhance intensively cultivated agricultural landscapes is known to increase the abundances of native insect pollinators in and around restored areas. Whether this is a result of local short-term concentration at flowers or indicative of true increases in the persistence and species richness of these communities remains unclear. It is also unknown whether this practice supports species of conservation concern (e.g., those with more specialized dietary requirements). Analyzing occupancies of native bees and syrphid flies from 330 surveys across 15 sites over eight years, we found that hedgerow restoration promotes rates of between-season persistence and colonization as compared with unrestored field edges. Enhanced persistence and colonization, in turn, led to the formation of more species-rich communities. We also find that hedgerows benefit floral resource specialists more than generalists, emphasizing the value of this restoration technique for conservation in agricultural landscapes.

Innate colour preferences of the Australian native stingless bee Tetragonula carbonaria Sm.

PubMed

Dyer, Adrian G; Boyd-Gerny, Skye; Shrestha, Mani; Lunau, Klaus; Garcia, Jair E; Koethe, Sebastian; Wong, Bob B M

2016-10-01

Innate preferences promote the capacity of pollinators to find flowers. Honeybees and bumblebees have strong preferences for 'blue' stimuli, and flowers of this colour typically present higher nectar rewards. Interestingly, flowers from multiple different locations around the world independently have the same distribution in bee colour space. Currently, however, there is a paucity of data on the innate colour preferences of stingless bees that are often implicated as being key pollinators in many parts of the world. In Australia, the endemic stingless bee Tetragonula carbonaria is widely distributed and known to be an efficient pollinator of both native plants and agricultural crops. In controlled laboratory conditions, we tested the innate colour responses of naïve bees using standard broadband reflectance stimuli representative of common flower colours. Colorimetric analyses considering hymenopteran vision and a hexagon colour space revealed a difference between test colonies, and a significant effect of green contrast and an interaction effect of green contrast with spectral purity on bee choices. We also observed colour preferences for stimuli from the blue and blue-green categorical regions of colour space. Our results are discussed in relation to the similar distribution of flower colours observed from bee pollination around the world.

Pollination efficiency of Apis mellifera Linnaeus, 1758 (Hymenoptera, Apidae) on the monoecious plants Jatropha mollissima (Pohl) Baill. and Jatropha mutabilis (Pohl) Baill. (Euphorbiaceae) in a semi-arid Caatinga area, northeastern Brazil.

PubMed

Neves, E L; Viana, B F

2011-02-01

Previous studies have shown the superior competitive ability of honeybees compared with native bees in the exploitation of floral resources and nesting sites besides their low efficiency in pollinating native plant species. However, there is little evidence of the effect of this invading species on autochthonous plant populations in natural environments. Thus experiments were performed to test the pollination efficiency of honeybees in two species of Jatropha (Euphorbiaceae), J. mollissima (Pohl) Baill. and J. mutabilis (Pohl) Baill., after a single flower visitation. Samplings were carried out between March and April 2006 in a hyperxerophilous shrub-arboreal Caatinga at Estação Biológica de Canudos, Bahia (9º 56´ 34" S, 38º 59´ 17" W), the property of Fundação Biodiversitas. Apis mellifera was efficient at pollinating J. mollissima (100%) and J. mutabilis (85%). This high efficiency may be explained by 1) the simple floral characteristics of both plant species, which facilitate access to the sexual organs of the plant; and 2) the body size of A. mellifera that fits the flower's dimensions.

Stingless Bees as Alternative Pollinators of Canola.

PubMed

Witter, Sidia; Nunes-Silva, Patrícia; Lisboa, Bruno B; Tirelli, Flavia P; Sattler, Aroni; Both Hilgert-Moreira, Suzane; Blochtein, Betina

2015-06-01

Alternative pollinators can ensure pollination services if the availability of the managed or most common pollinator is compromised. In this study, the behavior and pollination efficiency of Apis mellifera L. and two species of stingless bees, Plebeia emerina Friese and Tetragonisca fiebrigi Schwarz, were evaluated and compared in flowers of Brassica napus L. 'Hyola 61'. A. mellifera was an efficient pollinator when collecting nectar because it effectively touched the reproductive organs of the flower. In contrast, stingless bees were efficient pollinators only when collecting pollen. The number of pollen grains deposited on the stigma after a single visit by worker bees of the three species was greater than the number of grains resulting from pollination without the bee visits. On average, the three species deposited enough pollen grains to fertilize all of the flower ovules. A. mellifera and P. emerina had similar pollination efficiency because no significant differences were observed in the characteristics of the siliques produced. Although T. fiebrigi is also an effective pollinator, the seed mass produced by their pollination was lower. Native bees promoted similar rates of fruit set compared with A. mellifera. Thus, P. emerina has potential to be used for pollination in canola crops. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Tracing impacts of partner abundance in facultative pollination mutualisms: from individuals to populations.

PubMed

Geib, Jennifer C; Galen, Candace

2012-07-01

Partner abundance affects costs and benefits in obligate mutualisms, but its role in facultative partnerships is less clear. We address this gap in a pollination web consisting of two clovers (Trifolium) that differ in specialization on a bumble bee pollinator Bombus balteatus. We examine how pollination niche breadth affects plant responses to pollinator abundance, comparing early-flowering (specialized) and late-flowering (generalized) cohorts of T. parryi and early T. parryi to T. dasyphyllum, a pollination generalist. Co-pollinators disrupt the link between B. halteatus visitation and pollination rate for both clovers. Only for early-flowering T. parryi do visitation, pollination, and seed set increase with density of B. balteatus. Bumble bee density also alters timing of seed germination in T. parryi, with seeds from plants receiving augmented B. balteatus germinating sooner than seeds of open-pollinated counterparts. Benefits saturate at intermediate bumble bee densities. Despite strong effects of B. balteatus density on individual plant fitness components, population models suggest little impact of B. balteatus density on lamda in T. parryi or T. dasyphyllum. Findings show that functional redundancy in a pollinator guild mediates host-plant responses to partner density. Unexpected effects of pollinator density on life history schedule have implications for recruitment under pollinator decline.

Generalised pollination systems for three invasive milkweeds in Australia.

PubMed

Ward, M; Johnson, S D

2013-05-01

Because most plants require pollinator visits for seed production, the ability of an introduced plant species to establish pollinator relationships in a new ecosystem may have a central role in determining its success or failure as an invader. We investigated the pollination ecology of three milkweed species - Asclepias curassavica, Gomphocarpus fruticosus and G. physocarpus - in their invaded range in southeast Queensland, Australia. The complex floral morphology of milkweeds has often been interpreted as a general trend towards specialised pollination requirements. Based on this interpretation, invasion by milkweeds contradicts the expectation than plant species with specialised pollination systems are less likely to become invasive that those with more generalised pollination requirements. However, observations of flower visitors in natural populations of the three study species revealed that their pollination systems are essentially specialised at the taxonomic level of the order, but generalised at the species level. Specifically, pollinators of the two Gomphocarpus species included various species of Hymenoptera (particularly vespid wasps), while pollinators of A. curassavica were primarily Lepidoptera (particularly nymphalid butterflies). Pollinators of all three species are rewarded with copious amounts of highly concentrated nectar. It is likely that successful invasion by these three milkweed species is attributable, at least in part, to their generalised pollinator requirements. The results of this study are discussed in terms of how data from the native range may be useful in predicting pollination success of species in a new environment. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Exotic species enhance response diversity to land-use change but modify functional composition.

PubMed

Stavert, Jamie R; Pattemore, David E; Gaskett, Anne C; Beggs, Jacqueline R; Bartomeus, Ignasi

2017-08-16

Two main mechanisms may buffer ecosystem functions despite biodiversity loss. First, multiple species could share similar ecological roles, thus providing functional redundancy. Second, species may respond differently to environmental change (response diversity). However, ecosystem function would be best protected when functionally redundant species also show response diversity. This linkage has not been studied directly, so we investigated whether native and exotic pollinator species with similar traits (functional redundancy) differed in abundance (response diversity) across an agricultural intensification gradient. Exotic pollinator species contributed most positive responses, which partially stabilized overall abundance of the pollinator community. However, although some functionally redundant species exhibited response diversity, this was not consistent across functional groups and aggregate abundances within each functional group were rarely stabilized. This shows functional redundancy and response diversity do not always operate in concert. Hence, despite exotic species becoming increasingly dominant in human-modified systems, they cannot replace the functional composition of native species. © 2017 The Author(s).

A Survey of Cavity-Nesting Bees and Wasps in Loblolly Pine Stands of the Savannah River Site, Aiken County, South Carolina

Treesearch

Scott Horn; James L. Hanula

2004-01-01

In recent years concern over widespread losses in biodiversity has grown to include a possible decline of many native pollinators, primarily bees (Buchmann and Nabhan 1996, The Forgotten Pollinators, Island Press). Factors such as habitat fragmentation, agricultural practices, use of pesticides, the introduction of invasive species, or changes in land use may...

How exotic plants integrate into pollination networks

PubMed Central

Stouffer, Daniel B; Cirtwill, Alyssa R; Bascompte, Jordi; Bartomeus, Ignasi

2014-01-01

Summary There is increasing world-wide concern about the impact of the introduction of exotic species on ecological communities. Since many exotic plants depend on native pollinators to successfully establish, it is of paramount importance that we understand precisely how exotic species integrate into existing plant–pollinator communities. In this manuscript, we have studied a global data base of empirical pollination networks to determine whether community, network, species or interaction characteristics can help identify invaded communities. We found that a limited number of community and network properties showed significant differences across the empirical data sets – namely networks with exotic plants present are characterized by greater total, plant and pollinator richness, as well as higher values of relative nestedness. We also observed significant differences in terms of the pollinators that interact with the exotic plants. In particular, we found that specialist pollinators that are also weak contributors to community nestedness are far more likely to interact with exotic plants than would be expected by chance alone. Synthesis. By virtue of their interactions, it appears that exotic plants may provide a key service to a community's specialist pollinators as well as fill otherwise vacant ‘coevolutionary niches’. PMID:25558089

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.

Imidacloprid-Induced Impairment of Mushroom Bodies and Behavior of the Native Stingless Bee Melipona quadrifasciata anthidioides

PubMed Central

Tomé, Hudson Vaner V.; Martins, Gustavo F.; Lima, Maria Augusta P.; Campos, Lúcio Antonio O.; Guedes, Raul Narciso C.

2012-01-01

Declines in pollinator colonies represent a worldwide concern. The widespread use of agricultural pesticides is recognized as a potential cause of these declines. Previous studies have examined the effects of neonicotinoid insecticides such as imidacloprid on pollinator colonies, but these investigations have mainly focused on adult honey bees. Native stingless bees (Hymenoptera: Apidae: Meliponinae) are key pollinators in neotropical areas and are threatened with extinction due to deforestation and pesticide use. Few studies have directly investigated the effects of pesticides on these pollinators. Furthermore, the existing impact studies did not address the issue of larval ingestion of contaminated pollen and nectar, which could potentially have dire consequences for the colony. Here, we assessed the effects of imidacloprid ingestion by stingless bee larvae on their survival, development, neuromorphology and adult walking behavior. Increasing doses of imidacloprid were added to the diet provided to individual worker larvae of the stingless bee Melipona quadrifasciata anthidioides throughout their development. Survival rates above 50% were only observed at insecticide doses lower than 0.0056 µg active ingredient (a.i.)/bee. No sublethal effect on body mass or developmental time was observed in the surviving insects, but the pesticide treatment negatively affected the development of mushroom bodies in the brain and impaired the walking behavior of newly emerged adult workers. Therefore, stingless bee larvae are particularly susceptible to imidacloprid, as it caused both high mortality and sublethal effects that impaired brain development and compromised mobility at the young adult stage. These findings demonstrate the lethal effects of imidacloprid on native stingless bees and provide evidence of novel serious sublethal effects that may compromise colony survival. The ecological and economic importance of neotropical stingless bees as pollinators, their susceptibility to insecticides and the vulnerability of their larvae to insecticide exposure emphasize the importance of studying these species. PMID:22675559

Imidacloprid-induced impairment of mushroom bodies and behavior of the native stingless bee Melipona quadrifasciata anthidioides.

PubMed

Tomé, Hudson Vaner V; Martins, Gustavo F; Lima, Maria Augusta P; Campos, Lúcio Antonio O; Guedes, Raul Narciso C

2012-01-01

Declines in pollinator colonies represent a worldwide concern. The widespread use of agricultural pesticides is recognized as a potential cause of these declines. Previous studies have examined the effects of neonicotinoid insecticides such as imidacloprid on pollinator colonies, but these investigations have mainly focused on adult honey bees. Native stingless bees (Hymenoptera: Apidae: Meliponinae) are key pollinators in neotropical areas and are threatened with extinction due to deforestation and pesticide use. Few studies have directly investigated the effects of pesticides on these pollinators. Furthermore, the existing impact studies did not address the issue of larval ingestion of contaminated pollen and nectar, which could potentially have dire consequences for the colony. Here, we assessed the effects of imidacloprid ingestion by stingless bee larvae on their survival, development, neuromorphology and adult walking behavior. Increasing doses of imidacloprid were added to the diet provided to individual worker larvae of the stingless bee Melipona quadrifasciata anthidioides throughout their development. Survival rates above 50% were only observed at insecticide doses lower than 0.0056 µg active ingredient (a.i.)/bee. No sublethal effect on body mass or developmental time was observed in the surviving insects, but the pesticide treatment negatively affected the development of mushroom bodies in the brain and impaired the walking behavior of newly emerged adult workers. Therefore, stingless bee larvae are particularly susceptible to imidacloprid, as it caused both high mortality and sublethal effects that impaired brain development and compromised mobility at the young adult stage. These findings demonstrate the lethal effects of imidacloprid on native stingless bees and provide evidence of novel serious sublethal effects that may compromise colony survival. The ecological and economic importance of neotropical stingless bees as pollinators, their susceptibility to insecticides and the vulnerability of their larvae to insecticide exposure emphasize the importance of studying these species.

The risks of introduction of the Amazonian palm Euterpe oleracea in the Atlantic rainforest.

PubMed

Tiberio, F C S; Sampaio-E-Silva, T A; Matos, D M S; Antunes, A Z

2016-02-01

The introduction of a species may alter ecological processes of native populations, such as pollination and dispersal patterns, leading to changes in population structure. When the introduced and the native species are congeners, interference in pollination can also lead to hybridization. We aimed to understand the ecological aspects of Euterpe oleracea introduction in the Atlantic forest and the possible consequences for the conservation of the native congener Euterpe edulis. We analysed the population structure of palm populations, including hybrids, and observed the interaction with frugivorous birds of both palm species after E. oleracea introduction. We observed that E. edulis had significantly lower density and a smaller number of seedlings when occurring with E. oleracea. Native and introduced Euterpe species shared nine frugivorous bird species. E. oleracea and hybrids had dispersed outside the original planting area. Consequently, the risks of introduction of E. oleracea may mostly be related to the disruption of interactions between E. edulis and frugivorous birds and the spontaneous production of hybrids. Finally, the cultivation of E. oleracea and hybrids in Atlantic rainforest could affect the conservation of the already endangered E. edulis.

Simple Enough--Even for Web Virgins: Lisa Mitten's Access to Native American Web Sites. Web Site Review Essay.

ERIC Educational Resources Information Center

Belgarde, Mary Jiron

1998-01-01

A mixed-blood Mohawk urban Indian and university librarian, Lisa Mitten provides access to Web sites with solid information about American Indians. Links are provided to 10 categories--Native nations, Native organizations, Indian education, Native media, powwows and festivals, Indian music, Native arts, Native businesses, and Indian-oriented home…

Investigating Temporal Patterns of a Native Bee Community in a Remnant North American Bunchgrass Prairie using Blue Vane Traps

PubMed Central

Kimoto, Chiho; DeBano, Sandra J.; Thorp, Robbin W.; Rao, Sujaya; Stephen, William P.

2012-01-01

Native bees are important ecologically and economically because their role as pollinators fulfills a vital ecosystem service. Pollinators are declining due to various factors, including habitat degradation and destruction. Grasslands, an important habitat for native bees, are particularly vulnerable. One highly imperiled and understudied grassland type in the United States is the Pacific Northwest Bunchgrass Prairie. No studies have examined native bee communities in this prairie type. To fill this gap, the bee fauna of the Zumwalt Prairie, a large, relatively intact remnant of the Pacific Northwest Bunchgrass Prairie, was examined. Native bees were sampled during the summers of 2007 and 2008 in sixteen 40-ha study pastures on a plateau in northeastern Oregon, using a sampling method not previously used in grassland studies—blue vane traps. This grassland habitat contained an abundant and diverse community of native bees that experienced marked seasonal and inter-annual variation, which appears to be related to weather and plant phenology. Temporal variability evident over the entire study area was also reflected at the individual trap level, indicating a consistent response across the spatial scale of the study. These results demonstrate that temporal variability in bee communities can have important implications for long-term monitoring protocols. In addition, the blue vane trap method appears to be well-suited for studies of native bees in large expanses of grasslands or other open habitats, and may be a useful tool for monitoring native bee communities in these systems. PMID:23438086

Investigating temporal patterns of a native bee community in a remnant North American bunchgrass prairie using blue vane traps.

PubMed

Kimoto, Chiho; Debano, Sandra J; Thorp, Robbin W; Rao, Sujaya; Stephen, William P

2012-01-01

Native bees are important ecologically and economically because their role as pollinators fulfills a vital ecosystem service. Pollinators are declining due to various factors, including habitat degradation and destruction. Grasslands, an important habitat for native bees, are particularly vulnerable. One highly imperiled and understudied grassland type in the United States is the Pacific Northwest Bunchgrass Prairie. No studies have examined native bee communities in this prairie type. To fill this gap, the bee fauna of the Zumwalt Prairie, a large, relatively intact remnant of the Pacific Northwest Bunchgrass Prairie, was examined. Native bees were sampled during the summers of 2007 and 2008 in sixteen 40-ha study pastures on a plateau in northeastern Oregon, using a sampling method not previously used in grassland studies-blue vane traps. This grassland habitat contained an abundant and diverse community of native bees that experienced marked seasonal and inter-annual variation, which appears to be related to weather and plant phenology. Temporal variability evident over the entire study area was also reflected at the individual trap level, indicating a consistent response across the spatial scale of the study. These results demonstrate that temporal variability in bee communities can have important implications for long-term monitoring protocols. In addition, the blue vane trap method appears to be well-suited for studies of native bees in large expanses of grasslands or other open habitats, and may be a useful tool for monitoring native bee communities in these systems.

Pollinator specialization and pollination syndromes of three related North American Silene.

PubMed

Reynolds, Richard J; Westbrook, M Jody; Rohde, Alexandra S; Cridland, Julie M; Fenster, Charles B; Dudash, Michele R

2009-08-01

Community and biogeographic surveys often conclude that plant-pollinator interactions are highly generalized. Thus, a central implication of the pollination syndrome concept, that floral trait evolution occurs primarily via specialized interactions of plants with their pollinators, has been questioned. However, broad surveys may not distinguish whether flower visitors are actual pollen vectors and hence lack power to assess the relationship between syndrome traits and the pollinators responsible for their evolution. Here we address whether the floral traits of three closely related hermaphroditic Silene spp. native to eastern North America (S. caroliniana, S. virginica, and S. stellata) correspond to predicted specialized pollination based on floral differences among the three species and the congruence of these floral features with recognized pollination syndromes. A nocturnal/diurnal pollinator exclusion experiment demonstrated that all three Silene spp. have diurnal pollinators, and only S. stellata has nocturnal pollinators. Multiyear studies of visitation rates demonstrated that large bees, hummingbirds, and nocturnal moths were the most frequent pollinators of S. caroliniana, S. virginica, and S. stellata, respectively. Estimates of pollen grains deposited and removed per visit generally corroborated the visitation rate results for all three species. However, the relatively infrequent diurnal hawkmoth pollinators of S. caroliniana were equally effective and more efficient than the most frequent large bee visitors. Pollinator importance (visitation X deposition) of each of the animal visitors to each species was estimated and demonstrated that in most years large bees and nocturnal moths were the most important pollinators of S. caroliniana and S. stellata, respectively. By quantifying comprehensive aspects of the pollination process we determined that S. virginica and S. stellata were specialized on hummingbirds and nocturnal moths, respectively, and S. caroliniana was the least specialized with diurnal hawkmoth and large bee pollinators. Compared across the Silene species, divergent floral character states are consistent with increasing the attraction and/or pollen transfer efficiency of their respective major pollinators, which suggests that the pollinators are past and/or contemporary selective agents for floral trait evolution in these three Silene species. We conclude that the pollination syndrome concept allows us to effectively relate the functional significance of floral morphology to the major pollinators of these Silene species.

Exotic plant infestation is associated with decreased modularity and increased numbers of connectors in mixed-grass prairie pollination networks

USGS Publications Warehouse

Larson, Diane L.; Rabie, Paul A.; Droege, Sam; Larson, Jennifer L.; Haar, Milton

2016-01-01

The majority of pollinating insects are generalists whose lifetimes overlap flowering periods of many potentially suitable plant species. Such generality is instrumental in allowing exotic plant species to invade pollination networks. The particulars of how existing networks change in response to an invasive plant over the course of its phenology are not well characterized, but may shed light on the probability of long-term effects on plant-pollinator interactions and the stability of network structure. Here we describe changes in network topology and modular structure of infested and non-infested networks during the flowering season of the generalist non-native flowering plant, Cirsium arvense in mixed-grass prairie at Badlands National Park, South Dakota, USA. Objectives were to compare network-level effects of infestation as they propagate over the season in infested and non-infested (with respect to C. arvense) networks. We characterized plant-pollinator networks on 5 non-infested and 7 infested 1-ha plots during 4 sample periods that collectively covered the length of C. arvense flowering period. Two other abundantly-flowering invasive plants were present during this time: Melilotus officinalis had highly variable floral abundance in both C. arvense-infested and non-infested plots andConvolvulus arvensis, which occurred almost exclusively in infested plots and peaked early in the season. Modularity, including roles of individual species, and network topology were assessed for each sample period as well as in pooled infested and non-infested networks. Differences in modularity and network metrics between infested and non-infested networks were limited to the third and fourth sample periods, during flower senescence of C. arvenseand the other invasive species; generality of pollinators rose concurrently, suggesting rewiring of the network and a lag effect of earlier floral abundance. Modularity was lower and number of connectors higher in infested networks, whether they were assessed in individual sample periods or pooled into infested and non-infested networks over the entire blooming period of C.arvense. Connectors typically did not reside within the same modules as C. arvense, suggesting that effects of the other invasive plants may also influence the modularity results, and that effects of infestation extend to co-flowering native plants. We conclude that the presence of abundantly flowering invasive species is associated with greater network stability due to decreased modularity, but whether this is advantageous for the associated native plant-pollinator communities depends on the nature of perturbations they experience.

Efficiency of local Indonesia honey bees (Apis cerana L.) and stingless bee (Trigona iridipennis) on tomato (Lycopersicon esculentum Mill.) pollination.

PubMed

Putra, Ramadhani Eka; Kinasih, Ida

2014-01-01

Tomato (Lycopersicon esculentum Mill.) is considered as one of major agricultural commodity of Indonesia farming. However, monthly production is unstable due to lack of pollination services. Common pollinator agent of tomatoes is bumblebees which is unsuitable for tropical climate of Indonesia and the possibility of alteration of local wild plant interaction with their pollinator. Indonesia is rich with wild bees and some of the species already domesticated for years with prospect as pollinating agent for tomatoes. This research aimed to assess the efficiency of local honey bee (Apis cerana L.) and stingless bee (Trigona iridipennis), as pollinator of tomato. During this research, total visitation rate and total numbers of pollinated flowers by honey bee and stingless bee were compared between them with bagged flowers as control. Total fruit production, average weight and size also measured in order to correlated pollination efficiency with quantity and quality of fruit produced. Result of this research showed that A. cerana has slightly higher rate of visitation (p>0.05) and significantly shorter handling time (p < 0.05) than T. iridipennis due to their larger colony demand and low reward provide by tomato flowers. However, honey bee pollinated tomato flowers more efficient pollinator than stingless bee (80.3 and 70.2% efficiency, respectively; p < 0.05) even though the average weight and size of tomatoes were similar (p>0.05). Based on the results, it is concluded that the use of Apis cerana and Trigona spp., for pollinating tomatoes in tropical climates could be an alternative to the use of non-native Apis mellifera and bumblebees (Bombus spp.). However, more researches are needed to evaluate the cost/benefit on large-scale farming and greenhouse pollination using both bees against other bee species and pollination methods.

Has pollination mode shaped the evolution of ficus pollen?

PubMed

Wang, Gang; Chen, Jin; Li, Zong-Bo; Zhang, Feng-Ping; Yang, Da-Rong

2014-01-01

The extent to which co-evolutionary processes shape morphological traits is one of the most fascinating topics in evolutionary biology. Both passive and active pollination modes coexist in the fig tree (Ficus, Moraceae) and fig wasp (Agaonidae, Hymenoptera) mutualism. This classic obligate relationship that is about 75 million years old provides an ideal system to consider the role of pollination mode shifts on pollen evolution. Twenty-five fig species, which cover all six Ficus subgenera, and are native to the Xishuangbanna region of southwest China, were used to investigate pollen morphology with scanning electron microscope (SEM). Pollination mode was identified by the Anther/Ovule ratio in each species. Phylogenetic free regression and a correlated evolution test between binary traits were conducted based on a strong phylogenetic tree. Seventeen of the 25 fig species were actively pollinated and eight species were passively pollinated. Three pollen shape types and three kinds of exine ornamentation were recognized among these species. Pollen grains with ellipsoid shape and rugulate ornamentation were dominant. Ellipsoid pollen occurred in all 17 species of actively pollinated figs, while for the passively pollinated species, two obtuse end shapes were identified: cylinder and sphere shapes were identified in six of the eight species. All passively pollinated figs presented rugulate ornamentation, while for actively pollinated species, the smoother types - psilate and granulate-rugulate ornamentations - accounted for just five and two among the 17 species, respectively. The relationship between pollen shape and pollination mode was shown by both the phylogenetic free regression and the correlated evolution tests. Three pollen shape and ornamentation types were found in Ficus, which show characteristics related to passive or active pollination mode. Thus, the pollen shape is very likely shaped by pollination mode in this unique obligate mutualism.

Has Pollination Mode Shaped the Evolution of Ficus Pollen?

PubMed Central

Wang, Gang; Chen, Jin; Li, Zong-Bo; Zhang, Feng-Ping; Yang, Da-Rong

2014-01-01

Background The extent to which co-evolutionary processes shape morphological traits is one of the most fascinating topics in evolutionary biology. Both passive and active pollination modes coexist in the fig tree (Ficus, Moraceae) and fig wasp (Agaonidae, Hymenoptera) mutualism. This classic obligate relationship that is about 75 million years old provides an ideal system to consider the role of pollination mode shifts on pollen evolution. Methods and Main Findings Twenty-five fig species, which cover all six Ficus subgenera, and are native to the Xishuangbanna region of southwest China, were used to investigate pollen morphology with scanning electron microscope (SEM). Pollination mode was identified by the Anther/Ovule ratio in each species. Phylogenetic free regression and a correlated evolution test between binary traits were conducted based on a strong phylogenetic tree. Seventeen of the 25 fig species were actively pollinated and eight species were passively pollinated. Three pollen shape types and three kinds of exine ornamentation were recognized among these species. Pollen grains with ellipsoid shape and rugulate ornamentation were dominant. Ellipsoid pollen occurred in all 17 species of actively pollinated figs, while for the passively pollinated species, two obtuse end shapes were identified: cylinder and sphere shapes were identified in six of the eight species. All passively pollinated figs presented rugulate ornamentation, while for actively pollinated species, the smoother types - psilate and granulate-rugulate ornamentations - accounted for just five and two among the 17 species, respectively. The relationship between pollen shape and pollination mode was shown by both the phylogenetic free regression and the correlated evolution tests. Conclusions Three pollen shape and ornamentation types were found in Ficus, which show characteristics related to passive or active pollination mode. Thus, the pollen shape is very likely shaped by pollination mode in this unique obligate mutualism. PMID:24465976

Recent introduction of an allodapine bee into Fiji: A new model system for understanding biological invasions by pollinators.

PubMed

Groom, Scott V C; Tuiwawa, Marika V; Stevens, Mark I; Schwarz, Michael P

2015-08-01

Morphology-based studies have suggested a very depauperate bee fauna for islands in the South West Pacific, and recent genetic studies since have indicated an even smaller endemic fauna with many bee species in this region resulting from human-aided dispersal. These introduced species have the potential to both disrupt native pollinator suites as well as augment crop pollination, but for most species the timings of introduction are unknown. We examined the distribution and nesting biology of the long-tongued bee Braunsapis puangensis that was first recorded from Fiji in 2007. This bee has now become widespread in Fiji and both its local abundance and geographical range are likely to increase dramatically. The impacts of this invasion are potentially enormous for agriculture and native ecosystems, but they also provide opportunities for understanding how social insect species adapt to new environments. We outline the major issues associated with this recent invasion and argue that a long-term monitoring study is needed. © 2014 Institute of Zoology, Chinese Academy of Sciences.

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

Field Populations of Wild Apis cerana Honey Bees Exhibit Increased Genetic Diversity Under Pesticide Stress Along an Agricultural Intensification Gradient in Eastern India.

PubMed

Chakrabarti, Priyadarshini; Sarkar, Sagartirtha; Basu, Parthiba

2018-05-01

Pesticides have been reported to be one of the major drivers in the global pollinator losses. The large-scale decline in honey bees, an important pollinator group, has resulted in comprehensive studies on honey bee colonies. Lack of information on native wild pollinators has paved the way for this study, which highlights the underlying evolutionary changes occurring in the wild honey bee populations exposed to pesticides along an agricultural intensification landscape. The study reports an increased genetic diversity in native Apis cerana Fabricius (Hymenoptera: Apidae) populations continually exposed to pesticide stress. An increased heterozygosity, evidenced by a higher electrophoretic banding pattern, was observed in the pesticide-exposed populations for two isozymes involved with xenobiotic metabolism-esterase and glucose-6-phosphate dehydrogenase. Differential banding patterns also revealed a higher percentage of polymorphic loci, number of polymorphic bands, Nei's genetic distance, etc. observed in these populations in the Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) experiments using three random decamer primers. Higher heterozygosity, being indicative of a more resistant population, implies population survival within the threshold pesticide stress. This study reports such changes for the first time in native wild Indian honey bee populations exposed to pesticides and has far-reaching implications on the population adaptability under pesticide stress.

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.

Linking Native and Invader Traits Explains Native Spider Population Responses to Plant Invasion.

PubMed

Smith, Jennifer N; Emlen, Douglas J; Pearson, Dean E

2016-01-01

Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders' web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 times more abundant on simulated invasion plots compared to controls. Additionally, irregular web-spiders on simulated invasion plots built webs that were 4.4 times larger and 5.0 times more likely to capture prey, leading to >2-fold increases in recruitment. Orb-weavers showed no differences in web size or prey captures between treatments. Web-spider responses to simulated invasion mimicked patterns following natural invasions, confirming that C. stoebe's architecture is likely the primary attribute driving native spider responses to these invasions. Differences in spider responses were attributable to differences in web construction behaviors relative to historic web substrate constraints. Orb-weavers in this system constructed webs between multiple plants, so they were limited by the overall quantity of native substrates but not by the architecture of individual native plant species. Irregular web-spiders built their webs within individual plants and were greatly constrained by the diminutive architecture of native plant substrates, so they were limited both by quantity and quality of native substrates. Evaluating native species traits in the context of invader-driven change can explain invasion outcomes and help to identify factors limiting native populations.

Linking Native and Invader Traits Explains Native Spider Population Responses to Plant Invasion

PubMed Central

Emlen, Douglas J.; Pearson, Dean E.

2016-01-01

Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders’ web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 times more abundant on simulated invasion plots compared to controls. Additionally, irregular web-spiders on simulated invasion plots built webs that were 4.4 times larger and 5.0 times more likely to capture prey, leading to >2-fold increases in recruitment. Orb-weavers showed no differences in web size or prey captures between treatments. Web-spider responses to simulated invasion mimicked patterns following natural invasions, confirming that C. stoebe’s architecture is likely the primary attribute driving native spider responses to these invasions. Differences in spider responses were attributable to differences in web construction behaviors relative to historic web substrate constraints. Orb-weavers in this system constructed webs between multiple plants, so they were limited by the overall quantity of native substrates but not by the architecture of individual native plant species. Irregular web-spiders built their webs within individual plants and were greatly constrained by the diminutive architecture of native plant substrates, so they were limited both by quantity and quality of native substrates. Evaluating native species traits in the context of invader-driven change can explain invasion outcomes and help to identify factors limiting native populations. PMID:27082240

Infestation of Japanese native honey bees by tracheal mite and virus from non-native European honey bees in Japan.

PubMed

Kojima, Yuriko; Toki, Taku; Morimoto, Tomomi; Yoshiyama, Mikio; Kimura, Kiyoshi; Kadowaki, Tatsuhiko

2011-11-01

Invasion of alien species has been shown to cause detrimental effects on habitats of native species. Insect pollinators represent such examples; the introduction of commercial bumble bee species for crop pollination has resulted in competition for an ecological niche with native species, genetic disturbance caused by mating with native species, and pathogen spillover to native species. The European honey bee, Apis mellifera, was first introduced into Japan for apiculture in 1877, and queen bees have been imported from several countries for many years. However, its effects on Japanese native honey bee, Apis cerana japonica, have never been addressed. We thus conducted the survey of honey bee viruses and Acarapis mites using both A. mellifera and A. c. japonica colonies to examine their infestation in native and non-native honey bee species in Japan. Honey bee viruses, Deformed wing virus (DWV), Black queen cell virus (BQCV), Israeli acute paralysis virus (IAPV), and Sacbrood virus (SBV), were found in both A. mellifera and A. c. japonica colonies; however, the infection frequency of viruses in A. c. japonica was lower than that in A. mellifera colonies. Based on the phylogenies of DWV, BQCV, and SBV isolates from A. mellifera and A. c. japonica, DWV and BQCV may infect both honey bee species; meanwhile, SBV has a clear species barrier. For the first time in Japan, tracheal mite (Acarapis woodi) was specifically found in the dead honey bees from collapsing A. c. japonica colonies. This paper thus provides further evidence that tracheal-mite-infested honey bee colonies can die during cool winters with no other disease present. These results demonstrate the infestation of native honey bees by parasite and pathogens of non-native honey bees that are traded globally.

Floral features, pollination biology and breeding system of Chloraea membranacea Lindl. (Orchidaceae: Chloraeinae)

PubMed Central

Sanguinetti, Agustin; Buzatto, Cristiano Roberto; Pedron, Marcelo; Davies, Kevin L.; Ferreira, Pedro Maria de Abreu; Maldonado, Sara; Singer, Rodrigo B.

2012-01-01

Background and Aims The pollination biology of very few Chloraeinae orchids has been studied to date, and most of these studies have focused on breeding systems and fruiting success. Chloraea membranacea Lindl. is one of the few non-Andean species in this group, and the aim of the present contribution is to elucidate the pollination biology, functional floral morphology and breeding system in native populations of this species from Argentina (Buenos Aires) and Brazil (Rio Grande do Sul State). Methods Floral features were examined using light microscopy, and scanning and transmission electron microscopy. The breeding system was studied by means of controlled pollinations applied to plants, either bagged in the field or cultivated in a glasshouse. Pollination observations were made on natural populations, and pollinator behaviour was recorded by means of photography and video. Key Results Both Argentinean and Brazilian plants were very consistent regarding all studied features. Flowers are nectarless but scented and anatomical analysis indicates that the dark, clavate projections on the adaxial labellar surface are osmophores (scent-producing glands). The plants are self-compatible but pollinator-dependent. The fruit-set obtained through cross-pollination and manual self-pollination was almost identical. The main pollinators are male and female Halictidae bees that withdraw the pollinarium when leaving the flower. Remarkably, the bees tend to visit more than one flower per inflorescence, thus promoting self-pollination (geitonogamy). Fruiting success in Brazilian plants reached 60·78 % in 2010 and 46 % in 2011. Some pollinarium-laden female bees were observed transferring pollen from the carried pollinarium to their hind legs. The use of pollen by pollinators is a rare record for Orchidaceae in general. Conclusions Chloraea membrancea is pollinated by deceit. Together, self-compatibility, pollinarium texture, pollinator abundance and behaviour may account for the observed high fruiting success. It is suggested that a reappraisal and re-analysis of important flower features in Chloraeinae orchids is necessary. PMID:23071217

Floral features, pollination biology and breeding system of Chloraea membranacea Lindl. (Orchidaceae: Chloraeinae).

PubMed

Sanguinetti, Agustin; Buzatto, Cristiano Roberto; Pedron, Marcelo; Davies, Kevin L; Ferreira, Pedro Maria de Abreu; Maldonado, Sara; Singer, Rodrigo B

2012-12-01

The pollination biology of very few Chloraeinae orchids has been studied to date, and most of these studies have focused on breeding systems and fruiting success. Chloraea membranacea Lindl. is one of the few non-Andean species in this group, and the aim of the present contribution is to elucidate the pollination biology, functional floral morphology and breeding system in native populations of this species from Argentina (Buenos Aires) and Brazil (Rio Grande do Sul State). Floral features were examined using light microscopy, and scanning and transmission electron microscopy. The breeding system was studied by means of controlled pollinations applied to plants, either bagged in the field or cultivated in a glasshouse. Pollination observations were made on natural populations, and pollinator behaviour was recorded by means of photography and video. Both Argentinean and Brazilian plants were very consistent regarding all studied features. Flowers are nectarless but scented and anatomical analysis indicates that the dark, clavate projections on the adaxial labellar surface are osmophores (scent-producing glands). The plants are self-compatible but pollinator-dependent. The fruit-set obtained through cross-pollination and manual self-pollination was almost identical. The main pollinators are male and female Halictidae bees that withdraw the pollinarium when leaving the flower. Remarkably, the bees tend to visit more than one flower per inflorescence, thus promoting self-pollination (geitonogamy). Fruiting success in Brazilian plants reached 60·78 % in 2010 and 46 % in 2011. Some pollinarium-laden female bees were observed transferring pollen from the carried pollinarium to their hind legs. The use of pollen by pollinators is a rare record for Orchidaceae in general. Chloraea membrancea is pollinated by deceit. Together, self-compatibility, pollinarium texture, pollinator abundance and behaviour may account for the observed high fruiting success. It is suggested that a reappraisal and re-analysis of important flower features in Chloraeinae orchids is necessary.

Economic Risk of Bee Pollination in Maine Wild Blueberry, Vaccinium angustifolium.

PubMed

Asare, Eric; Hoshide, Aaron K; Drummond, Francis A; Criner, George K; Chen, Xuan

2017-10-01

Recent pollinator declines highlight the importance of evaluating economic risk of agricultural systems heavily dependent on rented honey bees or native pollinators. Our study analyzed variability of native bees and honey bees, and the risks these pose to profitability of Maine's wild blueberry industry. We used cross-sectional data from organic, low-, medium-, and high-input wild blueberry producers in 1993, 1997-1998, 2005-2007, and from 2011 to 2015 (n = 162 fields). Data included native and honey bee densities (count/m2/min) and honey bee stocking densities (hives/ha). Blueberry fruit set, yield, and honey bee hive stocking density models were estimated. Fruit set is impacted about 1.6 times more by native bees than honey bees on a per bee basis. Fruit set significantly explained blueberry yield. Honey bee stocking density in fields predicted honey bee foraging densities. These three models were used in enterprise budgets for all four systems from on-farm surveys of 23 conventional and 12 organic producers (2012-2013). These budgets formed the basis of Monte Carlo simulations of production and profit. Stochastic dominance of net farm income (NFI) cumulative distribution functions revealed that if organic yields are high enough (2,345 kg/ha), organic systems are economically preferable to conventional systems. However, if organic yields are lower (724 kg/ha), it is riskier with higher variability of crop yield and NFI. Although medium-input systems are stochastically dominant with lower NFI variability compared with other conventional systems, the high-input system breaks even with the low-input system if honey bee hive rental prices triple in the future. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Potential pollinators of tomato, Lycopersicon esculentum (Solanaceae), in open crops and the effect of a solitary bee in fruit set and quality.

PubMed

Santos, A O R; Bartelli, B F; Nogueira-Ferreira, F H

2014-06-01

We identified native bees that are floral visitors and potential pollinators of tomato in Cerrado areas, described the foraging behavior of these species, and verified the influence of the visitation of a solitary bee on the quantity and quality of fruits. Three areas of tomato crops, located in Minas Gerais, Brazil, were sampled between March and November 2012. We collected 185 bees belonging to 13 species. Exomalopsis (Exomalopsis) analis Spinola, 1853 (Hymenoptera: Apidae) was the most abundant. Ten species performed buzz pollination. Apis mellifera L. 1758 (Hymenoptera: Apidae) and Paratrigona lineata (Lepeletier, 1836) (Hymenoptera: Apidae) could also act as pollinators. The fruit set and number of seeds obtained from the pollination treatment by E. analis were higher than those in the control group. Our results allowed the identification of potential tomato pollinators in Cerrado areas and also contributed information regarding the impact of a single species (E. analis) on fruit set and quality. Although most of the visiting bees show the ability for tomato pollination, there is an absence of adequate management techniques, and its usage is difficult with the aim of increasing the crop production, which is the case for E. analis. Species such as Melipona quinquefasciata, P. lineata, and A. mellifera, which are easy to handle, are not used for pollination services. Finally, it is suggested that a combination of different bee species that are able to pollinate the tomato is necessary to prevent the super-exploitation of only a single species for pollination services and to guarantee the occurrence of potential pollinators in the crop area.

Genetic connectivity of the moth pollinated tree Glionnetia sericea in a highly fragmented habitat.

PubMed

Finger, Aline; Kaiser-Bunbury, Christopher N; Kettle, Chris J; Valentin, Terence; Ghazoul, Jaboury

2014-01-01

Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to adults. A Bayesian structure analysis and a tentative paternity analysis indicate extensive historical and contemporary gene flow among remnant populations. Pollination experiments and a paternity analysis show that Glionnetia sericea is self-compatible. Nevertheless, outcrossing is present with 7% of mating events resulting from pollen transfer between populations. Artificial pollination provided no evidence for pollen limitation in isolated populations. The highly mobile and specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi; Sphingidae) appear to promote extensive gene flow, thus mitigating the potential negative ecological and genetic effects of habitat fragmentation in this species. We conclude that contemporary gene flow is sufficient to maintain genetic connectivity in this rare and restricted Seychelles endemic, in contrast to other island endemic tree species with limited contemporary gene flow.

Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat

PubMed Central

Finger, Aline; Valentin, Terence; Ghazoul, Jaboury

2014-01-01

Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to adults. A Bayesian structure analysis and a tentative paternity analysis indicate extensive historical and contemporary gene flow among remnant populations. Pollination experiments and a paternity analysis show that Glionnetia sericea is self-compatible. Nevertheless, outcrossing is present with 7% of mating events resulting from pollen transfer between populations. Artificial pollination provided no evidence for pollen limitation in isolated populations. The highly mobile and specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi; Sphingidae) appear to promote extensive gene flow, thus mitigating the potential negative ecological and genetic effects of habitat fragmentation in this species. We conclude that contemporary gene flow is sufficient to maintain genetic connectivity in this rare and restricted Seychelles endemic, in contrast to other island endemic tree species with limited contemporary gene flow. PMID:25347541

Nectar alkaloids decrease pollination and female reproduction in a native plant.

PubMed

Adler, Lynn S; Irwin, Rebecca E

2012-04-01

The evolution of floral traits may be shaped by a community of floral visitors that affect plant fitness, including pollinators and floral antagonists. The role of nectar in attracting pollinators has been extensively studied, but its effects on floral antagonists are less understood. Furthermore, the composition of non-sugar nectar components, such as secondary compounds, may affect plant reproduction via changes in both pollinator and floral antagonist behavior. We manipulated the nectar alkaloid gelsemine in wild plants of the native perennial vine Gelsemium sempervirens. We crossed nectar gelsemine manipulations with a hand-pollination treatment, allowing us to determine the effect of both the trait and the interaction on plant female reproduction. We measured pollen deposition, pollen removal, and nectar robbing to assess whether gelsemine altered the behavior of mutualists and antagonists. High nectar gelsemine reduced conspecific pollen receipt by nearly half and also reduced the proportion of conspecific pollen grains received, but had no effect on nectar robbing. Although high nectar gelsemine reduced pollen removal, an estimate of male reproduction, by one-third, this effect was not statistically significant. Fruit set was limited by pollen receipt. However, this effect varied across sites such that the sites that were most pollen-limited were also the sites where nectar alkaloids had the least effect on pollen receipt, resulting in no significant effect of nectar alkaloids on fruit set. Finally, high nectar gelsemine significantly reduced seed weight; however, this effect was mediated by a mechanism other than pollen limitation. Taken together, our work suggests that nectar alkaloids are more costly than beneficial in our system, and that relatively small-scale spatial variation in trait effects and interactions could determine the selective impacts of traits such as nectar composition.

Do managed bees have negative effects on wild bees?: A systematic review of the literature

PubMed Central

Gratton, Claudio

2017-01-01

Managed bees are critical for crop pollination worldwide. As the demand for pollinator-dependent crops increases, so does the use of managed bees. Concern has arisen that managed bees may have unintended negative impacts on native wild bees, which are important pollinators in both agricultural and natural ecosystems. The goal of this study was to synthesize the literature documenting the effects of managed honey bees and bumble bees on wild bees in three areas: (1) competition for floral and nesting resources, (2) indirect effects via changes in plant communities, including the spread of exotic plants and decline of native plants, and (3) transmission of pathogens. The majority of reviewed studies reported negative effects of managed bees, but trends differed across topical areas. Of studies examining competition, results were highly variable with 53% reporting negative effects on wild bees, while 28% reported no effects and 19% reported mixed effects (varying with the bee species or variables examined). Equal numbers of studies examining plant communities reported positive (36%) and negative (36%) effects, with the remainder reporting no or mixed effects. Finally, the majority of studies on pathogen transmission (70%) reported potential negative effects of managed bees on wild bees. However, most studies across all topical areas documented the potential for impact (e.g. reporting the occurrence of competition or pathogens), but did not measure direct effects on wild bee fitness, abundance, or diversity. Furthermore, we found that results varied depending on whether managed bees were in their native or non-native range; managed bees within their native range had lesser competitive effects, but potentially greater effects on wild bees via pathogen transmission. We conclude that while this field has expanded considerably in recent decades, additional research measuring direct, long-term, and population-level effects of managed bees is needed to understand their potential impact on wild bees. PMID:29220412

Do managed bees have negative effects on wild bees?: A systematic review of the literature.

PubMed

Mallinger, Rachel E; Gaines-Day, Hannah R; Gratton, Claudio

2017-01-01

Managed bees are critical for crop pollination worldwide. As the demand for pollinator-dependent crops increases, so does the use of managed bees. Concern has arisen that managed bees may have unintended negative impacts on native wild bees, which are important pollinators in both agricultural and natural ecosystems. The goal of this study was to synthesize the literature documenting the effects of managed honey bees and bumble bees on wild bees in three areas: (1) competition for floral and nesting resources, (2) indirect effects via changes in plant communities, including the spread of exotic plants and decline of native plants, and (3) transmission of pathogens. The majority of reviewed studies reported negative effects of managed bees, but trends differed across topical areas. Of studies examining competition, results were highly variable with 53% reporting negative effects on wild bees, while 28% reported no effects and 19% reported mixed effects (varying with the bee species or variables examined). Equal numbers of studies examining plant communities reported positive (36%) and negative (36%) effects, with the remainder reporting no or mixed effects. Finally, the majority of studies on pathogen transmission (70%) reported potential negative effects of managed bees on wild bees. However, most studies across all topical areas documented the potential for impact (e.g. reporting the occurrence of competition or pathogens), but did not measure direct effects on wild bee fitness, abundance, or diversity. Furthermore, we found that results varied depending on whether managed bees were in their native or non-native range; managed bees within their native range had lesser competitive effects, but potentially greater effects on wild bees via pathogen transmission. We conclude that while this field has expanded considerably in recent decades, additional research measuring direct, long-term, and population-level effects of managed bees is needed to understand their potential impact on wild bees.

Multitasking in a plant-ant interaction: how does Acacia myrtifolia manage both ants and pollinators?

PubMed

Martínez-Bauer, Angélica E; Martínez, Gerardo Cerón; Murphy, Daniel J; Burd, Martin

2015-06-01

Plant associations with protective ants are widespread among angiosperms, but carry the risk that ants will deter pollinators as well as herbivores. Such conflict, and adaptations to ameliorate or prevent the conflict, have been documented in African and neotropical acacias. Ant-acacia associations occur in Australia, but little is known of their ecology. Moreover, recent phylogenetic evidence indicates that Australian acacias are only distantly related to African and American acacias, providing an intercontinental natural experiment in the management of ant-pollinator conflict. We examined four populations of Acacia myrtifolia over a 400-km environmental gradient in southeastern Australia using ant and pollinator exclusion as well as direct observation of ants and pollinators to assess the potential for ant-pollinator conflict to affect seed set. Native bees were the only group of floral visitors whose visitation rates were a significant predictor of fruiting success, although beetles and wasps may play an important role as "insurance" pollinators. We found no increase in pollinator visitation or fruiting success following ant exclusion, even with large sample sizes and effective exclusion. Because ants are facultative visitors to A. myrtifolia plants, their presence may be insufficient to interfere greatly with floral visitors. It is also likely that the morphological location of extrafloral nectaries tends to draw ants away from reproductive parts, although we commonly observed ants on inflorescences, so the spatial separation is not strict. A. myrtifolia appears to maintain a generalized mutualism over a wide geographic range without the need for elaborate adaptations to resolve ant-pollinator conflict.

Using publicly available data to quantify plant–pollinator interactions and evaluate conservation seeding mixes in the Northern Great Plains

USGS Publications Warehouse

Otto, Clint R.; O'Dell, Samuel; Bryant, R. B.; Euliss, Ned H. Jr.; Bush, Rachel; Smart, Matthew

2017-01-01

Concern over declining pollinators has led to multiple conservation initiatives for improving forage for bees in agroecosystems. Using data available through the Pollinator Library (npwrc.usgs.gov/pollinator/), we summarize plant–pollinator interaction data collected from 2012–2015 on lands managed by the U.S. Fish and Wildlife Service and private lands enrolled in U.S. Department of Agriculture conservation programs in eastern North Dakota (ND). Furthermore, we demonstrate how plant–pollinator interaction data from the Pollinator Library and seed cost information can be used to evaluate hypothetical seeding mixes for pollinator habitat enhancements. We summarize records of 314 wild bee and 849 honey bee (Apis mellifera L.) interactions detected on 63 different plant species. The wild bee observations consisted of 46 species, 15 genera, and 5 families. Over 54% of all wild bee observations were represented by three genera―Bombus, Lassioglossum, and Melissodes. The most commonly visited forbs by wild bees were Monarda fistulosa, Sonchus arvensis, and Zizia aurea. The most commonly visited forbs by A. mellifera were Cirsium arvense, Melilotus officinalis, and Medicago sativa. Among all interactions, 13% of A. mellifera and 77% of wild bee observations were made on plants native to ND. Our seed mix evaluation shows that mixes may often need to be tailored to meet the unique needs of wild bees and managed honey bees in agricultural landscapes. Our evaluation also demonstrates the importance of incorporating both biologic and economic information when attempting to design cost-effective seeding mixes for supporting pollinators in a critically important part of the United States.

Pollinator-mediated competition between two congeners, Limnanthes douglasii subsp. rosea and L. alba (Limnanthaceae).

PubMed

Briscoe Runquist, Ryan D

2012-07-01

Pollinator visits are essential for reproduction in many plants, yet interspecific movements of pollinators can also lead to competitive interactions between coflowering species. Pollination-mediated reductions in fertility could potentially lead to exclusion of competing plant species, and may generate spatial variation in the associations among coflowering species across a landscape. I documented the potential for heterospecific pollen transfer to cause competitive interactions between two annual grassland species native to California, Limnanthes douglasii subsp. rosea and L. alba, two reproductively incompatible species that have broadly overlapping geographic ranges in the foothills of the Sierra Nevada. I observed pollinator movement in constructed arrays and controlled crosses in the greenhouse and field to investigate the consequences of heterospecific pollen transfer. Pollinators move readily between species when they are presented together in experimental arrays. In the greenhouse, deposition of heterospecific pollen decreased fertility in both species. The decrease in seeds produced per flower was much more pronounced in L. d. rosea (90.6% reduction) than in L. alba (40.8% reduction). In field experiments, L. d. rosea plants that received pollen from heterospecific neighbors first showed >50% reduction in per-flower fertility. Under natural pollination conditions, heterospecific pollen transfer has the ability to decrease the fertility of L. d. rosea when it occurs at low frequency in mixed stands. Accordingly, pollinator-mediated competition may contribute to the locally disjunct distributions of these two species. It may also influence important restoration decisions in vernal pool habitats.

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

The worldwide importance of honey bees as pollinators in natural habitats.

PubMed

Hung, Keng-Lou James; Kingston, Jennifer M; Albrecht, Matthias; Holway, David A; Kohn, Joshua R

2018-01-10

The western honey bee ( Apis mellifera ) is the most frequent floral visitor of crops worldwide, but quantitative knowledge of its role as a pollinator outside of managed habitats is largely lacking. Here we use a global dataset of 80 published plant-pollinator interaction networks as well as pollinator effectiveness measures from 34 plant species to assess the importance of A. mellifera in natural habitats. Apis mellifera is the most frequent floral visitor in natural habitats worldwide, averaging 13% of floral visits across all networks (range 0-85%), with 5% of plant species recorded as being exclusively visited by A. mellifera For 33% of the networks and 49% of plant species, however, A. mellifera visitation was never observed, illustrating that many flowering plant taxa and assemblages remain dependent on non- A. mellifera visitors for pollination. Apis mellifera visitation was higher in warmer, less variable climates and on mainland rather than island sites, but did not differ between its native and introduced ranges. With respect to single-visit pollination effectiveness, A. mellifera did not differ from the average non- A. mellifera floral visitor, though it was generally less effective than the most effective non- A. mellifera visitor. Our results argue for a deeper understanding of how A. mellifera , and potential future changes in its range and abundance, shape the ecology, evolution, and conservation of plants, pollinators, and their interactions in natural habitats. © 2018 The Author(s).

Introduction of Non-Native Pollinators Can Lead to Trans-Continental Movement of Bee-Associated Fungi.

PubMed

Hedtke, Shannon M; Blitzer, Eleanor J; Montgomery, Graham A; Danforth, Bryan N

2015-01-01

Bees are essential pollinators for many flowering plants, including agriculturally important crops such as apple. As geographic ranges of bees or their host plants change as a result of human activities, we need to identify pathogens that could be transmitted among newly sympatric species to evaluate and anticipate their effects on bee communities. We used PCR screening and DNA sequencing to evaluate exposure to potentially disease-causing microorganisms in a pollinator of apple, the horned mason bee (Osmia cornifrons). We did not detect microsporidia, Wolbachia, or trypanosomes, which are common pathogens of bees, in any of the hundreds of mason bees screened. We did detect both pathogenic and apathogenic (saprophytic) fungal species in the genus Ascosphaera (chalkbrood), an unidentified species of Aspergillus fungus, and a strain of bacteria in the genus Paenibacillus that is probably apathogenic. We detected pathogenic fungal strains in asymptomatic adult bees that therefore may be carriers of disease. We demonstrate that fungi from the genus Ascosphaera have been transported to North America along with the bee from its native range in Japan, and that O. cornifrons is exposed to fungi previously only identified from nests of other related bee species. Further study will be required to quantify pathogenicity and health effects of these different microbial species on O. cornifrons and on closely-related native North American mason bees that may now be exposed to novel pathogens. A global perspective is required for pathogen research as geographic ranges of insects and microorganisms shift due to intentional or accidental introductions.

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

Using Publicly Available Data to Quantify Plant-Pollinator Interactions and Evaluate Conservation Seeding Mixes in the Northern Great Plains.

PubMed

Otto, C R V; O'Dell, S; Bryant, R B; Euliss, N H; Bush, R M; Smart, M D

2017-06-01

Concern over declining pollinators has led to multiple conservation initiatives for improving forage for bees in agroecosystems. Using data available through the Pollinator Library (npwrc.usgs.gov/pollinator/), we summarize plant-pollinator interaction data collected from 2012-2015 on lands managed by the U.S. Fish and Wildlife Service and private lands enrolled in U.S. Department of Agriculture conservation programs in eastern North Dakota (ND). Furthermore, we demonstrate how plant-pollinator interaction data from the Pollinator Library and seed cost information can be used to evaluate hypothetical seeding mixes for pollinator habitat enhancements. We summarize records of 314 wild bee and 849 honey bee (Apis mellifera L.) interactions detected on 63 different plant species. The wild bee observations consisted of 46 species, 15 genera, and 5 families. Over 54% of all wild bee observations were represented by three genera-Bombus, Lassioglossum, and Melissodes. The most commonly visited forbs by wild bees were Monarda fistulosa, Sonchus arvensis, and Zizia aurea. The most commonly visited forbs by A. mellifera were Cirsium arvense, Melilotus officinalis, and Medicago sativa. Among all interactions, 13% of A. mellifera and 77% of wild bee observations were made on plants native to ND. Our seed mix evaluation shows that mixes may often need to be tailored to meet the unique needs of wild bees and managed honey bees in agricultural landscapes. Our evaluation also demonstrates the importance of incorporating both biologic and economic information when attempting to design cost-effective seeding mixes for supporting pollinators in a critically important part of the United States. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.

When bigger is not better: intraspecific competition for pollination increases with population size in invasive milkweeds.

PubMed

Ward, Megan; Johnson, Steven D; Zalucki, Myron P

2013-04-01

One of the essential requirements for an introduced plant species to become invasive is an ability to reproduce outside the native range, particularly when initial populations are small. If a reproductive Allee effect is operating, plants in small populations will have reduced reproductive success relative to plants in larger populations. Alternatively, if plants in small populations experience less competition for pollination than those in large populations, they may actually have higher levels of reproductive success than plants in large populations. To resolve this uncertainty, we investigated how the per capita fecundity of plants was affected by population size in three invasive milkweed species. Field surveys of seed production in natural populations of different sizes but similar densities were conducted for three pollinator-dependent invasive species, namely Asclepias curassavica, Gomphocarpus fruticosus and G. physocarpus. Additionally, supplemental hand-pollinations were performed in small and large populations in order to determine whether reproductive output was limited by pollinator activity in these populations. Reproductive Allee effects were not detected in any of the study species. Instead, plants in small populations exhibited remarkably high levels of reproductive output compared to those in large populations. Increased fruit production following supplemental hand-pollinations suggested that the lower reproductive output of naturally pollinated plants in large populations is a consequence of pollen limitation rather than limitation due to abiotic resources. This is consistent with increased intraspecific competition for pollination amongst plants in large populations. It is likely that the invasion of these milkweed species in Australia has been enhanced because plants in small founding populations experience less intraspecific competition for pollinators than those in large populations, and thus have the ability to produce copious amounts of seeds.

Economic value of tropical forest to coffee production

PubMed Central

Ricketts, Taylor H.; Daily, Gretchen C.; Ehrlich, Paul R.; Michener, Charles D.

2004-01-01

Can economic forces be harnessed for biodiversity conservation? The answer hinges on characterizing the value of nature, a tricky business from biophysical, socioeconomic, and ethical perspectives. Although the societal benefits of native ecosystems are clearly immense, they remain largely unquantified for all but a few services. Here, we estimate the value of tropical forest in supplying pollination services to agriculture. We focus on coffee because it is one of the world's most valuable export commodities and is grown in many of the world's most biodiverse regions. Using pollination experiments along replicated distance gradients, we found that forest-based pollinators increased coffee yields by 20% within ≈1 km of forest. Pollination also improved coffee quality near forest by reducing the frequency of “peaberries” (i.e., small misshapen seeds) by 27%. During 2000–2003, pollination services from two forest fragments (46 and 111 hectares) translated into ≈$60,000 (U.S.) per year for one Costa Rican farm. This value is commensurate with expected revenues from competing land uses and far exceeds current conservation incentive payments. Conservation investments in human-dominated landscapes can therefore yield double benefits: for biodiversity and agriculture. PMID:15306689

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).

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...

Potential pollinators of Comolia ovalifolia DC Triana (Melastomataceae) and Chamaecrista ramosa (Vog.) H.S. Irwin and Barneby var. ramosa (Leguminosae-Caesalpinioideae), in restinga, Bahia, Brazil.

PubMed

Oliveira-Rebouças, P; Gimenes, M

2011-05-01

Comolia ovalifolia DC Triana (Melastomataceae) and Chamaecrista ramosa (Vog.) H.S. Irwin and Barneby var. ramosa (Leguminosae-Caesalpinioideae) are tropical plant species found in restinga (herbaceous-shrubby, sandy costal ecosystems). They have flowers with poricidal anthers and are pollinated by bees. The study sought to analyse potential pollinators of both plants during visits to their flowers in a restinga area in Bahia. The flowering displayed by both species was considered continuous and long duration, constantly providing pollen to floral visitors. C. ovalifolia was visited by 17 species of bees and C. ramosa by 16 species, predominantly from the Apidae family (with a similarity index of 74%). The behavior displayed by these visiting bees was of vibrating anthers. The small-sized Euglossa sp. Latreille, 1802 and Florilegus similis Urban, 1970 bees played less of a role as pollinators, since they rarely touched the flower stigma during harvests and were thus considered opportunist visitors or casual pollinators. Centris decolorata Lepetier, 1841 (= C. leprieuri) and Xylocopa subcyanea Perez, 1901 are large bees and were considered efficient pollinators of C. ovalifolia and C. ramosa because of the higher frequency and constancy of their visits, and their favourable behaviour and size for pollen transfer between flowers, which guarantees the survival of these native restinga plant species.

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.

Pollinators and pesticides

USDA-ARS?s Scientific Manuscript database

As part of the Bee-Fungicide Workshop at NACREW, there will be updates on the latest evidence characterizing how fungicides may cause colony declines in native bee species. Findings will cover recent work with Bombus impatiens and Osmia lignaria. Discussions will be focusing on how the US cranberry ...

Invasive plant architecture alters trophic interactions by changing predator abundance and behavior.

PubMed

Pearson, Dean E

2009-03-01

As primary producers, plants are known to influence higher trophic interactions by initiating food chains. However, as architects, plants may bypass consumers to directly affect predators with important but underappreciated trophic ramifications. Invasion of western North American grasslands by the perennial forb, spotted knapweed (Centaurea maculosa), has fundamentally altered the architecture of native grassland vegetation. Here, I use long-term monitoring, observational studies, and field experiments to document how changes in vegetation architecture have affected native web spider populations and predation rates. Native spiders that use vegetation as web substrates were collectively 38 times more abundant in C. maculosa-invaded grasslands than in uninvaded grasslands. This increase in spider abundance was accompanied by a large shift in web spider community structure, driven primarily by the strong response of Dictyna spiders to C. maculosa invasion. Dictyna densities were 46-74 times higher in C. maculosa-invaded than native grasslands, a pattern that persisted over 6 years of monitoring. C. maculosa also altered Dictyna web building behavior and foraging success. Dictyna webs on C. maculosa were 2.9-4.0 times larger and generated 2.0-2.3 times higher total prey captures than webs on Achillea millefolium, their primary native substrate. Dictyna webs on C. maculosa also captured 4.2 times more large prey items, which are crucial for reproduction. As a result, Dictyna were nearly twice as likely to reproduce on C. maculosa substrates compared to native substrates. The overall outcome of C. maculosa invasion and its transformative effects on vegetation architecture on Dictyna density and web building behavior were to increase Dictyna predation on invertebrate prey >/=89 fold. These results indicate that invasive plants that change the architecture of native vegetation can substantially impact native food webs via nontraditional plant --> predator --> consumer linkages.

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.

Ecology and Economics of Using Native Managed Bees for Almond Pollination.

PubMed

Koh, Insu; Lonsdorf, Eric V; Artz, Derek R; Pitts-Singer, Theresa L; Ricketts, Taylor H

2018-02-09

Native managed bees can improve crop pollination, but a general framework for evaluating the associated economic costs and benefits has not been developed. We conducted a cost-benefit analysis to assess how managing blue orchard bees (Osmia lignaria Say [Hymenoptera: Megachildae]) alongside honey bees (Apis mellifera Linnaeus [Hymenoptera: Apidae]) can affect profits for almond growers in California. Specifically, we studied how adjusting three strategies can influence profits: (1) number of released O. lignaria bees, (2) density of artificial nest boxes, and (3) number of nest cavities (tubes) per box. We developed an ecological model for the effects of pollinator activity on almond yields, validated the model with published data, and then estimated changes in profits for different management strategies. Our model shows that almond yields increase with O. lignaria foraging density, even where honey bees are already in use. Our cost-benefit analysis shows that profit ranged from -US$1,800 to US$2,800/acre given different combinations of the three strategies. Adding nest boxes had the greatest effect; we predict an increase in profit between low and high nest box density strategies (2.5 and 10 boxes/acre). In fact, the number of released bees and the availability of nest tubes had relatively small effects in the high nest box density strategies. This suggests that growers could improve profits by simply adding more nest boxes with moderate number of tubes in each. Our approach can support grower decisions regarding integrated crop pollination and highlight the importance of a comprehensive ecological economic framework for assessing these decisions. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Leaf Fertilizers Affect Survival and Behavior of the Neotropical Stingless Bee Friesella schrottkyi (Meliponini: Apidae: Hymenoptera).

PubMed

Rodrigues, Cleiton G; Krüger, Alexandra P; Barbosa, Wagner F; Guedes, Raul Narciso C

2016-04-11

The ongoing concern about bee decline has largely focused on honey bees and neonicotinoid insecticides, while native pollinators such as Neotropical stingless bees and agrochemicals such as other insecticide groups, pesticides in general, and fertilizers-especially leaf fertilizers-remain neglected as potential contributors to pollination decline. In an effort to explore this knowledge gap, we assessed the lethal and sublethal behavioral impact of heavy metal-containing leaf fertilizers in a native pollinator of ecological importance in the Neotropics: the stingless beeFriesella schrottkyi(Friese). Two leaf fertilizers-copper sulfate (24% Cu) and a micronutrient mix (Arrank L: 5% S, 5% Zn, 3% Mn, 0.6% Cu, 0.5% B, and 0.06% Mo)-were used in oral and contact exposure bioassays. The biopesticide spinosad and water were used as positive and negative controls, respectively. Copper sulfate compromised the survival of stingless bee workers, particularly with oral exposure, although less than spinosad under contact exposure. Sublethal exposure to both leaf fertilizers at their field rates also caused significant effects in exposed workers. Copper sulfate enhanced flight take-off on stingless bee workers, unlike workers exposed to the micronutrient mix. There was no significant effect of leaf fertilizers on the overall activity and walking behavior of worker bees. No significant effect was observed for the respiration rate of worker bees under contact exposure, but workers orally exposed to the micronutrient mix exhibited a reduced respiration rate. Therefore, leaf fertilizers do affectF. schrottkyi, what may also occur with other stingless bees, potentially compromising their pollination activity deserving attention. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Optimal foraging in seasonal environments: implications for residency of Australian flying foxes in food-subsidized urban landscapes.

PubMed

Páez, David J; Restif, Olivier; Eby, Peggy; Plowright, Raina K

2018-05-05

Bats provide important ecosystem services such as pollination of native forests; they are also a source of zoonotic pathogens for humans and domestic animals. Human-induced changes to native habitats may have created more opportunities for bats to reside in urban settings, thus decreasing pollination services to native forests and increasing opportunities for zoonotic transmission. In Australia, fruit bats ( Pteropus spp. flying foxes) are increasingly inhabiting urban areas where they feed on anthropogenic food sources with nutritional characteristics and phenology that differ from native habitats. We use optimal foraging theory to investigate the relationship between bat residence time in a patch, the time it takes to search for a new patch (simulating loss of native habitat) and seasonal resource production. We show that it can be beneficial to reside in a patch, even when food productivity is low, as long as foraging intensity is low and the expected searching time is high. A small increase in the expected patch searching time greatly increases the residence time, suggesting nonlinear associations between patch residence and loss of seasonal native resources. We also found that sudden increases in resource consumption due to an influx of new bats has complex effects on patch departure times that again depend on expected searching times and seasonality. Our results suggest that the increased use of urban landscapes by bats may be a response to new spatial and temporal configurations of foraging opportunities. Given that bats are reservoir hosts of zoonotic diseases, our results provide a framework to study the effects of foraging ecology on disease dynamics.One contribution of 14 to a theme isssue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'. © 2018 The Author(s).

Bumble bees of the western United States

USDA-ARS?s Scientific Manuscript database

Bumble bees (genus Bombus) are critical pollinators of flowering plants. Thirty species of bumble bees are native to the western United States and this publication is a guide to the natural history and identification of these species. We present phenology graphs, host-plant associations, detailed ...

Nosema ceranae in South American Native Stingless Bees and Social Wasp.

PubMed

Porrini, Martín Pablo; Porrini, Leonardo Pablo; Garrido, Paula Melisa; de Melo E Silva Neto, Carlos; Porrini, Darío Pablo; Muller, Fernando; Nuñez, Laura Alejandra; Alvarez, Leopoldo; Iriarte, Pedro Fernandez; Eguaras, Martín Javier

2017-11-01

Besides the incipient research effort, the role of parasites as drivers of the reduction affecting pollinator populations is mostly unknown. Given the worldwide extension of the beekeeping practice and the diversity of pathogens affecting Apis mellifera populations, honey bee colonies are a certain source of parasite dispersion to other species. Here, we communicate the detection of the microsporidium Nosema ceranae, a relatively new parasite of honey bees, in stingless bees (Meliponini) and the social wasp Polybia scutellaris (Vespidae) samples from Argentina and Brazil by means of duplex PCR. Beyond the geographic location of the nests, N. ceranae was detected in seven from the eight Meliponini species analyzed, while Nosema apis, another common parasite of A. mellifera, was absent in all samples tested. Further research is necessary to determine if the presence of the parasite is also associated with established infection in host tissues. The obtained information enriches the current knowledge about pathologies that can infect or, at least, be vectored by native wild pollinators from South America.

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

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.

Bumble bee nest abundance, foraging distance, and host-plant reproduction: implications for management and conservation.

PubMed

Geib, Jennifer C; Strange, James P; Galenj, Candace

2015-04-01

Recent reports of global declines in pollinator species imply an urgent need to assess the abundance of native pollinators and density-dependent benefits for linked plants. In this study, we investigated (1) pollinator nest distributions and estimated colony abundances, (2) the relationship between abundances of foraging workers and the number of nests they represent, (3) pollinator foraging ranges, and (4) the relationship between pollinator abundance and plant reproduction. We examined these questions in an alpine ecosystem in the Colorado Rocky Mountains, focusing on four alpine bumble bee species (Bombus balteatus, B. flavifrons, B. bifarius, and B. sylvicola), and two host plants that differ in their degrees of pollinator specialization (Trifolium dasyphyllum and T. parryi). Using microsatellites, we found that estimated colony abundances among Bombus species ranged from ~18 to 78 colonies/0.01 km2. The long-tongued species B. balteatus was most common, especially high above treeline, but the subalpine species B. bifarius was unexpectedly abundant for this elevation range. Nests detected among sampled foragers of each species were correlated with the number of foragers caught. Foraging ranges were smaller than expected for all Bombus species, ranging from 25 to 110 m. Fruit set for the specialized plant, Trifolium parryi, was positively related to the abundance of its Bombus pollinator. In contrast, fruit set for the generalized plant, T. dasyphyllum, was related to abundance of all Bombus species. Because forager abundance was related to nest abundance of each Bombus species and was an equally effective predictor of plant fecundity, forager inventories are probably suitable for assessing the health of outcrossing plant populations. However, nest abundance, rather than forager abundance, better reflects demographic and genetic health in populations of eusocial pollinators such as bumble bees. Development of models incorporating the parameters we have measured here (nest abundance, forager abundance, and foraging distance) could increase the usefulness of foraging worker inventories in nionitoring, managing, and conserving pollinator populations.

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.

Effects of low levels of herbicides on prairie species of the Willamette Valley, Oregon

EPA Science Inventory

Non-crop plants (native and introduced) growing adjacent to agricultural fields provide essential habitat for wildlife and pollinators, and may be exposed to low levels of non-target pesticide drift during routine weed control activities. This study evaluated the relative sensiti...

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.

Competitive interactions between a native spider (Frontinella communis, Araneae: Linyphiidae) and an invasive spider (Linyphia triangularis, Araneae: Linyphiidae)

USGS Publications Warehouse

Bednarski, Julie V.; Ginsberg, Howard S.; Jakob, Elizabeth M.

2010-01-01

There are numerous reports of spiders that have become established outside of their native ranges, but few studies examine their impact on native spiders. We examined the effect of the European hammock spider Linyphia triangularis (Araneae, Linyphiidae) on the native bowl-and-doily spider Frontinella communis (Araneae, Linyphiidae) in Acadia National Park, Maine, USA. First, we added L. triangularis to established plots of F. communis. Significantly more F. communis abandoned their webs when L. triangularis were added compared to control plots. Second, we tested whether F. communis were deterred from building webs in areas where L. triangularis was established. Significantly fewer F. communis built webs on plots with L. triangularis than on control plots. In both experiments, L. triangularis sometimes took over webs of F. communis or incorporated F. communis webs into their own webs, but F. communisnever took over or incorporated L. triangularis webs. Competition between L. triangularis and F. communis for both webs and web sites may contribute to the decline of F. communis.

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.

Floral guilds of bees in sagebrush steppe: Comparing bee usage of wildflowers available for postfire restoration

USDA-ARS?s Scientific Manuscript database

Healthy plant communities of the American sagebrush-steppe consist of mostly wind-pollinated shrubs and grasses interspersed with a diverse mix of mostly spring-blooming, herbaceous perennial wildflowers. Native, non-social bees are the common floral visitors, but their floral associations and abund...

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.

The discovery of 2,5-dialkylcyclohexan-1,3-diones as a new class of natural products

PubMed Central

Franke, S.; Ibarra, F.; Schulz, C. M.; Twele, R.; Poldy, J.; Barrow, R. A.; Peakall, R.; Schiestl, F. P.; Francke, W.

2009-01-01

Orchids employing sexual deceit attract males of their pollinator species through specific volatile signals that mimic female-released sex pheromones. One of these signals proved to be 2-ethyl-5-propylcyclohexan-1,3-dione (chiloglottone1), a new natural product that was shown to be most important in the relations between orchids of the genus Chiloglottis, native to Australia, and corresponding pollinator species. Systematic investigations on the mass spectrometric fragmentation pattern of 2,5-dialkylcyclohexan-1,3-diones identified key ions providing information about the structures of the substituents at positions 2 and 5. Results enabled us to identify 2-ethyl-5-pentylcyclohexan-1,3-dione (chiloglottone2) and 2-butyl-5-methylcyclohexan-1,3-dione (chiloglottone3) as new natural products that play a decisive role in the pollination syndrome of some Chiloglottis species. During field bioassays, pure synthetic samples of chiloglottone1–3 or mixtures thereof proved to be attractive to the corresponding orchid pollinators. Because of their likely biogenesis from ubiquitous fatty acid precursors, 2,5-dialkylcyclohexan-1,3-diones may represent a hitherto overlooked, widespread class of natural products. PMID:19470640

Oxalis debilis in China: Distribution of Flower Morphs, Sterile Pollen and Polyploidy

PubMed Central

LUO, SHIXIAO; ZHANG, DIANXIANG; RENNER, SUSANNE S.

2006-01-01

• Background and Aims Oxalis debilis is a South American tristylous species that is currently naturalizing in China. Based on field observations and herbarium data a report is made on its pollination, morph frequencies, pollen viability, seed set and chromosome number. In addition, a new chromosome count for the species in Africa is provided. • Methods Field observations were conducted in six provinces in south-east China. Flower visitors were recorded and nectar sugar was measured with a refractometer. The species' compatibility system was determined by carrying out experimental self- and cross-pollinations on bagged inflorescences. Stigma receptivity and pollen viability was determined using the MTT test. • Key Results and Conclusions Populations of O. debilis in China contain either the mid-style-length morph or the short morph, but not both. Pollination is by nectar- and pollen-foraging bees; pollen viability is low; and seed set in natural and experimentally self- or cross-pollinated flowers is extremely low. Chromosome counts indicate that O. debilis contains diploid and tetraploid forms in its native as well as introduced range, which does not support a previous hypothesis that the predominant vegetative reproduction in this species is an escape from pentaploidy. PMID:16735406

Impact of Non-Native Terrestrial Mammals on the Structure of the Terrestrial Mammal Food Web of Newfoundland, Canada

PubMed Central

Strong, Justin S.; Leroux, Shawn J.

2014-01-01

The island of Newfoundland is unique because it has as many non-native terrestrial mammals as native ones. The impacts of non-native species on native flora and fauna can be profound and invasive species have been identified as one of the primary drivers of species extinction. Few studies, however, have investigated the effects of a non-native species assemblage on community and ecosystem properties. We reviewed the literature to build the first terrestrial mammal food web for the island of Newfoundland and then used network analyses to investigate how the timing of introductions and trophic position of non-native species has affected the structure of the terrestrial mammal food web in Newfoundland. The first non-native mammals (house mouse and brown rat) became established in Newfoundland with human settlement in the late 15th and early 16th centuries. Coyotes and southern red-backed voles are the most recent mammals to establish themselves on the island in 1985 and 1998, respectively. The fraction of intermediate species increased with the addition of non-native mammals over time whereas the fraction of basal and top species declined over time. This increase in intermediate species mediated by non-native species arrivals led to an overall increase in the terrestrial mammal food web connectance and generality (i.e. mean number of prey per predator). This diverse prey base and sources of carrion may have facilitated the natural establishment of coyotes on the island. Also, there is some evidence that the introduction of non-native prey species such as the southern red-backed vole has contributed to the recovery of the threatened American marten. Long-term monitoring of the food web is required to understand and predict the impacts of the diverse novel interactions that are developing in the terrestrial mammal food web of Newfoundland. PMID:25170923

Pollination Services Provided by Bees in Pumpkin Fields Supplemented with Either Apis mellifera or Bombus impatiens or Not Supplemented

PubMed Central

Petersen, Jessica D.; Reiners, Stephen; Nault, Brian A.

2013-01-01

Pollinators provide an important service in many crops. Managed honey bees (Apis mellifera L.) are used to supplement pollination services provided by wild bees with the assumption that they will enhance pollination, fruit set and crop yield beyond the levels provided by the wild bees. Recent declines in managed honey bee populations have stimulated interest in finding alternative managed pollinators to service crops. In the eastern U.S., managed hives of the native common eastern bumble bee (Bombus impatiens Cresson) may be an excellent choice. To examine this issue, a comprehensive 2-yr study was conducted to compare fruit yield and bee visits to flowers in pumpkin (Cucurbita pepo L.) fields that were either supplemented with A. mellifera hives, B. impatiens hives or were not supplemented. We compared pumpkin yield, A. mellifera flower visitation frequency and B. impatiens flower visitation frequency between treatments. Results indicated that supplementing pumpkin fields with either A. mellifera or B. impatiens hives did not increase their visitation to pumpkin flowers or fruit yield compared with those that were not supplemented. Next, the relationship between frequency of pumpkin flower visitation by the most prominent bee species (Peponapis pruinosa (Say), B. impatiens and A. mellifera) and fruit yield was determined across all pumpkin fields sampled. Fruit yield increased as the frequency of flower visits by A. mellifera and B. impatiens increased in 2011 and 2012, respectively. These results suggest that supplementation with managed bees may not improve pumpkin production and that A. mellifera and B. impatiens are important pollinators of pumpkin in our system. PMID:23894544

Pollination services provided by bees in pumpkin fields supplemented with either Apis mellifera or Bombus impatiens or not supplemented.

PubMed

Petersen, Jessica D; Reiners, Stephen; Nault, Brian A

2013-01-01

Pollinators provide an important service in many crops. Managed honey bees (Apis mellifera L.) are used to supplement pollination services provided by wild bees with the assumption that they will enhance pollination, fruit set and crop yield beyond the levels provided by the wild bees. Recent declines in managed honey bee populations have stimulated interest in finding alternative managed pollinators to service crops. In the eastern U.S., managed hives of the native common eastern bumble bee (Bombus impatiens Cresson) may be an excellent choice. To examine this issue, a comprehensive 2-yr study was conducted to compare fruit yield and bee visits to flowers in pumpkin (Cucurbita pepo L.) fields that were either supplemented with A. mellifera hives, B. impatiens hives or were not supplemented. We compared pumpkin yield, A. mellifera flower visitation frequency and B. impatiens flower visitation frequency between treatments. Results indicated that supplementing pumpkin fields with either A. mellifera or B. impatiens hives did not increase their visitation to pumpkin flowers or fruit yield compared with those that were not supplemented. Next, the relationship between frequency of pumpkin flower visitation by the most prominent bee species (Peponapis pruinosa (Say), B. impatiens and A. mellifera) and fruit yield was determined across all pumpkin fields sampled. Fruit yield increased as the frequency of flower visits by A. mellifera and B. impatiens increased in 2011 and 2012, respectively. These results suggest that supplementation with managed bees may not improve pumpkin production and that A. mellifera and B. impatiens are important pollinators of pumpkin in our system.

Reproductive biology of Ferocactus recurvus (Mill.) Borg subsp. recurvus (Cactaceae) in the Tehuacán-Cuicatlán Valley, Mexico.

PubMed

Córdova-Acosta, E; Zavala-Hurtado, J A; Golubov, J; Casas, A

2017-09-01

Mexico has one of the highest diversities of barrel cacti species worldwide; however, all are threatened and require conservation policies. Information on their reproductive biology is crucial, but few studies are available. Ferocactus recurvus subsp. recurvus is a barrel cactus endemic to the Tehuacán-Cuicatlán Valley. Our research aimed to characterise its floral and pollination biology. We hypothesised bee pollination, as suggested by its floral morphology and behaviour, and self-incompatibility, like most barrel cacti studied. Three study sites were selected in the semiarid Zapotitlán Valley, Mexico. We examined 190 flowers from 180 plants to determine: morphometry and behaviour of flowers, flower visitors and probable pollinators, and breeding system. Flowers showed diurnal anthesis, lasting 2-5 days, the stigma being receptive on day 2 or 3 after the start of anthesis. Flowers produced scarce/no nectar and main visitors were bees (Apidae), followed by flies (Muscidae), ants (Formicidae), thrips (Thripidae) and hummingbirds (Throchilidae); however, only native bees and occasionally wasps contacted the stigma and anthers. Pollination experiments revealed that this species is self-incompatible and xenogamous. In natural conditions, fruit set was 60% and cross-pollination fruit set was 100%. Percentage seed germination resulting from cross-pollination was higher than in the control treatment. Our results provide ecological information for conservation programmes to ensure a high probability of breeding and seed production in natural populations of F. recurvus. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Web 2 Technologies for Net Native Language Learners: A "Social CALL"

ERIC Educational Resources Information Center

Karpati, Andrea

2009-01-01

In order to make optimal educational use of social spaces offered by thousands of international communities in the second generation web applications termed Web 2 or Social Web, ICT competences as well as social skills are needed for both teachers and learners. The paper outlines differences in competence structures of Net Natives (who came of age…

Creating and Evaluating Artificial Domiciles for Bumble Bees

ERIC Educational Resources Information Center

Golick, Douglas A.; Ellis, Marion D.; Beecham, Brady

2006-01-01

Bumble bees are valuable pollinators of native and cultivated flora. Despite our knowledge of bumble bee nest site selection, most efforts to attract bumble bees to artificial domiciles have been met with limited success. Creating and evaluating artificial domiciles provides students an opportunity to investigate a real problem. In this lesson,…

A prototype application of state and transition simulation modeling in support of grassland management

Treesearch

Matt Reeves; Paulette Ford; Leonardo Frid; David Augustine; Justin Derner

2016-01-01

The Great Plains grasslands of North America provide a multitude of ecosystem services including clean water, forage, habitat, recreation, and pollination of native and agricultural plants. A general lack of quantitative information regarding the effects of varied management strategies on these spatially heterogeneous landscapes complicates our understanding...

Colonies of bumble bees (Bombus impatiens) produce fewer workers, less bee biomass, and have smaller mother queens following fungicide exposure

USDA-ARS?s Scientific Manuscript database

Bees provide vital pollination services to the majority of flowering plants in both natural and agricultural systems. Unfortunately, both native and managed bee populations are experiencing serious declines, threatening the persistence of these plants and crops. Agricultural chemicals are one possib...

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...

Breeding biologies, seed production and species-rich bee guilds of Cleome lutea and Cleome serrulata (Cleomaceae)

Treesearch

James H. Cane

2008-01-01

The summer-blooming annual forbs Cleome lutea and Cleome serrulata (Cleomaceae) are native across the US Intermountain West and Rocky Mountains, respectively. Their farmed seed is sought to help rehabilitate western rangelands in those regions. This study of the reproductive biologies and pollinator faunas of C. lutea...

Landscaping pebbles attract nesting by the native ground-nesting bee Halictus rubicundus (Hymenoptera: Halictidae)

USDA-ARS?s Scientific Manuscript database

Most species of bees nest underground. Recent interest in pollinator-friendly gardens and landscaping focuses on planting suitable flowering species for bees, but we know little about providing for the ground-nesting needs of bees other than leaving them bare dirt surfaces. In this study, a surfac...

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...

Pollinators in peril? A multipark approach to evaluating bee communities in habitats vulnerable to effects from climate change

USGS Publications Warehouse

Rykken, Jessica; Rodman, Ann; Droege, Sam; Grundel, Ralph

2014-01-01

In 2010, collaborators from the National Park Service (Ann Rodman, Yellowstone National Park), USGS (Sam Droege and Ralph Grundel), and Harvard University (Jessica Rykken) were awarded funding from the NPS Climate Change Response Program to launch just such an investigation in almost 50 units of the National Park System (fig. 1). The main objectives of this multiyear project were to: Compare bee communities in three “vulnerable” habitats (high elevation, inland arid, coastal) and paired “common” habitats, representative of the landscape matrix, in order to determine whether vulnerable habitats have a distinctive bee fauna that may be at higher risk under climate change scenarios. Inform natural resource managers at each park about the bee fauna at their paired sites, including the presence of rare and endemic species, and make suggestions for active management strategies to promote native bee habitat if warranted. Increase awareness among park natural resource staffs, interpreters, and visitors of native bee diversity and natural history, the essential role of bees in maintaining healthy ecosystems, and potential threats from climate change to pollinator-dependent ecosystems.

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

Experimental studies of adaptation in Clarkia xantiana. II. Fitness variation across a subspecies border.

PubMed

Geber, Monica A; Eckhart, Vincent M

2005-03-01

Because the range boundary is the locale beyond which a taxon fails to persist, it provides a unique opportunity for studying the limits on adaptive evolution. Adaptive constraints on range expansion are perplexing in view of widespread ecotypic differentiation by habitat and region within a species' range (regional adaptation) and rapid evolutionary response to novel environments. In this study of two parapatric subspecies, Clarkia xantiana ssp. xantiana and C. x. ssp. parviflora, we compared the fitness of population transplants within their native region, in a non-native region within the native range, and in the non-native range to assess whether range expansion might be limited by a greater intensity of selection on colonists of a new range versus a new region within the range. The combined range of the two subspecies spans a west-to-east gradient of declining precipitation in the Sierra Nevada of California, with ssp. xantiana in the west being replaced by ssp. parviflora in the east. Both subspecies had significantly higher fitness in the native range (range adaptation), whereas regional adaptation was weak and was found only in the predominantly outcrossing ssp. xantiana but was absent in the inbreeding ssp. parvifilora. Because selection intensity on transplants was much stronger in the non-native range relative to non-native regions, there is a larger adaptive barrier to range versus regional expansion. Three of five sequential fitness components accounted for regional and range adaptation, but only one of them, survivorship from germination to flowering, contributed to both. Flower number contributed to regional adaptation in ssp. xantiana and fruit set (number of fruits per flower) to range adaptation. Differential survivorship of the two taxa or regional populations of ssp. xantiana in non-native environments was attributable, in part, to biotic interactions, including competition, herbivory, and pollination. For example, low fruit set in ssp. xantiana in the east was likely due to the absence of its principal specialist bee pollinators in ssp. parviflora's range. Thus, convergence on self-fertilization may be necessary for ssp. xantiana to invade ssp. parviflora's range, but the evolution of outcrossing would not be required for ssp. parviflora to invade ssp. xantiana's range.

Sequential generations of honey bee (Apis mellifera) queens produced using cryopreserved semen.

PubMed

Hopkins, Brandon K; Herr, Charles; Sheppard, Walter S

2012-01-01

Much of the world's food production is dependent on honey bees for pollination, and expanding food production will further increase the demand for managed pollination services. Apiculturists outside the native range of the honey bee, in the Americas, Australia and eastern Asia, have used only a few of the 27 described subspecies of honey bees (Apis mellifera) for beekeeping purposes. Within the endemic ranges of a particular subspecies, hybridisation can threaten native subspecies when local beekeepers import and propagate non-native honey bees. For many threatened species, cryopreserved germplasm can provide a resource for the preservation of diversity and recovery of endangered populations. However, although instrumental insemination of queen honey bees is well established, the absence of an effective means to cryopreserve honey bee semen has limited the success of efforts to preserve genetic diversity within the species or to develop repositories of honey bee germplasm for breeding purposes. Herein we report that some queens inseminated with cryopreserved semen were capable of producing a substantial number of fertilised offspring. These diploid female larvae were used to produce two additional sequential generations of new queens, which were then back-crossed to the same stock of frozen semen. Our results demonstrate the ability to produce queens using cryopreserved honey bee spermatozoa and the potential for the establishment of a honey bee genetic repository.

A history of plant improvement by the USDA-ARS Forage and Range Research Laboratory for rehabilitation of degraded western U.S. rangelands

USDA-ARS?s Scientific Manuscript database

The semi-arid and arid rangelands and irrigated pastures of the western U.S. provide a broad array of ecosystem services, includig wildlife/livestock feed, a diversity of native plants, pollinators, wildlife, and recreational activities. However, disturbances by wildfire, livestock, wildlife, and h...

Penstemons are for Great Basin gardens

Treesearch

Heidi Kratsch

2013-01-01

Penstemons are flowering perennials much loved by the gardening public. Gardeners appreciate their diversity of flower colors that are at peak bloom in June and July, their many shapes and sizes, and their attractiveness to hummingbirds and other native pollinators. You may even have planted some in your own garden. Most people don't realize there are about 280...

Does reproductive isolation reflect the segregation of color forms in Spiranthes sinensis (Pers.) Ames complex (Orchidaceae) in the Chinese Himalayas?

PubMed

Tao, Zhi-Bin; Ren, Zong-Xin; Bernhardt, Peter; Liang, Huan; Li, Hai-Dong; Zhao, Yan-Hui; Wang, Hong; Li, De-Zhu

2018-06-01

Isolation between species, or taxa sharing a common lineage, depends primarily on the relative strengths of various reproductive barriers. Previous studies on reproductive isolation between orchids emphasized mechanical and ethological barriers in flowers of species showing food and/or sexual mimicry. In this study, we investigated and quantified a series of prepollination and postpollination barriers between pink and white forms of Spiranthes sinensis sl, a nectar-secreting complex. We generated ML trees based on trn S-G and mat K to explore phylogenetic relationships in this species complex. Spiranthes sinensis sl segregated from some other congeners, but the white form constituted a distinct clade in relation to the pink form. The white form secreted 2-Phenylethanol as it is a single-scent compound and was pollinated almost exclusively by native, large-bodied Apis cerana and Bombus species (Apidae). Apis cerana showed a high floral constancy to this form. The scentless, pink form was pollinated primarily by smaller bees in the genera Ceratina (Apidae), and members of the family Halictidae, with infrequent visits by A. cerana and Bombus species. Fruit set and the production of large embryos following interform pollination treatments were significantly lower compared to intraform pollination results for the white form. Our results suggested that pollinator isolation, based on color and scent cues, may result in greater floral constancy in white populations when both forms are sympatric as two different, guilds of pollinators forage selectively preventing or reducing prospective gene flow. Postpollination barriers appear weaker than prepollination barriers but they also play a role in interform isolation, especially in the white form. Our findings suggest that floral color forms in S. sinensis do not represent an unbalanced polymorphism. Interpretations of the evolutionary status of these forms are discussed.

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

The importance of plant diversity in maintaining the pollinator bee, Eulaema nigrita (Hymenoptera: Apidae) in sweet passion fruit fields.

PubMed

da Silva, Cláudia Inês; Bordon, Natali Gomes; da Rocha Filho, Léo Correia; Garófalo, Carlos Alberto

2012-12-01

The euglossine bee Eulaema nigrita plays an important role for the pollination of native and economically important plants, such as the sweet passion-fruit Passiflora alata. E. nigrita uniquely collects the nectar from the flowers of P. alata, nevertheless, it needs to visit other plants to collect pollen, nectar and other resources for its survival. There are two methods to identify the species of plants used by bees in their diet: by direct observation of the bees in the flowers, and through identification of pollen grains present in brood cells, feces, or in the bees' body. In order to identify the other plants that E. nigrita visits, we analyzed samples of pollen grains removed from the bee's body in the course of the flowering period of P. alata. Among our results, the flora visited by E. nigrita comprised 40 species from 32 genera and 19 families, some of them used as a pollen source or just nectar. In spite of being a polyletic species, E. nigrita exhibited preference for some plant species with poricidal anthers. P. alata which has high sugar concentration nectar was the main source of nectar for this bee in the studied area. Nonetheless, the pollinic analysis indicated that others nectariferous plant species are necessary to keep the populations of E. nigrita. Studies such as this one are important since they indicate supplementary pollen-nectar sources which must be used for the conservation of the populations of E. nigrita in crops neighbouring areas. In the absence of pollinators, growers are forced to pay for hand pollination, which increases production costs; keeping pollinators in cultivated areas is still more feasible to ensure sweet passion fruit production.

Flowering mechanisms, pollination strategies and floral scent analyses of syntopically co-flowering Homalomena spp. (Araceae) on Borneo.

PubMed

Hoe, Y C; Gibernau, M; Maia, A C D; Wong, S Y

2016-07-01

In this study, the flowering mechanisms and pollination strategies of seven species of the highly diverse genus Homalomena (Araceae) were investigated in native populations of West Sarawak, Borneo. The floral scent compositions were also recorded for six of these species. The selected taxa belong to three out of four complexes of the section Cyrtocladon (Hanneae, Giamensis and Borneensis). The species belonging to the Hanneae complex exhibited longer anthesis (53-62 h) than those of the Giamensis and Borneensis complexes (ca. 30 h). Species belonging to the Hanneae complex underwent two floral scent emission events in consecutive days, during the pistillate and staminate phases of anthesis. In species belonging to the Giamensis and Borneensis complexes, floral scent emission was only evident to the human nose during the pistillate phase. A total of 33 volatile organic compounds (VOCs) were detected in floral scent analyses of species belonging to the Hanneae complex, whereas 26 VOCs were found in samples of those belonging to the Giamensis complex. The floral scent blends contained uncommon compounds in high concentration, which could ensure pollinator discrimination. Our observations indicate that scarab beetles (Parastasia gestroi and P. nigripennis; Scarabaeidae, Rutelinae) are the pollinators of the investigated species of Homalomena, with Chaloenus schawalleri (Chrysomelidae, Galeuricinae) acting as a secondary pollinator. The pollinators utilise the inflorescence for food, mating opportunities and safe mating arena as rewards. Flower-breeding flies (Colocasiomyia nigricauda and C. aff. heterodonta; Diptera, Drosophilidae) and terrestrial hydrophilid beetles (Cycreon sp.; Coleoptera, Hydrophilidae) were also frequently recovered from inflorescences belonging to all studied species (except H. velutipedunculata), but they probably do not act as efficient pollinators. Future studies should investigate the post-mating isolating barriers among syntopically co-flowering Homalomena sharing the same visiting insects. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Colony-level variation in pollen collection and foraging preferences among wild-caught bumble bees (Hymenoptera: Apidae).

PubMed

Saifuddin, Mustafa; Jha, Shalene

2014-04-01

Given that many pollinators have exhibited dramatic declines related to habitat destruction, an improved understanding of pollinator resource collection across human-altered landscapes is essential to conservation efforts. Despite the importance of bumble bees (Bombus spp.) as global pollinators, little is known regarding how pollen collection patterns vary between individuals, colonies, and landscapes. In this study, Vosnesensky bumble bees (Bombus vosnesenskii Radoszkowski) were collected from a range of human-altered and natural landscapes in northern California. Extensive vegetation surveys and Geographic Information System (GIS)-based habitat classifications were conducted at each site, bees were genotyped to identify colony mates, and pollen loads were examined to identify visited plants. In contrast to predictions based on strong competitive interactions, pollen load composition was significantly more similar for bees captured in a shared study region compared with bees throughout the research area but was not significantly more similar for colony mates. Preference analyses revealed that pollen loads were not composed of the most abundant plant species per study region. The majority of ranked pollen preference lists were significantly correlated for pairwise comparisons of colony mates and individuals within a study region, whereas the majority of pairwise comparisons of ranked pollen preference lists between individuals located at separate study regions were uncorrelated. Results suggest that pollen load composition and foraging preferences are similar for bees throughout a shared landscape regardless of colony membership. The importance of native plant species in pollen collection is illustrated through preference analyses, and we suggest prioritization of specific rare native plant species for enhanced bumble bee pollen collection.

Greater male fitness of a rare invader (Spartina alterniflora, Poaceae) threatens a common native (Spartina foliosa) with hybridization.

PubMed

Anttila, C K; Daehler, C C; Rank, N E; Strong, D R

1998-11-01

Hybridization with abundant invaders is a well-known threat to rare native species. Our study addresses mechanisms of hybridization between a rare invader, smooth cordgrass (Spartina alterniflora) and the common native California cordgrass (S. foliosa) in the salt marshes of San Francisco Bay. These species are wind-pollinated and flower in summer. The invader produced 21-fold the viable pollen of the native, and 28% of invader pollen germinated on native stigmas (1.5-fold the rate of the native's own pollen). Invader pollen increased the seed set of native plants almost eightfold over that produced with native pollen, while native pollen failed to increase seed set of the invader. This pollen swamping and superior siring ability by the invader could lead to serial genetic assimilation of a very large native population. Unlike California cordgrass, smooth cordgrass can grow into low intertidal habitats and cover open mud necessary to foraging shorebirds, marine life, navigation, and flood control in channels. To the extent that intertidal range of the hybrids is more similar to the invader than to the native parent, introgression will lead to habitat loss for shore birds and marine life as well to genetic pollution of native California cordgrass.

Invasive Species Science Update (No. 10)

Treesearch

Justin Runyon

2018-01-01

In this issue, we cover new research on wide-ranging topics from the longterm effects of drought on competition between native and invasive plant species, to the effects of drought on pollinator visitation to invasive plants, to a novel use of insect pheromones to improve biocontrol of invasive saltcedar. There’s also big news to report in weed biocontrol: two new...

Phenological notes on Latin American Pinus and Abies

Treesearch

William B. Critchfield

1966-01-01

Very little information has been reported on the time of pollen shedding of the many pines and firs native to Mexico and northern Central America. This kind of information is necessary for any breeding operation, and is often of considerable taxonomic and evolutionary interest as well. An example is the difference in pollination time of a month to six weeks between...

Exposure of native bees foraging in an agricultural landscape to current-use pesticides.

PubMed

Hladik, Michelle L; Vandever, Mark; Smalling, Kelly L

2016-01-15

The awareness of insects as pollinators and indicators of environmental quality has grown in recent years, partially in response to declines in honey bee (Apis mellifera) populations. While most pesticide research has focused on honey bees, there has been less work on native bee populations. To determine the exposure of native bees to pesticides, bees were collected from an existing research area in northeastern Colorado in both grasslands (2013-2014) and wheat fields (2014). Traps were deployed bi-monthly during the summer at each land cover type and all bees, regardless of species, were composited as whole samples and analyzed for 136 current-use pesticides and degradates. This reconnaissance approach provides a sampling of all species and represents overall pesticide exposure (internal and external). Nineteen pesticides and degradates were detected in 54 composite samples collected. Compounds detected in >2% of the samples included: insecticides thiamethoxam (46%), bifenthrin (28%), clothianidin (24%), chlorpyrifos (17%), imidacloprid (13%), fipronil desulfinyl (7%; degradate); fungicides azoxystrobin (17%), pyraclostrobin (11%), fluxapyroxad (9%), and propiconazole (9%); herbicides atrazine (19%) and metolachlor (9%). Concentrations ranged from 1 to 310 ng/g for individual pesticides. Pesticides were detected in samples collected from both grasslands and wheat fields; the location of the sample and the surrounding land cover at the 1000 m radius influenced the pesticides detected but because of a small number of temporally comparable samples, correlations between pesticide concentration and land cover were not significant. The results show native bees collected in an agricultural landscape are exposed to multiple pesticides, these results can direct future research on routes/timing of pesticide exposure and the design of future conservation efforts for pollinators. Published by Elsevier B.V.

Exposure of native bees foraging in an agricultural landscape to current-use pesticides

USGS Publications Warehouse

Hladik, Michelle; Vandever, Mark W.; Smalling, Kelly L.

2016-01-01

The awareness of insects as pollinators and indicators of environmental quality has grown in recent years, partially in response to declines in honey bee (Apis mellifera) populations. While most pesticide research has focused on honey bees, there has been less work on native bee populations. To determine the exposure of native bees to pesticides, bees were collected from an existing research area in northeastern Colorado from two land cover types: grasslands (2013-2014) and wheat fields (2014). Traps were deployed bi-monthly during the summer at each land cover type and all bees, regardless of species, were composited as whole samples and analyzed for 136 current-use pesticides and degradates. This reconnaissance approach provides a sampling of all species and represents overall pesticide exposure (internal and external). Nineteen pesticides and degradates were detected in 54 composite samples collected. Compounds detected in >10% of the samples included the insecticides thiamethoxam (46%), bifenthrin (28%), clothianidin (24%), chlorpyrifos (17%), and imidacloprid (13%), the fungicides azoxystrobin (17%), and pyraclostrobin (11%), and the herbicide atrazine (19%). Concentrations ranged from 1.1 to 312 ng/g for individual pesticides. Pesticides were detected in samples collected from both grasslands and wheat fields; the location of the sample and the surrounding land cover at the 1000 m buffer influenced the pesticides detected but because of a small number of temporally comparable samples, correlations between pesticide concentration and land cover were not significant. The results show native bees collected in both grasslands and wheat fields are exposed to multiple pesticides, these results can direct future research on routes/timing of pesticide exposure and the design of future conservation efforts for pollinators.

A survey of cavity-nesting bees and wasps in loblolly pine stands of the Savannah River Site, Aiken County, South Carolina.

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

Horn, S.; Hanula, J., L.

2004-03-10

Horn, Scott, and James L. Hanula. 2004. A survey of cavity-nesting bees and wasps in loblolly pine stands of the Savannah River Site, Aiken County, South Carolina. 39(3): 464-469. Abstract: In recent years concern over widespread losses in biodiversity has grown to include a possible decline of many native pollinators, primarily bees. Factors such as habitat fragmentation, agricultural practices, use of pesticides, the introduction of invasive species, or changes in land use may negatively impact these vital organisims. Most reported studies show that human impacts on pollinators are overwhelmingly negative. Reductions in pollinator populations may profoundly impact plant population dynamicsmore » and ecosystem function. Little baseline data exists on the diversity and relative abundance of bees and wasps in southern forests. The objective of this study was to develop a simple, effective method of surveying cavity-nesting bees and wasps and to determine species diversity in mature forests of loblolly pine, the most widely planted tree species in the southern United States.« less

Parasites reduce food web robustness because they are sensitive to secondary extinction as illustrated by an invasive estuarine snail

USGS Publications Warehouse

Lafferty, Kevin D.; Kuris, Armand M.

2009-01-01

A robust food web is one in which few secondary extinctions occur after removing species. We investigated how parasites affected the robustness of the Carpinteria Salt Marsh food web by conducting random species removals and a hypothetical, but plausible, species invasion. Parasites were much more likely than free-living species to suffer secondary extinctions following the removal of a free-living species from the food web. For this reason, the food web was less robust with the inclusion of parasites. Removal of the horn snail, Cerithidea californica, resulted in a disproportionate number of secondary parasite extinctions. The exotic Japanese mud snail, Batillaria attramentaria, is the ecological analogue of the native California horn snail and can completely replace it following invasion. Owing to the similarities between the two snail species, the invasion had no effect on predator–prey interactions. However, because the native snail is host for 17 host-specific parasites, and the invader is host to only one, comparison of a food web that includes parasites showed significant effects of invasion on the native community. The hypothetical invasion also significantly reduced the connectance of the web because the loss of 17 native trematode species eliminated many links.

Native and Non-Native Supergeneralist Bee Species Have Different Effects on Plant-Bee Networks

PubMed Central

Giannini, Tereza C.; Garibaldi, Lucas A.; Acosta, Andre L.; Silva, Juliana S.; Maia, Kate P.; Saraiva, Antonio M.; Guimarães, Paulo R.; Kleinert, Astrid M. P.

2015-01-01

Supergeneralists, defined as species that interact with multiple groups of species in ecological networks, can act as important connectors of otherwise disconnected species subsets. In Brazil, there are two supergeneralist bees: the honeybee Apis mellifera, a non-native species, and Trigona spinipes, a native stingless bee. We compared the role of both species and the effect of geographic and local factors on networks by addressing three questions: 1) Do both species have similar abundance and interaction patterns (degree and strength) in plant-bee networks? 2) Are both species equally influential to the network structure (nestedness, connectance, and plant and bee niche overlap)? 3) How are these species affected by geographic (altitude, temperature, precipitation) and local (natural vs. disturbed habitat) factors? We analyzed 21 plant-bee weighted interaction networks, encompassing most of the main biomes in Brazil. We found no significant difference between both species in abundance, in the number of plant species with which each bee species interacts (degree), and in the sum of their dependencies (strength). Structural equation models revealed the effect of A. mellifera and T. spinipes, respectively, on the interaction network pattern (nestedness) and in the similarity in bee’s interactive partners (bee niche overlap). It is most likely that the recent invasion of A. mellifera resulted in its rapid settlement inside the core of species that retain the largest number of interactions, resulting in a strong influence on nestedness. However, the long-term interaction between native T. spinipes and other bees most likely has a more direct effect on their interactive behavior. Moreover, temperature negatively affected A. mellifera bees, whereas disturbed habitats positively affected T. spinipes. Conversely, precipitation showed no effect. Being positively (T. spinipes) or indifferently (A. mellifera) affected by disturbed habitats makes these species prone to pollinate plant species in these areas, which are potentially poor in pollinators. PMID:26356234

Effective range of reproductive interference exerted by an alien dandelion, Taraxacum officinale, on a native congener.

PubMed

Takakura, Koh-Ichi; Matsumoto, Takashi; Nishida, Takayoshi; Nishida, Sachiko

2011-03-01

Reproductive interference (RI), defined as the fitness cost of interspecific sexual interactions, such as interspecific pollen transfer (IPT) in plants, is ecologically important. Theoretically, RI could result in competitive exclusion, as it operates in a frequency-dependent manner. Additionally, IPT may have a greater range than resource competition, although information about the range of IPT is lacking. In the present study, we measured the range of IPT exerted by Taraxacum officinale (an alien species) on a native dandelion, T. japonicum. We used two approaches. In one, we analyzed the RI effect on a native seed set at three spatial scales. In the second, we tracked IPT from alien to native flower heads using fluorescent pigments as markers. We estimated that pollination distances were in the order of several meters. These distances exceeded the mean distance from each native plant to the nearest alien. As hypothesized, the effect of RI reached farther than neighboring individuals. These data indicate the spatial range from which alien dandelions should be removed to allow the conservation of natives.

Soil fungal effects on floral signals, rewards, and aboveground interactions in an alpine pollination web.

PubMed

Becklin, Katie M; Gamez, Guadalupe; Uelk, Bryan; Raguso, Robert A; Galen, Candace

2011-08-01

Plants interact with above- and belowground organisms; the combined effects of these interactions determine plant fitness and trait evolution. To better understand the ecological and evolutionary implications of multispecies interactions, we explored linkages between soil fungi, pollinators, and floral larcenists in Polemonium viscosum (Polemoniaceae). Using a fungicide, we experimentally reduced fungal colonization of krummholz and tundra P. viscosum in 2008-2009. We monitored floral signals and rewards, interactions with pollinators and larcenists, and seed set for fungicide-treated and control plants. Fungicide effects varied among traits, between interactions, and with environmental context. Treatment effects were negligible in 2008, but stronger in 2009, especially in the less-fertile krummholz habitat. There, fungicide increased nectar sugar content and damage by larcenist ants, but did not affect pollination. Surprisingly, fungicide also enhanced seed set, suggesting that direct resource costs of soil fungi exceed indirect benefits from reduced larceny. In the tundra, fungicide effects were negligible in both years. However, pooled across treatments, colonization by mycorrhizal fungi in 2009 correlated negatively with the intensity and diversity of floral volatile organic compounds, suggesting integrated above- and belowground signaling pathways. Fungicide effects on floral rewards in P. viscosum link soil fungi to ecological costs of pollinator attraction. Trait-specific linkages to soil fungi should decouple expression of sensitive and buffered floral phenotypes in P. viscosum. Overall, this study demonstrates how multitrophic linkages may lead to shifting selection pressures on interaction traits, restricting the evolution of specialization.

Host specificity of two pollinating seed-consuming fly species is not related to soil moisture of host plant in the high Himalayas.

PubMed

Song, Bo; Stöcklin, Jürg; Gao, Yong-Qian; Peng, De-Li; Sun, Hang

2017-01-01

Studying the drivers of host specificity can contribute to our understanding of the origin and evolution of obligate pollination mutualisms. The preference-performance hypothesis predicts that host plant choice of female insects is related mainly to the performance of their offspring. Soil moisture is thought to be particularly important for the survival of larvae and pupae that inhabit soil. In the high Himalayas, Rheum nobile and R. alexandrae differ in their distribution in terms of soil moisture; that is, R. nobile typically occurs in scree with well-drained soils, R. alexandrae in wetlands. The two plant species are pollinated by their respective mutualistic seed-consuming flies, Bradysia sp1. and Bradysia sp2. We investigated whether soil moisture is important for regulating host specificity by comparing pupation and adult emergence of the two fly species using field and laboratory experiments. Laboratory experiments revealed soil moisture did have significant effects on larval and pupal performances in both fly species, but the two fly species had similar optimal soil moisture requirements for pupation and adult emergence. Moreover, a field reciprocal transfer experiment showed that there was no significant difference in adult emergence for both fly species between their native and non-native habitats. Nevertheless, Bradysia sp1., associated with R. nobile , was more tolerant to drought stress, while Bradysia sp2., associated with R. alexandrae , was more tolerant to flooding stress. These results indicate that soil moisture is unlikely to play a determining role in regulating host specificity of the two fly species. However, their pupation and adult emergence in response to extremely wet or dry soils are habitat-specific.

A transcriptome-snp-derived linkage map of Apios americana (potato bean) provides insights about genome re-organization and synteny conservation in the phaseolid legumes

USDA-ARS?s Scientific Manuscript database

Apios (Apios americana; “apios”), a tuberous perennial legume in the Phaseoleae tribe, was widely used as a food by Native Americans. Work in the last 40 years has led to several improved breeding lines. Aspects of the pollination biology (complex floral structure and tripping mechanism) have made c...

Creating a Culturally Appropriate Web-Based Behavioral Intervention for American Indian/Alaska Native Women in Southern California: The Healthy Women Healthy Native Nation Study

ERIC Educational Resources Information Center

Gorman, Jessica R.; Clapp, John D.; Calac, Daniel; Kolander, Chelsea; Nyquist, Corinna; Chambers, Christina D.

2013-01-01

Health disparities in fetal alcohol spectrum disorders (FASD) are of high importance to American Indian/Alaska Native (AI/AN) communities. We conducted focus groups and interviews with 21 AI/AN women and key informants in Southern California to modify a brief, Web-based program for screening and prevention of prenatal alcohol use. This process…

Effect of phenology on agonistic competitive interactions between invasive and native sheet-web spiders

USGS Publications Warehouse

Houser, Jeremy D.; Porter, Adam H.; Ginsberg, Howard; Jakob, Elizabeth M.

2016-01-01

The phenologies of introduced relative to native species can greatly influence the degree and symmetry of competition between them. The European spider Linyphia triangularis (Clerck, 1757) (Linyphiidae) reaches very high densities in coastal Maine (USA). Previous studies suggest thatL. triangularis negatively affects native linyphiid species, with competition for webs as one mechanism. We documented phenological differences between L. triangularis and three native species that illustrate the potential for the reversal of size-based competitive advantage over the course of the year. To test whether relative size influences interaction outcome, we allowed a resident spider to build a web and then introduced an intruder. We examined whether the outcomes of agonistic interactions over the webs were influenced by the species of the resident (invasive or native), the relative size of the contestants, and the species × size interaction. We found that the importance of relative size differed among species. In interactions between L. triangularis and each of two native species, size played a greater role than resident species on the outcome of interactions, suggesting that competitive advantage reverses over the season based on phenology-related size differences. Linyphia triangularis had a negative impact on the third species regardless of relative size.

FReD: the floral reflectance database--a web portal for analyses of flower colour.

PubMed

Arnold, Sarah E J; Faruq, Samia; Savolainen, Vincent; McOwan, Peter W; Chittka, Lars

2010-12-10

Flower colour is of great importance in various fields relating to floral biology and pollinator behaviour. However, subjective human judgements of flower colour may be inaccurate and are irrelevant to the ecology and vision of the flower's pollinators. For precise, detailed information about the colours of flowers, a full reflectance spectrum for the flower of interest should be used rather than relying on such human assessments. The Floral Reflectance Database (FReD) has been developed to make an extensive collection of such data available to researchers. It is freely available at http://www.reflectance.co.uk. The database allows users to download spectral reflectance data for flower species collected from all over the world. These could, for example, be used in modelling interactions between pollinator vision and plant signals, or analyses of flower colours in various habitats. The database contains functions for calculating flower colour loci according to widely-used models of bee colour space, reflectance graphs of the spectra and an option to search for flowers with similar colours in bee colour space. The Floral Reflectance Database is a valuable new tool for researchers interested in the colours of flowers and their association with pollinator colour vision, containing raw spectral reflectance data for a large number of flower species.

Heterosis May Result in Selection Favouring the Products of Long-Distance Pollen Dispersal in Eucalyptus

PubMed Central

Costa e Silva, João; Potts, Brad M.; Lopez, Gustavo A.

2014-01-01

Using native trees from near the northern and southern extremities of the relatively continuous eastern distribution of Eucalyptus globulus in Tasmania, we compared the progenies derived from natural open-pollination (OP) with those generated from within-region and long-distance outcrossing. Controlled outcrossing amongst eight parents - with four parents from each of the northern and southern regions - was undertaken using a diallel mating scheme. The progeny were planted in two field trials located within the species native range in southern Tasmania, and their survival and diameter growth were monitored over a 13-year-period. The survival and growth performances of all controlled cross types exceeded those of the OP progenies, consistent with inbreeding depression due to a combination of selfing and bi-parental inbreeding. The poorer survival of the northern regional (♀N♂N) outcrosses compared with the local southern regional outcrosses (♀S♂S) indicated differential selection against the former. Despite this mal-adaptation of the non-local ♀N♂N crosses at both southern sites, the survival of the inter-regional hybrids (♀N♂S and ♀S♂N) was never significantly different from that of the local ♀S♂S crosses. Significant site-dependent heterosis was detected for the growth of the surviving long-distance hybrids. This was expressed as mid-parent heterosis, particularly at the more northern planting site. Heterosis increased with age, while the difference between the regional ♀N♂N and ♀S♂S crosses remained insignificant at any age at either site. Nevertheless, the results for growth suggest that the fitness of individuals derived from long-distance crossing may be better at the more northern of the planting sites. Our results demonstrate the potential for early-age assessments of pollen dispersal to underestimate realised gene flow, with local inbreeding under natural open-pollination resulting in selection favouring the products of longer-distance pollinations. Indeed, heterosis derived from long-distance pollinations may be sufficient to counter local mal-adaptation, at least in the first generation. PMID:24751722

Food web structure in exotic and native mangroves: A Hawaii-Puerto Rico comparison

USGS Publications Warehouse

Demopoulos, A.W.J.; Fry, B.; Smith, C.R.

2007-01-01

Plant invasions can fundamentally alter detrital inputs and the structure of detritus-based food webs. We examined the detrital pathways in mangrove food webs in native (Puerto Rican) and introduced (Hawaiian) Rhizophora mangle forests using a dual isotope approach and a mixing model. Based on trophic-level fractionation of 0-1??? for ?? 13C and 2-3??? for ?? 15N, among the invertebrates, only nematodes, oligochaetes, and nereid polychaetes from native mangroves exhibited stable isotopes consistent with a mangrove-derived diet. Certain fauna, in particular tubificid oligochaetes, had ?? 13C values consistent with the consumption of mangrove leaves, but they were depleted in 15N, suggesting their primary nitrogen source was low in 15N, and was possibly N 2-fixing bacteria. In introduced mangroves, all feeding groups appeared to rely heavily on non-mangrove sources, especially phytoplankton inputs. Mixing model results and discriminant analysis showed clear separation of introduced and native mangrove sites based on differential food source utilization within feeding groups, with stronger and more diverse use of benthic foods observed in native forests. Observed differences between native and invasive mangrove food webs may be due to Hawaiian detritivores being poorly adapted to utilizing the tannin-rich, nitrogen-poor mangrove detritus. In addition, differential utilization of mangrove detritus between native and introduced mangroves may be a consequence of forest age. We postulate that increasing mangrove forest age may promote diversification of bacterial food webs important in N and S cycling. Our results also suggest a potentially important role for sulfur bacteria in supporting the most abundant infaunal consumers, nematodes, in the most mature systems. ?? 2007 Springer-Verlag.

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.

Bee Fauna and Floral Abundance Within Lawn-Dominated Suburban Yards in Springfield, MA.

PubMed

Lerman, S B; Milam, J

2016-09-01

Private yards comprise a significant component of urban lands, with managed lawns representing the dominant land cover. Lawns blanket > 163,000 km 2 of the United States, and 50% of urban and suburban areas. When not treated with herbicides, lawns have the capacity to support a diversity of spontaneous (e.g., not planted) flowers, with the potential to provide nectar and pollen resources for pollinators such as native bees. In order to determine the extent to which suburban lawns support these important species, we surveyed lawns in 17 suburban yards in Springfield, MA, between May and September 2013 and 2014. Householders participating in the study did not apply chemical pesticides or herbicides to lawns for the duration of the study. We collected 5,331 individual bees, representing 111 species, and 29% of bee species reported for the state. The majority of species were native to North America (94.6%), nested in soil (73%), and solitary (48.6%). Species richness was lower for oligolectic (specialists on a single plant; 9.9%) and parasitic species (12.6%). Abundance percentages for number of individuals were similar. We documented 63 plant species in the lawns, the majority of which were not intentionally planted. The most abundant lawn flowers were dandelion ( Taraxacum officinale ) and clover ( Trifolium sp. ). Nearly 30% of the spontaneous plant species growing in the lawns were native to North America. Our study suggests that the spontaneous lawn flowers could be viewed as supplemental floral resources and support pollinators, thereby enhancing the value of urban green spaces.

Complete mitochondrial genome sequence of Melipona scutellaris, a Brazilian stingless bee.

PubMed

Pereira, Ulisses de Padua; Bonetti, Ana Maria; Goulart, Luiz Ricardo; Santos, Anderson Rodrigues Dos; Oliveira, Guilherme Correa de; Cuadros-Orellana, Sara; Ueira-Vieira, Carlos

2016-09-01

Melipona scutellaris is a Brazilian stingless bee species and a highly important native pollinator besides its use in rational rearing for honey production. In this study, we present the whole mitochondrial DNA sequence of M. scutellaris from a haploid male. The mitogenome has a size of 14,862 bp and harbors 13 protein-coding genes (PCGs), 2 rRNA genes and 21 tRNA genes.

Invasive plants as potential food resource for native pollinators: A case study with two invasive species and a generalist bumble bee.

PubMed

Drossart, Maxime; Michez, Denis; Vanderplanck, Maryse

2017-11-24

It is now well established that invasive plants may induce drifts in the quantity and/or quality of floral resources. They are then often pointed out as a potential driver of bee decline. However, their impact on bee population remains quite unclear and still controversial, as bee responses are highly variable among species. Here, we compared the amino acid composition of pollen from three native and two invasive plant species included in diets of common pollinators in NW Europe. Moreover, the nutritional intake (i.e., pollen and amino acid intakes) of Bombus terrestris colonies and the pollen foraging behaviour of workers (i.e., visiting rate, number of foraging trips, weight of pollen loads) were considered. We found significant differences in pollen nutrients among the studied species according to the plant invasive behaviour. We also found significant differences in pollen foraging behaviour according to the plant species, from few to several foraging trips carrying small or large pollen loads. Such behavioural differences directly impacted the pollen intake but depended more likely on plant morphology rather than on plant invasive behaviour. These results suggest that common generalist bumble bees might not always suffer from plant invasions, depending on their behavioural plasticity and nutritional requirements.

Parallel evolution of angiosperm colour signals: common evolutionary pressures linked to hymenopteran vision

PubMed Central

Dyer, Adrian G.; Boyd-Gerny, Skye; McLoughlin, Stephen; Rosa, Marcello G. P.; Simonov, Vera; Wong, Bob B. M.

2012-01-01

Flowering plants in Australia have been geographically isolated for more than 34 million years. In the Northern Hemisphere, previous work has revealed a close fit between the optimal discrimination capabilities of hymenopteran pollinators and the flower colours that have most frequently evolved. We collected spectral data from 111 Australian native flowers and tested signal appearance considering the colour discrimination capabilities of potentially important pollinators. The highest frequency of flower reflectance curves is consistent with data reported for the Northern Hemisphere. The subsequent mapping of Australian flower reflectances into a bee colour space reveals a very similar distribution of flower colour evolution to the Northern Hemisphere. Thus, flowering plants in Australia are likely to have independently evolved spectral signals that maximize colour discrimination by hymenoptera. Moreover, we found that the degree of variability in flower coloration for particular angiosperm species matched the range of reflectance colours that can only be discriminated by bees that have experienced differential conditioning. This observation suggests a requirement for plasticity in the nervous systems of pollinators to allow generalization of flowers of the same species while overcoming the possible presence of non-rewarding flower mimics. PMID:22673351

Are ecosystem services stabilized by differences among species? A test using crop pollination.

PubMed

Winfree, Rachael; Kremen, Claire

2009-01-22

Biological diversity could enhance ecosystem service provision by increasing the mean level of services provided, and/or by providing more consistent (stable) services over space and time. Ecological theory predicts that when an ecosystem service is provided by many species, it will be stabilized against disturbance by a variety of 'stabilizing mechanisms.' However, few studies have investigated whether stabilizing mechanisms occur in real landscapes affected by human disturbance. We used two datasets on crop pollination by wild native bees to screen for and differentiate among three stabilizing mechanisms: density compensation (negative co-variance among species' abundances); response diversity (differential response to environmental variables among species); and cross-scale resilience (response to the same environmental variable at different scales by different species). In both datasets, we found response diversity and cross-scale resilience, but not density compensation. We conclude that stabilizing mechanisms may contribute to the stability of pollination services in our study areas, emphasizing the insurance value of seemingly 'redundant' species. Furthermore, the absence of density compensation that we found at the landscape scale contrasts with findings of previous small-scale experimental and modelling work, suggesting that we should not assume that density compensation will stabilize ecosystem services in real landscapes.

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

FReD: The Floral Reflectance Database — A Web Portal for Analyses of Flower Colour

PubMed Central

Savolainen, Vincent; McOwan, Peter W.; Chittka, Lars

2010-01-01

Background Flower colour is of great importance in various fields relating to floral biology and pollinator behaviour. However, subjective human judgements of flower colour may be inaccurate and are irrelevant to the ecology and vision of the flower's pollinators. For precise, detailed information about the colours of flowers, a full reflectance spectrum for the flower of interest should be used rather than relying on such human assessments. Methodology/Principal Findings The Floral Reflectance Database (FReD) has been developed to make an extensive collection of such data available to researchers. It is freely available at http://www.reflectance.co.uk. The database allows users to download spectral reflectance data for flower species collected from all over the world. These could, for example, be used in modelling interactions between pollinator vision and plant signals, or analyses of flower colours in various habitats. The database contains functions for calculating flower colour loci according to widely-used models of bee colour space, reflectance graphs of the spectra and an option to search for flowers with similar colours in bee colour space. Conclusions/Significance The Floral Reflectance Database is a valuable new tool for researchers interested in the colours of flowers and their association with pollinator colour vision, containing raw spectral reflectance data for a large number of flower species. PMID:21170326

Variation in the strength of reproductive interference from an alien congener to a native species in Taraxacum.

PubMed

Nishida, Sachiko; Hashimoto, Keisuke; Kanaoka, Masahiro M; Takakura, Ko-Ichi; Nishida, Takayoshi

2017-01-01

Reproductive interference (RI) may be a contributing factor to the displacement of native species by an alien congener, and RI strength has been shown theoretically to affect distributional relationships between species. Thus, variations in RI strength from alien to native species result in different consequences of invasions and efforts to conserve native species, but the variations have seldom been examined empirically. We therefore investigated RI strength variations from the alien species Taraxacum officinale and its hybrids to eight populations of native dandelions, four T. japonicum populations and two populations each of two subspecies of T. platycarpum. We examined the association between alien relative abundance and native seed set in field surveys, and we also performed hand-pollination experiments to investigate directly the sensitivity of native flowers to alien pollen. We found that the effect of alien relative abundance on native seed set of even the same native species could differ greatly in different regions, and that the sensitivity of native flowers to alien pollen was also dependent on region. Our results, together with those of previous studies, show that RI from the alien to the native species is strong in regions where the alien species outnumbers the native species and marginal where it does not; this result suggests that alien RI can critically affect distributional relationships between native and alien species. Our study highlights the importance of performing additional empirical investigations of RI strength variation and of giving due attention to alien RI in efforts to conserve regional native biodiversity.

Incorporation of an invasive plant into a native insect herbivore food web

PubMed Central

Santos Pimenta, Lúcia P.; Lammers, Youri; Steenbergen, Peter J.; Flohil, Marco; Beveridge, Nils G.P.; van Duijn, Pieter T.; Meulblok, Marjolein M.; Sosef, Nils; van de Ven, Robin; Werring, Ralf; Beentjes, Kevin K.; Meijer, Kim; Vos, Rutger A.; Vrieling, Klaas; Gravendeel, Barbara; Choi, Young; Verpoorte, Robert; Smit, Chris; Beukeboom, Leo W.

2016-01-01

The integration of invasive species into native food webs represent multifarious dynamics of ecological and evolutionary processes. We document incorporation of Prunus serotina (black cherry) into native insect food webs. We find that P. serotina harbours a herbivore community less dense but more diverse than its native relative, P. padus (bird cherry), with similar proportions of specialists and generalists. While herbivory on P. padus remained stable over the past century, that on P. serotina gradually doubled. We show that P. serotina may have evolved changes in investment in cyanogenic glycosides compared with its native range. In the leaf beetle Gonioctena quinquepunctata, recently shifted from native Sorbus aucuparia to P. serotina, we find divergent host preferences on Sorbus- versus Prunus-derived populations, and weak host-specific differentiation among 380 individuals genotyped for 119 SNP loci. We conclude that evolutionary processes may generate a specialized herbivore community on an invasive plant, allowing prognoses of reduced invasiveness over time. On the basis of the results presented here, we would like to caution that manual control might have the adverse effect of a slowing down of processes of adaptation, and a delay in the decline of the invasive character of P. serotina. PMID:27190702

Ecology, Behaviour and Control of Apis cerana with a Focus on Relevance to the Australian Incursion

PubMed Central

Koetz, Anna H.

2013-01-01

Apis cerana Fabricius is endemic to most of Asia, where it has been used for honey production and pollination services for thousands of years. Since the 1980s, A. cerana has been introduced to areas outside its natural range (namely New Guinea, the Solomon Islands, and Australia), which sparked fears that it may become a pest species that could compete with, and negatively affect, native Australian fauna and flora, as well as commercially kept A. mellifera and commercial crops. This literature review is a response to these concerns and reviews what is known about the ecology and behaviour of A. cerana. Differences between temperate and tropical strains of A. cerana are reviewed, as are A. cerana pollination, competition between A. cerana and A. mellifera, and the impact and control strategies of introduced A. cerana, with a particular focus on gaps of current knowledge. PMID:26462524

Linking native and invader traits explains native spider population responses to plant invasion

Treesearch

Jennifer N. Smith; Douglas J. Emlen; Dean E. Pearson

2016-01-01

Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders' web-building behaviors could explain differences in spider population responses to...

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.

Feedback about Astronomical Application Developments for Mobile Devices

NASA Astrophysics Data System (ADS)

Schaaff, A.; Boch, T.; Fernique, P.; Houpin, R.; Kaestlé, V.; Royer, M.; Scheffmann, J.; Weiler, A.

2013-10-01

Within a few years, Smartphones have become the standard for mobile telephony, and we are now witnessing a rapid development of Internet tablets. These mobile devices have enough powerful hardware features to run more and more complex applications. In the field of astronomy it is not only possible to use these tools to access data via a simple browser, but also to develop native applications reusing libraries (Java for Android, Objective-C for iOS) developed for desktops. We have been working for two years on mobile application development and we now have the skills in native iOS and Android development, Web development (especially HTML5, JavaScript, CSS3) and conversion tools (PhoneGap) from Web development to native applications. The biggest change comes from human/computer interaction that is radically changed by the use of multitouch. This interaction requires a redesign of interfaces to take advantage of new features (simultaneous selections in different parts of the screen, etc.). In the case of native applications, the distribution is usually done through online stores (App Store, Google Play, etc.) which gives visibility to a wider audience. Our approach is not only to perform testing of materials and developing of prototypes, but also operational applications. The native application development is costly in development time, but the possibilities are broader because it is possible to use native hardware such as the gyroscope and the accelerometer, to point out an object in the sky. Development depends on the Web browser and the rendering and performance are often very different between different browsers. It is also possible to convert Web developments to native applications, but currently it is better to restrict this possibility to light applications in terms of functionality. Developments in HTML5 are promising but are far behind those available on desktops. HTML5 has the advantage of allowing development independent from the evolution of the mobile platforms (“write once, run everywhere”). The upcoming Windows 8 support on desktops and Internet tablets as well as a mobile version for smartphones will further expand the native systems family. This will enhance the interest of Web development.

Effects of invasive plants on arthropods.

PubMed

Litt, Andrea R; Cord, Erin E; Fulbright, Timothy E; Schuster, Greta L

2014-12-01

Non-native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer-reviewed literature to evaluate responses of arthropod communities and functional groups to non-native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty-two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web-building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to ecological change, arthropods may be ideal targets for restoration and conservation activities. © 2014 Society for Conservation Biology.

Behavior and pollination efficiency of Nannotrigona perilampoides (Hymenoptera: Meliponini) on greenhouse tomatoes (Lycopersicon esculentum) in subtropical México.

PubMed

Cauich, Orlando; Quezada-Euán, José Javier G; Macias-Macias, José Octavio; Reyes-Oregel, Vicente; Medina-Peralta, Salvador; Parra-Tabla, Victor

2004-04-01

The acclimation, foraging behavior, and pollination efficiency of stingless bees of the species Nannotrigona perilampoides Cresson were evaluated in tomato (Lycopersicon esculentum Mill.) plants cultivated in two greenhouses. The greenhouses were divided into three areas of 16 m2, and one of the following treatments was used for pollination: stingless bees (SB), mechanical vibration (MV), and no pollination (NP). Observations were conducted once a week from 0800 to 1600 hours during 2 mo. The acclimation of the bees to the greenhouses was estimated by the number of bees that did not return to the hive (lost bees) and by comparing the population of the colonies (brood and adults). The foraging activity of the bees across the day was evaluated by comparing the number of foragers per hour. The influence of environmental variables on the foraging activity was also analyzed. The pollination efficiency was compared among treatments through the percentage of fruit set, weight of individual fruit, kilograms of fruit produced per square meter, and the number of seed per fruit. The bees started foraging on the flowers approximately 7 d after the colonies were introduced to the greenhouse. There was a decline in the population of the colonies across the experiment, but colonies did not die out. Correlations of environmental variables with the foraging activity of the bees showed that none of them had a significant influence on pollen foraging. However, water collection was positively correlated with the temperature and negatively correlated with the humidity inside the greenhouse. The estimation of the pollination efficiency per treatment showed that there were significant differences in fruit set in SB (83 +/- 4.2) and MV (78.5 +/- 6.4) compared with NP (52.6 +/- 7.6). However, the average weight of the fruit was similar for the three treatments (65 g). There were significant differences for seed number in SB (200 +/- 15.3) and MV (232 +/- 21.4) compared with NP (120 +/- 16.6). The productivity in kilograms of fruit per square meter was higher in SB (5.72 +/- 0.61) and MV (5.66 +/- 0.58 kg) compared with NP (3.34 +/- 0.72). The number of seed was positively correlated with the weight of the fruit. We conclude that the use of Nannotrigona testaceicornis Rondani, for pollinating greenhouse tomatoes in tropical climates, could be an alternative to the use of highly defensive African-derived Apis mellifera or non-native bumble bees (Bombus spp.). However, more research is needed to evaluate the cost/benefit on large-scale greenhouse pollination using N. perilampoides Cresson against other bee species and pollination methods.

Asymmetric Hybridization in Cattails (Typha spp.) and Its Implications for the Evolutionary Maintenance of Native Typha latifolia.

PubMed

Pieper, Sara J; Nicholls, Allison A; Freeland, Joanna R; Dorken, Marcel E

2017-07-01

Cattails (Typha spp.) have become an increasingly dominant component of wetlands in eastern North America and this dominance is largely attributable to the high frequency of Typha × glauca, the hybrid of native Typha latifolia and putatively introduced Typha angustifolia. Hybridization in this group is asymmetric, with T. angustifolia nearly always the maternal parent of F1 hybrids. However, the magnitude of hybrid infertility and whether mating asymmetries extend to the formation of advanced-generation hybrids have not been examined. We used hand-crosses to measure seed set and germination success. We found that mating asymmetries extend to the formation of back-crosses, with ~0 seeds set when T. latifolia was pollinated by hybrid cattails. Seed set was unaffected by pollen source for T. × glauca or T. angustifolia. However, seed production by T. angustifolia was consistently high while that of T. × glauca was variable and when pollinated by other T. × glauca more than 75% lower than for any other intraspecific cross indicating reduced hybrid fertility. We used these results to parameterize a model of hybrid zone evolution in which mating patterns and fertility were governed by interactions between alleles at nuclear and cytoplasmic loci. The model revealed that asymmetric mating and reduced hybrid fertility should favor the maintenance of T. latifolia over T. angustifolia compared to null expectations. However, the model also indicated restrictive conditions for the long-term maintenance of T. latifolia within populations, indicating that asymmetric mating might only stall rather than prevent the displacement of native cattails by hybrids. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Native wildflower plantings support wild bee abundance and diversity in agricultural landscapes across the United States.

PubMed

Williams, Neal M; Ward, Kimiora L; Pope, Nathaniel; Isaacs, Rufus; Wilson, Julianna; May, Emily A; Ellis, Jamie; Daniels, Jaret; Pence, Akers; Ullmann, Katharina; Peters, Jeff

2015-12-01

Global trends in pollinator-dependent crops have raised awareness of the need to support managed and wild bee populations to ensure sustainable crop production. Provision of sufficient forage resources is a key element for promoting bee populations within human impacted landscapes, particularly those in agricultural lands where demand for pollination service is high and land use and management practices have reduced available flowering resources. Recent government incentives in North America and Europe support the planting of wildflowers to benefit pollinators; surprisingly, in North America there has been almost no rigorous testing of the performance of wildflower mixes, or their ability to support wild bee abundance and diversity. We tested different wildflower mixes in a spatially replicated, multiyear study in three regions of North America where production of pollinator-dependent crops is high: Florida, Michigan, and California. In each region, we quantified flowering among wildflower mixes composed of annual and perennial species, and with high and low relative diversity. We measured the abundance and species richness of wild bees, honey bees, and syrphid flies at each mix over two seasons. In each region, some but not all wildflower mixes provided significantly greater floral display area than unmanaged weedy control plots. Mixes also attracted greater abundance and richness of wild bees, although the identity of best mixes varied among regions. By partitioning floral display size from mix identity we show the importance of display size for attracting abundant and diverse wild bees. Season-long monitoring also revealed that designing mixes to provide continuous bloom throughout the growing season is critical to supporting the greatest pollinator species richness. Contrary to expectation, perennials bloomed in their first season, and complementarity in attraction of pollinators among annuals and perennials suggests that inclusion of functionally diverse species may provide the greatest benefit. Wildflower mixes may be particularly important for providing resources for some taxa, such as bumble bees, which are known to be in decline in several regions of North America. No mix consistently attained the full diversity that was planted. Further study is needed on how to achieve the desired floral display and diversity from seed mixes.

Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program: Plan and Summary of 1982 Progress.

DTIC Science & Technology

1983-08-01

Program Acquisition Schedule A-8 LIST OF TABLES TABLE TITLE Page 1 Evolution of the ELF Communications Ecological 2 Moni tori ng Program 2 Summary of...performed on plots in maple-dominant, mixed hardwood stands in Michigan. NATIVE BEES Bees are important pollinators of flowering plants and are...SMALL MAMMALS AND NESTING BIRDS Small mammals and nesting birds represent an ecological level inter- mediate between plants and strict carnivores

Effects of honey bee (Hymenoptera: Apidae) and bumble bee (Hymenoptera: Apidae) presence on cranberry (Ericales: Ericaceae) pollination.

PubMed

Evans, E C; Spivak, M

2006-06-01

Honey bees, Apis mellifera L., are frequently used to pollinate commercial cranberries, Vaccinium macrocarpon Ait., but information is lacking on the relative contribution of honey bees and native bees, the effects of surrounding vegetation on bee visitation, and on optimal timing for honey bee introduction. We begin with a descriptive study of numbers of honey bees, bumble bees, and other bees visiting cranberry blossoms, and their subsequent effect on cranberry yield, on three cranberry properties in 1999. The property surrounded by agricultural land, as opposed to wetlands and woodlands, had fewer numbers of all bee types. In 2000, one property did not introduce honey bee colonies, providing an opportunity to document the effect of lack of honey bees on yield. With no honey bees, plants along the edge of the bed had significantly higher berry weights compared with nonedge plants, suggesting that wild pollinators were only effective along the edge. Comparing the same bed between 1999, with three honey bee colonies per acre, and 2000, with no honey bees, we found a significant reduction in average berry size. In 2000, we compared stigma loading on properties with and without honey bees. Significantly more stigmas received the minimum number of tetrads required for fruit set on the property with honey bees. Significantly more tetrads were deposited during mid-bloom compared with early bloom, indicating that mid-bloom was the best time to have honey bees present. This study emphasizes the importance and effectiveness of honey bees as pollinators of commercial size cranberry plantings.

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.

'Bee hotels' as tools for native pollinator conservation: a premature verdict?

PubMed

MacIvor, J Scott; Packer, Laurence

2015-01-01

Society is increasingly concerned with declining wild bee populations. Although most bees nest in the ground, considerable effort has centered on installing 'bee hotels'--also known as nest boxes or trap nests--which artificially aggregate nest sites of above ground nesting bees. Campaigns to 'save the bees' often promote these devices despite the absence of data indicating they have a positive effect. From a survey of almost 600 bee hotels set up over a period of three years in Toronto, Canada, introduced bees nested at 32.9% of sites and represented 24.6% of more than 27,000 total bees and wasps recorded (47.1% of all bees recorded). Native bees were parasitized more than introduced bees and females of introduced bee species provisioned nests with significantly more female larva each year. Native wasps were significantly more abundant than both native and introduced bees and occupied almost 3/4 of all bee hotels each year; further, introduced wasps were the only group to significantly increase in relative abundance year over year. More research is needed to elucidate the potential pitfalls and benefits of using bee hotels in the conservation and population dynamics of wild native bees.

‘Bee Hotels’ as Tools for Native Pollinator Conservation: A Premature Verdict?

PubMed Central

MacIvor, J. Scott; Packer, Laurence

2015-01-01

Society is increasingly concerned with declining wild bee populations. Although most bees nest in the ground, considerable effort has centered on installing ‘bee hotels’—also known as nest boxes or trap nests—which artificially aggregate nest sites of above ground nesting bees. Campaigns to ‘save the bees’ often promote these devices despite the absence of data indicating they have a positive effect. From a survey of almost 600 bee hotels set up over a period of three years in Toronto, Canada, introduced bees nested at 32.9% of sites and represented 24.6% of more than 27,000 total bees and wasps recorded (47.1% of all bees recorded). Native bees were parasitized more than introduced bees and females of introduced bee species provisioned nests with significantly more female larva each year. Native wasps were significantly more abundant than both native and introduced bees and occupied almost 3/4 of all bee hotels each year; further, introduced wasps were the only group to significantly increase in relative abundance year over year. More research is needed to elucidate the potential pitfalls and benefits of using bee hotels in the conservation and population dynamics of wild native bees. PMID:25785609

Climate warming and the potential extinction of fig wasps, the obligate pollinators of figs.

PubMed

Jevanandam, Nanthinee; Goh, Alexander G R; Corlett, Richard T

2013-06-23

Figs (Ficus) have a reciprocally obligate mutualism with tiny, short-lived (1-2 days) fig wasps (Agaonidae). The small size and short life of these pollinators is expected to make them more vulnerable to climate change than their larger and longer-lived hosts. We experimentally tested the thermal tolerances of four species of adult female fig wasp from equatorial Singapore. The results suggest that an increase of 3°C or more above the current temperatures experienced across much of the equatorial tropics would markedly decrease the active adult lifespan of all four species. Fig plants are the centre of an intricate web of specialist and generalist animals. Unless fig wasps can acclimate or adapt to warmer temperatures in time, these responses may disrupt the mutualism, potentially affecting multiple trophic levels.

Isolating Fungal Pathogens from a Dynamic Disease Outbreak in a Native Plant Population to Establish Plant-Pathogen Bioassays for the Ecological Model Plant Nicotiana attenuata

PubMed Central

Schuck, Stefan; Baldwin, Ian T.

2014-01-01

The wild tobacco species Nicotiana attenuata has been intensively used as a model plant to study its interaction with insect herbivores and pollinators in nature, however very little is known about its native pathogen community. We describe a fungal disease outbreak in a native N. attenuata population comprising 873 plants growing in an area of about 1500 m2. The population was divided into 14 subpopulations and disease symptom development in the subpopulations was monitored for 16 days, revealing a waxing and waning of visible disease symptoms with some diseased plants recovering fully. Native fungal N. attenuata pathogens were isolated from diseased plants, characterized genetically, chemotaxonomically and morphologically, revealing several isolates of the ascomycete genera Fusarium and Alternaria, that differed in the type and strength of the disease symptoms they caused in bioassays on either detached leaves or intact soil-grown plants. These isolates and the bioassays will empower the study of N. attenuata-pathogen interactions in a realistic ecological context. PMID:25036191

Safeguarding Ecosystem Services: A Methodological Framework to Buffer the Joint Effect of Habitat Configuration and Climate Change.

PubMed

Giannini, Tereza C; Tambosi, Leandro R; Acosta, André L; Jaffé, Rodolfo; Saraiva, Antonio M; Imperatriz-Fonseca, Vera L; Metzger, Jean Paul

2015-01-01

Ecosystem services provided by mobile agents are increasingly threatened by the loss and modification of natural habitats and by climate change, risking the maintenance of biodiversity, ecosystem functions, and human welfare. Research oriented towards a better understanding of the joint effects of land use and climate change over the provision of specific ecosystem services is therefore essential to safeguard such services. Here we propose a methodological framework, which integrates species distribution forecasts and graph theory to identify key conservation areas, which if protected or restored could improve habitat connectivity and safeguard ecosystem services. We applied the proposed framework to the provision of pollination services by a tropical stingless bee (Melipona quadrifasciata), a key pollinator of native flora from the Brazilian Atlantic Forest and important agricultural crops. Based on the current distribution of this bee and that of the plant species used to feed and nest, we projected the joint distribution of bees and plants in the future, considering a moderate climate change scenario (following IPPC). We then used this information, the bee's flight range, and the current mapping of Atlantic Forest remnants to infer habitat suitability and quantify local and regional habitat connectivity for 2030, 2050 and 2080. Our results revealed north to south and coastal to inland shifts in the pollinator distribution during the next 70 years. Current and future connectivity maps unraveled the most important corridors, which if protected or restored, could facilitate the dispersal and establishment of bees during distribution shifts. Our results also suggest that coffee plantations from eastern São Paulo and southern Minas Gerais States could suffer a pollinator deficit in the future, whereas pollination services seem to be secured in southern Brazil. Landowners and governmental agencies could use this information to implement new land use schemes. Overall, our proposed methodological framework could help design novel conservational and agricultural practices that can be crucial to conserve ecosystem services by buffering the joint effect of habitat configuration and climate change.

Effects of a non-native cichlid fish (African jewelfish, Hemichromis letourneuxi Sauvage 1880) on a simulated Everglades aquatic community

USGS Publications Warehouse

Schofield, Pamela J.; Slone, Daniel H.; Gregoire, Denise R.; Loftus, William F.

2014-01-01

In an 8-month mesocosm experiment, we examined how a simulated Everglades aquatic community of small native fishes, snails, and shrimp changed with the addition of either a native predator (dollar sunfish Lepomis marginatus) or a non-native predator (African jewelfish Hemichromis letourneuxi) compared to a no-predator control. Two snail species (Planorbella duryi, Physella cubensis) and the shrimp (Palaemonetes paludosus) displayed the strongest predator-treatment effects, with significantly lower biomasses in tanks with Hemichromis. One small native fish (Heterandria formosa) was significantly less abundant in Hemichromis tanks, but there were no significant treatment effects for Gambusia holbrooki, Jordanella floridae, or Pomacea paludosa (applesnail). Overall, there were few treatment differences between native predator and no-predator control tanks. The results suggest that the potential of Hemichromis to affect basal food-web species that link primary producers with higher-level consumers in the aquatic food web, with unknown consequences for Florida waters.

Local bumble bee decline linked to recovery of honey bees, drought effects on floral resources.

PubMed

Thomson, Diane M

2016-10-01

Time series of abundances are critical for understanding how abiotic factors and species interactions affect population dynamics, but are rarely linked with experiments and also scarce for bee pollinators. This gap is important given concerns about declines in some bee species. I monitored honey bee (Apis mellifera) and bumble bee (Bombus spp.) foragers in coastal California from 1999, when feral A. mellifera populations were low due to Varroa destructor, until 2014. Apis mellifera increased substantially, except between 2006 and 2011, coinciding with declines in managed populations. Increases in A. mellifera strongly correlated with declines in Bombus and reduced diet overlap between them, suggesting resource competition consistent with past experimental results. Lower Bombus numbers also correlated with diminished floral resources. Declines in floral abundances were associated with drought and reduced spring rainfall. These results illustrate how competition with an introduced species may interact with climate to drive local decline of native pollinators. © 2016 John Wiley & Sons Ltd/CNRS.

Ascosphaera apis, the entomopathogenic fungus affecting larvae of native bees (Xylocopa augusti): First report in South America.

PubMed

Reynaldi, Francisco J; Lucia, Mariano; Genchi Garcia, María L

2015-01-01

Nowadays several invertebrate pollinators of crops and wild plants are in decline as result of multiple and, sometimes, unknown factors; among them, the modern agricultural practices, pests and diseases are postulated as the most important factors. Bees of the genus Xylocopa are considered effective pollinators of passion fruit crops in tropical regions, as well as important pollinators in wild plants, but these bees are attacked by several pathogens that affect different stages in their life cycle. The fungal species of the genus Ascosphaera are commonly associated with social and solitary bee larvae causing chalkbrood disease. The aim of the present study was to demonstrate the presence of Ascosphaera apis affecting larvae of Xylocopa augusti in South America. For this purpose, A. apis was isolated from affected larvae in YGPSA medium. Final identification was run out by three techniques: (1) Microscopic examination of the hyphae and sizes of the fruiting bodies; (2) Mating test, and specific sexual compatibility test, and (3) PCR detection, using specific primers. This study demonstrates for the first time the presence of A. apis affecting larvae of X. augusti in South America. The evidence of A. apis affecting the larvae of X. augusti, and the fact that the sharing of pathogens between different bee species has been underestimated, suggests the need for further epidemiological studies in order to determine not only the prevalence of this pathogen among wild pollinators, but also its relationship to the sudden collapse of honey bee colonies in this region. Copyright © 2014 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Desiccation tolerance, longevity and seed-siring ability of entomophilous pollen from UK native orchid species

PubMed Central

Marks, Timothy R.; Seaton, Philip T.; Pritchard, Hugh W.

2014-01-01

Background and Aims Pollinator-limited seed-set in some terrestrial orchids is compensated for by the presence of long-lived flowers. This study tests the hypothesis that pollen from these insect-pollinated orchids should be desiccation tolerant and relatively long lived using four closely related UK terrestrial species; Anacamptis morio, Dactylorhiza fuchsii, D. maculata and Orchis mascula. Methods Pollen from the four species was harvested from inflorescences and germinated in vitro, both immediately and also after drying to simulate interflower transit. Their tolerance to desiccation and short-term survival was additionally assessed after 3 d equilibration at a range of relative humidities (RHs), and related to constructed sorption isotherms (RH vs. moisture content, MC). Ageing of D. fuchsii pollen was further tested over 2 months against temperature and RH, and the resultant survival curves were subjected to probit analysis, and the distribution of pollen death in time (σ) was determined. The viability and siring ability, following artificial pollinations, were determined in D. fuchsii pollen following storage for 6 years at –20 °C. Key Results The pollen from all four species exhibited systematic increases in germinability and desiccation tolerance as anthesis approached, and pollen from open flowers generally retained high germinability. Short-term storage revealed sensitivity to low RH, whilst optimum survival occurred at comparable RHs in all species. Similarly, estimated pollen life spans (σ) at differing temperatures were longest under the dry conditions. Despite a reduction in germination and seeds per capsule, long-term storage of D. fuchsii pollen did not impact on subsequent seed germination in vitro. Conclusions Substantial pollen desiccation tolerance and life span of the four entomophilous orchids reflects a resilient survival strategy in response to unpredictable pollinator visitation, and presents an alternative approach to germplasm conservation. PMID:25006180

Native and nonnative fish populations of the Colorado River are food limited--evidence from new food web analyses

USGS Publications Warehouse

Kennedy, Theodore A.; Cross, Wyatt F.; Hall, Robert O.; Baxter, Colden V.; Rosi-Marshall, Emma J.

2013-01-01

Fish populations in the Colorado River downstream from Glen Canyon Dam appear to be limited by the availability of high-quality invertebrate prey. Midge and blackfly production is low and nonnative rainbow trout in Glen Canyon and native fishes in Grand Canyon consume virtually all of the midge and blackfly biomass that is produced annually. In Glen Canyon, the invertebrate assemblage is dominated by nonnative New Zealand mudsnails, the food web has a simple structure, and transfers of energy from the base of the web (algae) to the top of the web (rainbow trout) are inefficient. The food webs in Grand Canyon are more complex relative to Glen Canyon, because, on average, each species in the web is involved in more interactions and feeding connections. Based on theory and on studies from other ecosystems, the structure and organization of Grand Canyon food webs should make them more stable and less susceptible to large changes following perturbations of the flow regime relative to food webs in Glen Canyon. In support of this hypothesis, Grand Canyon food webs were much less affected by a 2008 controlled flood relative to the food web in Glen Canyon.

Competition between introduced and native spiders (Araneae: Linyphiidae)

USGS Publications Warehouse

Houser, J.D.; Ginsberg, Howard S.; Jakob, Elizabeth M.

2014-01-01

The European sheet-web spider Linyphia triangularis (Araneae: Linyphiidae) has become established in Maine, where it often reaches very high densities. Two lines of evidence from previous work suggest that L. triangularis affects populations of the native linyphiid spider Frontinella communis. First, F. communis individuals are relatively scarce in both forest and coastal habitat where L. triangularis is common, but more common where L. triangularis is at low density. Second, in field experiments, F. communis species are less likely to settle in experimental plots when L. triangularis is present, and F. communis disappears from study plots when L. triangularis is introduced. Here we test two mechanisms that may underlie these patterns. First, we tested whether L. triangularis invades and usurps the webs of F. communis. When spiders were released onto webs of heterospecifics, L. triangularis was more likely to take over or share webs of F. communis than the reverse. We also observed natural takeovers of F. communis webs. Second, we explored the hypothesis that L. triangularis reduces prey availability for native species. We sampled flying prey in areas with L. triangularis and those where it had been removed, and found no effect of spider presence on measured prey density. We also found no effect of prey supplementation on web tenacity in F. communis, suggesting that F. communis movements are not highly dependent on prey availability. We conclude that web takeover is likely more important than prey reduction in driving negative effects of L. triangularis on F. communis.

Big city Bombus: using natural history and land-use history to find significant environmental drivers in bumble-bee declines in urban development.

PubMed

Glaum, Paul; Simao, Maria-Carolina; Vaidya, Chatura; Fitch, Gordon; Iulinao, Benjamin

2017-05-01

Native bee populations are critical sources of pollination. Unfortunately, native bees are declining in abundance and diversity. Much of this decline comes from human land-use change. While the effects of large-scale agriculture on native bees are relatively well understood, the effects of urban development are less clear. Understanding urbanity's effect on native bees requires consideration of specific characteristics of both particular bee species and their urban landscape. We surveyed bumble-bee ( Bombus spp.) abundance and diversity in gardens across multiple urban centres in southeastern Michigan. There are significant declines in Bombus abundance and diversity associated with urban development when measured on scales in-line with Bombus flight ability. These declines are entirely driven by declines in females; males showed no response to urbanization. We hypothesize that this is owing to differing foraging strategies between the sexes, and it suggests reduced Bombus colony density in more urban areas. While urbanity reduced Bombus prevalence, results in Detroit imply that 'shrinking cities' potentially offer unique urban paradigms that must be considered when studying wild bee ecology. Results show previously unidentified differences in the effects of urbanity on female and male bumble-bee populations and suggest that urban landscapes can be managed to support native bee conservation.

Big city Bombus: using natural history and land-use history to find significant environmental drivers in bumble-bee declines in urban development

PubMed Central

Simao, Maria-Carolina; Vaidya, Chatura; Fitch, Gordon; Iulinao, Benjamin

2017-01-01

Native bee populations are critical sources of pollination. Unfortunately, native bees are declining in abundance and diversity. Much of this decline comes from human land-use change. While the effects of large-scale agriculture on native bees are relatively well understood, the effects of urban development are less clear. Understanding urbanity's effect on native bees requires consideration of specific characteristics of both particular bee species and their urban landscape. We surveyed bumble-bee (Bombus spp.) abundance and diversity in gardens across multiple urban centres in southeastern Michigan. There are significant declines in Bombus abundance and diversity associated with urban development when measured on scales in-line with Bombus flight ability. These declines are entirely driven by declines in females; males showed no response to urbanization. We hypothesize that this is owing to differing foraging strategies between the sexes, and it suggests reduced Bombus colony density in more urban areas. While urbanity reduced Bombus prevalence, results in Detroit imply that ‘shrinking cities’ potentially offer unique urban paradigms that must be considered when studying wild bee ecology. Results show previously unidentified differences in the effects of urbanity on female and male bumble-bee populations and suggest that urban landscapes can be managed to support native bee conservation. PMID:28573023

Native American Youth and Culturally Sensitive Interventions: A Systematic Review

ERIC Educational Resources Information Center

Jackson, Kelly F.; Hodge, David R.

2010-01-01

Objective: A systematic evaluation of the effectiveness of culturally sensitive interventions (CSIs) with Native American youth was conducted. Method: Electronic bibliographic databases, Web sites, and manual searches were used to identify 11 outcome studies that examined CSI effectiveness with Native American youth. Results: This review found…

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.

Bumble Bee Fauna of Palouse Prairie: Survey of Native Bee Pollinators in a Fragmented Ecosystem

PubMed Central

Hatten, T. D.; Looney, C.; Strange, J. P.; Bosque-Pérez, N. A.

2013-01-01

Bumble bees, Bombus Latreille (Hymenoptera: Apidae:), are dominant pollinators in the northern hemisphere, providing important pollination services for commercial crops and innumerable wild plants. Nationwide declines in several bumble bee species and habitat losses in multiple ecosystems have raised concerns about conservation of this important group. In many regions, such as the Palouse Prairie, relatively little is known about bumble bee communities, despite their critical ecosystem functions. Pitfall trap surveys for ground beetles in Palouse prairie remnants conducted in 2002–2003 contained considerable by-catch of bumble bees. The effects of landscape context, remnant features, year, and season on bumble bee community composition were examined. Additionally, bees captured in 2002–2003 were compared with historic records for the region to assess changes in the presence of individual species. Ten species of bumble bee were captured, representing the majority of the species historically known from the region. Few detectable differences in bumble bee abundances were found among remnants. Community composition differed appreciably, however, based on season, landscape context, and elevation, resulting in different bee assemblages between western, low-lying remnants and eastern, higherelevation remnants. The results suggest that conservation of the still species-rich bumble bee fauna should take into account variability among prairie remnants, and further work is required to adequately explain bumble bee habitat associations on the Palouse. PMID:23902138

Ficus (Moraceae) and fig wasps (Hymenoptera: Chalcidoidea) in Taiwan.

PubMed

Bain, Anthony; Tzeng, Hsy-Yu; Wu, Wen-Jer; Chou, Lien-Siang

2015-12-01

Although Ficus-associated wasp fauna have been extensively researched in Australasia, information on these fauna in Taiwan is not well accessible to scientists worldwide. In this study, we compiled records on the Ficus flora of Taiwan and its associated wasp fauna. Initial agronomic research reports on Ficus were published in Japanese in 1917, followed by reports on applied biochemistry, taxonomy, and phenology in Chinese. On the basis of the phenological knowledge of 15 species of the Ficus flora of Taiwan, recent research has examined the pollinating and nonpollinating agaonid and chalcid wasps (Hymenoptera: Chalcidoidea). Updating records according to the current nomenclature revealed that there are 30 taxa (27 species) of native or naturalized Ficus with an unusually high proportion of dioecious species (78%). Four species were observed to exhibit mutualism with more than one pollinating wasp species, and 18 of the 27 Ficus species were reported with nonpollinating wasp species. The number of nonpollinating wasp species associated with specific Ficus species ranges from zero (F. pumila) to 24 (F. microcarpa). Approximately half of the Taiwanese fig tree species have been studied with basic information on phenology and biology described in peer-reviewed journals or theses. This review provides a solid basis for future in-depth comparative studies. This summary of knowledge will encourage and facilitate continuing research on the pollination dynamics of Ficus and the associated insect fauna in Taiwan.

A food web modeling analysis of a Midwestern, USA eutrophic lake dominated by non-native Common Carp and Zebra Mussels

USGS Publications Warehouse

Colvin, Michael E.; Pierce, Clay; Stewart, Timothy W.

2015-01-01

Food web modeling is recognized as fundamental to understanding the complexities of aquatic systems. Ecopath is the most common mass-balance model used to represent food webs and quantify trophic interactions among groups. We constructed annual Ecopath models for four consecutive years during the first half-decade of a zebra mussel invasion in shallow, eutrophic Clear Lake, Iowa, USA, to evaluate changes in relative biomass and total system consumption among food web groups, evaluate food web impacts of non-native common carp and zebra mussels on food web groups, and to interpret food web impacts in light of on-going lake restoration. Total living biomass increased each year of the study; the majority of the increase due to a doubling in planktonic blue green algae, but several other taxa also increased including a more than two-order of magnitude increase in zebra mussels. Common carp accounted for the largest percentage of total fish biomass throughout the study even with on-going harvest. Chironomids, common carp, and zebra mussels were the top-three ranking consumer groups. Non-native common carp and zebra mussels accounted for an average of 42% of the total system consumption. Despite the relatively high biomass densities of common carp and zebra mussel, food web impacts was minimal due to excessive benthic and primary production in this eutrophic system. Consumption occurring via benthic pathways dominated system consumption in Clear Lake throughout our study, supporting the argument that benthic food webs are significant in shallow, eutrophic lake ecosystems and must be considered if ecosystem-level understanding is to be obtained.

Streamlining Data for Cross-Platform Web Delivery

ERIC Educational Resources Information Center

Watkins, Sean; Battles, Jason; Vacek, Rachel

2013-01-01

Smartphone users expect the presentation of Web sites on their mobile browsers to look and feel like native applications. With the pressure on library Web developers to produce app-like mobile sites, there is often a rush to get a site up without considering the importance of reusing or even restructuring the data driving the Web sites. An…

A neonicotinoid impairs olfactory learning in Asian honey bees (Apis cerana) exposed as larvae or as adults

PubMed Central

Tan, Ken; Chen, Weiwen; Dong, Shihao; Liu, Xiwen; Wang, Yuchong; Nieh, James C.

2015-01-01

Xenobiotics such as the neonicotinoid pesticide, imidacloprid, are used globally, but their effects on native bee species are poorly understood. We studied the effects of sublethal doses of imidacloprid on olfactory learning in the native honey bee species, Apis cerana, an important pollinator of agricultural and native plants throughout Asia. We provide the first evidence that imidacloprid can impair learning in A. cerana workers exposed as adults or as larvae. Adults that ingested a single imidacloprid dose as low as 0.1 ng/bee had significantly reduced olfactory learning acquisition, which was 1.6-fold higher in control bees. Longer-term learning (1-17 h after the last learning trial) was also impaired. Bees exposed as larvae to a total dose of 0.24 ng/bee did not have reduced survival to adulthood. However, these larval-treated bees had significantly impaired olfactory learning when tested as adults: control bees exhibited up to 4.8-fold better short-term learning acquisition, though longer-term learning was not affected. Thus, sublethal cognitive deficits elicited by neonicotinoids on a broad range of native bee species deserve further study. PMID:26086769

Communication and Gamification in the Web-Based Foreign Language Educational System: Web- Based Foreign Language Educational System

ERIC Educational Resources Information Center

Osipov, Ilya V.; Volinsky, Alex A.; Nikulchev, Evgeny; Prasikova, Anna Y.

2016-01-01

The paper describes development of the educational online web communication platform for teaching and learning foreign languages. The main objective was to develop a web application for teaching foreigners to understand casual fluent speech. The system is based on the time bank principle, allowing users to teach others their native language along…

Safeguarding Ecosystem Services: A Methodological Framework to Buffer the Joint Effect of Habitat Configuration and Climate Change

PubMed Central

Giannini, Tereza C.; Tambosi, Leandro R.; Acosta, André L.; Jaffé, Rodolfo; Saraiva, Antonio M.; Imperatriz-Fonseca, Vera L.; Metzger, Jean Paul

2015-01-01

Ecosystem services provided by mobile agents are increasingly threatened by the loss and modification of natural habitats and by climate change, risking the maintenance of biodiversity, ecosystem functions, and human welfare. Research oriented towards a better understanding of the joint effects of land use and climate change over the provision of specific ecosystem services is therefore essential to safeguard such services. Here we propose a methodological framework, which integrates species distribution forecasts and graph theory to identify key conservation areas, which if protected or restored could improve habitat connectivity and safeguard ecosystem services. We applied the proposed framework to the provision of pollination services by a tropical stingless bee (Melipona quadrifasciata), a key pollinator of native flora from the Brazilian Atlantic Forest and important agricultural crops. Based on the current distribution of this bee and that of the plant species used to feed and nest, we projected the joint distribution of bees and plants in the future, considering a moderate climate change scenario (following IPPC). We then used this information, the bee’s flight range, and the current mapping of Atlantic Forest remnants to infer habitat suitability and quantify local and regional habitat connectivity for 2030, 2050 and 2080. Our results revealed north to south and coastal to inland shifts in the pollinator distribution during the next 70 years. Current and future connectivity maps unraveled the most important corridors, which if protected or restored, could facilitate the dispersal and establishment of bees during distribution shifts. Our results also suggest that coffee plantations from eastern São Paulo and southern Minas Gerais States could suffer a pollinator deficit in the future, whereas pollination services seem to be secured in southern Brazil. Landowners and governmental agencies could use this information to implement new land use schemes. Overall, our proposed methodological framework could help design novel conservational and agricultural practices that can be crucial to conserve ecosystem services by buffering the joint effect of habitat configuration and climate change. PMID:26091014

American Indian and Alaska Native Heart Disease and Stroke

MedlinePlus

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No Natives Here: A Focus Group Study of Student Perceptions of Web 2.0 and the Academic Library

ERIC Educational Resources Information Center

Burhanna, Kenneth J.; Seeholzer, Jamie

2009-01-01

This study explores Web 2.0 technologies in an academic library through focus groups with undergraduates at Kent State University. Results reveal that students, despite being heavy users, are less sophisticated and expressive in their use of Web 2.0 than presumed. Students set clear boundaries between educational and social spaces on the Web, and…

Plugin free remote visualization in the browser

NASA Astrophysics Data System (ADS)

Tamm, Georg; Slusallek, Philipp

2015-01-01

Today, users access information and rich media from anywhere using the web browser on their desktop computers, tablets or smartphones. But the web evolves beyond media delivery. Interactive graphics applications like visualization or gaming become feasible as browsers advance in the functionality they provide. However, to deliver large-scale visualization to thin clients like mobile devices, a dedicated server component is necessary. Ideally, the client runs directly within the browser the user is accustomed to, requiring no installation of a plugin or native application. In this paper, we present the state-of-the-art of technologies which enable plugin free remote rendering in the browser. Further, we describe a remote visualization system unifying these technologies. The system transfers rendering results to the client as images or as a video stream. We utilize the upcoming World Wide Web Consortium (W3C) conform Web Real-Time Communication (WebRTC) standard, and the Native Client (NaCl) technology built into Chrome, to deliver video with low latency.

Exploring Fish Diversity as a Determinant of Ecosystem Properties in Aquatic Food Webs

ERIC Educational Resources Information Center

Carey, Michael P.

2009-01-01

Dramatic biodiversity changes occurring globally from species loss and invasion have altered native food webs and ecosystem processes. My research objectives are to understand the consequences of fish diversity to freshwater systems by (1) examining the food web consequences of multiple top predators, (2) determining how biodiversity influences…

Pollination and reproduction of an invasive plant inside and outside its ancestral range

NASA Astrophysics Data System (ADS)

Petanidou, Theodora; Price, Mary V.; Bronstein, Judith L.; Kantsa, Aphrodite; Tscheulin, Thomas; Kariyat, Rupesh; Krigas, Nikos; Mescher, Mark C.; De Moraes, Consuelo M.; Waser, Nickolas M.

2018-05-01

Comparing traits of invasive species within and beyond their ancestral range may improve our understanding of processes that promote aggressive spread. Solanum elaeagnifolium (silverleaf nightshade) is a noxious weed in its ancestral range in North America and is invasive on other continents. We compared investment in flowers and ovules, pollination success, and fruit and seed set in populations from Arizona, USA ("AZ") and Greece ("GR"). In both countries, the populations we sampled varied in size and types of present-day disturbance. Stature of plants increased with population size in AZ samples whereas GR plants were uniformly tall. Taller plants produced more flowers, and GR plants produced more flowers for a given stature and allocated more ovules per flower. Similar functional groups of native bees pollinated in AZ and GR populations, but visits to flowers decreased with population size and we observed no visits in the largest GR populations. As a result, plants in large GR populations were pollen-limited, and estimates of fecundity were lower on average in GR populations despite the larger allocation to flowers and ovules. These differences between plants in our AZ and GR populations suggest promising directions for further study. It would be useful to sample S. elaeagnifolium in Mediterranean climates within the ancestral range (e.g., in California, USA), to study asexual spread via rhizomes, and to use common gardens and genetic studies to explore the basis of variation in allocation patterns and of relationships between visitation and fruit set.

Pollen dispersal of tropical trees (Dinizia excelsa: Fabaceae) by native insects and African honeybees in pristine and fragmented Amazonian rainforest.

PubMed

Dick, Christopher W; Etchelecu, Gabriela; Austerlitz, Frédéric

2003-03-01

Tropical rainforest trees typically occur in low population densities and rely on animals for cross-pollination. It is of conservation interest therefore to understand how rainforest fragmentation may alter the pollination and breeding structure of remnant trees. Previous studies of the Amazonian tree Dinizia excelsa (Fabaceae) found African honeybees (Apis mellifera scutellata) as the predominant pollinators of trees in highly disturbed habitats, transporting pollen up to 3.2 km between pasture trees. Here, using microsatellite genotypes of seed arrays, we compare outcrossing rates and pollen dispersal distances of (i) remnant D. excelsa in three large ranches, and (ii) a population in undisturbed forest in which African honeybees were absent. Self-fertilization was more frequent in the disturbed habitats (14%, n = 277 seeds from 12 mothers) than in undisturbed forest (10%, n = 295 seeds from 13 mothers). Pollen dispersal was extensive in all three ranches compared to undisturbed forest, however. Using a twogener analysis, we estimated a mean pollen dispersal distance of 1509 m in Colosso ranch, assuming an exponential dispersal function, and 212 m in undisturbed forest. The low effective density of D. excelsa in undisturbed forest (approximately 0.1 trees/ha) indicates that large areas of rainforest must be preserved to maintain minimum viable populations. Our results also suggest, however, that in highly disturbed habitats Apis mellifera may expand genetic neighbourhood areas, thereby linking fragmented and continuous forest populations.

Trap Nesting Wasps and Bees in Agriculture: A Comparison of Sown Wildflower and Fallow Plots in Florida

PubMed Central

Smithers, Cherice; Irvin, Allyn; Stanley-Stahr, Cory; Daniels, Jaret C.; Ellis, James D.

2017-01-01

Wildflower strip plantings in intensive agricultural systems have become a widespread tool for promoting pollination services and biological conservation because of their use by wasps and bees. Many of the trap-nesting wasps are important predators of common crop pests, and cavity-nesting bees that utilize trap-nests are important pollinators for native plants and many crops. The impact of wildflower strips on the nesting frequency of trap-nesting wasps or bees within localized areas has not been thoroughly investigated. Trap-nests made of bamboo reeds (Bambusa sp.) were placed adjacent to eight 0.1 ha wildflower plots and paired fallow areas (control plots) to determine if wildflower strips encourage the nesting of wasps and bees. From August 2014 to November 2015, occupied reeds were gathered and adults were collected as they emerged from the trap-nests. Treatment (wildflower or fallow plots) did not impact the number of occupied reeds or species richness of trap-nesting wasps using the occupied reeds. The wasps Pachodynerus erynnis, Euodynerus megaera, Parancistrocerus pedestris, and Isodontia spp. were the most common trap-nesting species collected. Less than 2% of the occupied reeds contained bees, and all were from the genus Megachile. The nesting wasp and bee species demonstrated preferences for reeds with certain inside diameters (IDs). The narrow range of ID preferences exhibited by each bee/wasp may provide opportunities to take advantage of their natural histories for biological control and/or pollination purposes. PMID:28994726

The Complex Demographic History and Evolutionary Origin of the Western Honey Bee, Apis Mellifera

PubMed Central

Tsutsui, Neil D.; Ramírez, Santiago R.

2017-01-01

The western honey bee, Apis mellifera, provides critical pollination services to agricultural crops worldwide. However, despite substantial interest and prior investigation, the early evolution and subsequent diversification of this important pollinator remain uncertain. The primary hypotheses place the origin of A. mellifera in either Asia or Africa, with subsequent radiations proceeding from one of these regions. Here, we use two publicly available whole-genome data sets plus newly sequenced genomes and apply multiple population genetic analysis methods to investigate the patterns of ancestry and admixture in native honey bee populations from Europe, Africa, and the Middle East. The combination of these data sets is critical to the analyses, as each contributes samples from geographic locations lacking in the other, thereby producing the most complete set of honey bee populations available to date. We find evidence supporting an origin of A. mellifera in the Middle East or North Eastern Africa, with the A and Y lineages representing the earliest branching lineages. This finding has similarities with multiple contradictory hypotheses and represents a disentangling of genetic relationships, geographic proximity, and secondary contact to produce a more accurate picture of the origins of A. mellifera. We also investigate how previous studies came to their various conclusions based on incomplete sampling of populations, and illustrate the importance of complete sampling in understanding evolutionary processes. These results provide fundamental knowledge about genetic diversity within Old World honey bee populations and offer insight into the complex history of an important pollinator. PMID:28164223

A 4-year study of invasive and native spider populations in Maine

USGS Publications Warehouse

Jakob, Elizabeth M.; Porter, Adam H.; Ginsberg, Howard; Bednarski, Julie V.; Houser, Jeremy

2011-01-01

Invasive spiders pose potential threats to native spiders. In 2002, the European spider Linyphia triangularis (Clerck, 1757) (Araneae: Linyphiidae) was discovered in all but one county in Maine. At Acadia National Park, we conducted a 4-year study of L. triangularis and three native linyphiid species of a similar size (Frontinella communis (Hentz, 1850), Pityohyphantes subarcticus Chamberlin and Ivie, 1943, and Neriene radiata (Walckenaer, 1842)). Using line-transect surveys, we measured population densities in coastal and forest habitat. The density of L. triangularis varied across years but was always significantly higher on the coast than in the forest. In contrast, only one native species was present on the coast and at very low numbers. Coastal L. triangularis were larger and in better condition than those in the forest, and numbers and biomass of insect prey were also higher on the coast. In 2 years, we also conducted transects at a second coastal location in Maine where the invader was at low density. At that site, native densities were substantially higher than at either Acadia site. Our data are consistent with the hypothesis that L. triangularis is reducing populations of native spiders. Companion studies suggest that L. triangularis negatively impacts natives by usurping both web sites and webs.

Phraseology and Frequency of Occurrence on the Web: Native Speakers' Perceptions of Google-Informed Second Language Writing

ERIC Educational Resources Information Center

Geluso, Joe

2013-01-01

Usage-based theories of language learning suggest that native speakers of a language are acutely aware of formulaic language due in large part to frequency effects. Corpora and data-driven learning can offer useful insights into frequent patterns of naturally occurring language to second/foreign language learners who, unlike native speakers, are…

Sharing Tails®: A State-Wide Public Outreach Program Teaching Children about Native Arizona Fish

ERIC Educational Resources Information Center

Pacey, Carol A.; Marsh, Paul C.

2013-01-01

Limited public outreach programs about Arizona native fish exist and those that do are passive, fee-based, or Web-oriented, while others limit their geographic range. The program this article addresses sought to improve this situation with development of a state-wide outreach program with a goal to educate Arizona's children about native fish with…

Colonies of Bumble Bees (Bombus impatiens) Produce Fewer Workers, Less Bee Biomass, and Have Smaller Mother Queens Following Fungicide Exposure.

PubMed

Bernauer, Olivia M; Gaines-Day, Hannah R; Steffan, Shawn A

2015-06-01

Bees provide vital pollination services to the majority of flowering plants in both natural and agricultural systems. Unfortunately, both native and managed bee populations are experiencing declines, threatening the persistence of these plants and crops. Agricultural chemicals are one possible culprit contributing to bee declines. Even fungicides, generally considered safe for bees, have been shown to disrupt honey bee development and impair bumble bee behavior. Little is known, however, how fungicides may affect bumble bee colony growth. We conducted a controlled cage study to determine the effects of fungicide exposure on colonies of a native bumble bee species (Bombus impatiens). Colonies of B. impatiens were exposed to flowers treated with field-relevant levels of the fungicide chlorothalonil over the course of one month. Colony success was assessed by the number and biomass of larvae, pupae, and adult bumble bees. Bumble bee colonies exposed to fungicide produced fewer workers, lower total bee biomass, and had lighter mother queens than control colonies. Our results suggest that fungicides negatively affect the colony success of a native bumble bee species and that the use of fungicides during bloom has the potential to severely impact the success of native bumble bee populations foraging in agroecosystems.

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.

XMM-Newton Mobile Web Application

NASA Astrophysics Data System (ADS)

Ibarra, A.; Kennedy, M.; Rodríguez, P.; Hernández, C.; Saxton, R.; Gabriel, C.

2013-10-01

We present the first XMM-Newton web mobile application, coded using new web technologies such as HTML5, the Query mobile framework, and D3 JavaScript data-driven library. This new web mobile application focuses on re-formatted contents extracted directly from the XMM-Newton web, optimizing the contents for mobile devices. The main goals of this development were to reach all kind of handheld devices and operating systems, while minimizing software maintenance. The application therefore has been developed as a web mobile implementation rather than a more costly native application. New functionality will be added regularly.

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.

Desiccation tolerance, longevity and seed-siring ability of entomophilous pollen from UK native orchid species.

PubMed

Marks, Timothy R; Seaton, Philip T; Pritchard, Hugh W

2014-09-01

Pollinator-limited seed-set in some terrestrial orchids is compensated for by the presence of long-lived flowers. This study tests the hypothesis that pollen from these insect-pollinated orchids should be desiccation tolerant and relatively long lived using four closely related UK terrestrial species; Anacamptis morio, Dactylorhiza fuchsii, D. maculata and Orchis mascula. Pollen from the four species was harvested from inflorescences and germinated in vitro, both immediately and also after drying to simulate interflower transit. Their tolerance to desiccation and short-term survival was additionally assessed after 3 d equilibration at a range of relative humidities (RHs), and related to constructed sorption isotherms (RH vs. moisture content, MC). Ageing of D. fuchsii pollen was further tested over 2 months against temperature and RH, and the resultant survival curves were subjected to probit analysis, and the distribution of pollen death in time (σ) was determined. The viability and siring ability, following artificial pollinations, were determined in D. fuchsii pollen following storage for 6 years at -20 °C. The pollen from all four species exhibited systematic increases in germinability and desiccation tolerance as anthesis approached, and pollen from open flowers generally retained high germinability. Short-term storage revealed sensitivity to low RH, whilst optimum survival occurred at comparable RHs in all species. Similarly, estimated pollen life spans (σ) at differing temperatures were longest under the dry conditions. Despite a reduction in germination and seeds per capsule, long-term storage of D. fuchsii pollen did not impact on subsequent seed germination in vitro. Substantial pollen desiccation tolerance and life span of the four entomophilous orchids reflects a resilient survival strategy in response to unpredictable pollinator visitation, and presents an alternative approach to germplasm conservation. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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.

A simple model of bipartite cooperation for ecological and organizational networks.

PubMed

Saavedra, Serguei; Reed-Tsochas, Felix; Uzzi, Brian

2009-01-22

In theoretical ecology, simple stochastic models that satisfy two basic conditions about the distribution of niche values and feeding ranges have proved successful in reproducing the overall structural properties of real food webs, using species richness and connectance as the only input parameters. Recently, more detailed models have incorporated higher levels of constraint in order to reproduce the actual links observed in real food webs. Here, building on previous stochastic models of consumer-resource interactions between species, we propose a highly parsimonious model that can reproduce the overall bipartite structure of cooperative partner-partner interactions, as exemplified by plant-animal mutualistic networks. Our stochastic model of bipartite cooperation uses simple specialization and interaction rules, and only requires three empirical input parameters. We test the bipartite cooperation model on ten large pollination data sets that have been compiled in the literature, and find that it successfully replicates the degree distribution, nestedness and modularity of the empirical networks. These properties are regarded as key to understanding cooperation in mutualistic networks. We also apply our model to an extensive data set of two classes of company engaged in joint production in the garment industry. Using the same metrics, we find that the network of manufacturer-contractor interactions exhibits similar structural patterns to plant-animal pollination networks. This surprising correspondence between ecological and organizational networks suggests that the simple rules of cooperation that generate bipartite networks may be generic, and could prove relevant in many different domains, ranging from biological systems to human society.

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

Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants.

PubMed

Friedman, Jannice; Barrett, Spencer C H

2009-06-01

The rich literature that characterizes the field of pollination biology has focused largely on animal-pollinated plants. At least 10 % of angiosperms are wind pollinated, and this mode of pollination has evolved on multiple occasions among unrelated lineages, and hence this discrepancy in research interest is surprising. Here, the evolution and functional ecology of pollination and mating in wind-pollinated plants are discussed, a theoretical framework for modelling the selection of wind pollination is outlined, and pollen capture and the occurrence of pollen limitation in diverse wind-pollinated herbs are investigated experimentally. Wind pollination may commonly evolve to provide reproductive assurance when pollinators are scarce. Evidence is presented that pollen limitation in wind-pollinated plants may not be as common as it is in animal-pollinated species. The studies of pollen capture in wind-pollinated herbs demonstrate that pollen transfer efficiency is not substantially lower than in animal-pollinated plants as is often assumed. These findings challenge the explanation that the evolution of few ovules in wind-pollinated flowers is associated with low pollen loads. Floral and inflorescence architecture is crucial to pollination and mating because of the aerodynamics of wind pollination. Evidence is provided for the importance of plant height, floral position, and stamen and stigma characteristics in promoting effective pollen dispersal and capture. Finally, it is proposed that geitonogamous selfing may alleviate pollen limitation in many wind-pollinated plants with unisexual flowers.

Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants

PubMed Central

Friedman, Jannice; Barrett, Spencer C. H.

2009-01-01

Background The rich literature that characterizes the field of pollination biology has focused largely on animal-pollinated plants. At least 10 % of angiosperms are wind pollinated, and this mode of pollination has evolved on multiple occasions among unrelated lineages, and hence this discrepancy in research interest is surprising. Here, the evolution and functional ecology of pollination and mating in wind-pollinated plants are discussed, a theoretical framework for modelling the selection of wind pollination is outlined, and pollen capture and the occurrence of pollen limitation in diverse wind-pollinated herbs are investigated experimentally. Scope and Conclusions Wind pollination may commonly evolve to provide reproductive assurance when pollinators are scarce. Evidence is presented that pollen limitation in wind-pollinated plants may not be as common as it is in animal-pollinated species. The studies of pollen capture in wind-pollinated herbs demonstrate that pollen transfer efficiency is not substantially lower than in animal-pollinated plants as is often assumed. These findings challenge the explanation that the evolution of few ovules in wind-pollinated flowers is associated with low pollen loads. Floral and inflorescence architecture is crucial to pollination and mating because of the aerodynamics of wind pollination. Evidence is provided for the importance of plant height, floral position, and stamen and stigma characteristics in promoting effective pollen dispersal and capture. Finally, it is proposed that geitonogamous selfing may alleviate pollen limitation in many wind-pollinated plants with unisexual flowers. PMID:19218583

The relative contribution of diurnal and nocturnal pollinators to plant female fitness in a specialized nursery pollination system.

PubMed

Scopece, Giovanni; Campese, Lucia; Duffy, Karl J; Cozzolino, Salvatore

2018-02-01

Plants involved in specialized pollinator interactions, such as nursery pollination, may experience trade-offs in their female fitness, as the larvae of their pollinators may also consume seeds produced by the flowers they pollinate. These interactions could potentially shift between mutualism and parasitism, depending on the presence and abundance of both the nursery pollinator and of other pollinators. We investigated the fitness trade-off in a Mediterranean plant ( Silene latifolia ), which has a specialist nocturnal nursery pollinator moth ( Hadena bicruris ) and is also visited by several diurnal pollinators. We estimated the pollination rates and fecundity of S. latifolia in both natural and experimental populations in the Mediterranean. We estimated natural pollination rates in different flowering times and with presence/absence of the H. bicruis moth. Then by exposing plants to each pollinator group either during the day or at night, we quantified the contribution of other diurnal pollinators and the specialized nocturnal nursery pollinator to plant female fitness. We found no difference in plant fruit set mediated by diurnal versus nocturnal pollinators, indicating that non-specialist pollinators contribute to plant female fitness. However, in both natural and experimental populations, H. bicruris was the most efficient pollinator in terms of seeds produced per fruit. These results suggest that the female fitness costs generated by nursery pollination can be overcome through higher fertilization rates relative to predation rates, even in the presence of co-pollinators. Quantifying such interactions is important for our understanding of the selective pressures that promote highly specialized mutualisms, such as nursery pollination, in the Mediterranean region, a centre of diversification of the carnation family.

Are there pollination syndromes in the Australian epacrids (Ericaceae: Styphelioideae)? A novel statistical method to identify key floral traits per syndrome

PubMed Central

Johnson, Karen A.

2013-01-01

Background and Aims Convergent floral traits hypothesized as attracting particular pollinators are known as pollination syndromes. Floral diversity suggests that the Australian epacrid flora may be adapted to pollinator type. Currently there are empirical data on the pollination systems for 87 species (approx. 15 % of Australian epacrids). This provides an opportunity to test for pollination syndromes and their important morphological traits in an iconic element of the Australian flora. Methods Data on epacrid–pollinator relationships were obtained from published literature and field observation. A multivariate approach was used to test whether epacrid floral attributes related to pollinator profiles. Statistical classification was then used to rank floral attributes according to their predictive value. Data sets excluding mixed pollination systems were used to test the predictive power of statistical classification to identify pollination models. Key Results Floral attributes are correlated with bird, fly and bee pollination. Using floral attributes identified as correlating with pollinator type, bird pollination is classified with 86 % accuracy, red flowers being the most important predictor. Fly and bee pollination are classified with 78 and 69 % accuracy, but have a lack of individually important floral predictors. Excluding mixed pollination systems improved the accuracy of the prediction of both bee and fly pollination systems. Conclusions Although most epacrids have generalized pollination systems, a correlation between bird pollination and red, long-tubed epacrids is found. Statistical classification highlights the relative importance of each floral attribute in relation to pollinator type and proves useful in classifying epacrids to bird, fly and bee pollination systems. PMID:23681546

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

Perspectives on trans-Pacific biological invasions

USGS Publications Warehouse

Guo, Q.

2002-01-01

Trans-Pacific biological invasion is one of the most striking and influential biological phenomena occurring in modern times and the process is still accelerating, and the associated invasives form neo-disjuncts (cf. many well-known paleo-disjuncts) between eastern Asia and North America. To better understand this phenomenon and the related taxa, I address the following questions: 1) what types of species (e.g., life/growth form) have been, or are likely to be, associated with trans-Pacific (eastern Asia, North America) invasions; 2) what has happened or may happen to these species after their remote geographic separation, and 3) what aspects of these species and their native and non-native habitats should be better understood for improved control. To answer these questions, comparisons of the invasive species' characteristics in their native and invaded habitats need to be examined, including: l) genetics, 2) life history/morphology (e.g., plant size, seed size, etc.), 3) ecology (e.g., life/growth forms, pollinators, competitors), 4) distributions (e.g., range size, shape, latitude) in their native (source) and introduced (target) ranges or habitats, and 5) physical factors such as soil, water, and climate. The purpose of these studies is 1) to identify the limiting factors that restrict the distributions of exotic species in native ranges, 2) to understand why invasive species are successful in the introduced ranges, 3) to predict possible future invasions, and, ultimately, 4) to provide information for more efficient and effective management.

Pollination implications of the diverse diet of tropical nectar-feeding bats roosting in an urban cave.

PubMed

Lim, Voon-Ching; Ramli, Rosli; Bhassu, Subha; Wilson, John-James

2018-01-01

Intense landscaping often alters the plant composition in urban areas. Knowing which plant species that pollinators are visiting in urban areas is necessary for understanding how landscaping impacts biodiversity and associated ecosystem services. The cave nectar bat, Eonycteris spelaea , is an important pollinator for many plants and is often recorded in human-dominated habitats. Previous studies of the diet of E. spelaea relied on morphological identification of pollen grains found in faeces and on the body of bats and by necessity disregarded other forms of digested plant material present in the faeces (i.e., plant juice and remnants). The main objective of this study was to examine the diet of the nectarivorous bat, E. spelaea, roosting in an urban cave at Batu Caves, Peninsular Malaysia by identifying the plant material present in the faeces of bats using DNA metabarcoding. Faeces were collected under the roost of E. spelaea once a week from December 2015 to March 2016. Plant DNA was extracted from the faeces, Polymerase chain reaction (PCR) amplified at ITS2 and rbcL regions and mass sequenced. The resultant plant operational taxonomic units were searched against NCBI GenBank for identification. A total of 55 species of plants were detected from faeces of E. spelaea including Artocarpus heterophyllus, Duabanga grandiflora and Musa spp. which are likely to be important food resources for the cave nectar bat. Many native plant species that had not been reported in previous dietary studies of E. spelaea were detected in this study including Bauhinia strychnoidea and Urophyllum leucophlaeum , suggesting that E. spelaea remains a crucial pollinator for these plants even in highly disturbed habitats. The detection of many introduced plant species in the bat faeces indicates that E. spelaea are exploiting them, particularly Xanthostemon chrysanthus, as food resources in urban area. Commercial food crops were detected from all of the faecal samples, suggesting that E. spelaea feed predominantly on the crops particularly jackfruit and banana and play a significant role in pollination of economically important plants. Ferns and figs were also detected in the faeces of E. spelaea suggesting future research avenues to determine whether the 'specialised nectarivorous' E. spelaea feed opportunistically on other parts of plants.

Floral resource availability from groundcover promotes bee abundance in coffee agroecosystems.

PubMed

Fisher, Kaleigh; Gonthier, David J; Ennis, Katherine K; Perfecto, Ivette

2017-09-01

Patterns of bee abundance and diversity across different spatial scales have received thorough research consideration. However, the impact of short- and long-term temporal resource availability on biodiversity has been less explored. This is highly relevant in tropical agricultural systems for pollinators, as many foraging periods of pollinators extend beyond flowering of any single crop species. In this study, we sought to understand how bee communities in tropical agroecosystems changed between seasons, and if short- and long-term floral resource availability influenced their diversity and abundance. We used a threshold analysis approach in order to explore this relationship at two time scales. This study took place in a region dominated by coffee agroecosystems in Southern Mexico. This was an ideal system because the landscape offers a range of coffee management regimes that maintain heterogeneity in floral resource availability spatially and temporally. We found that the bee community varies significantly between seasons. There were higher abundances of native social, solitary and managed honey bees during the dry season when coffee flowers. Additionally, we found that floral resources from groundcover, but not trees, were associated with bee abundance. Further, the temporal scale of the availability of these resources is important, whereby short-term floral resource availability appears particularly important in maintaining high bee abundance at sites with lower seasonal complementarity. We argue that in addition to spatial resource heterogeneity, temporal resource heterogeneity is critical in explaining bee community patterns, and should thus be considered to promote pollinator conservation. © 2017 by the Ecological Society of America.

The Complex Demographic History and Evolutionary Origin of the Western Honey Bee, Apis Mellifera.

PubMed

Cridland, Julie M; Tsutsui, Neil D; Ramírez, Santiago R

2017-02-01

The western honey bee, Apis mellifera, provides critical pollination services to agricultural crops worldwide. However, despite substantial interest and prior investigation, the early evolution and subsequent diversification of this important pollinator remain uncertain. The primary hypotheses place the origin of A. mellifera in either Asia or Africa, with subsequent radiations proceeding from one of these regions. Here, we use two publicly available whole-genome data sets plus newly sequenced genomes and apply multiple population genetic analysis methods to investigate the patterns of ancestry and admixture in native honey bee populations from Europe, Africa, and the Middle East. The combination of these data sets is critical to the analyses, as each contributes samples from geographic locations lacking in the other, thereby producing the most complete set of honey bee populations available to date. We find evidence supporting an origin of A. mellifera in the Middle East or North Eastern Africa, with the A and Y lineages representing the earliest branching lineages. This finding has similarities with multiple contradictory hypotheses and represents a disentangling of genetic relationships, geographic proximity, and secondary contact to produce a more accurate picture of the origins of A. mellifera. We also investigate how previous studies came to their various conclusions based on incomplete sampling of populations, and illustrate the importance of complete sampling in understanding evolutionary processes. These results provide fundamental knowledge about genetic diversity within Old World honey bee populations and offer insight into the complex history of an important pollinator. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Competitive Interactions between Invasive Nile Tilapia and Native Fish: The Potential for Altered Trophic Exchange and Modification of Food Webs

PubMed Central

Martin, Charles W.; Valentine, Marla M.; Valentine, John F.

2010-01-01

Recent studies have highlighted both the positive and negative impacts of species invasions. Most of these studies have been conducted on either immobile invasive plants or sessile fauna found at the base of food webs. Fewer studies have examined the impacts of vagile invasive consumers on native competitors. This is an issue of some importance given the controlling influence that consumers have on lower order plants and animals. Here, we present results of laboratory experiments designed to assess the impacts of unintended aquaculture releases of the Nile tilapia (Oreochromis niloticus), in estuaries of the Gulf of Mexico, on the functionally similar redspotted sunfish (Lepomis miniatus). Laboratory choice tests showed that tilapia prefer the same structured habitat that native sunfish prefer. In subsequent interspecific competition experiments, agonistic tilapia displaced sunfish from their preferred structured habitats. When a piscivore (largemouth bass) was present in the tank with both species, the survival of sunfish decreased. Based on these findings, if left unchecked, we predict that the proliferation of tilapia (and perhaps other aggressive aquaculture fishes) will have important detrimental effects on the structure of native food webs in shallow, structured coastal habitats. While it is likely that the impacts of higher trophic level invasive competitors will vary among species, these results show that consequences of unintended releases of invasive higher order consumers can be important. PMID:21200433

Food sources of dominant macrozoobenthos between native and non-native mangrove forests: A comparative study

NASA Astrophysics Data System (ADS)

Chen, Luzhen; Yan, Ting; Xiong, Yiyi; Zhang, Yihui; Lin, Guanghui

2017-03-01

The macrozoobenthos is an important link of the food web in coastal wetlands. Diet-habitat relationships may significantly depend on qualitative differences and seasonal availability of food sources. Increasing interest has been shown in food web structure altered by non-native plants. In particular, however, a non-native mangrove species from Bangladesh, Sonneratia apetala, has been widely planted in China, but little is known about its possible impact on food sources of macrozoobenthos living in these non-native mangrove forests. Therefore, in this study, we used fatty acid analysis to compare the food sources of one littorinid snail and two grapsid crab species between two native mangrove forests and one non-native S. apetala plantation in the Zhanjiang Mangrove National Nature Reserve of China. We found that the sediment of all three forests had high diatom and bacteria signals, but low mangrove leaf signals, while the opposite patterns were detected in the three macrozoobenthos. Specifically, the gastropod Littoraria melanostoma relied mainly on mangrove leaves and brown algae as food sources, with significant differences among the three mangrove forests, and showed significant seasonal variation in its diet. The grapsidae species (Perisesarma bidens and Parasesarma plicatum) mainly grazed on mangrove litter, brown and green algae, and occasionally consumed diatoms and bacteria, also showing significant seasonal variation in their diet. Overall, Principle Components Analysis (PCA) of the fatty acid profiles showed a significant overlapping in food sources among the macrozoobenthos living in the non-native and native mangrove forests, but significant seasonal variations in their food sources. This suggests that the planting of non-native S. apetala near original mangrove forests has had little effect on the feeding behavior of macrozoobenthos some 10 years after planting.

A Quantitative Study of Factors Related to Adult E-Learner's Adoption of Web 2.0 Technology

ERIC Educational Resources Information Center

Bledsoe, Johnny Mark

2012-01-01

The content created by digital natives via collaborative Web 2.0 applications provides a rich source of unique knowledge and social capital for their virtual communities of interest. The problem addressed in this study was the limited understanding of older digital immigrants who use Web 2.0 applications to access, distribute, or enhance these…

78 FR 7450 - Final Environmental Impact Statement for Protecting and Restoring Native Ecosystems by Managing...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-01

...-Native Ungulates, Hawaii Volcanoes National Park, HI AGENCY: National Park Service, Interior. ACTION..., HI 96718, and in local libraries (locations noted on above Web site). A limited number of compact... 52, Hawaii Volcanoes National Park, HI 96718-0052; (808) 985-6098. SUPPLEMENTARY INFORMATION: The...

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.

Effects of invasive parasites on bumble bee declines.

PubMed

Meeus, Ivan; Brown, Mark J F; De Graaf, Dirk C; Smagghe, Guy

2011-08-01

Bumble bees are a group of pollinators that are both ecologically and economically important and declining worldwide. Numerous mechanisms could be behind this decline, and the spread of parasites from commercial colonies into wild populations has been implicated recently in North America. Commercial breeding may lead to declines because commercial colonies may have high parasite loads, which can lead to colonization of native bumble bee populations; commercial rearing may allow higher parasite virulence to evolve; and global movement of commercial colonies may disrupt spatial patterns in local adaptation between hosts and parasites. We assessed parasite virulence, transmission mode, and infectivity. Microparasites and so-called honey bee viruses may pose the greatest threat to native bumble bee populations because certain risk factors are present; for example, the probability of horizontal transmission of the trypanosome parasite Crithidia bombi is high. The microsporidian parasite Nosema bombi may play a role in declines of bumble bees in the United States. Preliminary indications that C. bombi and the neogregarine Apicystis bombi may not be native in parts of South America. We suggest that the development of molecular screening protocols, thorough sanitation efforts, and cooperation among nongovernmental organizations, governments, and commercial breeders might immediately mitigate these threats. © 2011 Society for Conservation Biology.

Pollinators show flower colour preferences but flowers with similar colours do not attract similar pollinators

PubMed Central

Reverté, Sara; Retana, Javier; Gómez, José M.; Bosch, Jordi

2016-01-01

Background and aims Colour is one of the main floral traits used by pollinators to locate flowers. Although pollinators show innate colour preferences, the view that the colour of a flower may be considered an important predictor of its main pollinators is highly controversial because flower choice is highly context-dependent, and initial innate preferences may be overridden by subsequent associative learning. Our objective is to establish whether there is a relationship between flower colour and pollinator composition in natural communities. Methods We measured the flower reflectance spectrum and pollinator composition in four plant communities (85 plant species represented by 109 populations, and 32 305 plant–pollinator interactions in total). Pollinators were divided into six taxonomic groups: bees, ants, wasps, coleopterans, dipterans and lepidopterans. Key Results We found consistent associations between pollinator groups and certain colours. These associations matched innate preferences experimentally established for several pollinators and predictions of the pollination syndrome theory. However, flowers with similar colours did not attract similar pollinator assemblages. Conclusions The explanation for this paradoxical result is that most flower species are pollination generalists. We conclude that although pollinator colour preferences seem to condition plant–pollinator interactions, the selective force behind these preferences has not been strong enough to mediate the appearance and maintenance of tight colour-based plant–pollinator associations. PMID:27325897

Persistence of pollination mutualisms in the presence of ants.

PubMed

Wang, Yuanshi; Wang, Shikun

2015-01-01

This paper considers plant-pollinator-ant systems in which the plant-pollinator interaction is mutualistic but ants have both positive and negative effects on plants. The ants also interfere with pollinators by preventing them from accessing plants. While a Beddington-DeAngelis (BD) formula can describe the plant-pollinator interaction, the formula is extended in this paper to characterize the pollination mutualism under the ant interference. Then, a plant-pollinator-ant system with the extended BD functional response is discussed, and global dynamics of the model demonstrate the mechanisms by which pollination mutualism can persist in the presence of ants. When the ant interference is strong, it can result in extinction of pollinators. Moreover, if the ants depend on pollination mutualism for survival, the strong interference could drive pollinators into extinction, which consequently lead to extinction of the ants themselves. When the ant interference is weak, a cooperation between plant-ant and plant-pollinator mutualisms could occur, which promotes survival of both ants and pollinators, especially in the case that ants (respectively, pollinators) cannot survive in the absence of pollinators (respectively, ants). Even when the level of ant interference remains invariant, varying ants' negative effect on plants can result in survival/extinction of both ants and pollinators. Therefore, our results provide an explanation for the persistence of pollination mutualism when there exist ants.

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

Separating selection by diurnal and nocturnal pollinators on floral display and spur length in Gymnadenia conopsea.

PubMed

Sletvold, Nina; Trunschke, Judith; Wimmergren, Carolina; Agren, Jon

2012-08-01

Most plants attract multiple flower visitors that may vary widely in their effectiveness as pollinators. Floral evolution is expected to reflect interactions with the most important pollinators, but few studies have quantified the contribution of different pollinators to current selection on floral traits. To compare selection mediated by diurnal and nocturnal pollinators on floral display and spur length in the rewarding orchid Gymnadenia conopsea, we manipulated the environment by conducting supplemental hand-pollinations and selective pollinator exclusions in two populations in central Norway. In both populations, the exclusion of diurnal pollinators significantly reduced seed production compared to open pollination, whereas the exclusion of nocturnal pollinators did not. There was significant selection on traits expected to influence pollinator attraction and pollination efficiency in both the diurnal and nocturnal pollination treatment. The relative strength of selection among plants exposed to diurnal and nocturnal visitors varied among traits and populations, but the direction of selection was consistent. The results suggest that diurnal pollinators are more important than nocturnal pollinators for seed production in the study populations, but that both categories contribute to selection on floral morphology. The study illustrates how experimental manipulations can link specific categories of pollinators to observed selection on floral traits, and thus improve our understanding of how species interactions shape patterns of selection.

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

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.

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.

The Robustness of Plant-Pollinator Assemblages: Linking Plant Interaction Patterns and Sensitivity to Pollinator Loss

PubMed Central

Astegiano, Julia; Massol, François; Vidal, Mariana Morais; Cheptou, Pierre-Olivier; Guimarães, Paulo R.

2015-01-01

Most flowering plants depend on pollinators to reproduce. Thus, evaluating the robustness of plant-pollinator assemblages to species loss is a major concern. How species interaction patterns are related to species sensitivity to partner loss may influence the robustness of plant-pollinator assemblages. In plants, both reproductive dependence on pollinators (breeding system) and dispersal ability may modulate plant sensitivity to pollinator loss. For instance, species with strong dependence (e.g. dioecious species) and low dispersal (e.g. seeds dispersed by gravity) may be the most sensitive to pollinator loss. We compared the interaction patterns of plants differing in dependence on pollinators and dispersal ability in a meta-dataset comprising 192 plant species from 13 plant-pollinator networks. In addition, network robustness was compared under different scenarios representing sequences of plant extinctions associated with plant sensitivity to pollinator loss. Species with different dependence on pollinators and dispersal ability showed similar levels of generalization. Although plants with low dispersal ability interacted with more generalized pollinators, low-dispersal plants with strong dependence on pollinators (i.e. the most sensitive to pollinator loss) interacted with more particular sets of pollinators (i.e. shared a low proportion of pollinators with other plants). Only two assemblages showed lower robustness under the scenario considering plant generalization, dependence on pollinators and dispersal ability than under the scenario where extinction sequences only depended on plant generalization (i.e. where higher generalization level was associated with lower probability of extinction). Overall, our results support the idea that species generalization and network topology may be good predictors of assemblage robustness to species loss, independently of plant dispersal ability and breeding system. In contrast, since ecological specialization among partners may increase the probability of disruption of interactions, the fact that the plants most sensitive to pollinator loss interacted with more particular pollinator assemblages suggest that the persistence of these plants and their pollinators might be highly compromised. PMID:25646762

Valuing Insect Pollination Services with Cost of Replacement

PubMed Central

Allsopp, Mike H.; de Lange, Willem J.; Veldtman, Ruan

2008-01-01

Value estimates of ecosystem goods and services are useful to justify the allocation of resources towards conservation, but inconclusive estimates risk unsustainable resource allocations. Here we present replacement costs as a more accurate value estimate of insect pollination as an ecosystem service, although this method could also be applied to other services. The importance of insect pollination to agriculture is unequivocal. However, whether this service is largely provided by wild pollinators (genuine ecosystem service) or managed pollinators (commercial service), and which of these requires immediate action amidst reports of pollinator decline, remains contested. If crop pollination is used to argue for biodiversity conservation, clear distinction should be made between values of managed- and wild pollination services. Current methods either under-estimate or over-estimate the pollination service value, and make use of criticised general insect and managed pollinator dependence factors. We apply the theoretical concept of ascribing a value to a service by calculating the cost to replace it, as a novel way of valuing wild and managed pollination services. Adjusted insect and managed pollinator dependence factors were used to estimate the cost of replacing insect- and managed pollination services for the Western Cape deciduous fruit industry of South Africa. Using pollen dusting and hand pollination as suitable replacements, we value pollination services significantly higher than current market prices for commercial pollination, although lower than traditional proportional estimates. The complexity associated with inclusive value estimation of pollination services required several defendable assumptions, but made estimates more inclusive than previous attempts. Consequently this study provides the basis for continued improvement in context specific pollination service value estimates. PMID:18781196

Pollinators show flower colour preferences but flowers with similar colours do not attract similar pollinators.

PubMed

Reverté, Sara; Retana, Javier; Gómez, José M; Bosch, Jordi

2016-08-01

Colour is one of the main floral traits used by pollinators to locate flowers. Although pollinators show innate colour preferences, the view that the colour of a flower may be considered an important predictor of its main pollinators is highly controversial because flower choice is highly context-dependent, and initial innate preferences may be overridden by subsequent associative learning. Our objective is to establish whether there is a relationship between flower colour and pollinator composition in natural communities. We measured the flower reflectance spectrum and pollinator composition in four plant communities (85 plant species represented by 109 populations, and 32 305 plant-pollinator interactions in total). Pollinators were divided into six taxonomic groups: bees, ants, wasps, coleopterans, dipterans and lepidopterans. We found consistent associations between pollinator groups and certain colours. These associations matched innate preferences experimentally established for several pollinators and predictions of the pollination syndrome theory. However, flowers with similar colours did not attract similar pollinator assemblages. The explanation for this paradoxical result is that most flower species are pollination generalists. We conclude that although pollinator colour preferences seem to condition plant-pollinator interactions, the selective force behind these preferences has not been strong enough to mediate the appearance and maintenance of tight colour-based plant-pollinator associations. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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.

Pollination services enhanced with urbanization despite increasing pollinator parasitism.

PubMed

Theodorou, Panagiotis; Radzevičiūtė, Rita; Settele, Josef; Schweiger, Oliver; Murray, Tomás E; Paxton, Robert J

2016-06-29

Animal-mediated pollination is required for the reproduction of the majority of angiosperms, and pollinators are therefore essential for ecosystem functioning and the economy. Two major threats to insect pollinators are anthropogenic land-use change and the spread of pathogens, whose effects may interact to impact pollination. Here, we investigated the relative effects on the ecosystem service of pollination of (i) land-use change brought on by agriculture and urbanization as well as (ii) the prevalence of pollinator parasites, using experimental insect pollinator-dependent plant species in natural pollinator communities. We found that pollinator habitat (i.e. availability of nesting resources for ground-nesting bees and local flower richness) was strongly related to flower visitation rates at the local scale and indirectly influenced plant pollination success. At the landscape scale, pollination was positively related to urbanization, both directly and indirectly via elevated visitation rates. Bumblebees were the most abundant pollinator group visiting experimental flowers. Prevalence of trypanosomatids, such as the common bumblebee parasite Crithidia bombi, was higher in urban compared with agricultural areas, a relationship which was mediated through higher Bombus abundance. Yet, we did not find any top-down, negative effects of bumblebee parasitism on pollination. We conclude that urban areas can be places of high transmission of both pollen and pathogens. © 2016 The Author(s).

Pollination services enhanced with urbanization despite increasing pollinator parasitism

PubMed Central

Radzevičiūtė, Rita; Murray, Tomás E.

2016-01-01

Animal-mediated pollination is required for the reproduction of the majority of angiosperms, and pollinators are therefore essential for ecosystem functioning and the economy. Two major threats to insect pollinators are anthropogenic land-use change and the spread of pathogens, whose effects may interact to impact pollination. Here, we investigated the relative effects on the ecosystem service of pollination of (i) land-use change brought on by agriculture and urbanization as well as (ii) the prevalence of pollinator parasites, using experimental insect pollinator-dependent plant species in natural pollinator communities. We found that pollinator habitat (i.e. availability of nesting resources for ground-nesting bees and local flower richness) was strongly related to flower visitation rates at the local scale and indirectly influenced plant pollination success. At the landscape scale, pollination was positively related to urbanization, both directly and indirectly via elevated visitation rates. Bumblebees were the most abundant pollinator group visiting experimental flowers. Prevalence of trypanosomatids, such as the common bumblebee parasite Crithidia bombi, was higher in urban compared with agricultural areas, a relationship which was mediated through higher Bombus abundance. Yet, we did not find any top-down, negative effects of bumblebee parasitism on pollination. We conclude that urban areas can be places of high transmission of both pollen and pathogens. PMID:27335419

Moonlight pollination in the gymnosperm Ephedra (Gnetales).

PubMed

Rydin, Catarina; Bolinder, Kristina

2015-04-01

Most gymnosperms are wind-pollinated, but some are insect-pollinated, and in Ephedra (Gnetales), both wind pollination and insect pollination occur. Little is, however, known about mechanisms and evolution of pollination syndromes in gymnosperms. Based on four seasons of field studies, we show an unexpected correlation between pollination and the phases of the moon in one of our studied species, Ephedra foeminea. It is pollinated by dipterans and lepidopterans, most of them nocturnal, and its pollination coincides with the full moon of July. This may be adaptive in two ways. Many nocturnal insects navigate using the moon. Further, the spectacular reflection of the full-moonlight in the pollination drops is the only apparent means of nocturnal attraction of insects in these plants. In the sympatric but wind-pollinated Ephedra distachya, pollination is not correlated to the full moon but occurs at approximately the same dates every year. The lunar correlation has probably been lost in most species of Ephedra subsequent an evolutionary shift to wind pollination in the clade. When the services of insects are no longer needed for successful pollination, the adaptive value of correlating pollination with the full moon is lost, and conceivably also the trait. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

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

Pollinators visit related plant species across 29 plant–pollinator networks

PubMed Central

Vamosi, Jana C; Moray, Clea M; Garcha, Navdeep K; Chamberlain, Scott A; Mooers, Arne Ø

2014-01-01

Understanding the evolution of specialization in host plant use by pollinators is often complicated by variability in the ecological context of specialization. Flowering communities offer their pollinators varying numbers and proportions of floral resources, and the uniformity observed in these floral resources is, to some degree, due to shared ancestry. Here, we find that pollinators visit related plant species more so than expected by chance throughout 29 plant–pollinator networks of varying sizes, with “clade specialization” increasing with community size. As predicted, less versatile pollinators showed more clade specialization overall. We then asked whether this clade specialization varied with the ratio of pollinator species to plant species such that pollinators were changing their behavior when there was increased competition (and presumably a forced narrowing of the realized niche) by examining pollinators that were present in at least three of the networks. Surprisingly, we found little evidence that variation in clade specialization is caused by pollinator species changing their behavior in different community contexts, suggesting that clade specialization is observed when pollinators are either restricted in their floral choices due to morphological constraints or innate preferences. The resulting pollinator sharing between closely related plant species could result in selection for greater pollinator specialization. PMID:25360269

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

Reproductive biology and nectar secretion dynamics of Penstemon gentianoides (Plantaginaceae): a perennial herb with a mixed pollination system?

PubMed Central

Salas-Arcos, Lucía; Ornelas, Juan Francisco

2017-01-01

Background In many plant species, pollination syndromes predict the most effective pollinator. However, other floral visitors may also offer effective pollination services and promote mixed pollination systems. Several species of the species-rich Penstemon (Plantaginaceae) exhibit a suite of floral traits that suggest adaptation for pollination by both hymenopterans and hummingbirds. Transitions from the ancestral hymenopteran pollination syndrome to more derived hummingbird pollination syndrome may be promoted if the quantity or quality of visits by hummingbirds is increased and if the ancestral pollinator group performs less efficiently. The quantification of such shifts in pollination systems in the group is still limited. We aimed to investigate floral traits linked to this pollination syndrome in Penstemon gentianoides with flowers visited by bumblebees and hummingbirds. Methods We investigated the floral biology, pollinator assemblages, breeding system and nectar production patterns ofP. gentianoides inhabiting a temperate montane forest in central Mexico. Pollination experiments were also conducted to assess the pollinator effectiveness of bumblebees and hummingbirds. Results P. gentianoides flowers are protandrous, with 8-d male phase (staminate) flowers, followed by the ∼1–7 d female phase (pistillate phase). Flowers display traits associated with hymenopteran pollination, including purple flowers abruptly ampliate-ventricose to a broad throat with anthers and stigmas included, and long lifespans. However, the nectar available in the morning hours was abundant and dilute, traits linked to flowers with a hummingbird pollination syndrome. Two hummingbird species made most of the visits to flowers, Selasphorus platycercus (30.3% of all visits), followed by Archilochus colubris (11.3%). Bumblebees (Bombus ephippiatus, B. huntii and B. weisi) accounted for 51.8% of all recorded visits, but their foraging activity was restricted to the warmer hours. Hummingbirds made more foraging bouts and visited more flowers than hymenopteran species. Flowers experimentally pollinated by B. ephippiatus produced significantly more fruits than those pollinated by S. platycercus. However, there was no statistical difference in the number of seeds produced per fruit when a bumblebee or a hummingbird was the pollinator. Conclusions We have shown that bumblebees and hummingbirds visit and pollinate P. gentianoides flowers. Despite floral traits resembling the hymenoptera pollination syndrome, flowers of P. gentianoides offer characteristic nectar rewards to flowers with a hummingbird pollination syndrome. Although pollination efficiency is higher among flowers visited by hymenoptera, the noteworthy percentage of fruit production and number of seeds per fruit derived from hummingbird pollination highlights the importance of hummingbirds as a functional group of pollinators that might have potential evolutionary consequences to the plants. PMID:28828248

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.

Pollinator Foraging Adaptation and Coexistence of Competing Plants.

PubMed

Revilla, Tomás A; Křivan, Vlastimil

2016-01-01

We use the optimal foraging theory to study coexistence between two plant species and a generalist pollinator. We compare conditions for plant coexistence for non-adaptive vs. adaptive pollinators that adjust their foraging strategy to maximize fitness. When pollinators have fixed preferences, we show that plant coexistence typically requires both weak competition between plants for resources (e.g., space or nutrients) and pollinator preferences that are not too biased in favour of either plant. We also show how plant coexistence is promoted by indirect facilitation via the pollinator. When pollinators are adaptive foragers, pollinator's diet maximizes pollinator's fitness measured as the per capita population growth rate. Simulations show that this has two conflicting consequences for plant coexistence. On the one hand, when competition between pollinators is weak, adaptation favours pollinator specialization on the more profitable plant which increases asymmetries in plant competition and makes their coexistence less likely. On the other hand, when competition between pollinators is strong, adaptation promotes generalism, which facilitates plant coexistence. In addition, adaptive foraging allows pollinators to survive sudden loss of the preferred plant host, thus preventing further collapse of the entire community.

Functional morphology and wasp pollination of two South American asclepiads (Asclepiadoideae-Apocynaceae).

PubMed

Wiemer, A P; Sérsic, A N; Marino, S; Simões, A O; Cocucci, A A

2012-01-01

BACKGROUND AND AIMS The extreme complexity of asclepiad flowers (Asclepiadoideae-Apocynaceae) has generated particular interest in the pollination biology of this group of plants especially in the mechanisms involved in the pollination processes. This study compares two South American species, Morrenia odorata and Morrenia brachystephana, with respect to morphology and anatomy of flower structures, dynamic aspects of the pollination mechanism, diversity of visitors and effectiveness of pollinators. Floral structure was studied with fresh and fixed flowers following classical techniques. The pollination mechanism was studied by visiting fresh flowers in the laboratory with artificial pollinator body parts created with an eyelash. Morphometric and nectar measurements were also taken. Pollen transfer efficiency in the flowers was calculated by recording the frequency of removed and inserted pollinia. Visitor activity was recorded in the field, and floral visitors were captured for subsequent analysis of pollen loads. Finally, pollinator effectiveness was calculated with an index. The detailed structure of the flowers revealed a complex system of guide rails and chambers precisely arranged in order to achieve effective pollinaria transport. Morrenia odorata is functionally specialized for wasp pollination, and M. brachystephana for wasp and bee pollination. Pollinators transport chains of pollinaria adhered to their mouthparts. Morrenia odorata and M. brachystephana present differences in the morphology and size of their corona, gynostegium and pollinaria, which explain the differences in details of the functioning of the general pollination mechanism. Pollination is performed by different groups of highly effective pollinators. Morrenia species are specialized for pollination mainly by several species of wasps, a specialized pollination which has been poorly studied. In particular, pompilid wasps are reported as important pollinators in other regions outside South Africa. A putative new function of nectar in asclepiads is presented, as it would be contributing to the pollination mechanism.

Enhancing e-Learning Content by Using Semantic Web Technologies

ERIC Educational Resources Information Center

García-González, Herminio; Gayo, José Emilio Labra; del Puerto Paule-Ruiz, María

2017-01-01

We describe a new educational tool that relies on Semantic Web technologies to enhance lessons content. We conducted an experiment with 32 students whose results demonstrate better performance when exposed to our tool in comparison with a plain native tool. Consequently, this prototype opens new possibilities in lessons content enhancement.

More than euglossines: the diverse pollinators and floral scents of Zygopetalinae orchids.

PubMed

Nunes, Carlos E P; Wolowski, Marina; Pansarin, Emerson Ricardo; Gerlach, Günter; Aximoff, Izar; Vereecken, Nicolas J; Salvador, Marcos José; Sazima, Marlies

2017-10-13

Floral volatile organic compounds (VOCs) play important roles in plant-pollinator interactions. We investigated the reproductive ecology and floral VOCs of Zygopetalinae orchids to understand the relationship between floral scents and pollinators. We performed focal observations, phenological censuses and breeding system experiments in eight species in southeast Brazil. Floral scents were collected and analysed using SPME/GC-MS. We performed multivariate analyses to group species according to affinities of their VOCs and define compounds associated to each plant. Dichaea cogniauxiana was pollinated by weevils which use their developing ovules, while D. pendula was pollinated by the same weevils and perfume-collecting male euglossine bees. The other species were deceit-pollinated by bees. Zygopetalum crinitum was pollinated by carpenter bees, while W. warreana, Z. mackayi and Z. maxillare were bumblebee-pollinated. The latter was also pollinated by Centris confusa. Breeding system varied widely with no association to any pollinator group. Most VOCs are common to other floral scents. Zygopetalum crinitum presented an exclusive blend of VOCs, mainly composed of benzenoids. The scents of Pabstia jugosa, Promenaea xanthina and the Zygopetalum spp. were similar. The bumblebee-pollinated species have flowering periods partially overlapped, thus neither phenology nor pollinators constitute hybridization barriers among these species. Euglossines are not the only pollinators of Zygopetalinae. Different VOCs, size and lifespan of flowers are associated with distinct pollinators. A distinctive VOC bouquet may determine specialisation in carpenter bees or male euglossines within bee-pollinated flowers. Finally, visitation of deceit-pollinated flowers by perfume-collecting euglossines allows us to hypothesise how pollination by this group of bees had evolved.

Apple Pollination: Demand Depends on Variety and Supply Depends on Pollinator Identity

PubMed Central

Garratt, M. P. D.; Breeze, T. D.; Boreux, V.; Coston, D. J.; Jenner, N.; Dean, R.; Westbury, D. B.; Biesmeijer, J. C.; Potts, S. G.

2016-01-01

Insect pollination underpins apple production but the extent to which different pollinator guilds supply this service, particularly across different apple varieties, is unknown. Such information is essential if appropriate orchard management practices are to be targeted and proportional to the potential benefits pollinator species may provide. Here we use a novel combination of pollinator effectiveness assays (floral visit effectiveness), orchard field surveys (flower visitation rate) and pollinator dependence manipulations (pollinator exclusion experiments) to quantify the supply of pollination services provided by four different pollinator guilds to the production of four commercial varieties of apple. We show that not all pollinators are equally effective at pollinating apples, with hoverflies being less effective than solitary bees and bumblebees, and the relative abundance of different pollinator guilds visiting apple flowers of different varieties varies significantly. Based on this, the taxa specific economic benefits to UK apple production have been established. The contribution of insect pollinators to the economic output in all varieties was estimated to be £92.1M across the UK, with contributions varying widely across taxa: solitary bees (£51.4M), honeybees (£21.4M), bumblebees (£18.6M) and hoverflies (£0.7M). This research highlights the differences in the economic benefits of four insect pollinator guilds to four major apple varieties in the UK. This information is essential to underpin appropriate investment in pollination services management and provides a model that can be used in other entomolophilous crops to improve our understanding of crop pollination ecology. PMID:27152628

Apple Pollination: Demand Depends on Variety and Supply Depends on Pollinator Identity.

PubMed

Garratt, M P D; Breeze, T D; Boreux, V; Fountain, M T; McKerchar, M; Webber, S M; Coston, D J; Jenner, N; Dean, R; Westbury, D B; Biesmeijer, J C; Potts, S G

2016-01-01

Insect pollination underpins apple production but the extent to which different pollinator guilds supply this service, particularly across different apple varieties, is unknown. Such information is essential if appropriate orchard management practices are to be targeted and proportional to the potential benefits pollinator species may provide. Here we use a novel combination of pollinator effectiveness assays (floral visit effectiveness), orchard field surveys (flower visitation rate) and pollinator dependence manipulations (pollinator exclusion experiments) to quantify the supply of pollination services provided by four different pollinator guilds to the production of four commercial varieties of apple. We show that not all pollinators are equally effective at pollinating apples, with hoverflies being less effective than solitary bees and bumblebees, and the relative abundance of different pollinator guilds visiting apple flowers of different varieties varies significantly. Based on this, the taxa specific economic benefits to UK apple production have been established. The contribution of insect pollinators to the economic output in all varieties was estimated to be £92.1M across the UK, with contributions varying widely across taxa: solitary bees (£51.4M), honeybees (£21.4M), bumblebees (£18.6M) and hoverflies (£0.7M). This research highlights the differences in the economic benefits of four insect pollinator guilds to four major apple varieties in the UK. This information is essential to underpin appropriate investment in pollination services management and provides a model that can be used in other entomolophilous crops to improve our understanding of crop pollination ecology.

Diurnal and nocturnal pollination of Marginatocereus marginatus (Pachycereeae: Cactaceae) in Central Mexico.

PubMed

Dar, Saleem; del Coro Arizmendi, Ma; Valiente-Banuet, Alfonso

2006-03-01

Chiropterophillous and ornithophillous characteristics can form part of a single reproductive strategy in plants that have flowers with diurnal and nocturnal anthesis. This broader pollination strategy can ensure seed set when pollinators are scarce or unpredictable. This appears to be true of hummingbirds, which presumably pollinate Marginatocereus marginatus, a columnar cactus with red nocturnal and diurnal flowers growing as part of dense bat-pollinated columnar cacti forests in arid regions of central Mexico. The aim of this study was to study the floral biology of M. marginatus, and evaluate the effectiveness of nocturnal vs. diurnal pollinators and the contribution of each pollinator group to overall plant fitness. Individual flower buds were marked and followed to evaluate flower phenology and anthesis time. Flowers and nectar production were measured. An exclusion experiment was conducted to measure the relative contribution of nocturnal and diurnal pollinators to seed set. Marginatocereus marginatus has red hermaphroditic flowers with nocturnal and diurnal anthesis. The plant cannot produce seeds by selfing and was pollinated during the day by hummingbirds and during the night by bats, demonstrating that both pollinator groups were important for plant reproduction. Strong pollen limitation was found in the absence of one of the pollinator guilds. Marginatocereus marginatus has an open pollination system in which both diurnal and nocturnal pollinators are needed to set seeds. This represents a fail-safe pollination system that can ensure both pollination, in a situation of low abundance of one of the pollinator groups (hummingbirds), and high competition for nocturnal pollinators with other columnar cacti that bloom synchronously with M. marginatus in the Tehuacan Valley, Mexico.

Promoting Books and Media: A Native American Indian Web.

ERIC Educational Resources Information Center

Brodie, Carolyn S.

1991-01-01

Discusses children's literature on Native American Indians and suggests ideas for using the literature in the school library media center or classroom by the library media specialist or by the classroom teacher. Activities and appropriate materials are suggested for the topics of housing, poetry, food, biography, crafts and music, and traditional…

Phenotypic selection on flowering phenology and pollination efficiency traits between Primula populations with different pollinator assemblages.

PubMed

Wu, Yun; Li, Qing-Jun

2017-10-01

Floral traits have largely been attributed to phenotypic selection in plant-pollinator interactions. However, the strength of this link has rarely been ascertained with real pollinators. We conducted pollinator observations and estimated selection through female fitness on flowering phenology and floral traits between two Primula secundiflora populations. We quantified pollinator-mediated selection by subtracting estimates of selection gradients of plants receiving supplemental hand pollination from those of plants receiving open pollination. There was net directional selection for an earlier flowering start date at populations where the dominant pollinators were syrphid flies, and flowering phenology was also subjected to stabilized quadratic selection. However, a later flowering start date was significantly selected at populations where the dominant pollinators were legitimate (normal pollination through the corolla tube entrance) and illegitimate bumblebees (abnormal pollination through nectar robbing hole which located at the corolla tube), and flowering phenology was subjected to disruptive quadratic selection. Wider corolla tube entrance diameter was selected at both populations. Furthermore, the strength of net directional selection on flowering start date and corolla tube entrance diameter was stronger at the population where the dominant pollinators were syrphid flies. Pollinator-mediated selection explained most of the between-population variations in the net directional selection on flowering phenology and corolla tube entrance diameter. Our results suggested the important influence of pollinator-mediated selection on floral evolution. Variations in pollinator assemblages not only resulted in variation in the direction of selection but also the strength of selection on floral traits.

Landowner and practitioner perspectives on private land conservation programs

USGS Publications Warehouse

Lute, Michelle L.; Gillespie, Caitlyn R.; Fontaine, Joseph J.; Martin, Dustin R.

2018-01-01

Efforts to reverse declines in native grasslands benefit from agricultural policies that encourage private land conservation. The U.S. Department of Agriculture’s Conservation Reserve Program (CRP) improved conservation across landscapes but enrollment has declined. We used sequential exploratory mixed methods to compare landowner and conservation practitioners’ perceptions, evaluate perceived benefits, and identify potential improvements to CRP. Focus groups of practitioners informed a quantitative survey of landowners who had properties >160 total acres in Nebraska. Results suggest potential misalignment in perceptions between practitioners and landowners. Practitioners were concerned that conservation, especially of wildlife, was secondary to profit. But the majority of landowners valued CRP-related ecosystem services, including native pollinators. Practitioners posited that younger landowners were primarily profit motivated, but CRP enrollment did not differ by demographics. Practitioners and landowners identified rule complexity as a major challenge and practitioner–landowner relationships as critical to success. Findings suggest that practitioners may underestimate non-economic motivations and illuminate opportunities to encourage private land conservation.

Native bee diversity and pollen foraging specificity in cultivated highbush blueberry (Ericaceae: Vaccinium corymbosum) in Rhode Island

USGS Publications Warehouse

Scott, Zachary; Ginsberg, Howard; Alm, Steven R.

2016-01-01

We identified 41 species of native bees from a total of 1,083 specimens collected at cultivated highbush blueberry plantings throughout Rhode Island in 2014 and 2015. Andrena spp., Bombus spp., and Xylocopa virginica (L.) were collected most often. Bombus griseocollis (DeGeer), B. impatiens Cresson, B. bimaculatus Cresson, B. perplexus Cresson, and Andrena vicina Smith collected the largest mean numbers of blueberry pollen tetrads. The largest mean percent blueberry pollen loads were carried by the miner bees Andrena bradleyi Viereck (91%), A. carolina Viereck (90%), and Colletes validus Cresson (87%). The largest mean total pollen grain loads were carried by B. griseocollis (549,844), B. impatiens (389,558), X. virginica (233,500), and B. bimaculatus (193,132). Xylocopa virginica was the fourth and fifth most commonly collected bee species in 2014 and 2015, respectively. They exhibit nectar robbing and females carried relatively low blueberry pollen loads (mean 33%). Overall, we found 10 species of bees to be the primary pollinators of blueberries in Rhode Island.

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

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

Interaction intensity and pollinator-mediated selection.

PubMed

Trunschke, Judith; Sletvold, Nina; Ågren, Jon

2017-05-01

In animal-pollinated plants, the opportunity for selection and the strength of pollinator-mediated selection are expected to increase with the degree of pollen limitation. However, whether differences in pollen limitation can explain variation in pollinator-mediated and net selection among animal-pollinated species is poorly understood. In the present study, we quantified pollen limitation, variance in relative fitness and pollinator-mediated selection on five traits important for pollinator attraction (flowering start, plant height, flower number, flower size) and pollination efficiency (spur length) in natural populations of 12 orchid species. Pollinator-mediated selection was quantified by subtracting estimates of selection gradients for plants receiving supplemental hand-pollination from estimates obtained for open-pollinated control plants. Mean pollen limitation ranged from zero to 0.96. Opportunity for selection, pollinator-mediated selection and net selection were all positively related to pollen limitation, whereas nonpollinator-mediated selection was not. Opportunity for selection varied five-fold, strength of pollinator-mediated selection varied three-fold and net selection varied 1.5-fold among species. Supplemental hand-pollination reduced both opportunity for selection and selection on floral traits. The results show that the intensity of biotic interactions is an important determinant of the selection regime, and indicate that the potential for pollinator-mediated selection and divergence in floral traits is particularly high in species that are strongly pollen-limited. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Nutrient Presses and Pulses Differentially Impact Plants, Herbivores, Detritivores and Their Natural Enemies

PubMed Central

Murphy, Shannon M.; Wimp, Gina M.; Lewis, Danny

2012-01-01

Anthropogenic nutrient inputs into native ecosystems cause fluctuations in resources that normally limit plant growth, which has important consequences for associated food webs. Such inputs from agricultural and urban habitats into nearby natural systems are increasing globally and can be highly variable, spanning the range from sporadic to continuous. Despite the global increase in anthropogenically-derived nutrient inputs into native ecosystems, the consequences of variation in subsidy duration on native plants and their associated food webs are poorly known. Specifically, while some studies have examined the effects of nutrient subsidies on native ecosystems for a single year (a nutrient pulse), repeated introductions of nutrients across multiple years (a nutrient press) better reflect the persistent nature of anthropogenic nutrient enrichment. We therefore contrasted the effects of a one-year nutrient pulse with a four-year nutrient press on arthropod consumers in two salt marshes. Salt marshes represent an ideal system to address the differential impacts of nutrient pulses and presses on ecosystem and community dynamics because human development and other anthropogenic activities lead to recurrent introductions of nutrients into these natural systems. We found that plant biomass and %N as well as arthropod density fell after the nutrient pulse ended but remained elevated throughout the nutrient press. Notably, higher trophic levels responded more strongly than lower trophic levels to fertilization, and the predator/prey ratio increased each year of the nutrient press, demonstrating that food web responses to anthropogenic nutrient enrichment can take years to fully manifest themselves. Vegetation at the two marshes also exhibited an apparent tradeoff between increasing %N and biomass in response to fertilization. Our research emphasizes the need for long-term, spatially diverse studies of nutrient enrichment in order to understand how variation in the duration of anthropogenic nutrient subsidies affects native ecosystems. PMID:22952814

Native birds and insects, and introduced honey bees visiting Echium wildpretii (Boraginaceae) in the Canary Islands

NASA Astrophysics Data System (ADS)

Valido, Alfredo; Dupont, Yoko L.; Hansen, Dennis M.

2002-12-01

In this paper, we report observations of flower visitors of the endemic Echium wildpretii in Tenerife, Canary Islands. This plant inhabits the high altitudinal sub-alpine zone, which is characterized by a harsh climate, low species diversity and a short growing season. Echium wildpretii is a monocarpic perennial, producing a 2-3 m column-shaped, red-flowered, nectar-rich inflorescence. Although these floral traits have previously been suggested as being typical of ornithophilous flowers, this is the first study reporting observations of native birds ( Phylloscopus collybita and Serinus canarius) in addition to insects visiting the flowers for nectar. The purposes of this study were firstly to investigate levels of visitation by native birds, native insects, and introduced honey bees. Secondly, we studied the influence of floral display (plant height and number of flowers), nearest neighbours (distance and size) and local vegetation structure on visitation rate. Finally, we discuss the evolution of ornithophily in an otherwise entomophilous plant lineage. We found that the level of bird visitation was relatively high early in the flowering season, but decreased in mid/late season, while the opposite pattern was found for introduced honey bees. For native insects, the frequency of visits was similar in early and late season. Bird visits were correlated with floral display. In the early season, visitation rates of honey bees and the two most common native bee species were correlated with size of the plant or its nearest neighbours, consistent with preference patterns for larger resource patches. Since only insects visit the flowers of other species in the Echium clade, E. wildpretii appears to have evolved from a truly insect-pollinated lineage.

Spatial variation in pollinator-mediated selection on phenology, floral display and spur length in the orchid Gymnadenia conopsea.

PubMed

Chapurlat, Elodie; Ågren, Jon; Sletvold, Nina

2015-12-01

Spatial variation in plant-pollinator interactions may cause variation in pollinator-mediated selection on floral traits, but to establish this link conclusively experimental studies are needed. We quantified pollinator-mediated selection on flowering phenology and morphology in four populations of the fragrant orchid Gymnadenia conopsea, and compared selection mediated by diurnal and nocturnal pollinators in two of the populations. Variation in pollinator-mediated selection explained most of the among-population variation in the strength of directional and correlational selection. Pollinators mediated correlational selection on pairs of display traits, and on one display trait and spur length, a trait affecting pollination efficiency. Only nocturnal pollinators selected for longer spurs, and mediated stronger selection on the number of flowers compared with diurnal pollinators in one population. The two types of pollinators caused correlational selection on different pairs of traits and selected for different combinations of spur length and number of flowers. The results demonstrate that spatial variation in interactions with pollinators may result in differences in directional and correlational selection on floral traits in a plant with a semi-generalized pollination system, and suggest that differences in the relative importance of diurnal and nocturnal pollinators can cause variation in selection. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Wind-dragged corolla enhances self-pollination: a new mechanism of delayed self-pollination.

PubMed

Qu, Rongming; Li, Xiaojie; Luo, Yibo; Dong, Ming; Xu, Huanli; Chen, Xuan; Dafni, Amots

2007-12-01

Delayed self-pollination is a mechanism that allows animal-pollinated plants to outcross while ensuring seed production in the absence of pollinators. This study aims to explore a new mechanism of delayed self-pollination facilitated by wind-driven corolla abscission in Incarvillea sinensis var. sinensis. Floral morphology and development, and the process of delayed self-pollination were surveyed. Experiments dealing with pollinator and wind exclusion, pollination manipulations, and pollinator observations were conducted in the field. Delayed self-pollination occurs when the abscising corolla driven by wind drags the adherent epipetalous stamens, thus leading to contact of anthers with stigma in late anthesis. There is no dichogamy and self-incompatibility in this species. The significantly higher proportion of abscised corolla under natural conditions as compared with that in wind-excluding tents indicates the importance of wind in corolla abscission. When pollinators were excluded, corolla abscission significantly increased the number of pollen grains deposited on the stigma and, as a result, the fruit and seed set. Only half of the flowers in plots were visited by pollinators, and the fruit set of emasculated flowers was significantly lower than that of untreated flowers in open pollination. This species has a sensitive stigma, and its two open stigmatic lobes closed soon after being touched by a pollinator, but always reopened if no or only little pollen was deposited. This delayed self-pollination, which involved the movement of floral parts, the active participation of the wind and sensitive stigma, is quite different from that reported previously. This mechanism provides reproductive assurance for this species. The sensitive stigma contributes to ensuring seed production and reducing the interference of selfing with outcrossing. The pollination pattern, which combines actions by bees with indirect participation by wind, is also a new addition to ambophily.

Diurnal and Nocturnal Pollination of Marginatocereus marginatus (Pachycereeae: Cactaceae) in Central Mexico

PubMed Central

DAR, SALEEM; ARIZMENDI, Ma. del CORO; VALIENTE-BANUET, ALFONSO

2006-01-01

• Background and Aims Chiropterophillous and ornithophillous characteristics can form part of a single reproductive strategy in plants that have flowers with diurnal and nocturnal anthesis. This broader pollination strategy can ensure seed set when pollinators are scarce or unpredictable. This appears to be true of hummingbirds, which presumably pollinate Marginatocereus marginatus, a columnar cactus with red nocturnal and diurnal flowers growing as part of dense bat-pollinated columnar cacti forests in arid regions of central Mexico. The aim of this study was to study the floral biology of M. marginatus, and evaluate the effectiveness of nocturnal vs. diurnal pollinators and the contribution of each pollinator group to overall plant fitness. • Methods Individual flower buds were marked and followed to evaluate flower phenology and anthesis time. Flowers and nectar production were measured. An exclusion experiment was conducted to measure the relative contribution of nocturnal and diurnal pollinators to seed set. • Key Results Marginatocereus marginatus has red hermaphroditic flowers with nocturnal and diurnal anthesis. The plant cannot produce seeds by selfing and was pollinated during the day by hummingbirds and during the night by bats, demonstrating that both pollinator groups were important for plant reproduction. Strong pollen limitation was found in the absence of one of the pollinator guilds. • Conclusions Marginatocereus marginatus has an open pollination system in which both diurnal and nocturnal pollinators are needed to set seeds. This represents a fail-safe pollination system that can ensure both pollination, in a situation of low abundance of one of the pollinator groups (hummingbirds), and high competition for nocturnal pollinators with other columnar cacti that bloom synchronously with M. marginatus in the Tehuacan Valley, Mexico. PMID:16394025

Acceptability of a Web-based Community Reinforcement Approach for Substance Use Disorders with Treatment-seeking American Indians/Alaska Natives

PubMed Central

Campbell, Aimee N. C.; Turrigiano, Eva; Moore, Michelle; Miele, Gloria M.; Rieckmann, Traci; Hu, Mei-Chen; Kropp, Frankie; Ringor-Carty, Roz; Nunes, Edward V.

2014-01-01

Longstanding disparities in substance use disorders and treatment access exist among American Indian/Alaska Natives (AI/AN). Computerized, web-delivered interventions have potential to increase access to quality treatment and improve patient outcomes. Prior research supports the efficacy of a web-based version (Therapeutic Education System [TES]) of the Community Reinforcement Approach to improve outcomes among outpatients in substance abuse treatment; however, TES has not been tested among AI/AN. The results from this mixed method acceptability study among a diverse sample of urban AI/AN (N=40) show that TES was acceptable across seven indices (range=7.8 to 9.4 on 0 to 10 scales with 10 indicating highest acceptability). Qualitative interviews suggest adaptation specific to AI/AN culture could improve adoption. Additional efforts to adapt TES and conduct a larger effectiveness study are warranted. PMID:25022913

Acceptability of a web-based community reinforcement approach for substance use disorders with treatment-seeking American Indians/Alaska Natives.

PubMed

Campbell, Aimee N C; Turrigiano, Eva; Moore, Michelle; Miele, Gloria M; Rieckmann, Traci; Hu, Mei-Chen; Kropp, Frankie; Ringor-Carty, Roz; Nunes, Edward V

2015-05-01

Longstanding disparities in substance use disorders and treatment access exist among American Indians/Alaska Natives (AI/AN). Computerized, web-delivered interventions have potential to increase access to quality treatment and improve patient outcomes. Prior research supports the efficacy of a web-based version [therapeutic education system (TES)] of the community reinforcement approach to improve outcomes among outpatients in substance abuse treatment; however, TES has not been tested among AI/AN. The results from this mixed method acceptability study among a diverse sample of urban AI/AN (N = 40) show that TES was acceptable across seven indices (range 7.8-9.4 on 0-10 scales with 10 indicating highest acceptability). Qualitative interviews suggest adaptation specific to AI/AN culture could improve adoption. Additional efforts to adapt TES and conduct a larger effectiveness study are warranted.

Management of arthropod pathogen vectors in North America: Minimizing adverse effects on pollinators

USGS Publications Warehouse

Ginsberg, Howard; Bargar, Timothy A.; Hladik, Michelle L.; Lubelczyk, Charles

2017-01-01

Tick and mosquito management is important to public health protection. At the same time, growing concerns about declines of pollinator species raise the question of whether vector control practices might affect pollinator populations. We report the results of a task force of the North American Pollinator Protection Campaign (NAPPC) that examined potential effects of vector management practices on pollinators, and how these programs could be adjusted to minimize negative effects on pollinating species. The main types of vector control practices that might affect pollinators are landscape manipulation, biocontrol, and pesticide applications. Some current practices already minimize effects of vector control on pollinators (e.g., short-lived pesticides and application-targeting technologies). Nontarget effects can be further diminished by taking pollinator protection into account in the planning stages of vector management programs. Effects of vector control on pollinator species often depend on specific local conditions (e.g., proximity of locations with abundant vectors to concentrations of floral resources), so planning is most effective when it includes collaborations of local vector management professionals with local experts on pollinators. Interventions can then be designed to avoid pollinators (e.g., targeting applications to avoid blooming times and pollinator nesting habitats), while still optimizing public health protection. Research on efficient targeting of interventions, and on effects on pollinators of emerging technologies, will help mitigate potential deleterious effects on pollinators in future management programs. In particular, models that can predict effects of integrated pest management on vector-borne pathogen transmission, along with effects on pollinator populations, would be useful for collaborative decision-making.

Radiation of Pollination Systems in the Iridaceae of sub-Saharan Africa

PubMed Central

GOLDBLATT, PETER; MANNING, JOHN C.

2006-01-01

• Background Seventeen distinct pollination systems are known for genera of sub-Saharan African Iridaceae and recurrent shifts in pollination system have evolved in those with ten or more species. Pollination by long-tongued anthophorine bees foraging for nectar and coincidentally acquiring pollen on some part of their bodies is the inferred ancestral pollination strategy for most genera of the large subfamilies Iridoideae and Crocoideae and may be ancestral for the latter. Derived strategies include pollination by long-proboscid flies, large butterflies, night-flying hovering and settling moths, hopliine beetles and sunbirds. Bee pollination is diverse, with active pollen collection by female bees occurring in several genera, vibratile systems in a few and non-volatile oil as a reward in one species. Long-proboscid fly pollination, which is apparently restricted to southern Africa, includes four separate syndromes using different sets of flies and plant species in different parts of the subcontinent. Small numbers of species use bibionid flies, short-proboscid flies or wasps for their pollination; only about 2 % of species use multiple pollinators and can be described as generalists. • Scope Using pollination observations for 375 species and based on repeated patterns of floral attractants and rewards, we infer pollination mechanisms for an additional 610 species. Matching pollination system to phylogeny or what is known about species relationships based on shared derived features, we infer repeated shifts in pollination system in some genera, as frequently as one shift for every five or six species of southern African Babiana or Gladiolus. Specialized systems using pollinators of one pollination group, or even a single pollinator species are the rule in the family. Shifts in pollination system are more frequent in genera of Crocoideae that have bilaterally symmetric flowers and a perianth tube, features that promote adaptive radiation by facilitating precise shifts in pollen placement, in conjunction with changes in flower colour, scent and tube length. • Conclusions Diversity of pollination systems explains in part the huge species diversity of Iridaceae in sub-Saharan Africa, and permits species packing locally. Pollination shifts are, however, seen as playing a secondary role in speciation by promoting reproductive isolation in peripheral, ecologically distinct populations in areas of diverse topography, climate and soils. Pollination of Iridaceae in Eurasia and the New World, where the family is also well represented, is poorly studied but appears less diverse, although pollination by both pollen- and oil-collecting bees is frequent and bird pollination rare. PMID:16377653

Radiation of pollination systems in the Iridaceae of sub-Saharan Africa.

PubMed

Goldblatt, Peter; Manning, John C

2006-03-01

Seventeen distinct pollination systems are known for genera of sub-Saharan African Iridaceae and recurrent shifts in pollination system have evolved in those with ten or more species. Pollination by long-tongued anthophorine bees foraging for nectar and coincidentally acquiring pollen on some part of their bodies is the inferred ancestral pollination strategy for most genera of the large subfamilies Iridoideae and Crocoideae and may be ancestral for the latter. Derived strategies include pollination by long-proboscid flies, large butterflies, night-flying hovering and settling moths, hopliine beetles and sunbirds. Bee pollination is diverse, with active pollen collection by female bees occurring in several genera, vibratile systems in a few and non-volatile oil as a reward in one species. Long-proboscid fly pollination, which is apparently restricted to southern Africa, includes four separate syndromes using different sets of flies and plant species in different parts of the subcontinent. Small numbers of species use bibionid flies, short-proboscid flies or wasps for their pollination; only about 2 % of species use multiple pollinators and can be described as generalists. Using pollination observations for 375 species and based on repeated patterns of floral attractants and rewards, we infer pollination mechanisms for an additional 610 species. Matching pollination system to phylogeny or what is known about species relationships based on shared derived features, we infer repeated shifts in pollination system in some genera, as frequently as one shift for every five or six species of southern African Babiana or Gladiolus. Specialized systems using pollinators of one pollination group, or even a single pollinator species are the rule in the family. Shifts in pollination system are more frequent in genera of Crocoideae that have bilaterally symmetric flowers and a perianth tube, features that promote adaptive radiation by facilitating precise shifts in pollen placement, in conjunction with changes in flower colour, scent and tube length. Diversity of pollination systems explains in part the huge species diversity of Iridaceae in sub-Saharan Africa, and permits species packing locally. Pollination shifts are, however, seen as playing a secondary role in speciation by promoting reproductive isolation in peripheral, ecologically distinct populations in areas of diverse topography, climate and soils. Pollination of Iridaceae in Eurasia and the New World, where the family is also well represented, is poorly studied but appears less diverse, although pollination by both pollen- and oil-collecting bees is frequent and bird pollination rare.

Species- and habitat-specific bioaccumulation of total mercury and methylmercury in the food web of a deep oligotrophic lake.

PubMed

Arcagni, Marina; Juncos, Romina; Rizzo, Andrea; Pavlin, Majda; Fajon, Vesna; Arribére, María A; Horvat, Milena; Ribeiro Guevara, Sergio

2018-01-15

Niche segregation between introduced and native fish in Lake Nahuel Huapi, a deep oligotrophic lake in Northwest Patagonia (Argentina), occurs through the consumption of different prey. Therefore, in this work we analyzed total mercury [THg] and methylmercury [MeHg] concentrations in top predator fish and in their main prey to test whether their feeding habits influence [Hg]. Results indicate that [THg] and [MeHg] varied by foraging habitat and they increased with greater percentage of benthic diet and decreased with pelagic diet in Lake Nahuel Huapi. This is consistent with the fact that the native creole perch, a mostly benthivorous feeder, which shares the highest trophic level of the food web with introduced salmonids, had higher [THg] and [MeHg] than the more pelagic feeder rainbow trout and bentho-pelagic feeder brown trout. This differential THg and MeHg bioaccumulation observed in native and introduced fish provides evidence to the hypothesis that there are two main Hg transfer pathways from the base of the food web to top predators: a pelagic pathway where Hg is transferred from water, through plankton (with Hg in inorganic species mostly), forage fish to salmonids, and a benthic pathway, as Hg is transferred from the sediments (where Hg methylation occurs mostly), through crayfish (with higher [MeHg] than plankton), to native fish, leading to one fold higher [Hg]. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Cone and seed yields from controlled breeding of southern pines

Treesearch

E. B. Snyder; A. E. Squillace

1966-01-01

Over a 10-year period, survivals of cones from controlled cross-pollinations were less than 40 percent, and seed yields per cone averaged about half those from wind-pollinations. Self-pollinations produced about 15 percent as much seed as cross-pollinations. Interspecific pollinations were generally less productive than intraspecific pollinations.

Functional morphology and wasp pollination of two South American asclepiads (Asclepiadoideae–Apocynaceae)

PubMed Central

Wiemer, A. P.; Sérsic, A. N.; Marino, S.; Simões, A. O.; Cocucci, A. A.

2012-01-01

Background and Aims The extreme complexity of asclepiad flowers (Asclepiadoideae–Apocynaceae) has generated particular interest in the pollination biology of this group of plants especially in the mechanisms involved in the pollination processes. This study compares two South American species, Morrenia odorata and Morrenia brachystephana, with respect to morphology and anatomy of flower structures, dynamic aspects of the pollination mechanism, diversity of visitors and effectiveness of pollinators. Methods Floral structure was studied with fresh and fixed flowers following classical techniques. The pollination mechanism was studied by visiting fresh flowers in the laboratory with artificial pollinator body parts created with an eyelash. Morphometric and nectar measurements were also taken. Pollen transfer efficiency in the flowers was calculated by recording the frequency of removed and inserted pollinia. Visitor activity was recorded in the field, and floral visitors were captured for subsequent analysis of pollen loads. Finally, pollinator effectiveness was calculated with an index. Key Results The detailed structure of the flowers revealed a complex system of guide rails and chambers precisely arranged in order to achieve effective pollinaria transport. Morrenia odorata is functionally specialized for wasp pollination, and M. brachystephana for wasp and bee pollination. Pollinators transport chains of pollinaria adhered to their mouthparts. Conclusions Morrenia odorata and M. brachystephana present differences in the morphology and size of their corona, gynostegium and pollinaria, which explain the differences in details of the functioning of the general pollination mechanism. Pollination is performed by different groups of highly effective pollinators. Morrenia species are specialized for pollination mainly by several species of wasps, a specialized pollination which has been poorly studied. In particular, pompilid wasps are reported as important pollinators in other regions outside South Africa. A putative new function of nectar in asclepiads is presented, as it would be contributing to the pollination mechanism. PMID:22025522

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.

Dynamics of an ant-plant-pollinator model

NASA Astrophysics Data System (ADS)

Wang, Yuanshi; DeAngelis, Donald L.; Nathaniel Holland, J.

2015-03-01

In this paper, we consider plant-pollinator-ant systems in which plant-pollinator interaction and plant-ant interaction are both mutualistic, but there also exists interference of pollinators by ants. The plant-pollinator interaction can be described by a Beddington-DeAngelis formula, so we extend the formula to characterize plant-pollinator mutualisms, including the interference by ants, and form a plant-pollinator-ant model. Using dynamical systems theory, we show uniform persistence of the model. Moreover, we demonstrate conditions under which boundary equilibria are globally asymptotically stable. The dynamics exhibit mechanisms by which the three species could coexist when ants interfere with pollinators. We define a threshold in ant interference. When ant interference is strong, it can drive plant-pollinator mutualisms to extinction. Furthermore, if the ants depend on pollination mutualism for their persistence, then sufficiently strong ant interference could lead to their own extinction as well. Yet, when ant interference is weak, plant-ant and plant-pollinator mutualisms can promote the persistence of one another.

Human Impacts and Climate Change Influence Nestedness and Modularity in Food-Web and Mutualistic Networks.

PubMed

Takemoto, Kazuhiro; Kajihara, Kosuke

2016-01-01

Theoretical studies have indicated that nestedness and modularity-non-random structural patterns of ecological networks-influence the stability of ecosystems against perturbations; as such, climate change and human activity, as well as other sources of environmental perturbations, affect the nestedness and modularity of ecological networks. However, the effects of climate change and human activities on ecological networks are poorly understood. Here, we used a spatial analysis approach to examine the effects of climate change and human activities on the structural patterns of food webs and mutualistic networks, and found that ecological network structure is globally affected by climate change and human impacts, in addition to current climate. In pollination networks, for instance, nestedness increased and modularity decreased in response to increased human impacts. Modularity in seed-dispersal networks decreased with temperature change (i.e., warming), whereas food web nestedness increased and modularity declined in response to global warming. Although our findings are preliminary owing to data-analysis limitations, they enhance our understanding of the effects of environmental change on ecological communities.

Oldest true orb-weaving spider (Araneae: Araneidae)

PubMed Central

Penney, David; Ortuño, Vicente M

2006-01-01

The aerial orb web woven by spiders of the family Araneidae typifies these organisms to laypersons and scientists alike. Here we describe the oldest fossil species of this family, which is preserved in amber from Álava, Spain and represents the first record of Araneidae from the Lower Cretaceous. The fossils provide direct evidence that all three major orb web weaving families: Araneidae, Tetragnathidae and Uloboridae had evolved by this time, confirming the antiquity of the use of this remarkable structure as a prey capture strategy by spiders. Given the complex and stereotyped movements that all orb weavers use to construct their webs, there is little question regarding their common origin, which must have occurred in the Jurassic or earlier. Thus, various forms of this formidable prey capture mechanism were already in place by the time of the explosive Cretaceous co-radiation of angiosperms and their flying insect pollinators. This permitted a similar co-radiation of spider predators with their flying insect prey, presumably without the need for a ‘catch-up lag phase’ for the spiders. PMID:17148427

The pollination niche and its role in the diversification and maintenance of the southern African flora

PubMed Central

Johnson, Steven D.

2010-01-01

The flora of southern Africa has exceptional species richness and endemism, making it an ideal system for studying the patterns and processes of evolutionary diversification. Using a wealth of recent case studies, I examine the evidence for pollinator-driven diversification in this flora. Pollination systems, which represent available niches for ecological diversification, are characterized in southern Africa by a high level of ecological and evolutionary specialization on the part of plants, and, in some cases, by pollinators as well. These systems are asymmetric, with entire plant guilds commonly specialized for a particular pollinator species or functional type, resulting in obvious convergent floral evolution among guild members. Identified modes of plant lineage diversification involving adaptation to pollinators in these guilds include (i) shifts between pollination systems, (ii) divergent use of the same pollinator, (iii) coevolution, (iv) trait tracking, and (v) floral mimicry of different model species. Microevolutionary studies confirm that pollinator shifts can be precipitated when a plant species encounters a novel pollinator fauna on its range margin, and macroevolutionary studies confirm frequent pollinator shifts associated with lineage diversification. As Darwin first noted, evolutionary specialization for particular pollinators, when resulting in ecological dependency, may increase the risk of plant extinction. I thus also consider the evidence that disturbance provokes pollination failure in some southern African plants with specialized pollination systems. PMID:20047876

Competition for pollinators and intra-communal spectral dissimilarity of flowers.

PubMed

van der Kooi, C J; Pen, I; Staal, M; Stavenga, D G; Elzenga, J T M

2016-01-01

Competition for pollinators occurs when, in a community of flowering plants, several simultaneously flowering plant species depend on the same pollinator. Competition for pollinators increases interspecific pollen transfer rates, thereby reducing the number of viable offspring. In order to decrease interspecific pollen transfer, plant species can distinguish themselves from competitors by having a divergent phenotype. Floral colour is an important signalling cue to attract potential pollinators and thus a major aspect of the flower phenotype. In this study, we analysed the amount of spectral dissimilarity of flowers among pollinator-competing plants in a Dutch nature reserve. We expected pollinator-competing plants to exhibit more spectral dissimilarity than non-competing plants. Using flower visitation data of 2 years, we determined the amount of competition for pollinators by different plant species. Plant species that were visited by the same pollinator were considered specialist and competing for that pollinator, whereas plant species visited by a broad array of pollinators were considered non-competing generalists. We used principal components analysis to quantify floral reflectance, and found evidence for enhanced spectral dissimilarity among plant species within specialist pollinator guilds (i.e. groups of plant species competing for the same pollinator). This is the first study that examined intra-communal dissimilarity in floral reflectance with a focus on the pollination system. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

The pollination niche and its role in the diversification and maintenance of the southern African flora.

PubMed

Johnson, Steven D

2010-02-12

The flora of southern Africa has exceptional species richness and endemism, making it an ideal system for studying the patterns and processes of evolutionary diversification. Using a wealth of recent case studies, I examine the evidence for pollinator-driven diversification in this flora. Pollination systems, which represent available niches for ecological diversification, are characterized in southern Africa by a high level of ecological and evolutionary specialization on the part of plants, and, in some cases, by pollinators as well. These systems are asymmetric, with entire plant guilds commonly specialized for a particular pollinator species or functional type, resulting in obvious convergent floral evolution among guild members. Identified modes of plant lineage diversification involving adaptation to pollinators in these guilds include (i) shifts between pollination systems, (ii) divergent use of the same pollinator, (iii) coevolution, (iv) trait tracking, and (v) floral mimicry of different model species. Microevolutionary studies confirm that pollinator shifts can be precipitated when a plant species encounters a novel pollinator fauna on its range margin, and macroevolutionary studies confirm frequent pollinator shifts associated with lineage diversification. As Darwin first noted, evolutionary specialization for particular pollinators, when resulting in ecological dependency, may increase the risk of plant extinction. I thus also consider the evidence that disturbance provokes pollination failure in some southern African plants with specialized pollination systems.

Plant signalling: the opportunities and dangers of chemical communication.

PubMed

Adler, Frederick R

2011-04-23

The notion of chemical communication between plants and other organisms has gone from being viewed as a fringe idea to an accepted ecological phenomenon only recently. An Organized Oral Session at the August 2010 Ecological Society of America meeting in Pittsburgh examined the role of plant signalling both within and between plants, with speakers addressing the remarkably wide array of effects that plant signals have on plant physiology, species interactions and entire communities. In addition to the familiar way that plants communicate with mutualists like pollinators and fruit dispersers through both chemical and visual cues, speakers at this session described how plants communicate with themselves, with each other, with herbivores and with predators of those herbivores. These plant signals create a complex odour web superimposed upon the more classical food web itself, with its own dynamics in the face of exotic species and rapid community assembly and disassembly.

Factors Predicting Pre-Service Teachers' Adoption of Web 2.0 Technologies

ERIC Educational Resources Information Center

Cheon, Jongpil; Coward, Fanni; Song, Jaeki; Lim, Sunho

2012-01-01

Classrooms full of "digital natives" represent the norm in U. S. schools, but like their predecessors, they mostly inhabit spaces characterized by a traditional view of teaching and learning. Understanding contributors to this mismatch, and especially teachers' role, is especially critical as Web 2.0 technologies enable greater learner…

Digital Ethnography: Library Web Page Redesign among Digital Natives

ERIC Educational Resources Information Center

Klare, Diane; Hobbs, Kendall

2011-01-01

Presented with an opportunity to improve Wesleyan University's dated library home page, a team of librarians employed ethnographic techniques to explore how its users interacted with Wesleyan's current library home page and web pages in general. Based on the data that emerged, a group of library staff and members of the campus' information…

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

Modularity, pollination systems, and interaction turnover in plant-pollinator networks across space.

PubMed

Carstensen, Daniel W; Sabatino, Malena; Morellato, Leonor Patricia C

2016-05-01

Mutualistic interaction networks have been shown to be structurally conserved over space and time while pairwise interactions show high variability. In such networks, modularity is the division of species into compartments, or modules, where species within modules share more interactions with each other than they do with species from other modules. Such a modular structure is common in mutualistic networks and several evolutionary and ecological mechanisms have been proposed as underlying drivers. One prominent explanation is the existence of pollination syndromes where flowers tend to attract certain pollinators as determined by a set of traits. We investigate the modularity of seven community level plant-pollinator networks sampled in rupestrian grasslands, or campos rupestres, in SE Brazil. Defining pollination systems as corresponding groups of flower syndromes and pollinator functional groups, we test the two hypotheses that (1) interacting species from the same pollination system are more often assigned to the same module than interacting species from different pollination systems and; that (2) interactions between species from the same pollination system are more consistent across space than interactions between species from different pollination systems. Specifically we ask (1) whether networks are consistently modular across space; (2) whether interactions among species of the same pollination system occur more often inside modules, compared to interactions among species of different pollination systems, and finally; (3) whether the spatial variation in interaction identity, i.e., spatial interaction rewiring, is affected by trait complementarity among species as indicated by pollination systems. We confirm that networks are consistently modular across space and that interactions within pollination systems principally occur inside modules. Despite a strong tendency, we did not find a significant effect of pollination systems on the spatial consistency of pairwise interactions. These results indicate that the spatial rewiring of interactions could be constrained by pollination systems, resulting in conserved network structures in spite of high variation in pairwise interactions. Our findings suggest a relevant role of pollination systems in structuring plant-pollinator networks and we argue that structural patterns at the sub-network level can help us to fully understand how and why interactions vary across space and time.

Molecular phylogenies of figs and fig-pollinating wasps in the Ryukyu and Bonin (Ogasawara) islands, Japan.

PubMed

Azuma, Hiroshi; Harrison, Rhett D; Nakamura, Keiko; Su, Zhi-Hui

2010-01-01

The interaction between figs (Ficus, Moraceae) and fig-pollinating wasps (Chalcidoidea, Agaonidae) is one of the most specific mutualisms, and thus is a model system for studying coevolution and cospeciation. In this study we focused on figs and their associated fig-wasps found in the Ryukyu and Bonin (Ogasawara) Islands, Japan, because it has been suggested that breakdown in the specificity may occur in islands or at edge of a species' distribution. We collected 136 samples of 15 native fig species and 95 samples of 13 associated fig-wasps from all major islands in the Ryukyu Islands, including two fig species and one fig-wasp species endemic to the Bonin Islands. We performed molecular phylogenetic analyses using plastid DNA and nuclear ITS sequences for the figs and nuclear 28S rRNA and mitochondrial COI genes for the fig-wasps to investigate the interspecific phylogenies and intraspecific variation within the mutualism. Our phylogenetic analyses using multiple samples per species show the single clade of each fig (except the Bonin endemic species) and fig-pollinating wasp species. Fig species belonging to the same subgenera formed well-supported clades in both plastid and ITS trees, except for the subgenus Urostigma. Likewise, fig wasps emerging from host fig species belonging to the same subgenera formed mostly well supported clades in both 28S and COI trees. Host specificity between the figs and fig-wasps functions strictly in these islands. There was very little sequence variation within species, and that no major geographic structure was found. The two Bonin endemic species (F. boninsimae and F. nishimurae) or their common ancestor and the associated fig-wasps (Blastophaga sp.) are apparently derived from F. erecta and its associated fig-wasps (B. nipponica), respectively, and probably migrated from the Ryukyu Islands.

Can fine-scale post-pollination variation of fig volatile compounds explain some steps of the temporal succession of fig wasps associated with Ficus racemosa?

NASA Astrophysics Data System (ADS)

Proffit, Magali; Bessière, Jean-Marie; Schatz, Bertrand; Hossaert-McKey, Martine

2018-07-01

Volatile organic compounds (VOCs) emitted by flowers play an essential role in mediating the attraction of pollinators. However, they also attract other species exploiting resources associated with flowers. For instance, VOCs emitted by figs play a major role in encounters between Ficus spp., their mutualistic pollinating wasps, and all the members of the community of non-pollinating fig wasps (NPFWs) that exploit the mutualistic interaction. Because pollinators might be in limited supply for a tree bearing many inflorescences, the plant might maximize its individual reproductive success by reducing the attractiveness of inflorescences once they are pollinated, so that pollinators orient only towards the tree's unpollinated figs. Changes in VOCs emission that bring this about could represent an important cue for NPFWs that exploit particular stages of fig development. In this study, by monitoring precisely the presence of fig-associated wasps on figs of F. racemosa, a common widespread fig species, we demonstrated that 4-5 days and 15 days following pollination represent two critical transitional steps in the succession of different wasp species. Then, focusing on the first one of these transitional steps, by investigating the composition of fig VOCs at receptivity and from 1 to 5 days following pollination, we detected progressive quantitative and qualitative variation of floral scent following pollination. These changes are significant at 5 days following pollination. The qualitative changes are mainly due to an increase in the relative proportions of two monoterpenes (α-pinene and limonene). These variations of the floral VOCs following pollination could explain why pollinating wasps stop visiting figs very shortly after the first pollinators enter receptive figs. They also possibly explain the succession of non-pollinating wasps on the figs following pollination.

Plant-pollinator interactions in a biodiverse meadow are rather stable and tight for 3 consecutive years.

PubMed

Fang, Qiang; Huang, Shuangquan

2016-05-01

Plant-pollinator interactions can be highly variable across years in natural communities. Although variation in the species composition and its basic structure has been investigated to understand the dynamic nature of pollination networks, little is known about the temporal dynamic of interaction strength between the same plant and pollinator species in any natural community. Pollinator-mediated selection on the evolution of floral traits could be diminished if plant-pollinator interactions vary temporally. To quantify the temporal variation in plant-pollinator interactions and the interaction strength (observed visits), we compared weighted networks between plants and pollinators in a biodiverse alpine meadow in Shangri-La, southwest China for 3 consecutive years. Although plant-pollinator interactions were highly dynamic such that identical interactions only accounted for 10.7% of the total between pair years, the diversity of interactions was stable. These identical interactions contributed 41.2% of total visits and were similar in strength and weighted nestedness. For plant species, 72.6% of species were visited by identical pollinator species between pair years, accounting for over half of the total visits and three-quarters at the functional group level. More generalized pollinators contributed more connectiveness and were more central in networks across years. However, there was no similar or even opposite trend for plant species, which suggested that specialized plant species may also be central in pollinator networks. The variation in pollinator composition decreased as pollinator species numbers increased, suggesting that generalized plants experienced stable pollinator partition. The stable, tight interactions between generalized pollinators and specialized plants represent cornerstones of the studied community. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

The good, the bad and the flexible: plant interactions with pollinators and herbivores over space and time are moderated by plant compensatory responses

PubMed Central

Lay, C. R.; Linhart, Y. B.; Diggle, P. K.

2011-01-01

Background and Aims Plants are sessile organisms that face selection by both herbivores and pollinators. Herbivores and pollinators may select on the same traits and/or mediate each others' effects. Erysimum capitatum (Brassicaceae) is a widespread and variable plant species with generalized pollination that is attacked by a number of herbivores. The following questions were addressed. (a) Are pollinators and herbivores attracted by similar plant traits? (b) Does herbivory affect pollinator preferences? (c) Do pollinators and/or herbivores affect fitness and select on plant traits? (d) Do plant compensatory responses affect the outcome of interactions among plants, pollinators and herbivores? (e) Do interactions among E. capitatum and its pollinators and herbivores differ among sites and years? Methods In 2005 and 2006, observational and experimental studies were combined in four populations at different elevations to examine selection by pollinators and herbivores on floral traits of E. capitatum. Key Results Pollinator and herbivore assemblages varied spatially and temporally, as did their effects on plant fitness and selection. Both pollinators and herbivores preferred plants with more flowers, and herbivory sometimes reduced pollinator visitation. Pollinators did not select on plant traits in any year or population and E. capitatum was not pollen limited; however, supplemental pollen resulted in altered plant resource allocation. Herbivores reduced fitness and selected for plant traits in some populations, and these effects were mediated by plant compensatory responses. Conclusions Individuals of Erysimum capitatum are visited by diverse groups of pollinators and herbivores that shift in abundance and importance in time and space. Compensatory reproductive mechanisms mediate interactions with both pollinators and herbivores and may allow E. capitatum to succeed in this complex selective environment. PMID:21724655

Evolution of pollination niches and floral divergence in the generalist plant Erysimum mediohispanicum

PubMed Central

Gómez, J. M.; Muñoz-Pajares, A. J.; Abdelaziz, M.; Lorite, J.; Perfectti, F.

2014-01-01

Background and Aims How generalist plants diverge in response to pollinator selection without becoming specialized is still unknown. This study explores this question, focusing on the evolution of the pollination system in the pollination generalist Erysimum mediohispanicum (Brassicaceae). Methods Pollinator assemblages were surveyed from 2001 to 2010 in 48 geo-referenced populations covering the entire geographic distribution of E. mediohispanicum. Bipartite modularity, a complex network tool, was used to find the pollination niche of each population. Evolution of the pollination niches and the correlated evolution of floral traits and pollination niches were explored using within-species comparative analyses. Key Results Despite being generalists, the E. mediohispanicum populations studied can be classified into five pollination niches. The boundaries between niches were not sharp, the niches differing among them in the relative frequencies of the floral visitor functional groups. The absence of spatial autocorrelation and phylogenetic signal indicates that the niches were distributed in a phylogeographic mosaic. The ancestral E. mediohispanicum populations presumably belonged to the niche defined by a high number of beetle and ant visits. A correlated evolution was found between pollination niches and some floral traits, suggesting the existence of generalist pollination ecotypes. Conclusions It is conjectured that the geographic variation in pollination niches has contributed to the observed floral divergence in E. mediohispanicum. The process mediating this floral divergence presumably has been adaptive wandering, but the adaptation to the local pollinator faunas has been not universal. The outcome is a landscape where a few populations locally adapted to their pollination environment (generalist pollination ecotypes) coexist with many populations where this local adaptation has failed and where the plant phenotype is not primarily shaped by pollinators. PMID:23965614

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.

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

Evolution of pollination niches in a generalist plant clade.

PubMed

Gómez, José María; Perfectti, Francisco; Abdelaziz, Mohamed; Lorite, Juan; Muñoz-Pajares, Antonio Jesús; Valverde, Javier

2015-01-01

It is widely assumed that floral diversification occurs by adaptive shifts between pollination niches. In contrast to specialized flowers, identifying pollination niches of generalist flowers is a challenge. Consequently, how generalist pollination niches evolve is largely unknown. We apply tools from network theory and comparative methods to investigate the evolution of pollination niches among generalist species belonging to the genus Erysimum. These species have similar flowers. We found that the studied species may be grouped in several multidimensional niches separated not by a shift of pollinators, but instead by quantitative variation in the relative abundance of pollinator functional groups. These pollination niches did not vary in generalization degree; we did not find any evolutionary trend toward specialization within the studied clade. Furthermore, the evolution of pollination niche fitted to a Brownian motion model without phylogenetic signal, and was characterized by frequent events of niche convergences and divergences. We presume that the evolution of Erysimum pollination niches has occurred mostly by recurrent shifts between slightly different generalized pollinator assemblages varying spatially as a mosaic and without any change in specialization degree. Most changes in pollination niches do not prompt floral divergence, a reason why adaptation to pollinators is uncommon in generalist plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Pollinator-mediated natural selection in Penstemon digitalis.

PubMed

Parachnowitsch, Amy; Kessler, André

2010-12-01

Measuring the agents of natural selection is important because it allows us to understand not only which traits are expected to evolve but also why they will evolve. Natural selection by pollinators on floral traits is often assumed because in outcrossing animal-pollinated plants flowers are generally thought to function as advertisements of rewards directed at pollinators. We tested the role of bee pollinators in selection on Penstemon digitalis and found that pollinators were driving selection for larger and more flowers. However, what makes our publication unique is the additional information we gained from reviewing the few other studies that also directly tested whether pollinators were agents of selection on floral traits. As we would expect if pollinators are important agents of selection, selection on floral traits was significantly stronger when pollinators were present than when they were experimentally removed. Taken together, these results suggest that pollinators can be important drivers of selection in contemporary populations.

Real-time divergent evolution in plants driven by pollinators

PubMed Central

Gervasi, Daniel D. L.; Schiestl, Florian P

2017-01-01

Pollinator-driven diversification is thought to be a major source of floral variation in plants. Our knowledge of this process is, however, limited to indirect assessments of evolutionary changes. Here, we employ experimental evolution with fast cycling Brassica rapa plants to demonstrate adaptive evolution driven by different pollinators. Our study shows pollinator-driven divergent selection as well as divergent evolution in plant traits. Plants pollinated by bumblebees evolved taller size and more fragrant flowers with increased ultraviolet reflection. Bumblebees preferred bumblebee-pollinated plants over hoverfly-pollinated plants at the end of the experiment, showing that plants had adapted to the bumblebees' preferences. Plants with hoverfly pollination became shorter, had reduced emission of some floral volatiles, but increased fitness through augmented autonomous self-pollination. Our study demonstrates that changes in pollinator communities can have rapid consequences on the evolution of plant traits and mating system. PMID:28291771

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

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.

Flowering and floral visitation predict changes in community structure provided that mycorrhizas remain intact.

PubMed

Bennett, Jonathan A; Cahill, James F

2018-06-01

Pollination is critical for plant fitness and population dynamics, yet little attention is paid to the role of flowering and plant-pollinator interactions in structuring plant communities, including community responses to environmental change. Changes in arbuscular mycorrhizal fungi (AMF), nutrient abundances, and plant litter all affect plant access to different resources, and are known regulators of community structure. Each factor can also affect flowering and plant-pollinator interactions, potentially contributing to changes in community structure. To test whether AMF, nutrients, and litter influenced the relationship between pollination and community structure, we conducted a 5-yr field experiment applying fungicide, adding fertilizer, and removing plant litter in native grassland. We measured the distribution of flowers and floral visits among species in year three and linked these measures to changes in plant composition and species richness between years three and five. We hypothesized that an uneven distribution of flowers and visits among species would lead to greater community change, but that the treatments would disrupt this relationship by altering sexual allocation and recruitment. Consistent with our hypothesis, communities with uneven flower distributions exhibited greater changes in community composition and richness under ambient conditions. However, AMF suppression neutralized this relationship and regulated the other treatment effects, highlighting the potential importance of AMF for stabilizing recruitment dynamics. Combined, AMF suppression and nutrient addition caused species losses when few species flowered, likely by compounding stresses for those species. The treatment effects on the relationship between flowering and community composition were more nuanced, but were likely driven by increased competition and altered flowering among species. By contrast, community composition was more stable when visitation rates were uneven among species, irrespective of any treatments. This suggests that some species require high visitation rates to maintain their populations due to greater dependence on sexual reproduction. Combined, these results highlight the importance of flowering and floral visitation to the dynamics of grassland communities. They also suggest that altered recruitment dynamics is a major, yet understudied, mechanism by which environmental change affects communities. Consequently, understanding the effects of environmental change on plant communities will require study of both plant growth and sexual reproduction. © 2018 by the Ecological Society of America.

ACHP | Native American Traditional Cultural Landscapes

Science.gov Websites

action plan in November 2011. The plan calls for the ACHP and the Department of the Interior (DOI) to Summit Implementation of the action plan is a long-term commitment of the ACHP. This Web page will serve Landscapes Action Plan Information on Cultural Landscapes Fact Sheet on the ACHP's Native American

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.

Pollination limitation to reproductive success in the Missouri evening primrose, Oenothera macrocarpa (Onagraceae).

PubMed

Moody-Weis, J M; Heywood, J S

2001-09-01

Habitat fragmentation may result in plant populations that are less attractive to pollinators and thus susceptible to reduced reproductive output due to pollination limitation. Pollination limitation was investigated in three Missouri populations of Oenothera macrocarpa, a hawk-moth-pollinated, perennial herb. The populations represented extremes in size and habitat quality. Following supplemental pollination, mean fertilization success (proportion of ovules fertilized) across populations increased from 24.3 to 44.8% and mean seed set (proportion of ovules that matured into seed) increased from 14.7 to 27.9%. These increases were statistically significant in two of the three populations. Failure to achieve 100% fertilization and seed set following supplementation indicates that other factors, in addition to pollination, were limiting to female reproductive success. Fruit set was pollination limited in only one population. Fruits matured with as few as one seed, suggesting that fruit set was not resource limited. The degree of pollination limitation was greatest in the most disturbed population. The population located in the highest-quality habitat was not significantly pollination limited. This suggests that pollination limitation is occurring, at least in part, because of reduced pollinator activity in degraded habitats.

Pollinator shifts and the evolution of spur length in the moth-pollinated orchid Platanthera bifolia.

PubMed

Boberg, Elin; Alexandersson, Ronny; Jonsson, Magdalena; Maad, Johanne; Ågren, Jon; Nilsson, L Anders

2014-01-01

Plant-pollinator interactions are thought to have shaped much of floral evolution. Yet the relative importance of pollinator shifts and coevolutionary interactions for among-population variation in floral traits in animal-pollinated species is poorly known. This study examined the adaptive significance of spur length in the moth-pollinated orchid Platanthera bifolia. Geographical variation in the length of the floral spur of P. bifolia was documented in relation to variation in the pollinator fauna across Scandinavia, and a reciprocal translocation experiment was conducted in south-east Sweden between a long-spurred woodland population and a short-spurred grassland population. Spur length and pollinator fauna varied among regions and habitats, and spur length was positively correlated with the proboscis length of local pollinators. In the reciprocal translocation experiment, long-spurred woodland plants had higher pollination success than short-spurred grassland plants at the woodland site, while no significant difference was observed at the grassland site. The results are consistent with the hypothesis that optimal floral phenotype varies with the morphology of the local pollinators, and that the evolution of spur length in P. bifolia has been largely driven by pollinator shifts.

Pollinator shifts and the evolution of spur length in the moth-pollinated orchid Platanthera bifolia

PubMed Central

Boberg, Elin; Alexandersson, Ronny; Jonsson, Magdalena; Maad, Johanne; Ågren, Jon; Nilsson, L. Anders

2014-01-01

Background and Aims Plant–pollinator interactions are thought to have shaped much of floral evolution. Yet the relative importance of pollinator shifts and coevolutionary interactions for among-population variation in floral traits in animal-pollinated species is poorly known. This study examined the adaptive significance of spur length in the moth-pollinated orchid Platanthera bifolia. Methods Geographical variation in the length of the floral spur of P. bifolia was documented in relation to variation in the pollinator fauna across Scandinavia, and a reciprocal translocation experiment was conducted in south-east Sweden between a long-spurred woodland population and a short-spurred grassland population. Key Results Spur length and pollinator fauna varied among regions and habitats, and spur length was positively correlated with the proboscis length of local pollinators. In the reciprocal translocation experiment, long-spurred woodland plants had higher pollination success than short-spurred grassland plants at the woodland site, while no significant difference was observed at the grassland site. Conclusions The results are consistent with the hypothesis that optimal floral phenotype varies with the morphology of the local pollinators, and that the evolution of spur length in P. bifolia has been largely driven by pollinator shifts. PMID:24169591

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

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.

Wind-Dragged Corolla Enhances Self-Pollination: A New Mechanism of Delayed Self-Pollination

PubMed Central

Qu, Rongming; Li, Xiaojie; Luo, Yibo; Dong, Ming; Xu, Huanli; Chen, Xuan; Dafni, Amots

2007-01-01

Background and Aims Delayed self-pollination is a mechanism that allows animal-pollinated plants to outcross while ensuring seed production in the absence of pollinators. This study aims to explore a new mechanism of delayed self-pollination facilitated by wind-driven corolla abscission in Incarvillea sinensis var. sinensis. Methods Floral morphology and development, and the process of delayed self-pollination were surveyed. Experiments dealing with pollinator and wind exclusion, pollination manipulations, and pollinator observations were conducted in the field. Key Results Delayed self-pollination occurs when the abscising corolla driven by wind drags the adherent epipetalous stamens, thus leading to contact of anthers with stigma in late anthesis. There is no dichogamy and self-incompatibility in this species. The significantly higher proportion of abscised corolla under natural conditions as compared with that in wind-excluding tents indicates the importance of wind in corolla abscission. When pollinators were excluded, corolla abscission significantly increased the number of pollen grains deposited on the stigma and, as a result, the fruit and seed set. Only half of the flowers in plots were visited by pollinators, and the fruit set of emasculated flowers was significantly lower than that of untreated flowers in open pollination. This species has a sensitive stigma, and its two open stigmatic lobes closed soon after being touched by a pollinator, but always reopened if no or only little pollen was deposited. Conclusions This delayed self-pollination, which involved the movement of floral parts, the active participation of the wind and sensitive stigma, is quite different from that reported previously. This mechanism provides reproductive assurance for this species. The sensitive stigma contributes to ensuring seed production and reducing the interference of selfing with outcrossing. The pollination pattern, which combines actions by bees with indirect participation by wind, is also a new addition to ambophily. PMID:17881336

Relative stability of core groups in pollination networks in a biodiversity hotspot over four years.

PubMed

Fang, Qiang; Huang, Shuang-Quan

2012-01-01

Plants and their pollinators form pollination networks integral to the evolution and persistence of species in communities. Previous studies suggest that pollination network structure remains nested while network composition is highly dynamic. However, little is known about temporal variation in the structure and function of plant-pollinator networks, especially in species-rich communities where the strength of pollinator competition is predicted to be high. Here we quantify temporal variation of pollination networks over four consecutive years in an alpine meadow in the Hengduan Mountains biodiversity hotspot in China. We found that ranked positions and idiosyncratic temperatures of both plants and pollinators were more conservative between consecutive years than in non-consecutive years. Although network compositions exhibited high turnover, generalized core groups--decomposed by a k-core algorithm--were much more stable than peripheral groups. Given the high rate of turnover observed, we suggest that identical plants and pollinators that persist for at least two successive years sustain pollination services at the community level. Our data do not support theoretical predictions of a high proportion of specialized links within species-rich communities. Plants were relatively specialized, exhibiting less variability in pollinator composition at pollinator functional group level than at the species level. Both specialized and generalized plants experienced narrow variation in functional pollinator groups. The dynamic nature of pollination networks in the alpine meadow demonstrates the potential for networks to mitigate the effects of fluctuations in species composition in a high biodiversity area.

The relationships between floral traits and specificity of pollination systems in three Scandinavian plant communities.

PubMed

Lázaro, Amparo; Hegland, Stein Joar; Totland, Orjan

2008-08-01

The pollination syndrome hypothesis has provided a major conceptual framework for how plants and pollinators interact. However, the assumption of specialization in pollination systems and the reliability of floral traits in predicting the main pollinators have been questioned recently. In addition, the relationship between ecological and evolutionary specialization in pollination interactions is still poorly understood. We used data of 62 plant species from three communities across southern Norway to test: (1) the relationships between floral traits and the identity of pollinators, (2) the association between floral traits (evolutionary specialization) and ecological generalization, and (3) the consistency of both relationships across communities. Floral traits significantly affected the identity of pollinators in the three communities in a way consistent with the predictions derived from the pollination syndrome concept. However, hover flies and butterflies visited flowers with different shapes in different communities, which we mainly attribute to among-community variation in pollinator assemblages. Interestingly, ecological generalization depended more on the community-context (i.e. the plant and pollinator assemblages in the communities) than on specific floral traits. While open yellow and white flowers were the most generalist in two communities, they were the most specialist in the alpine community. Our results warn against the use of single measures of ecological generalization to question the pollination syndrome concept, and highlight the importance of community comparisons to assess the pollination syndromes, and to understand the relationships between ecological and evolutionary specialization in plant-pollinator interactions.

Differences in dichogamy and herkogamy contribute to higher selfing in contrasting environments in the annual Blackstonia perfoliata (Gentianaceae)

PubMed Central

Brys, Rein; Geens, Bram; Beeckman, Tom; Jacquemyn, Hans

2013-01-01

Background and Aims The establishment of plant populations in novel environments may generate pronounced shifts in floral traits and plant mating systems, particularly when pollinators are scarce. In this study, floral morphology and mating system functioning are compared between recently established and older populations of the annual plant Blackstonia perfoliata that occur in different pollinator environments. Methods Hand-pollination and emasculation experiments were conducted to assess the extent of pollinator-mediated pollen deposition and pollen limitation, and the contribution of autonomous selfing to total seed production. Detailed measurements of key floral traits were performed to compare the flower morphology and mating system functioning between plants from both pollination environments. Key Results Pollinator-mediated pollen deposition was about twice as low in the recently colonized and pollinator-poor environment compared with the old and pollinator-rich sites, but total seed set was little affected by any type of pollen limitation. The contribution of autonomous selfing to total seed production was higher in the pollinator-poor sites than in the pollinator-rich sites (index of reproductive assurance = 0·56 and 0·17, respectively), and seed production was only poorly affected by selfing, whereas in the pollinator-rich populations selfing reduced total reproductive output by about 40 % compared with outcross pollination. Plants originating from pollinator-poor environments produced smaller flowers that showed significantly lower levels of dichogamy (i.e. protogyny) and herkogamy. These reductions resulted in a 2-fold higher capacity for autonomous selfing under pollinator-free conditions (index of autonomous selfing = 0·81 and 0·41 in plants originating from the pollinator-poor and pollinator-rich environment, respectively). Conclusions The results illustrate that plant populations colonizing novel environments can differ markedly in floral morphology and mating system functioning. Due to a temporal shift in the male phase, the breeding system of B. perfoliata shifted from delayed selfing under pollinator-rich conditions towards competing selfing in recently established populations, providing greater reproductive assurance when pollinators and/or reproductive partners are limited. PMID:23408833

Avoiding a bad apple: Insect pollination enhances fruit quality and economic value☆

PubMed Central

Garratt, M.P.D.; Breeze, T.D.; Jenner, N.; Polce, C.; Biesmeijer, J.C.; Potts, S.G.

2014-01-01

Insect pollination is important for food production globally and apples are one of the major fruit crops which are reliant on this ecosystem service. It is fundamentally important that the full range of benefits of insect pollination to crop production are understood, if the costs of interventions aiming to enhance pollination are to be compared against the costs of the interventions themselves. Most previous studies have simply assessed the benefits of pollination to crop yield and ignored quality benefits and how these translate through to economic values. In the present study we examine the influence of insect pollination services on farmgate output of two important UK apple varieties; Gala and Cox. Using field experiments, we quantify the influence of insect pollination on yield and importantly quality and whether either may be limited by sub-optimal insect pollination. Using an expanded bioeconomic model we value insect pollination to UK apple production and establish the potential for improvement through pollination service management. We show that insects are essential in the production of both varieties of apple in the UK and contribute a total of £36.7 million per annum, over £6 million more than the value calculated using more conventional dependence ratio methods. Insect pollination not only affects the quantity of production but can also have marked impacts on the quality of apples, influencing size, shape and effecting their classification for market. These effects are variety specific however. Due to the influence of pollination on both yield and quality in Gala, there is potential for insect pollination services to improve UK output by up to £5.7 million per annum. Our research shows that continued pollinator decline could have serious financial implications for the apple industry but there is considerable scope through management of wild pollinators or using managed pollinator augmentation, to improve the quality of production. Furthermore, we show that it is critically important to consider all production parameters including quality, varietal differences and management costs when valuing the pollination service of any crop so investment in pollinator management can be proportional to its contribution. PMID:24748698

Avoiding a bad apple: Insect pollination enhances fruit quality and economic value.

PubMed

Garratt, M P D; Breeze, T D; Jenner, N; Polce, C; Biesmeijer, J C; Potts, S G

2014-02-01

Insect pollination is important for food production globally and apples are one of the major fruit crops which are reliant on this ecosystem service. It is fundamentally important that the full range of benefits of insect pollination to crop production are understood, if the costs of interventions aiming to enhance pollination are to be compared against the costs of the interventions themselves. Most previous studies have simply assessed the benefits of pollination to crop yield and ignored quality benefits and how these translate through to economic values. In the present study we examine the influence of insect pollination services on farmgate output of two important UK apple varieties; Gala and Cox. Using field experiments, we quantify the influence of insect pollination on yield and importantly quality and whether either may be limited by sub-optimal insect pollination. Using an expanded bioeconomic model we value insect pollination to UK apple production and establish the potential for improvement through pollination service management. We show that insects are essential in the production of both varieties of apple in the UK and contribute a total of £36.7 million per annum, over £6 million more than the value calculated using more conventional dependence ratio methods. Insect pollination not only affects the quantity of production but can also have marked impacts on the quality of apples, influencing size, shape and effecting their classification for market. These effects are variety specific however. Due to the influence of pollination on both yield and quality in Gala, there is potential for insect pollination services to improve UK output by up to £5.7 million per annum. Our research shows that continued pollinator decline could have serious financial implications for the apple industry but there is considerable scope through management of wild pollinators or using managed pollinator augmentation, to improve the quality of production. Furthermore, we show that it is critically important to consider all production parameters including quality, varietal differences and management costs when valuing the pollination service of any crop so investment in pollinator management can be proportional to its contribution.

Plasticity of floral longevity and floral display in the self-compatible biennial Sabatia angularis (Gentianaceae): untangling the role of multiple components of pollination.

PubMed

Spigler, Rachel B

2017-01-01

Plasticity of floral traits in response to pollination can enable plants to maximize opportunities for pollen import and export under poor pollination conditions, while minimizing costs under favourable ones. Both floral longevity and display are key traits influencing pollination. While pollination-induced flower wilting is widely documented, we lack an understanding of the multifactorial complexity of this response, including the influence of other pollination components, costs of extended longevity and subsequent impacts on floral display. Plasticity of floral longevity was experimentally evaluated in Sabatia angularis in response to multiple pollination factors: pollen addition, removal, and source (self, single-donor outcross, multiple-donor outcross) and timing of pollination. Effects of pollen quantity were further evaluated by exploiting variation in autonomous self-pollen deposition. Delayed pollination costs were tested comparing seed set from early versus late pollinations. Finally, I compared floral display metrics (peak floral display, time to peak flower, flowering duration, mean flowering rate) between experimentally pollinated and control plants. Floral longevity was highly plastic in response to pollen addition and its timing, and the response was dose-dependent but insensitive to pollen source. Pollen removal tended to extend floral longevity, but only insofar as it precluded pollination-induced wilting via autonomous self-pollination. Under delayed pollination, the wilting response was faster and no cost was detected. Pollination further led to reduced peak floral displays and condensed flowering periods. Floral longevity and display plasticity could optimize fitness in S. angularis, a species prone to pollen limitation and high inbreeding depression. Under pollinator scarcity, extended floral longevities offer greater opportunities for pollen receipt and export at no cost to seed set, reproductive assurance via autonomous self-pollination and larger, more attractive floral displays. Under high pollinator availability, shortened longevities lead to smaller displays that should lower the risk of geitonogamy. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Repeated evolution of vertebrate pollination syndromes in a recently diverged Andean plant clade.

PubMed

Lagomarsino, Laura P; Forrestel, Elisabeth J; Muchhala, Nathan; Davis, Charles C

2017-08-01

Although specialized interactions, including those involving plants and their pollinators, are often invoked to explain high species diversity, they are rarely explored at macroevolutionary scales. We investigate the dynamic evolution of hummingbird and bat pollination syndromes in the centropogonid clade (Lobelioideae: Campanulaceae), an Andean-centered group of ∼550 angiosperm species. We demonstrate that flowers hypothesized to be adapted to different pollinators based on flower color fall into distinct regions of morphospace, and this is validated by morphology of species with known pollinators. This supports the existence of pollination syndromes in the centropogonids, an idea corroborated by ecological studies. We further demonstrate that hummingbird pollination is ancestral, and that bat pollination has evolved ∼13 times independently, with ∼11 reversals. This convergence is associated with correlated evolution of floral traits within selective regimes corresponding to pollination syndrome. Collectively, our results suggest that floral morphological diversity is extremely labile, likely resulting from selection imposed by pollinators. Finally, even though this clade's rapid diversification is partially attributed to their association with vertebrate pollinators, we detect no difference in diversification rates between hummingbird- and bat-pollinated lineages. Our study demonstrates the utility of pollination syndromes as a proxy for ecological relationships in macroevolutionary studies of certain species-rich clades. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

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.

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).

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.

Migrating Department of Defense (DoD) Web Service Based Applications to Mobile Computing Platforms

DTIC Science & Technology

2012-03-01

World Wide Web Consortium (W3C) Geolocation API to identify the device’s location and then center the map on the device. Finally, we modify the entry...THIS PAGE INTENTIONALLY LEFT BLANK xii List of Acronyms and Abbreviations API Application Programming Interface CSS Cascading Style Sheets CLIMO...Java API for XML Web Services Reference Implementation JS JavaScript JSNI JavaScript Native Interface METOC Meteorological and Oceanographic MAA Mobile

Reproductive success through high pollinator visitation rates despite self incompatibility in an endangered wallflower.

PubMed

Melen, Miranda K; Herman, Julie A; Lucas, Jessica; O'Malley, Rachel E; Parker, Ingrid M; Thom, Aaron M; Whittall, Justen B

2016-11-01

Self incompatibility (SI) in rare plants presents a unique challenge-SI protects plants from inbreeding depression, but requires a sufficient number of mates and xenogamous pollination. Does SI persist in an endangered polyploid? Is pollinator visitation sufficient to ensure reproductive success? Is there evidence of inbreeding/outbreeding depression? We characterized the mating system, primary pollinators, pollen limitation, and inbreeding/outbreeding depression in Erysimum teretifolium to guide conservation efforts. We compared seed production following self pollination and within- and between-population crosses. Pollen tubes were visualized after self pollinations and between-population pollinations. Pollen limitation was tested in the field. Pollinator observations were quantified using digital video. Inbreeding/outbreeding depression was assessed in progeny from self and outcross pollinations at early and later developmental stages. Self-pollination reduced seed set by 6.5× and quadrupled reproductive failure compared with outcross pollination. Pollen tubes of some self pollinations were arrested at the stigmatic surface. Seed-set data indicated strong SI, and fruit-set data suggested partial SI. Pollinator diversity and visitation rates were high, and there was no evidence of pollen limitation. Inbreeding depression (δ) was weak for early developmental stages and strong for later developmental stages, with no evidence of outbreeding depression. The rare hexaploid E. teretifolium is largely self incompatible and suffers from late-acting inbreeding depression. Reproductive success in natural populations was accomplished through high pollinator visitation rates consistent with a lack of pollen limitation. Future reproductive health for this species will require large population sizes with sufficient mates and a robust pollinator community. © 2016 Melen et al. Published by the Botanical Society of America. This work is licensed under a Creative Commons Attribution License (CC-BY).

The dilemma of being a fragrant flower: the major floral volatile attracts pollinators and florivores in the euglossine-pollinated orchid Dichaea pendula.

PubMed

Nunes, Carlos E P; Peñaflor, Maria Fernanda G V; Bento, José Maurício S; Salvador, Marcos José; Sazima, Marlies

2016-12-01

Volatile organic compounds (VOCs) mediate both mutualistic and antagonistic plant-animal interactions; thus, the attraction of mutualists and antagonists by floral VOCs constitutes an important trade-off in the evolutionary ecology of angiosperms. Here, we evaluate the role of VOCs in mediating communication between the plant and its mutualist and antagonist floral visitors. To assess the evolutionary consequences of VOC-mediated signalling to distinct floral visitors, we studied the reproductive ecology of Dichaea pendula, assessing the effects of florivores on fruit set, the pollination efficiency of pollinators and florivores, the floral scent composition and the attractiveness of the major VOC to pollinators and florivores. The orchid depends entirely on orchid-bees for sexual reproduction, and the major florivores, the weevils, feed on corollas causing self-pollination, triggering abortion of 26.4 % of the flowers. Floral scent was composed of approximately 99 % 2-methoxy-4-vinylphenol, an unusual floral VOC attractive to pollinators and florivores. The low fruit set from natural pollination (5.6 %) compared to hand cross-pollination (45.5 %) and low level of pollinator visitation [0.02 visits (flower hour) -1 ] represent the limitations to pollination. Our research found that 2-methoxy-4-vinylphenol mediates both mutualistic and antagonistic interactions, which could result in contrary evolutionary pressures on novo-emission. The scarcity of pollinators, not florivory, was the major constraint to fruit set. Our results suggest that, rather than anti-florivory adaptations, adaptations to enhance pollinator attraction and cross-pollination might be the primary drivers of the evolution of VOC emission in euglossine-pollinated flowers.

Mercury and selenium in the food web of Lake Nahuel Huapi, Patagonia, Argentina.

PubMed

Arcagni, Marina; Rizzo, Andrea; Juncos, Romina; Pavlin, Majda; Campbell, Linda M; Arribére, María A; Horvat, Milena; Ribeiro Guevara, Sergio

2017-01-01

Despite located far from point sources of Hg pollution, high concentrations were recorded in plankton from the deep oligotrophic Lake Nahuel Huapi, located in North Patagonia. Native and introduced top predator fish with differing feeding habits are a valuable economic resource to the region. Hence, Hg and Se trophic interactions and pathways to these fish were assessed in the food web of this lake at three sites, using stable nitrogen and carbon isotopes. As expected based on the high THg in plankton, mercury did not biomagnify in the food web of Lake Nahuel Huapi, as most of the THg in plankton is in the inorganic form. As was observed in other aquatic systems, Se did not biomagnify either. When trophic pathways to top predator fish were analyzed, they showed that THg biomagnified in the food chains of native fish but biodiluted in the food chains of introduced salmonids. A more benthic diet, typical of native fish, resulted in higher [THg] bioaccumulation than a more pelagic or mixed diet, as in the case of introduced fish. Se:THg molar ratios were higher than 1 in all the fish species, indicating that Se might be offering a natural protection against Hg toxicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Invasive crayfish as vectors of mercury in freshwater food webs of the Pacific Northwest

USGS Publications Warehouse

Johnson, Branden L.; Willacker, James J.; Eagles-Smith, Collin A.; Pearl, Christopher A.; Adams, Michael J.

2014-01-01

Invasive species are important drivers of environmental change in aquatic ecosystems and can alter habitat characteristics, community composition, and ecosystem energetics. Such changes have important implications for many ecosystem processes, including the bioaccumulation and biomagnification of contaminants through food webs. Mercury concentrations were measured in 2 nonnative and 1 native crayfish species from western Oregon (USA). Nonnative red swamp crayfish had mercury concentrations similar to those in native signal crayfish (0.29 ± 0.05 µg/g dry wt and 0.36 ± 0.06 µg/g dry wt, respectively), whereas the nonnative ringed crayfish had lower mercury concentrations (0.10 ± 0.02 µg/g dry wt) than either of the other species. The mean energy content of muscle was similar between the native signal crayfish and nonnative ringed crayfish but was significantly higher in the nonnative red swamp crayfish. Across species, mercury concentrations were negatively correlated with energy density. Such energetic differences could exacerbate changes in mercury transfer through trophic pathways of food webs, especially via alterations to the growth dynamics of consumers. Thus, it is important to consider the role of energy content in determining effective mercury exposure even when mercury concentrations on a per-unit mass basis do not differ between species.

Stable isotope evaluation of population- and individual-level diet variability in a large, oligotrophic lake with non-native lake trout

USGS Publications Warehouse

Ng, Elizabeth L.; Fredericks, Jim P.; Quist, Michael C.

2016-01-01

Non-native piscivores can alter food web dynamics; therefore, evaluating interspecific relationships is vital for conservation and management of ecosystems with introduced fishes. Priest Lake, Idaho, supports a number of introduced species, including lake troutSalvelinus namaycush, brook trout S. fontinalis and opossum shrimp Mysis diluviana. In this study, we used stable isotopes (δ13C and δ15N) to describe the food web structure of Priest Lake and to test hypotheses about apparent patterns in lake trout growth. We found that isotopic niches of species using pelagic-origin carbon did not overlap with those using more littoral-origin carbon. Species using more littoral-origin carbon, such as brook trout and westslope cutthroat trout Oncorhynchus clarki lewisi, exhibited a high degree of isotopic niche overlap and high intrapopulation variability in resource use. Although we hypothesised that lake trout would experience an ontogenetic diet shift, no such patterns were apparent in isotopic signatures. Lake trout growth rates were not associated with patterns in δ15N, indicating that variation in adult body composition may not be related to adult diet. Understanding trophic relationships at both the individual and species levels provides a more complete understanding of food webs altered by non-native species.

Degradation of soil fertility can cancel pollination benefits in sunflower.

PubMed

Tamburini, Giovanni; Berti, Antonio; Morari, Francesco; Marini, Lorenzo

2016-02-01

Pollination and soil fertility are important ecosystem services to agriculture but their relative roles and potential interactions are poorly understood. We explored the combined effects of pollination and soil fertility in sunflower using soils from a trial characterized by different long-term input management in order to recreate plausible levels of soil fertility. Pollinator exclusion was used as a proxy for a highly eroded pollination service. Pollination benefits to yield depended on soil fertility, i.e., insect pollination enhanced seed set and yield only under higher soil fertility indicating that limited nutrient availability may constrain pollination benefits. Our study provides evidence for interactions between above- and belowground ecosystem services, highlighting the crucial role of soil fertility in supporting agricultural production not only directly, but also indirectly through pollination. Management strategies aimed at enhancing pollination services might fail in increasing yield in landscapes characterized by high soil service degradation. Comprehensive knowledge about service interactions is therefore essential for the correct management of ecosystem services in agricultural landscapes.

Pollinators exert natural selection on flower size and floral display in Penstemon digitalis.

PubMed

Parachnowitsch, Amy L; Kessler, André

2010-10-01

• A major gap in our understanding of floral evolution, especially micro-evolutionary processes, is the role of pollinators in generating patterns of natural selection on floral traits. Here we explicitly tested the role of pollinators in selecting floral traits in a herbaceous perennial, Penstemon digitalis. • We manipulated the effect of pollinators on fitness through hand pollinations and compared phenotypic selection in open- and hand-pollinated plants. • Despite the lack of pollen limitation in our population, pollinators mediated selection on floral size and floral display. Hand pollinations removed directional selection for larger flowers and stabilizing selection on flower number, suggesting that pollinators were the agents of selection on both of these traits. • We reviewed studies that measured natural selection on floral traits by biotic agents and generally found stronger signatures of selection imposed by pollinators than by herbivores and co-flowering plant species. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

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

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

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.

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

PubMed

Walston, Leroy J; Mishra, Shruti K; Hartmann, Heidi M; Hlohowskyj, Ihor; McCall, James; Macknick, Jordan

2018-06-13

Of the many roles insects serve for ecosystem function, pollination is possibly the most important service directly linked to human well-being. However, land use changes have contributed to the decline of pollinators and their habitats. In agricultural landscapes that also support renewable energy developments such as utility-scale solar energy [USSE] facilities, opportunities may exist to conserve insect pollinators and locally restore their ecosystem services through the implementation of vegetation management approaches that aim to provide and maintain pollinator habitat at USSE facilities. As a first step toward understanding the potential agricultural benefits of solar-pollinator habitat, we identified areas of overlap between USSE facilities and surrounding pollinator-dependent crop types in the United States (U.S.). Using spatial data on solar energy developments and crop types across the U.S., and assuming a pollinator foraging distance of 1.5 km, we identified over 3,500 km 2 of agricultural land near existing and planned USSE facilities that may benefit from increased pollination services through the creation of pollinator habitat at the USSE facilities. The following five pollinator-dependent crop types accounted for over 90% of the agriculture near USSE facilities, and these could benefit most from the creation of pollinator habitat at existing and planned USSE facilities: soybeans, alfalfa, cotton, almonds, and citrus. We discuss how our results may be used to understand potential agro-economic implications of solar-pollinator habitat. Our results show that ecosystem service restoration through the creation of pollinator habitat could improve the sustainability of large-scale renewable energy developments in agricultural landscapes.

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.

Pollination drop in Juniperus communis: response to deposited material.

PubMed

Mugnaini, Serena; Nepi, Massimo; Guarnieri, Massimo; Piotto, Beti; Pacini, Ettore

2007-12-01

The pollination drop is a liquid secretion produced by the ovule and exposed outside the micropyle. In many gymnosperms, pollen lands on the surface of the pollination drop, rehydrates and enters the ovule as the drop retracts. The objective of this work was to study the formation of the pollination drop in Juniperus communis, its carbohydrate composition and the response to deposition of conspecific pollen, foreign pollen and other particulate material, in an attempt to clarify the mechanism of pollination drop retraction. Branches with female cones close to pollination drop secretion were collected. On the first day of pollination drop exposure, an eyelash mounted on a wooden stick with paraffin was used to collect pollen or silica gel particles, which were then deposited by contact with the drop. Volume changes in pollination drops were measured by using a stereomicroscope with a micrometer eyepiece 3 h after deposition. The volume of non-pollinated control drops was also recorded. On the first day of secretion, drops were also collected for sugar analysis by high-performance liquid chromatography. The pollination drop persisted for about 12 d if not pollinated, and formed again after removal for up to four consecutive days. After pollination with viable conspecific pollen, the drop retracted quickly and did not form again. Partial withdrawal occurred after deposition of other biological and non-biological material. Fructose was the dominant sugar; glucose was also present but at a much lower percentage. Sugar analysis confirmed the general trend of fructose dominance in gymnosperm pollination drops. Complete pollination drop withdrawal appears to be triggered by a biochemical mechanism resulting from interaction between pollen and drop constituents. The results of particle deposition suggest the existence of a non-specific, particle-size-dependent mechanism that induces partial pollination drop withdrawal. These results suggest that the non-specific response may decrease the probability of pollen landing on the drop, reducing pollination efficiency.

Pollination Drop in Juniperus communis: Response to Deposited Material

PubMed Central

Mugnaini, Serena; Nepi, Massimo; Guarnieri, Massimo; Piotto, Beti; Pacini, Ettore

2007-01-01

Background and Aims The pollination drop is a liquid secretion produced by the ovule and exposed outside the micropyle. In many gymnosperms, pollen lands on the surface of the pollination drop, rehydrates and enters the ovule as the drop retracts. The objective of this work was to study the formation of the pollination drop in Juniperus communis, its carbohydrate composition and the response to deposition of conspecific pollen, foreign pollen and other particulate material, in an attempt to clarify the mechanism of pollination drop retraction. Method Branches with female cones close to pollination drop secretion were collected. On the first day of pollination drop exposure, an eyelash mounted on a wooden stick with paraffin was used to collect pollen or silica gel particles, which were then deposited by contact with the drop. Volume changes in pollination drops were measured by using a stereomicroscope with a micrometer eyepiece 3 h after deposition. The volume of non-pollinated control drops was also recorded. On the first day of secretion, drops were also collected for sugar analysis by high-performance liquid chromatography. Key Results The pollination drop persisted for about 12 d if not pollinated, and formed again after removal for up to four consecutive days. After pollination with viable conspecific pollen, the drop retracted quickly and did not form again. Partial withdrawal occurred after deposition of other biological and non-biological material. Fructose was the dominant sugar; glucose was also present but at a much lower percentage. Conclusions Sugar analysis confirmed the general trend of fructose dominance in gymnosperm pollination drops. Complete pollination drop withdrawal appears to be triggered by a biochemical mechanism resulting from interaction between pollen and drop constituents. The results of particle deposition suggest the existence of a non-specific, particle-size-dependent mechanism that induces partial pollination drop withdrawal. These results suggest that the non-specific response may decrease the probability of pollen landing on the drop, reducing pollination efficiency. PMID:17942592

Pollinator Partnership | Pollinator.org

Science.gov Websites

about us Pollinator Partnership's mission is to promote the health of pollinators, critical to food and three bites of food. They also sustain our ecosystems and produce our natural resources by helping plants reproduce. Without the actions of pollinators agricultural economies, our food supply, and

Design and evaluation of web-based image transmission and display with different protocols

NASA Astrophysics Data System (ADS)

Tan, Bin; Chen, Kuangyi; Zheng, Xichuan; Zhang, Jianguo

2011-03-01

There are many Web-based image accessing technologies used in medical imaging area, such as component-based (ActiveX Control) thick client Web display, Zerofootprint thin client Web viewer (or called server side processing Web viewer), Flash Rich Internet Application(RIA) ,or HTML5 based Web display. Different Web display methods have different peformance in different network environment. In this presenation, we give an evaluation on two developed Web based image display systems. The first one is used for thin client Web display. It works between a PACS Web server with WADO interface and thin client. The PACS Web server provides JPEG format images to HTML pages. The second one is for thick client Web display. It works between a PACS Web server with WADO interface and thick client running in browsers containing ActiveX control, Flash RIA program or HTML5 scripts. The PACS Web server provides native DICOM format images or JPIP stream for theses clients.

Educating the Web-Savvy Urban Teacher: Website Evaluation Tips and Internet Resources for Secondary Educators

ERIC Educational Resources Information Center

Harushimana, Immaculee

2008-01-01

This article, "The Web-Savvy Urban Teacher," addresses the question of what educational technology educators and scholars can do to close the pedagogical mismatch, which exists today between "digital native" secondary students and their predigital educators. The infrequent use of the Internet as a resource in urban schools is detrimental for…

"UML Quiz": Automatic Conversion of Web-Based E-Learning Content in Mobile Applications

ERIC Educational Resources Information Center

von Franqué, Alexander; Tellioglu, Hilda

2014-01-01

Many educational institutions use Learning Management Systems to provide e-learning content to their students. This often includes quizzes that can help students to prepare for exams. However, the content is usually web-optimized and not very usable on mobile devices. In this work a native mobile application ("UML Quiz") that imports…

Investigating the Lecturers' Challenges to Embrace Collaborative Web Technologies in Higher Education Institutions

ERIC Educational Resources Information Center

Pima, John; Mtui, Jaqueline

2017-01-01

The paper investigated the challenges facing Lecturers in embracing Collaborative Web Technologies (CWTs) in Higher Education Institutions (HEIs) in Tanzania. The study was motivated by the fact that while students have become natives of the CWTs, for the Lecturers, the case if different. A case study was designed to answer two research questions…

Deconstructing Digital Natives: Young People, Technology, and the New Literacies

ERIC Educational Resources Information Center

Thomas, Michael, Ed.

2011-01-01

There have been many attempts to define the generation of students who emerged with the Web and new digital technologies in the early 1990s. The term "digital native" refers to the generation born after 1980, which has grown up in a world where digital technologies and the internet are a normal part of everyday life. Young people…

Pre-Service Teachers in Second Life: Are Digital Natives Prepared for a Web 2.0 Experience?

ERIC Educational Resources Information Center

Inman, Christopher T.

2010-01-01

Today's college students, "digital natives," have had digital technology at their fingertips (Rushkoff, 1996; Prensky, 2001a). Technology habits and expectations of young people are changing; the educational and business worlds have placed a focus on skills called "21st century skills," to prepare students for the digital age (Lemke, 2002). Skills…

KSC-2014-4339

NASA Image and Video Library

2014-09-09

CAPE CANAVERAL, Fla. – A bee goes about his business pollinating the flowers off Schwartz Road on NASA's Kennedy Space Center in Florida. There are 4,000 species of native bees in the United States. The members of the five most common families - Apidae, Halictidae, Andrenidae, Megachilidae, and Colletidae - can be found throughout North America, including in Florida. The undeveloped property on Kennedy Space Center is managed by the U.S. Fish and Wildlife Service through the Merritt Island National Wildlife Refuge. For information on the refuge, visit http://www.fws.gov/merrittisland/Index.html. For information on the alligators prowling the waterways at Kennedy, visit http://www.nasa.gov/content/ancient-creatures-on-the-prowl/. Photo credit: NASA/Daniel Casper

ELF communications system ecological monitoring program: Pollinating insect studies

NASA Astrophysics Data System (ADS)

Strickler, Karen; Schriber, J. Mark

1994-11-01

High voltage transmission lines and the earth's and other magnetic fields have been shown to affect honeybee reproduction, survival, orientation, and nest structure. ELY EM fields could have similar effects on native megachilid bees. Two species in the genus Megachile were abundant in artificial nests at experimental and control areas in Dickinson and Iron Counties in Michigan. Data on their nest architecture, nest activity, and emergence/mortality were collected between 1983 and 1993. Eight hypotheses concerning the possible effects of ELY EM fields were considered using these data. The ELY antenna has been fully operational since the summer of 1989. Tests of the hypotheses compare control vs. experimental areas before and after the ELY antenna became fully operational.

Some pollinators are more equal than others: Factors influencing pollen loads and seed set capacity of two actively and passively pollinating fig wasps

NASA Astrophysics Data System (ADS)

Kjellberg, Finn; Suleman, Nazia; Raja, Shazia; Tayou, Abelouahad; Hossaert-McKey, Martine; Compton, Stephen G.

2014-05-01

The nursery pollination system of fig trees (Ficus) results in the plants providing resources for pollinator fig wasp larvae as part of their male reproductive investment, with selection determining relative investment into pollinating wasps and the pollen they carry. The small size of Ficus pollen suggests that the quantities of pollen transported by individual wasps often limits male reproductive success. We assessed variation in fig wasp pollen loads and its influence on seed production in actively pollinated (Ficus montana) and passively pollinated (Ficus carica) dioecious fig trees.

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.

Uni-directional interaction and plant-pollinator-robber coexistence.

PubMed

Wang, Yuanshi; DeAngelis, Donald L; Holland, J Nathaniel

2012-09-01

A mathematical model for the plant-pollinator-robber interaction is studied to understand the factors leading to the widespread occurrence and stability of such interactions. In the interaction, a flowering plant provides resource for its pollinator and the pollinator has both positive and negative effects on the plant. A nectar robber acts as a plant predator, consuming a common resource with the pollinator, but with a different functional response. Using dynamical systems theory, mechanisms of species coexistence are investigated to show how a robber could invade the plant-pollinator system and persist stably with the pollinator. In addition, circumstances are demonstrated in which the pollinator's positive and negative effects on the plant could determine the robber's invasibility and the three-species coexistence.

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.

Ecological intensification to mitigate impacts of conventional intensive land use on pollinators and pollination.

PubMed

Kovács-Hostyánszki, Anikó; Espíndola, Anahí; Vanbergen, Adam J; Settele, Josef; Kremen, Claire; Dicks, Lynn V

2017-05-01

Worldwide, human appropriation of ecosystems is disrupting plant-pollinator communities and pollination function through habitat conversion and landscape homogenisation. Conversion to agriculture is destroying and degrading semi-natural ecosystems while conventional land-use intensification (e.g. industrial management of large-scale monocultures with high chemical inputs) homogenises landscape structure and quality. Together, these anthropogenic processes reduce the connectivity of populations and erode floral and nesting resources to undermine pollinator abundance and diversity, and ultimately pollination services. Ecological intensification of agriculture represents a strategic alternative to ameliorate these drivers of pollinator decline while supporting sustainable food production, by promoting biodiversity beneficial to agricultural production through management practices such as intercropping, crop rotations, farm-level diversification and reduced agrochemical use. We critically evaluate its potential to address and reverse the land use and management trends currently degrading pollinator communities and potentially causing widespread pollination deficits. We find that many of the practices that constitute ecological intensification can contribute to mitigating the drivers of pollinator decline. Our findings support ecological intensification as a solution to pollinator declines, and we discuss ways to promote it in agricultural policy and practice. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Bee pollination improves crop quality, shelf life and commercial value.

PubMed

Klatt, Björn K; Holzschuh, Andrea; Westphal, Catrin; Clough, Yann; Smit, Inga; Pawelzik, Elke; Tscharntke, Teja

2014-01-22

Pollination improves the yield of most crop species and contributes to one-third of global crop production, but comprehensive benefits including crop quality are still unknown. Hence, pollination is underestimated by international policies, which is particularly alarming in times of agricultural intensification and diminishing pollination services. In this study, exclusion experiments with strawberries showed bee pollination to improve fruit quality, quantity and market value compared with wind and self-pollination. Bee-pollinated fruits were heavier, had less malformations and reached higher commercial grades. They had increased redness and reduced sugar-acid-ratios and were firmer, thus improving the commercially important shelf life. Longer shelf life reduced fruit loss by at least 11%. This is accounting for 0.32 billion US$ of the 1.44 billion US$ provided by bee pollination to the total value of 2.90 billion US$ made with strawberry selling in the European Union 2009. The fruit quality and yield effects are driven by the pollination-mediated production of hormonal growth regulators, which occur in several pollination-dependent crops. Thus, our comprehensive findings should be transferable to a wide range of crops and demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.

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.

Pollinator Foraging Adaptation and Coexistence of Competing Plants

PubMed Central

Revilla, Tomás A.; Křivan, Vlastimil

2016-01-01

We use the optimal foraging theory to study coexistence between two plant species and a generalist pollinator. We compare conditions for plant coexistence for non-adaptive vs. adaptive pollinators that adjust their foraging strategy to maximize fitness. When pollinators have fixed preferences, we show that plant coexistence typically requires both weak competition between plants for resources (e.g., space or nutrients) and pollinator preferences that are not too biased in favour of either plant. We also show how plant coexistence is promoted by indirect facilitation via the pollinator. When pollinators are adaptive foragers, pollinator’s diet maximizes pollinator’s fitness measured as the per capita population growth rate. Simulations show that this has two conflicting consequences for plant coexistence. On the one hand, when competition between pollinators is weak, adaptation favours pollinator specialization on the more profitable plant which increases asymmetries in plant competition and makes their coexistence less likely. On the other hand, when competition between pollinators is strong, adaptation promotes generalism, which facilitates plant coexistence. In addition, adaptive foraging allows pollinators to survive sudden loss of the preferred plant host, thus preventing further collapse of the entire community. PMID:27505254

A novel mutualism between an ant-plant and its resident pollinator

NASA Astrophysics Data System (ADS)

Shenoy, Megha; Borges, Renee M.

2008-01-01

Pollination systems in which the host plant provides breeding sites for pollinators, invariably within flowers, are usually highly specialized mutualisms. We found that the pollinating bee Braunsapis puangensis breeds within the caulinary domatia of the semi-myrmecophyte Humboldtia brunonis (Fabaceae), an unusual ant-plant that is polymorphic for the presence of domatia and harbours a diverse invertebrate fauna including protective and non-protective ants in its domatia. B. puangensis is the most common flower visitor that carries the highest proportion of H. brunonis pollen. This myrmecophyte is pollen limited and cross-pollinated by bees in the daytime. Hence, the symbiotic pollinator could provide a benefit to trees bearing domatia by alleviating this limitation. We therefore report for the first time an unspecialised mutualism in which a pollinator is housed in a plant structure other than flowers. Here, the cost to the plant is lower than for conventional brood-site pollination mutualisms where the pollinator develops at the expense of plant reproductive structures. Myrmecophytes housing resident pollinators are unusual, as ants are known to be enemies of pollinators, and housing them together may decrease the benefits that these residents could individually provide to the host plant.

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

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

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.

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

Mixed pollen load and late-acting self-incompatibility flexibility in Adenocalymma peregrinum (Miers) L.G. Lohmann (Bignonieae: Bignoniaceae).

PubMed

Duarte, M O; Mendes-Rodrigues, C; Alves, M F; Oliveira, P E; Sampaio, D S

2017-03-01

Mixed cross and self-pollen load on the stigma (mixed pollination) of species with late-acting self-incompatibility system (LSI) can lead to self-fertilized seed production. This "cryptic self-fertility" may allow selfed seedling development in species otherwise largely self-sterile. Our aims were to check if mixed pollinations would lead to fruit set in LSI Adenocalymma peregrinum, and test for evidence of early-acting inbreeding depression in putative selfed seeds from mixed pollinations. Experimental pollinations were carried out in a natural population. Fruit and seed set from self-, cross and mixed pollinations were analysed. Further germination tests were carried out for the seeds obtained from treatments. Our results confirm self-incompatibility, and fruit set from cross-pollinations was three-fold that from mixed pollinations. This low fruit set in mixed pollinations is most likely due to a greater number of self- than cross-fertilized ovules, which promotes LSI action and pistil abortion. Likewise, higher percentage of empty seeds in surviving fruits from mixed pollinations compared with cross-pollinations is probably due to ovule discounting caused by self-fertilization. Moreover, germinability of seeds with developed embryos was lower in fruits from mixed than from cross-pollinations, and the non-viable seeds from mixed pollinations showed one-third of the mass of those from cross-pollinations. The great number of empty seeds, lower germinability, lower mass of non-viable seeds, and higher variation in seed mass distribution in mixed pollinations, strongly suggests early-acing inbreeding depression in putative selfed seeds. In this sense, LSI and inbreeding depression acting together probably constrain self-fertilized seedling establishment in A. peregrinum. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

On the success of a swindle: pollination by deception in orchids

NASA Astrophysics Data System (ADS)

Schiestl, Florian P.

2005-06-01

A standing enigma in pollination ecology is the evolution of pollinator attraction without offering reward in about one third of all orchid species. Here I review concepts of pollination by deception, and in particular recent findings in the pollination syndromes of food deception and sexual deception in orchids. Deceptive orchids mimic floral signals of rewarding plants (food deception) or mating signals of receptive females (sexual deception) to attract pollen vectors. In some food deceptive orchids, similarities in the spectral reflectance visible to the pollinator in a model plant and its mimic, and increased reproductive success of the mimic in the presence of the model have been demonstrated. Other species do not mimic specific model plants but attract pollinators with general attractive floral signals. In sexually deceptive orchids, floral odor is the key trait for pollinator attraction, and behaviorally active compounds in the orchids are identical to the sex pheromone of the pollinator species. Deceptive orchids often show high variability in floral signals, which may be maintained by negative frequency-dependent selection, since pollinators can learn and subsequently avoid common deceptive morphs more quickly than rare ones. The evolution of obligate deception in orchids seems paradoxical in the light of the typically lower fruit set than in rewarding species. Pollination by deception, however, can reduce self-pollination and encourage pollen flow over longer distances, thus promoting outbreeding. Although some food deceptive orchids are isolated through postzygotic reproductive barriers, sexually deceptive orchids lack post-mating barriers and species isolation is achieved via specific pollinator attraction. Recent population genetic and phylogenetic investigations suggest gene-flow within subgeneric clades, but pollinator-mediated selection may maintain species-specific floral traits.

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

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.

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.

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.

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

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.

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.

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

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

Tropical forest fragmentation affects floral visitors but not the structure of individual-based palm-pollinator networks.

PubMed

Dáttilo, Wesley; Aguirre, Armando; Quesada, Mauricio; Dirzo, Rodolfo

2015-01-01

Despite increasing knowledge about the effects of habitat loss on pollinators in natural landscapes, information is very limited regarding the underlying mechanisms of forest fragmentation affecting plant-pollinator interactions in such landscapes. Here, we used a network approach to describe the effects of forest fragmentation on the patterns of interactions involving the understory dominant palm Astrocaryum mexicanum (Arecaceae) and its floral visitors (including both effective and non-effective pollinators) at the individual level in a Mexican tropical rainforest landscape. Specifically, we asked: (i) Does fragment size affect the structure of individual-based plant-pollinator networks? (ii) Does the core of highly interacting visitor species change along the fragmentation size gradient? (iii) Does forest fragment size influence the abundance of effective pollinators of A. mexicanum? We found that fragment size did not affect the topological structure of the individual-based palm-pollinator network. Furthermore, while the composition of peripheral non-effective pollinators changed depending on fragment size, effective core generalist species of pollinators remained stable. We also observed that both abundance and variance of effective pollinators of male and female flowers of A. mexicanum increased with forest fragment size. These findings indicate that the presence of effective pollinators in the core of all forest fragments could keep the network structure stable along the gradient of forest fragmentation. In addition, pollination of A. mexicanum could be more effective in larger fragments, since the greater abundance of pollinators in these fragments may increase the amount of pollen and diversity of pollen donors between flowers of individual plants. Given the prevalence of fragmentation in tropical ecosystems, our results indicate that the current patterns of land use will have consequences on the underlying mechanisms of pollination in remnant forests.

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.

Temperature-driven flower longevity in a high-alpine species of Oxalis influences reproductive assurance.

PubMed

Arroyo, Mary T K; Dudley, Leah S; Jespersen, Gus; Pacheco, Diego A; Cavieres, Lohengrin A

2013-12-01

How high-alpine plants confront stochastic conditions for animal pollination is a critical question. We investigated the effect of temperature on potential flower longevity (FL) measured in pollinator-excluded flowers and actual FL measured in pollinated flowers in self-incompatible Oxalis compacta and evaluated if plastically prolonged potential FL can ameliorate slow pollination under cool conditions. Pollinator-excluded and hand-pollinated flowers were experimentally warmed with open-top chambers (OTCs) on a site at 3470 m above sea level (asl). Flower-specific temperatures, and pollinator-excluded and open-pollination flower life-spans were measured at six alpine sites between 3100 and 3470 m asl. Fruit set was analyzed in relation to inferred pollination time. Warming reduced potential FL. Variable thermal conditions across the alpine landscape predicted potential and actual FL; flower senescence was pollination-regulated. Actual FL and potential FL were coupled. Prolonged potential FL generally increased fruit set under cooler conditions. Plastic responses permit virgin flowers of O. compacta to remain open longer under cooler temperatures, thereby ameliorating slow pollination, and to close earlier when pollination tends to be faster under warmer conditions. Plastic potential FL provides adaptive advantages in the cold, thermally variable alpine habitat, and has important implications for reproductive success in alpine plants in a warming world. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Butterfly pollination in Pteroglossa (Orchidaceae, Orchidoideae): a comparative study on the reproductive biology of two species of a Neotropical genus of Spiranthinae.

PubMed

Pansarin, Emerson R; Ferreira, Alessandro W C

2015-05-01

Spiranthinae orchids are known for being self-compatible and offering nectar as a reward. Although data on their pollinators are scarce, members of this tribe are mostly pollinated by bees, hummingbirds and moths. Some of them even reproduce through facultative self-pollination. Nothing is known about the pollinators and reproduction system in Pteroglossa. Based on records on flowering phenology, floral morphology, reward production, pollinators and breeding system, this paper aims to study the reproductive biology of two Pteroglossa spp. Both species offer nectar as a resource and are pollinated exclusively by diurnal Lepidoptera at the studied areas. Nectar is produced by two glandular nectaries, and is stored in a spur. Pollinaria possess a ventrally adhesive viscidium that is deposited on the basal portion of butterfly proboscides. Both species are self-compatible but pollinator-dependent. The reproductive success is low when compared to other Spiranthinae. Although no evident mechanical barrier to avoid self-pollination or geitonogamy was identified, the erratic behavior of the butterflies, with their infrequent visits to only one flower per inflorescence, contributes to an increased fruit set produced through cross-pollination. The presence of ventrally adhesive viscidia in Spiranthinae is responsible for greater pollinator diversity when compared to bee-pollinated Goodyerinae with dorsally adhesive viscidia, adapted to attach to bee mouthparts.

Global malnutrition overlaps with pollinator-dependent micronutrient production

PubMed Central

Chaplin-Kramer, Rebecca; Dombeck, Emily; Gerber, James; Knuth, Katherine A.; Mueller, Nathaniel D.; Mueller, Megan; Ziv, Guy; Klein, Alexandra-Maria

2014-01-01

Pollinators contribute around 10% of the economic value of crop production globally, but the contribution of these pollinators to human nutrition is potentially much higher. Crops vary in the degree to which they benefit from pollinators, and many of the most pollinator-dependent crops are also among the richest in micronutrients essential to human health. This study examines regional differences in the pollinator dependence of crop micronutrient content and reveals overlaps between this dependency and the severity of micronutrient deficiency in people around the world. As much as 50% of the production of plant-derived sources of vitamin A requires pollination throughout much of Southeast Asia, whereas other essential micronutrients such as iron and folate have lower dependencies, scattered throughout Africa, Asia and Central America. Micronutrient deficiencies are three times as likely to occur in areas of highest pollination dependence for vitamin A and iron, suggesting that disruptions in pollination could have serious implications for the accessibility of micronutrients for public health. These regions of high nutritional vulnerability are understudied in the pollination literature, and should be priority areas for research related to ecosystem services and human well-being. PMID:25232140

RAPID EVOLUTION CAUSED BY POLLINATOR LOSS IN MIMULUS GUTTATUS

PubMed Central

Bodbyl Roels, Sarah A.; Kelly, John K.

2018-01-01

Anthropogenic perturbations including habitat loss and emerging disease are changing pollinator communities and generating novel selection pressures on plant populations. Disruption of plant–pollinator relationships is predicted to cause plant mating system evolution, although this process has not been directly observed. This study demonstrates the immediate evolutionary effects of pollinator loss within experimental populations of a predominately outcrossing wildflower. Initially equivalent populations evolved for five generations within two pollination treatments: abundant bumblebee pollinators versus no pollinators. The populations without pollinators suffered greatly reduced fitness in early generations but rebounded as they evolved an improved ability to self-fertilize. All populations diverged in floral, developmental, and life-history traits, but only a subset of characters showed clear association with pollination treatment. Pronounced treatment effects were noted for anther–stigma separation and autogamous seed set. Dramatic allele frequency changes at two chromosomal polymorphisms occurred in the no pollinator populations, explaining a large fraction of divergence in pollen viability. The pattern of phenotypic and genetic changes in this experiment favors a sequential model for the evolution of the multitrait “selfing syndrome” observed throughout angiosperms. PMID:21884055

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

Pollinators' mating rendezvous and the evolution of floral advertisement.

PubMed

Fishman, Michael A; Hadany, Lilach

2013-01-07

Successful cross-fertilization in plant species that rely on animal pollinators depends not just on the number of pollinator visits, but also on these visits' duration. Furthermore, in non-deceptive pollination, a visit's duration depends on the magnitude of the reward provided to the pollinator. Accordingly, plants that rely on biotic pollination have to partition their investment in cross-fertilization assurance between attracting pollinator visits - advertisement, and rewarding visitors to assure that the visit is of productive duration. Here we analyze these processes by a combination of optimality methods and game theoretical modeling. Our results indicate that the optimality in such allocation of resources depends on the types of reward offered to the pollinators. More precisely, we show that plants that offer both food reward and mating rendezvous to pollinators will evolve to allocate a higher proportion of their cross-fertilization assurance budget to advertisement than plants that offer only food reward. That is, our results indicate that pollinators' mating habits may play a role in floral evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.

On ‘various contrivances’: pollination, phylogeny and flower form in the Solanaceae

PubMed Central

Knapp, Sandra

2010-01-01

Members of the euasterid angiosperm family Solanaceae have been characterized as remarkably diverse in terms of flower morphology and pollinator type. In order to test the relative contribution of phylogeny to the pattern of distribution of floral characters related to pollination, flower form and pollinators have been mapped onto a molecular phylogeny of the family. Bilateral flower symmetry (zygomorphy) is prevalent in the basal grades of the family, and more derived clades have flowers that are largely radially symmetric, with some parallel evolution of floral bilateralism. Pollinator types (‘syndromes’) are extremely homoplastic in the family, but members of subfamily Solanoideae are exceptional in being largely bee pollinated. Pollinator relationships in those genera where they have been investigated more fully are not as specific as flower morphology and the classical pollinator syndrome models might suggest, and more detailed studies in some particularly variable genera, such as Iochroma and Nicotiana, are key to understanding the role of pollinators in floral evolution and adaptive radiation in the family. More studies of pollinators in the field are a priority. PMID:20047871

Rapid evolution caused by pollinator loss in Mimulus guttatus.

PubMed

Roels, Sarah A Bodbyl; Kelly, John K

2011-09-01

Anthropogenic perturbations including habitat loss and emerging disease are changing pollinator communities and generating novel selection pressures on plant populations. Disruption of plant-pollinator relationships is predicted to cause plant mating system evolution, although this process has not been directly observed. This study demonstrates the immediate evolutionary effects of pollinator loss within experimental populations of a predominately outcrossing wildflower. Initially equivalent populations evolved for five generations within two pollination treatments: abundant bumblebee pollinators versus no pollinators. The populations without pollinators suffered greatly reduced fitness in early generations but rebounded as they evolved an improved ability to self-fertilize. All populations diverged in floral, developmental, and life-history traits, but only a subset of characters showed clear association with pollination treatment. Pronounced treatment effects were noted for anther-stigma separation and autogamous seed set. Dramatic allele frequency changes at two chromosomal polymorphisms occurred in the no pollinator populations, explaining a large fraction of divergence in pollen viability. The pattern of phenotypic and genetic changes in this experiment favors a sequential model for the evolution of the multitrait "selfing syndrome" observed throughout angiosperms. © 2011 The Author(s).

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.

Potential problems of removing one invasive species at a time: a meta-analysis of the interactions between invasive vertebrates and unexpected effects of removal programs.

PubMed

Ballari, Sebastián A; Kuebbing, Sara E; Nuñez, Martin A

2016-01-01

Although the co-occurrence of nonnative vertebrates is a ubiquitous global phenomenon, the study of interactions between invaders is poorly represented in the literature. Limited understanding of the interactions between co-occurring vertebrates can be problematic for predicting how the removal of only one invasive-a common management scenario-will affect native communities. We suggest a trophic food web framework for predicting the effects of single-species management on native biodiversity. We used a literature search and meta-analysis to assess current understanding of how the removal of one invasive vertebrate affects native biodiversity relative to when two invasives are present. The majority of studies focused on the removal of carnivores, mainly within aquatic systems, which highlights a critical knowledge gap in our understanding of co-occurring invasive vertebrates. We found that removal of one invasive vertebrate caused a significant negative effect on native species compared to when two invasive vertebrates were present. These unexpected results could arise because of the positioning and hierarchy of the co-occurring invasives in the food web (e.g., carnivore-carnivore or carnivore-herbivore). We consider that there are important knowledge gaps to determinate the effects of multiple co-existing invaders on native ecosystems, and this information could be precious for management.

Potential problems of removing one invasive species at a time: a meta-analysis of the interactions between invasive vertebrates and unexpected effects of removal programs

PubMed Central

Kuebbing, Sara E.; Nuñez, Martin A.

2016-01-01

Although the co-occurrence of nonnative vertebrates is a ubiquitous global phenomenon, the study of interactions between invaders is poorly represented in the literature. Limited understanding of the interactions between co-occurring vertebrates can be problematic for predicting how the removal of only one invasive—a common management scenario—will affect native communities. We suggest a trophic food web framework for predicting the effects of single-species management on native biodiversity. We used a literature search and meta-analysis to assess current understanding of how the removal of one invasive vertebrate affects native biodiversity relative to when two invasives are present. The majority of studies focused on the removal of carnivores, mainly within aquatic systems, which highlights a critical knowledge gap in our understanding of co-occurring invasive vertebrates. We found that removal of one invasive vertebrate caused a significant negative effect on native species compared to when two invasive vertebrates were present. These unexpected results could arise because of the positioning and hierarchy of the co-occurring invasives in the food web (e.g., carnivore–carnivore or carnivore–herbivore). We consider that there are important knowledge gaps to determinate the effects of multiple co-existing invaders on native ecosystems, and this information could be precious for management. PMID:27280066

Population dynamics and the ecological stability of obligate pollination mutualisms

USGS Publications Warehouse

Holland, J. Nathaniel; DeAngelis, Donald L.

2001-01-01

Mutualistic interactions almost always produce both costs and benefits for each of the interacting species. It is the difference between gross benefits and costs that determines the net benefit and the per-capita effect on each of the interacting populations. For example, the net benefit of obligate pollinators, such as yucca and senita moths, to plants is determined by the difference between the number of ovules fertilized from moth pollination and the number of ovules eaten by the pollinator's larvae. It is clear that if pollinator populations are large, then, because many eggs are laid, costs to plants are large, whereas, if pollinator populations are small, gross benefits are low due to lack of pollination. Even though the size and dynamics of the pollinator population are likely to be crucial, their importance has been neglected in the investigation of mechanisms, such as selective fruit abortion, that can limit costs and increase net benefits. Here, we suggest that both the population size and dynamics of pollinators are important in determining the net benefits to plants, and that fruit abortion can significantly affect these. We develop a model of mutualism between populations of plants and their pollinating seed-predators to explore the ecological consequences of fruit abortion on pollinator population dynamics and the net effect on plants. We demonstrate that the benefit to a plant population is unimodal as a function of pollinator abundance, relative to the abundance of flowers. Both selective abortion of fruit with eggs and random abortion of fruit, without reference to whether they have eggs or not, can limit pollinator population size. This can increase the net benefits to the plant population by limiting the number of eggs laid, if the pollination rate remains high. However, fruit abortion can possibly destabilize the pollinator population, with negative consequences for the plant population.

POLLINATOR-MEDIATED COMPETITION, REPRODUCTIVE CHARACTER DISPLACEMENT, AND THE EVOLUTION OF SELFING IN ARENARIA UNIFLORA (CARYOPHYLLACEAE).

PubMed

Fishman, Lila; Wyatt, Robert

1999-12-01

Ecological factors that reduce the effectiveness of cross-pollination are likely to play a role in the frequent evolution of routine self-fertilization in flowering plants. However, we lack empirical evidence linking the reproductive assurance value of selfing in poor pollination environments to evolutionary shifts in mating system. Here, we investigated the adaptive significance of prior selfing in the polymorphic annual plant Arenaria uniflora (Caryophyllaceae), in which selfer populations occur only in areas of range overlap with congener A. glabra. To examine the hypothesis that secondary contact between the two species contributed to the evolution and maintenance of selfing, we used field competition experiments and controlled hand-pollinations to measure the female fitness consequences of pollinator-mediated interspecific interactions. Uniformly high fruit set by selfers in the naturally pollinated field arrays confirmed the reproductive assurance value of selfing, whereas substantial reductions in outcrosser fruit set (15%) and total seed production (20-35%) in the presence of A. glabra demonstrated that pollinator-mediated interactions can provide strong selection for self-pollination. Heterospecific pollen transfer, rather than competition for pollinator service, appears to be the primary mechanism of pollinator-mediated competition in Arenaria. Premating barriers to hybridization between outcrossers and A. glabra are extremely weak. The production of a few inviable hybrid seeds after heterospecific pollination and intermediate seed set after mixed pollinations indicates that A. glabra pollen can usurp A. uniflora ovules. Thus, any visit to A. uniflora by shared pollinators carries a potential female fitness cost. Moreover, patterns of fruit set and seed set in the competition arrays relative to controls were consistent with the receipt of mixed pollen loads, rather than a lack of pollinator visits. Competition through pollen transfer favors preemptive self-pollination and may be responsible for the evolution of a highly reduced floral morphology in A. uniflora selfers as well as their current geographical distribution. © 1999 The Society for the Study of Evolution.

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

Weak trophic links between a crab-spider and the effective pollinators of a rewardless orchid

NASA Astrophysics Data System (ADS)

Quintero, Carolina; Corley, Juan C.; Aizen, Marcelo A.

2015-01-01

Sit and wait predators hunting on flowers are considered to be exploiters of plant-pollinator mutualisms. Several studies have shown that plant-pollinator interactions can be highly susceptible to the impact of a third trophic level, via consumptive (direct) and non-consumptive (indirect) effects that alter pollinator behavior and, ultimately, plant fitness. However, most flowering plants attract a wide array of flower visitors, from which only a subset will be effective pollinators. Hence, a negative effect of an ambush predator on plant fitness should be expected only when: (i) the effective pollinators are part of the predators' diet and/or (ii) the non-consumptive effects of predator presence (e.g. dead prey) alter the behavior of effective pollinators and pollen movement among individual plants. We analyzed the direct and indirect effects of a crab-spider (Misumenops pallidus), on the pollination and reproductive success of Chloraea alpina, a Patagonian rewardless orchid. Our results indicate that most of the flower visitors do not behave as effective pollinators and most effective pollinators were not observed as prey for the crab-spider. In terms of non-consumptive effects, inflorescences with and without spiders and/or dead-prey did not vary the frequency of flower visitors, nor pollinia removal or deposition. Hence, it is not surprising that M. pallidus has a neutral effect on pollinia removal and deposition as well as on fruit and seed set. Similar to other rewardless orchids, the low reproductive success of C. alpina (∼6% fruit set) was associated with the limited number of visits by effective pollinators. Negative top-down effects of a flower-visitor predator on plant pollination may not be anticipated without studying the direct and indirect effects of this predator on the effective pollinators. In pollination systems where effective pollinators visited flowers erratically, such as in deceptive orchids, we expect weak or no effect of predators on plant fitness.

Pollinator Protection

EPA Pesticide Factsheets

What the EPA is doing to protect bees and other pollinators from pesticides; including addressing the issue of Colony Collapse Disorder (CCD), risk assessment, decline in pollinator health in general, and why pollinators are important.

Ecological and evolutionary conditions for fruit abortion to regulate pollinating seed-eaters and increase plant production

USGS Publications Warehouse

Holland, J. Nathaniel; DeAngelis, Donald L.

2002-01-01

Coevolved mutualisms, such as those between senita cacti, yuccas, and their respective obligate pollinators, benefit both species involved in the interaction. However, in these pollination mutualisms the pollinator's larvae impose a cost on plants through consumption of developing seeds and fruit. The effects of pollinators on benefits and costs are expected to vary with the abundance of pollinators, because large population sizes result in more eggs and larval seed-eaters. Here, we develop the hypothesis that fruit abortion, which is common in yucca, senita, and plants in general, could in some cases have the function of limiting pollinator abundance and, thereby, increasing fruit production. Using a general steady-state model of fruit production and pollinator dynamics, we demonstrate that plants involved in pollinating seed-eater mutualisms can increase their fecundity by randomly aborting fruit. We show that the ecological conditions under which fruit abortion can improve plants fecundity are not unusual. They are best met when the plant is long-lived, the population dynamics of the pollinator are much faster than those of the plant, the loss of one fruit via abortion kills a larva that would have the expectation of destroying more than one fruit through its future egg laying as an adult moth, and the effects of fruit abortion on pollinator abundance are spatially localized. We then use the approach of adaptive dynamics to find conditions under which a fruit abortion strategy based on regulating the pollinator population could feasibly evolve in this type of plant–pollinator interaction.

The reproductive strategy of a pollinator-limited Himalayan plant, Incarvillea mairei (Bignoniaceae)

PubMed Central

2013-01-01

Background Plants may adapt to alpine habitats by specialization in the reproductive strategy and functional aspects of their flowers and pollination systems. Alpine habitats reduce the opportunities for cross-pollination in a relatively high proportion of alpine plant species, and self-pollination may be favored in these adverse conditions. Here, we investigated the mating system and pollination of Incarvillea mairei, a perennial Himalayan herb typically found at altitudes between 3000 and 4500 m. Results Analyses of floral morphology, observation of plant-pollinator interactions, and hand pollination experiments were conducted in three natural populations. Outcrossing rates and effective numbers of pollen donors were assessed in 45 open-pollinated families by using progeny analysis based on seven microsatellite markers. Incarvillea mairei displayed a set of apparently specialized floral traits, the stigma is sensitive to touch and close immediately and its reopening allows a second opportunity for the receipt of pollen. The species is fully self-compatible but employs a predominantly outcrossing mating system according to parentage analysis (tm > 0.9). Fruit set was low (26.3%), whereas seed set was high (67.2%), indicating that this species suffers pollinator limitation. Its main effective pollinator was Halictus sp., and visitation frequency was low. Conclusions Floral features such as having a sensitive stigma and anther-prongs, in conjunction with pollinator behavior, function together contributing to a set of unique reproductive adaptations that enhance outcrossing success. The increased floral longevity and high pollination efficiency operated as compensatory mechanisms to counteract low pollinator visitation frequency. PMID:24289097

Pollination biology of fruit-bearing hedgerow plants and the role of flower-visiting insects in fruit-set.

PubMed

Jacobs, Jennifer H; Clark, Suzanne J; Denholm, Ian; Goulson, Dave; Stoate, Chris; Osborne, Juliet L

2009-12-01

In the UK, the flowers of fruit-bearing hedgerow plants provide a succession of pollen and nectar for flower-visiting insects for much of the year. The fruits of hedgerow plants are a source of winter food for frugivorous birds on farmland. It is unclear whether recent declines in pollinator populations are likely to threaten fruit-set and hence food supply for birds. The present study investigates the pollination biology of five common hedgerow plants: blackthorn (Prunus spinosa), hawthorn (Crataegus monogyna), dog rose (Rosa canina), bramble (Rubus fruticosus) and ivy (Hedera helix). The requirement for insect pollination was investigated initially by excluding insects from flowers by using mesh bags and comparing immature and mature fruit-set with those of open-pollinated flowers. Those plants that showed a requirement for insect pollination were then tested to compare fruit-set under two additional pollination service scenarios: (1) reduced pollination, with insects excluded from flowers bagged for part of the flowering period, and (2) supplemental pollination, with flowers hand cross-pollinated to test for pollen limitation. The proportions of flowers setting fruit in blackthorn, hawthorn and ivy were significantly reduced when insects were excluded from flowers by using mesh bags, whereas fruit-set in bramble and dog rose were unaffected. Restricting the exposure of flowers to pollinators had no significant effect on fruit-set. However, blackthorn and hawthorn were found to be pollen-limited, suggesting that the pollination service was inadequate in the study area. Ensuring strong populations of insect pollinators may be essential to guarantee a winter fruit supply for birds in UK hedgerows.

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.

Host specificity, phenotype matching and the evolution of reproductive isolation in a coevolved plant-pollinator mutualism.

PubMed

Himler, Anna G; Machado, Carlos A

2009-12-01

Coevolutionary interactions between plants and their associated pollinators and seed dispersers are thought to have promoted the diversification of flowering plants (Raven 1977; Regal 1977; Stebbins 1981). The actual mechanisms by which pollinators could drive species diversification in plants are not fully understood. However, it is thought that pollinator host specialization can influence the evolution of reproductive isolation among plant populations because the pollinator's choice of host is what determines patterns of gene flow in its host plant, and host choice may also have important consequences on pollinator and host fitness (Grant 1949; Bawa 1992). In this issue of Molecular Ecology, Smith et al. (2009) present a very interesting study that addresses how host specialization affects pollinator fitness and patterns of gene flow in a plant host. Several aspects of this study match elements of a seminal mathematical model of plant-pollinator codivergence (Kiester et al. 1984) suggesting that reciprocal selection for matched plant and pollinator reproductive traits may lead to speciation in the host and its pollinator when there is strong host specialization and a pattern of geographic subdivision. Smith et al.'s study represents an important step to fill the gap in our understanding of how reciprocal selection may lead to speciation in coevolved plant-pollinator mutualisms.

Ecology and evolution of plant–pollinator interactions

PubMed Central

Mitchell, Randall J.; Irwin, Rebecca E.; Flanagan, Rebecca J.; Karron, Jeffrey D.

2009-01-01

Background Some of the most exciting advances in pollination biology have resulted from interdisciplinary research combining ecological and evolutionary perspectives. For example, these two approaches have been essential for understanding the functional ecology of floral traits, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant–pollinator interactions. However, as research in these and other areas has progressed, many pollination biologists have become more specialized in their research interests, focusing their attention on either evolutionary or ecological questions. We believe that the continuing vigour of a synthetic and interdisciplinary field like pollination biology depends on renewed connections between ecological and evolutionary approaches. Scope In this Viewpoint paper we highlight the application of ecological and evolutionary approaches to two themes in pollination biology: (1) links between pollinator behaviour and plant mating systems, and (2) generalization and specialization in pollination systems. We also describe how mathematical models and synthetic analyses have broadened our understanding of pollination biology, especially in human-modified landscapes. We conclude with several suggestions that we hope will stimulate future research. This Viewpoint also serves as the introduction to this Special Issue on the Ecology and Evolution of Plant–Pollinator Interactions. These papers provide inspiring examples of the synergy between evolutionary and ecological approaches, and offer glimpses of great accomplishments yet to come. PMID:19482881

Ecology and evolution of plant-pollinator interactions.

PubMed

Mitchell, Randall J; Irwin, Rebecca E; Flanagan, Rebecca J; Karron, Jeffrey D

2009-06-01

Some of the most exciting advances in pollination biology have resulted from interdisciplinary research combining ecological and evolutionary perspectives. For example, these two approaches have been essential for understanding the functional ecology of floral traits, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant-pollinator interactions. However, as research in these and other areas has progressed, many pollination biologists have become more specialized in their research interests, focusing their attention on either evolutionary or ecological questions. We believe that the continuing vigour of a synthetic and interdisciplinary field like pollination biology depends on renewed connections between ecological and evolutionary approaches. In this Viewpoint paper we highlight the application of ecological and evolutionary approaches to two themes in pollination biology: (1) links between pollinator behaviour and plant mating systems, and (2) generalization and specialization in pollination systems. We also describe how mathematical models and synthetic analyses have broadened our understanding of pollination biology, especially in human-modified landscapes. We conclude with several suggestions that we hope will stimulate future research. This Viewpoint also serves as the introduction to this Special Issue on the Ecology and Evolution of Plant-Pollinator Interactions. These papers provide inspiring examples of the synergy between evolutionary and ecological approaches, and offer glimpses of great accomplishments yet to come.

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.

Pollinator-driven ecological speciation in plants: new evidence and future perspectives

PubMed Central

Van der Niet, Timotheüs; Peakall, Rod; Johnson, Steven D.

2014-01-01

Background The hypothesis that pollinators have been important drivers of angiosperm diversity dates back to Darwin, and remains an important research topic today. Mounting evidence indicates that pollinators have the potential to drive diversification at several different stages of the evolutionary process. Microevolutionary studies have provided evidence for pollinator-mediated floral adaptation, while macroevolutionary evidence supports a general pattern of pollinator-driven diversification of angiosperms. However, the overarching issue of whether, and how, shifts in pollination system drive plant speciation represents a critical gap in knowledge. Bridging this gap is crucial to fully understand whether pollinator-driven microevolution accounts for the observed macroevolutionary patterns. Testable predictions about pollinator-driven speciation can be derived from the theory of ecological speciation, according to which adaptation (microevolution) and speciation (macroevolution) are directly linked. This theory is a particularly suitable framework for evaluating evidence for the processes underlying shifts in pollination systems and their potential consequences for the evolution of reproductive isolation and speciation. Scope This Viewpoint paper focuses on evidence for the four components of ecological speciation in the context of plant-pollinator interactions, namely (1) the role of pollinators as selective agents, (2) floral trait divergence, including the evolution of ‘pollination ecotypes‘, (3) the geographical context of selection on floral traits, and (4) the role of pollinators in the evolution of reproductive isolation. This Viewpoint also serves as the introduction to a Special Issue on Pollinator-Driven Speciation in Plants. The 13 papers in this Special Issue range from microevolutionary studies of ecotypes to macroevolutionary studies of historical ecological shifts, and span a wide range of geographical areas and plant families. These studies further illustrate innovative experimental approaches, and they employ modern tools in genetics and floral trait quantification. Future advances to the field require better quantification of selection through male fitness and pollinator isolation, for instance by exploiting next-generation sequencing technologies. By combining these new tools with strategically chosen study systems, and smart experimental design, we predict that examples of pollinator-driven speciation will be among the most widespread and compelling of all cases of ecological speciation. PMID:24418954

Genetic Variability of the Neogregarine Apicystis bombi, an Etiological Agent of an Emergent Bumblebee Disease

PubMed Central

Maebe, Kevin; Arbetman, Marina; Morales, Carolina; Graystock, Peter; Hughes, William O. H.; Plischuk, Santiago; Lange, Carlos E.; de Graaf, Dirk C.; Zapata, Nelson; de la Rosa, Jose Javier Perez; Murray, Tomás E.; Brown, Mark J. F.; Smagghe, Guy

2013-01-01

The worldwide spread of diseases is considered a major threat to biodiversity and a possible driver of the decline of pollinator populations, particularly when novel species or strains of parasites emerge. Previous studies have suggested that populations of introduced European honeybee (Apis mellifera) and bumblebee species (Bombus terrestris and Bombus ruderatus) in Argentina share the neogregarine parasite Apicystis bombi with the native bumblebee (Bombus dahlbomii). In this study we investigated whether A. bombi is acting as an emergent parasite in the non-native populations. Specifically, we asked whether A. bombi, recently identified in Argentina, was introduced by European, non-native bees. Using ITS1 and ITS2 to assess the parasite’s intraspecific genetic variation in bees from Argentina and Europe, we found a largely unstructured parasite population, with only 15% of the genetic variation being explained by geographic location. The most abundant haplotype in Argentina (found in all 9 specimens of non-native species) was identical to the most abundant haplotype in Europe (found in 6 out of 8 specimens). Similarly, there was no evidence of structuring by host species, with this factor explaining only 17% of the genetic variation. Interestingly, parasites in native Bombus ephippiatus from Mexico were genetically distant from the Argentine and European samples, suggesting that sufficient variability does exist in the ITS region to identify continent-level genetic structure in the parasite. Thus, the data suggest that A. bombi from Argentina and Europe share a common, relatively recent origin. Although our data did not provide information on the direction of transfer, the absence of genetic structure across space and host species suggests that A. bombi may be acting as an emergent infectious disease across bee taxa and continents. PMID:24324696

Reducing Alaska Native paediatric oral health disparities: a systematic review of oral health interventions and a case study on multilevel strategies to reduce sugar-sweetened beverage intake.

PubMed

Chi, Donald L

2013-01-01

Tooth decay is the most common paediatric disease and there is a serious paediatric tooth decay epidemic in Alaska Native communities. When untreated, tooth decay can lead to pain, infection, systemic health problems, hospitalisations and in rare cases death, as well as school absenteeism, poor grades and low quality-of-life. The extent to which population-based oral health interventions have been conducted in Alaska Native paediatric populations is unknown. To conduct a systematic review of oral health interventions aimed at Alaska Native children below age 18 and to present a case study and conceptual model on multilevel intervention strategies aimed at reducing sugar-sweetened beverage (SSB) intake among Alaska Native children. Based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement, the terms "Alaska Native", "children" and "oral health" were used to search Medline, Embase, Web of Science, GoogleScholar and health foundation websites (1970-2012) for relevant clinical trials and evaluation studies. Eighty-five studies were found in Medline, Embase and Web of Science databases and there were 663 hits in GoogleScholar. A total of 9 publications were included in the qualitative review. These publications describe 3 interventions that focused on: reducing paediatric tooth decay by educating families and communities; providing dental chemotherapeutics to pregnant women; and training mid-level dental care providers. While these approaches have the potential to improve the oral health of Alaska Native children, there are unique challenges regarding intervention acceptability, reach and sustainability. A case study and conceptual model are presented on multilevel strategies to reduce SSB intake among Alaska Native children. Few oral health interventions have been tested within Alaska Native communities. Community-centred multilevel interventions are promising approaches to improve the oral and systemic health of Alaska Native children. Future investigators should evaluate the feasibility of implementing multilevel interventions and policies within Alaska Native communities as a way to reduce children's health disparities.

Choosing Web 2.0 Tools for Instruction: An Extension of Task-Technology Fit

ERIC Educational Resources Information Center

Gupta, Saurabh

2014-01-01

The growth of technology and the inclusion of "digital natives" as students in the education world have created a demand pull for the use of Web 2.0 technologies in education. Dominant among these tools have been wikis, blogs and discussion boards. Distance education experts view the use of these tools as differentiators when compared to…

Depth gradients in food-web processes linking habitats in large lakes: Lake Superior as an exemplar ecosystem

USGS Publications Warehouse

Sierszen, Michael E.; Hrabik, Thomas R.; Stockwell, Jason D.; Cotter, Anne M; Hoffman, Joel C.; Yule, Daniel L.

2014-01-01

Support of whole-lake food webs through trophic linkages among pelagic, profundal and littoral habitats appears to be integral to the functioning of large lakes. These linkages can be disrupted though ecosystem disturbance such as eutrophication or the effects of invasive species and should be considered in native species restoration efforts.

The effects of landscape fragmentation on pollination dynamics: absence of evidence not evidence of absence.

PubMed

Hadley, Adam S; Betts, Matthew G

2012-08-01

Animal-mediated pollination is essential for both ecosystem services and conservation of global biodiversity, but a growing body of work reveals that it is negatively affected by anthropogenic disturbance. Landscape-scale disturbance results in two often inter-related processes: (1) habitat loss, (2) disruptions of habitat configuration (i.e. fragmentation). Understanding the relative effects of such processes is critical in designing effective management strategies to limit pollination and pollinator decline. We reviewed existing published work from 1989 to 2009 and found that only six of 303 studies considering the influence of landscape context on pollination separated the effects of habitat loss from fragmentation. We provide a synthesis of the current landscape, behavioural, and pollination ecology literature in order to present preliminary multiple working hypotheses explaining how these two landscape processes might independently influence pollination dynamics. Landscape disturbance primarily influences three components of pollination interactions: pollinator density, movement, and plant demography. We argue that effects of habitat loss on each of these components are likely to differ substantially from the effects of fragmentation, which is likely to be more complex and may influence each pollination component in contrasting ways. The interdependency between plants and animals inherent to pollination systems also has the possibility to drive cumulative effects of fragmentation, initiating negative feedback loops between animals and the plants they pollinate. Alternatively, due to their asymmetrical structure, pollination networks may be relatively robust to fragmentation. Despite the potential importance of independent effects of habitat fragmentation, its effects on pollination remain largely untested. We postulate that variation across studies in the effects of 'fragmentation' owes much to artifacts of the sampling regimes adopted, particularly (1) incorrectly separating fragmentation from habitat loss, and (2) mis-matches in spatial scale between landscapes studied and the ecological processes of interest. The field of landscape pollination ecology could be greatly advanced through the consideration and quantification of the matrix, landscape functional connectivity, and pollinator movement behaviour in response to these elements. Studies designed to disentangle the independent effects of habitat loss and fragmentation are essential for gaining insight into landscape-mediated pollination declines, implementing effective conservation measures, and optimizing ecosystem services in complex landscapes. © 2011 The Authors. Biological Reviews © 2011 Cambridge Philosophical Society.

Head in the clouds: Re-imagining the experimental laboratory record for the web-based networked world

PubMed Central

2009-01-01

The means we use to record the process of carrying out research remains tied to the concept of a paginated paper notebook despite the advances over the past decade in web based communication and publication tools. The development of these tools offers an opportunity to re-imagine what the laboratory record would look like if it were re-built in a web-native form. In this paper I describe a distributed approach to the laboratory record based which uses the most appropriate tool available to house and publish each specific object created during the research process, whether they be a physical sample, a digital data object, or the record of how one was created from another. I propose that the web-native laboratory record would act as a feed of relationships between these items. This approach can be seen as complementary to, rather than competitive with, integrative approaches that aim to aggregate relevant objects together to describe knowledge. The potential for the recent announcement of the Google Wave protocol to have a significant impact on realizing this vision is discussed along with the issues of security and provenance that are raised by such an approach. PMID:20098590

Comparing Ease-of-Processing Values of the Same Set of Words for Native English Speakers and Japanese Learners of English

ERIC Educational Resources Information Center

Takashima, Hiroomi

2009-01-01

Ease of processing of 3,969 English words for native speakers and Japanese learners was investigated using lexical decision and naming latencies taken from the English Lexicon Project (Balota et al. The English Lexicon Project: A web-based repository of descriptive and behavioral measures for 40,481 English words and nonwords, 2002) and accuracy…

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

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

Landscape genetic approaches to guide native plant restoration in the Mojave Desert

USGS Publications Warehouse

Shryock, Daniel F.; Havrilla, Caroline A.; DeFalco, Lesley; Esque, Todd C.; Custer, Nathan; Wood, Troy E.

2016-01-01

Restoring dryland ecosystems is a global challenge due to synergistic drivers of disturbance coupled with unpredictable environmental conditions. Dryland plant species have evolved complex life-history strategies to cope with fluctuating resources and climatic extremes. Although rarely quantified, local adaptation is likely widespread among these species and potentially influences restoration outcomes. The common practice of reintroducing propagules to restore dryland ecosystems, often across large spatial scales, compels evaluation of adaptive divergence within these species. Such evaluations are critical to understanding the consequences of large-scale manipulation of gene flow and to predicting success of restoration efforts. However, genetic information for species of interest can be difficult and expensive to obtain through traditional common garden experiments. Recent advances in landscape genetics offer marker-based approaches for identifying environmental drivers of adaptive genetic variability in non-model species, but tools are still needed to link these approaches with practical aspects of ecological restoration. Here, we combine spatially-explicit landscape genetics models with flexible visualization tools to demonstrate how cost-effective evaluations of adaptive genetic divergence can facilitate implementation of different seed sourcing strategies in ecological restoration. We apply these methods to Amplified Fragment Length Polymorphism (AFLP) markers genotyped in two Mojave Desert shrub species of high restoration importance: the long-lived, wind-pollinated gymnosperm Ephedra nevadensis, and the short-lived, insect-pollinated angiosperm Sphaeralcea ambigua. Mean annual temperature was identified as an important driver of adaptive genetic divergence for both species. Ephedra showed stronger adaptive divergence with respect to precipitation variability, while temperature variability and precipitation averages explained a larger fraction of adaptive divergence in Sphaeralcea. We describe multivariate statistical approaches for interpolating spatial patterns of adaptive divergence while accounting for potential bias due to neutral genetic structure. Through a spatial bootstrapping procedure, we also visualize patterns in the magnitude of model uncertainty. Finally, we introduce an interactive, distance-based mapping approach that explicitly links marker-based models of adaptive divergence with local or admixture seed sourcing strategies, promoting effective native plant restoration.

[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.

Constraints imposed by pollinator behaviour on the ecology and evolution of plant mating systems.

PubMed

Devaux, C; Lepers, C; Porcher, E

2014-07-01

Most flowering plants rely on pollinators for their reproduction. Plant-pollinator interactions, although mutualistic, involve an inherent conflict of interest between both partners and may constrain plant mating systems at multiple levels: the immediate ecological plant selfing rates, their distribution in and contribution to pollination networks, and their evolution. Here, we review experimental evidence that pollinator behaviour influences plant selfing rates in pairs of interacting species, and that plants can modify pollinator behaviour through plastic and evolutionary changes in floral traits. We also examine how theoretical studies include pollinators, implicitly or explicitly, to investigate the role of their foraging behaviour in plant mating system evolution. In doing so, we call for more evolutionary models combining ecological and genetic factors, and additional experimental data, particularly to describe pollinator foraging behaviour. Finally, we show that recent developments in ecological network theory help clarify the impact of community-level interactions on plant selfing rates and their evolution and suggest new research avenues to expand the study of mating systems of animal-pollinated plant species to the level of the plant-pollinator networks. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

The role of pollinator diversity in the evolution of corolla-shape integration in a pollination-generalist plant clade

PubMed Central

Gómez, José María; Perfectti, Francisco; Klingenberg, Christian Peter

2014-01-01

Flowers of animal-pollinated plants are integrated structures shaped by the action of pollinator-mediated selection. It is widely assumed that pollination specialization increases the magnitude of floral integration. However, empirical evidence is still inconclusive. In this study, we explored the role of pollinator diversity in shaping the evolution of corolla-shape integration in Erysimum, a plant genus with generalized pollination systems. We quantified floral integration in Erysimum using geometric morphometrics and explored its evolution using phylogenetic comparative methods. Corolla-shape integration was low but significantly different from zero in all study species. Spatial autocorrelation and phylogenetic signal in corolla-shape integration were not detected. In addition, integration in Erysimum seems to have evolved in a way that is consistent with Brownian motion, but with frequent convergent evolution. Corolla-shape integration was negatively associated with the number of pollinators visiting the flowers of each Erysimum species. That is, it was lower in those species having a more generalized pollination system. This negative association may occur because the co-occurrence of many pollinators imposes conflicting selection and cancels out any consistent selection on specific floral traits, preventing the evolution of highly integrated flowers. PMID:25002702

How does climate warming affect plant-pollinator interactions?

PubMed

Hegland, Stein Joar; Nielsen, Anders; Lázaro, Amparo; Bjerknes, Anne-Line; Totland, Ørjan

2009-02-01

Climate warming affects the phenology, local abundance and large-scale distribution of plants and pollinators. Despite this, there is still limited knowledge of how elevated temperatures affect plant-pollinator mutualisms and how changed availability of mutualistic partners influences the persistence of interacting species. Here we review the evidence of climate warming effects on plants and pollinators and discuss how their interactions may be affected by increased temperatures. The onset of flowering in plants and first appearance dates of pollinators in several cases appear to advance linearly in response to recent temperature increases. Phenological responses to climate warming may therefore occur at parallel magnitudes in plants and pollinators, although considerable variation in responses across species should be expected. Despite the overall similarities in responses, a few studies have shown that climate warming may generate temporal mismatches among the mutualistic partners. Mismatches in pollination interactions are still rarely explored and their demographic consequences are largely unknown. Studies on multi-species plant-pollinator assemblages indicate that the overall structure of pollination networks probably are robust against perturbations caused by climate warming. We suggest potential ways of studying warming-caused mismatches and their consequences for plant-pollinator interactions, and highlight the strengths and limitations of such approaches.

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.

Effects of distance from models on the fitness of floral mimics.

PubMed

Duffy, K J; Johnson, S D

2017-05-01

Rewardless plants can attract pollinators by mimicking floral traits of rewarding heterospecific plants. This should result in the pollination success of floral mimics being dependent on the relative abundance of their models, as pollinator abundance and conditioning on model signals should be higher in the vicinity of the models. However, the attraction of pollinators to signals of the models may be partially innate, such that spatial isolation of mimics from model species may not strongly affect pollination success of mimics. We tested whether pollination rates and fruit set of the rewardless orchid Disa pulchra were influenced by proximity and abundance of its rewarding model species, Watsonia lepida. Pollination success of the orchid increased with proximity to the model species, while fruit set of the orchid increased with local abundance of the model species. Orchids that were experimentally translocated outside the model population experienced reduced pollinaria removal and increased pollinator-mediated self-pollination. These results confirm predictions that the pollination success of floral mimics should be dependent on the proximity and abundance of model taxa, and thus highlight the importance of ecological facilitation among species involved in mimicry systems. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Pollination biology of fruit-bearing hedgerow plants and the role of flower-visiting insects in fruit-set

PubMed Central

Jacobs, Jennifer H.; Clark, Suzanne J.; Denholm, Ian; Goulson, Dave; Stoate, Chris; Osborne, Juliet L.

2009-01-01

Background and Aims In the UK, the flowers of fruit-bearing hedgerow plants provide a succession of pollen and nectar for flower-visiting insects for much of the year. The fruits of hedgerow plants are a source of winter food for frugivorous birds on farmland. It is unclear whether recent declines in pollinator populations are likely to threaten fruit-set and hence food supply for birds. The present study investigates the pollination biology of five common hedgerow plants: blackthorn (Prunus spinosa), hawthorn (Crataegus monogyna), dog rose (Rosa canina), bramble (Rubus fruticosus) and ivy (Hedera helix). Methods The requirement for insect pollination was investigated initially by excluding insects from flowers by using mesh bags and comparing immature and mature fruit-set with those of open-pollinated flowers. Those plants that showed a requirement for insect pollination were then tested to compare fruit-set under two additional pollination service scenarios: (1) reduced pollination, with insects excluded from flowers bagged for part of the flowering period, and (2) supplemental pollination, with flowers hand cross-pollinated to test for pollen limitation. Key Results The proportions of flowers setting fruit in blackthorn, hawthorn and ivy were significantly reduced when insects were excluded from flowers by using mesh bags, whereas fruit-set in bramble and dog rose were unaffected. Restricting the exposure of flowers to pollinators had no significant effect on fruit-set. However, blackthorn and hawthorn were found to be pollen-limited, suggesting that the pollination service was inadequate in the study area. Conclusions Ensuring strong populations of insect pollinators may be essential to guarantee a winter fruit supply for birds in UK hedgerows. PMID:19770165

The influence of floral symmetry, dependence on pollinators and pollination generalization on flower size variation

PubMed Central

Lázaro, A.; Totland, Ø.

2014-01-01

Background and Aims The pollinator-mediated stabilizing selection hypothesis suggests that the specialized pollination system of zygomorphic flowers might cause stabilizing selection, reducing their flower size variation compared with actinomorphic flowers. However, the degree of ecological generalization and of dependence on pollinators varies greatly among species of both flower symmetry types and this may also affect flower size variation. Methods Data on 43 species from two contrasting communities (one alpine and one lowland community) were used to test the relationships and interactions between flower size phenotypic variation, floral symmetry, ecological pollination generalization and species' dependence on pollinators. Key Results Contrary to what was expected, higher flower size variation was found in zygomorphic than in actinomorphic species in the lowland community, and no difference in flower size variation was found between symmetry types in the alpine community. The relationship between floral symmetry and flower size variation depended on ecological generalization and species' dependence on pollinators, although the influence of ecological generalization was only detected in the alpine community. Zygomorphic species that were highly dependent on pollinators and that were ecologically specialized were less variable in flower size than ecologically generalist and selfing zygomorphic species, supporting the pollinator-mediated stabilizing selection hypothesis. However, these relationships were not found in actinomorphic species, probably because they are not dependent on any particular pollinator for efficient pollination and therefore their flower size always shows moderate levels of variation. Conclusions The study suggests that the relationship between flower size variation and floral symmetry may be influenced by population-dependent factors, such as ecological generalization and species' dependence on pollinators. PMID:24838838

The influence of floral symmetry, dependence on pollinators and pollination generalization on flower size variation.

PubMed

Lázaro, A; Totland, O

2014-07-01

The pollinator-mediated stabilizing selection hypothesis suggests that the specialized pollination system of zygomorphic flowers might cause stabilizing selection, reducing their flower size variation compared with actinomorphic flowers. However, the degree of ecological generalization and of dependence on pollinators varies greatly among species of both flower symmetry types and this may also affect flower size variation. Data on 43 species from two contrasting communities (one alpine and one lowland community) were used to test the relationships and interactions between flower size phenotypic variation, floral symmetry, ecological pollination generalization and species' dependence on pollinators. Contrary to what was expected, higher flower size variation was found in zygomorphic than in actinomorphic species in the lowland community, and no difference in flower size variation was found between symmetry types in the alpine community. The relationship between floral symmetry and flower size variation depended on ecological generalization and species' dependence on pollinators, although the influence of ecological generalization was only detected in the alpine community. Zygomorphic species that were highly dependent on pollinators and that were ecologically specialized were less variable in flower size than ecologically generalist and selfing zygomorphic species, supporting the pollinator-mediated stabilizing selection hypothesis. However, these relationships were not found in actinomorphic species, probably because they are not dependent on any particular pollinator for efficient pollination and therefore their flower size always shows moderate levels of variation. The study suggests that the relationship between flower size variation and floral symmetry may be influenced by population-dependent factors, such as ecological generalization and species' dependence on pollinators. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Heteranthery as a solution to the demand for pollen as food and for pollination - Legitimate flower visitors reject flowers without feeding anthers.

PubMed

Mesquita-Neto, J N; Costa, B K P; Schlindwein, C

2017-11-01

Heteranthery, the presence of feeding and pollinating anthers in the same flower, seems to mediate the evolutionary dilemma for plants to protect their gametes and yet provide food for pollinators. This study aims to elucidate the role of heteranthery in the buzz-pollinated Senna reniformis. The fecundity of pollen from long-, medium- and short-sized anthers was determined by hand cross-pollination experiments, and the quantity, size, ornamentation and viability of pollen of different anthers were compared. Rates of flower rejection by bees were measured in anther removal experiments to assess the preferences of flower visitors for feeding or pollinating anthers. Large bees, which were the effective pollinators of self-incompatible S. reniformis, avoided flowers without short feeding anthers, but not those without medium or long anthers. Illegitimate small and medium-sized bees were unresponsive to anther exclusion experiments. Long anthers deposited pollen on the back and short anthers on the venter of large bees. Pollen from long anthers had higher in vitro viability and higher fruit and seed set after cross-pollination than pollen from other sized anthers. Short anthers produce feeding pollen to effective pollinators and long anthers are related to pollination of S. reniformis. Bee behaviour and size was found to directly influence the role of anthers in the 'division of labour'. Only large bee pollinators that carry the pollinating pollen from long anthers in 'safe sites' associated short anthers with the presence of food. In the absence of these larger bee pollinators, the role of heteranthery in S. reniformis would be strongly compromised and its function would be lost. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

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...

Sterile flowers increase pollinator attraction and promote female success in the Mediterranean herb Leopoldia comosa

PubMed Central

Morales, Carolina L.; Traveset, Anna; Harder, Lawrence D.

2013-01-01

Background and Aims Large floral displays have opposing consequences for animal-pollinated angiosperms: they attract more pollinators but also enable elevated among-flower self-pollination (geitonogamy). The presence of sterile flowers as pollinator signals may enhance attraction while allowing displays of fewer open fertile flowers, limiting geitonogamy. The simultaneous contributions of fertile and non-fertile display components to pollinator attraction and reproductive output remain undetermined. Methods The simultaneous effects of the presence of sterile flowers and fertile-flower display size in two populations of Leopoldia comosa were experimentally assessed. Pollinator behaviour, pollen removal and deposition, and fruit and seed production were compared between intact plants and plants with sterile flowers removed. Key Results The presence of sterile flowers almost tripled pollinator attraction, supplementing the positive effect of the number of fertile flowers on the number of bees approaching inflorescences. Although attracted bees visited more flowers on larger inflorescences, the number visited did not additionally depend on the presence of sterile flowers. The presence of sterile flowers improved all aspects of plant performance, the magnitude of plant benefit being context dependent. During weather favourable to pollinators, the presence of sterile flowers increased pollen deposition on stigmas of young flowers, but this difference was not evident in older flowers, probably because of autonomous self-pollination in poorly visited flowers. Total pollen receipt per stigma decreased with increasing fertile display size. In the population with more pollinators, the presence of sterile flowers increased fruit number but not seed set or mass, whereas in the other population sterile flowers enhanced seeds per fruit, but not fruit production. These contrasts are consistent with dissimilar cross-pollination and autonomous self-pollination, coupled with the strong predispersal inbreeding depression exhibited by L. comosa populations. Conclusions Sterile flowers enrich pollination quality by promoting pollen export and import, while limiting the mating costs of geitonogamy associated with large fertile displays. PMID:23131298

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

Meta-Analysis of Pollen Limitation Reveals the Relevance of Pollination Generalization in the Atlantic Forest of Brazil

PubMed Central

Wolowski, Marina; Ashman, Tia-Lynn; Freitas, Leandro

2014-01-01

Despite the extensive knowledge of pollen limitation in angiosperms, its assessment within tropical forests is still limited. Especially lacking are large scale comparisons of species within this biome – one that is highly diverse but also becoming increasingly threatened. In fact, many tropical plant species depend upon pollinators for reproduction but evaluation of the impact of this dependence via different levels of pollination specialization has yet to be made at the biome scale. We assessed the occurrence and magnitude of pollen limitation for species in the Brazilian Atlantic forest and tested the association of pollination specialization, breeding system, and life habit with pollination efficiency. We compiled data from studies published between 1985 and 2012. We calculated species' effect size (d) from data on fruit set after hand cross-pollination and natural pollination and conducted standard and phylogenetically independent meta-analysis. Overall pollen limitation was moderate, with magnitude of 0.50, and 95% confidence interval [0.37, 0.62] for 126 species. Pollen limitation was observed in 39% of species. Pollination specialization was the factor that best explained the occurrence of pollen limitation. Specifically, phenotypic and ecological specialists (plants with zygomorphic flowers and pollinated by one species of pollinator, respectively) had higher pollen limitation than generalist plants (actinomorphic flowers and pollination by two or more species). Functional generalists (plants pollinated by three or more functional groups) were not pollen limited. On the other hand, breeding system and life habit were not associated to pollen limitation. Pollen limitation was observed in the Atlantic forest and its magnitude was comparable to that for angiosperms as a whole. The finding that pollination specialization was the strongest predictor of pollen limitation suggests that specialist plants in this biome may be most prone to the reproductive failure as a result of pollinator loss. PMID:24586827

Is floral diversification associated with pollinator divergence? Flower shape, flower colour and pollinator preference in Chilean Mimulus.

PubMed

Cooley, A M; Carvallo, G; Willis, J H

2008-04-01

Adaptation to different pollinators is thought to drive divergence in flower colour and morphology, and may lead to interspecific reproductive isolation. Floral diversity was tested for association with divergent pollinator preferences in a group of four closely related wildflower species: the yellow-flowered Mimulus luteus var. luteus and the red-pigmented M. l. variegatus, M. naiandinus and M. cupreus. Patterns of pollinator visitation were evaluated in natural plant populations in central Chile, including both single-species and mixed-species sites. Floral anthocyanin pigments were identified, and floral morphology and nectar variation were quantified in a common garden experiment using seeds collected from the study sites. Mimulus l. luteus, M. l. variegatus and M. naiandinus are morphologically similar and share a single generalist bumblebee pollinator, Bombus dahlbomii. Mimulus cupreus differs significantly from the first three taxa in corolla shape as well as nectar characteristics, and had far fewer pollinator visits. This system shows limited potential for pollinator-mediated restriction of gene flow as a function of flower colour, and no evidence of transition to a novel pollinator. Mimulus cupreus may experience reduced interspecific gene flow due to a lack of bumblebee visitation, but not because of its red pigmentation: rare yellow morphs are equally undervisited by pollinators. Overall, the results suggest that factors other than pollinator shifts may contribute to the maintenance of floral diversity in these Chilean Mimulus species.

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.

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.

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

Contribution of Pollinator-Mediated Crops to Nutrients in the Human Food Supply

PubMed Central

Eilers, Elisabeth J.; Kremen, Claire; Smith Greenleaf, Sarah; Garber, Andrea K.; Klein, Alexandra-Maria

2011-01-01

The contribution of nutrients from animal pollinated world crops has not previously been evaluated as a biophysical measure for the value of pollination services. This study evaluates the nutritional composition of animal-pollinated world crops. We calculated pollinator dependent and independent proportions of different nutrients of world crops, employing FAO data for crop production, USDA data for nutritional composition, and pollinator dependency data according to Klein et al. (2007). Crop plants that depend fully or partially on animal pollinators contain more than 90% of vitamin C, the whole quantity of Lycopene and almost the full quantity of the antioxidants β-cryptoxanthin and β-tocopherol, the majority of the lipid, vitamin A and related carotenoids, calcium and fluoride, and a large portion of folic acid. Ongoing pollinator decline may thus exacerbate current difficulties of providing a nutritionally adequate diet for the global human population. PMID:21731717

Floral advertisement scent in a changing plant-pollinators market.

PubMed

Filella, Iolanda; Primante, Clara; Llusià, Joan; Martín González, Ana M; Seco, Roger; Farré-Armengol, Gerard; Rodrigo, Anselm; Bosch, Jordi; Peñuelas, Josep

2013-12-05

Plant-pollinator systems may be considered as biological markets in which pollinators choose between different flowers that advertise their nectar/pollen rewards. Although expected to play a major role in structuring plant-pollinator interactions, community-wide patterns of flower scent signals remain largely unexplored. Here we show for the first time that scent advertisement is higher in plant species that bloom early in the flowering period when pollinators are scarce relative to flowers than in species blooming later in the season when there is a surplus of pollinators relative to flowers. We also show that less abundant flowering species that may compete with dominant species for pollinator visitation early in the flowering period emit much higher proportions of the generalist attractant β-ocimene. Overall, we provide a first community-wide description of the key role of seasonal dynamics of plant-specific flower scent emissions, and reveal the coexistence of contrasting plant signaling strategies in a plant-pollinator market.

pWeb: A High-Performance, Parallel-Computing Framework for Web-Browser-Based Medical Simulation.

PubMed

Halic, Tansel; Ahn, Woojin; De, Suvranu

2014-01-01

This work presents a pWeb - a new language and compiler for parallelization of client-side compute intensive web applications such as surgical simulations. The recently introduced HTML5 standard has enabled creating unprecedented applications on the web. Low performance of the web browser, however, remains the bottleneck of computationally intensive applications including visualization of complex scenes, real time physical simulations and image processing compared to native ones. The new proposed language is built upon web workers for multithreaded programming in HTML5. The language provides fundamental functionalities of parallel programming languages as well as the fork/join parallel model which is not supported by web workers. The language compiler automatically generates an equivalent parallel script that complies with the HTML5 standard. A case study on realistic rendering for surgical simulations demonstrates enhanced performance with a compact set of instructions.

Breaking and Fixing Origin-Based Access Control in Hybrid Web/Mobile Application Frameworks.

PubMed

Georgiev, Martin; Jana, Suman; Shmatikov, Vitaly

2014-02-01

Hybrid mobile applications (apps) combine the features of Web applications and "native" mobile apps. Like Web applications, they are implemented in portable, platform-independent languages such as HTML and JavaScript. Like native apps, they have direct access to local device resources-file system, location, camera, contacts, etc. Hybrid apps are typically developed using hybrid application frameworks such as PhoneGap. The purpose of the framework is twofold. First, it provides an embedded Web browser (for example, WebView on Android) that executes the app's Web code. Second, it supplies "bridges" that allow Web code to escape the browser and access local resources on the device. We analyze the software stack created by hybrid frameworks and demonstrate that it does not properly compose the access-control policies governing Web code and local code, respectively. Web code is governed by the same origin policy, whereas local code is governed by the access-control policy of the operating system (for example, user-granted permissions in Android). The bridges added by the framework to the browser have the same local access rights as the entire application, but are not correctly protected by the same origin policy. This opens the door to fracking attacks, which allow foreign-origin Web content included into a hybrid app (e.g., ads confined in iframes) to drill through the layers and directly access device resources. Fracking vulnerabilities are generic: they affect all hybrid frameworks, all embedded Web browsers, all bridge mechanisms, and all platforms on which these frameworks are deployed. We study the prevalence of fracking vulnerabilities in free Android apps based on the PhoneGap framework. Each vulnerability exposes sensitive local resources-the ability to read and write contacts list, local files, etc.-to dozens of potentially malicious Web domains. We also analyze the defenses deployed by hybrid frameworks to prevent resource access by foreign-origin Web content and explain why they are ineffectual. We then present NoFrak, a capability-based defense against fracking attacks. NoFrak is platform-independent, compatible with any framework and embedded browser, requires no changes to the code of the existing hybrid apps, and does not break their advertising-supported business model.