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Megachile rotundata (F.) is an important pollinator of alfalfa in the United States. Enhancing landscapes with wildflowers is a primary strategy for conserving pollinators and may improve the sustainability of M. rotundata. Changing cold storage temperatures from a traditionally static thermal regime (STR) to a fluctuating thermal regime (FTR) improves overwintering success and extends M. rotundata’s shelf life and pollination window. Whether floral resources enhance overwintering survival and/or interact with a thermal regime are unknown. We tested the combined effects of enhancing alfalfa fields with wildflowers and thermal regime on survival and macronutrient stores under extended cold storage (i.e., beyond one season). Megachile rotundata adults were released in alfalfa plots with and without wildflower strips. Completed nests were harvested in September and stored in STR. After a year, cells were randomly assigned to remain in STR for 6 months or in FTR for a year of extended cold storage; emergence rates were observed monthly. Macronutrient levels of emerged females were assessed. FTR improved M. rotundata survival but there was no measurable effect of wildflower strips on overwintering success or nutrient stores. Timing of nest establishment emerged as a key factor: offspring produced late in the season had lower winter survival and dry body mass. Sugars and glycogen stores increased under FTR but not STR. Trehalose levels were similar across treatments. Total lipid stores depleted faster under FTR. While wildflowers did not improve M. rotundata survival, our findings provide mechanistic insight into benefits and potential costs of FTR for this important pollinator.

Fil: Senapathi, Deepa. University of Reading. School of Agriculture, Policy & Development. Centre for Agri-Environmental Research. Reino Unido. Fil: Fründ, Jochen. University of Freiburg. Faculty of Environment and Natural Resources. Biometry and Environmental System Analysis. Alemania. Fil: Albrecht, Matthias. Agroscope. Institute for Sustainability Sciences. Suiza. Fil: Garratt, Michael P. D. University of Reading. School of Agriculture, Policy & Development. Centre for Agri-Environmental Research. Reino Unido. Fil: Kleijn, David. Wageningen University. Plant Ecology and Nature Conservation Group. Países Bajos. Fil: Pickles, Brian J. University of Reading. School of Biological Sciences. Reino Unido. Fil: Potts, Simon G. University of Reading. School of Agriculture, Policy & Development. Centre for Agri-Environmental Research. Reino Unido. Fil: An, Jiandong. Chinese Academy of Agricultural Sciences. Institute of Apicultural Research. China. Fil: Andersson, Georg K. S. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. Río Negro, Argentina. Fil: Andersson, Georg K. S. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. Río Negro, Argentina. Fil: Bänsch, Svenja. University of Göttingen. Department of Crop Sciences. Functional Agrobiodiversity. Alemania. Fil: Basu, Parthiba. University of Calcutta. Centre for Pollination Studies. India. Fil: Benjamin, Faye. The State University of New Jersey. Department of Ecology, Evolution and Natural Resources. Estados Unidos. Fil: Bezerra, Antonio Diego M. The State University of New Jersey. Department of Ecology, Evolution and Natural Resources. Estados Unidos. Fil: Bhattacharya, Ritam. University of Calcutta. Centre for Pollination Studies. India. Fil: Biesmeijer Jacobus C. Naturalis Biodiversity Centre. Países Bajos. Fil: Blaauw, Brett. University of Georgia. Department of Entomology. Estados Unidos. Fil: Blitzer, Eleanor J. Carroll College. Department of Biology. Estados Unidos. Fil: Brittain, Claire A. Jealott’s Hill International Research Centre. Syngenta. Reino Unido. Fil: Carvalheiro, Luísa G. Universidade Federal de Goiás. Departamento de Ecologia. Brasil. Fil: Cariveau, Daniel P. University of Minnesota. Department of Entomology. Estados Unidos. Fil: Chakraborty, Pushan. University of Calcutta. Centre for Pollination Studies. India. Fil: Chatterjee, Arnob. University of Calcutta. Centre for Pollination Studies. India. Fil: Chatterjee, Soumik. University of Calcutta. Centre for Pollination Studies. India. Fil: Cusser, Sarah. Michigan State University. W. K. Kellogg Biological Station. Estados Unidos. Fil: Danforth, Bryan N. Cornell University. Department of Entomology. Estados Unidos. Fil: Degani, Erika. University of Reading. School of Agriculture, Policy & Development. Centre for Agri-Environmental Research. Reino Unido. Fil: Freitas, Breno M. The State University of New Jersey. Department of Ecology, Evolution and Natural Resources. Estados Unidos. Fil: Garibaldi, Lucas A. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. Río Negro, Argentina. Fil: Garibaldi, Lucas A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. Río Negro, Argentina. Fil: Geslin, Benoit. Aix Marseille Univ, Avignon Université. IMBE. Francia. Fil: de Groot, G. Arjen. Wageningen University and Research. Wageningen Environmental Research. Países Bajos. Fil: Harrison, Tina. University of California Davis. Department of Entomology and Nematology. Estados Unidos. Fil: Howlett, Brad. The New Zealand Institute for Plant & Food Research Limited. Nueva Zelanda. Fil: Isaacs, Rufus. Michigan State University. Department of Entomology. Estados Unidos. Fil: Jha, Shalene. The University of Texas at Austin. Department of Integrative Biology. Estados Unidos. Fil: Klatt, Björn Kristian. University of Göttingen. Department of Crop Sciences. Agroecology. Alemania. Fil: Krewenka, Kristin. University of Heidelberg. Heidelberg Research Service. Alemania. Fil: Leigh, Samuel. University of Reading. School of Agriculture, Policy & Development. Centre for Agri-Environmental Research. Reino Unido. Fil: Lindström, Sandra A. M. Lund University. Department of Biology. Biodiversity. Suecia. Fil: Mandelik, Yael. The Hebrew University of Jerusalem. The Robert H. Smith Faculty of Agriculture, Food and Environment. Department of Entomology. Israel. Fil: McKerchar, Megan. University of Worcester. School of Science and Environment. Reino Unido. Fil: Park, Mia. Cornell University. Department of Entomology. Estados Unidos. Fil: Pisanty, Gideon. Canadian National Collection of Insects, Arachnids and Nematodes. Agriculture and Agri-Food Canada. Canada. Fil: Rader, Romina. University of New England. School of Environment and Rural Science. Australia. Fil: Reemer, Menno. Naturalis Biodiversity Centre. Países Bajos. Fil: Rundlöf, Maj. Lund University. Department of Biology. Biodiversity. Suecia. Fil: Smith, Barbara. University of Calcutta. Centre for Pollination Studies. India. Fil: Smith, Henrik G. Lund University. Centre of Environmental and Climate Research & Department of Biology. Suecia. Fil: Nunes Silva, Patrícia. Universidade do Vale do Rio dos Sinos. Programa de Pós-Graduação em Biologia. Brasil. Fil: Steffan-Dewenter, Ingolf. University of Würzburg. Department of Animal Ecology and Tropical Biology. Alemania. Fil: Tscharntke, Teja. University of Göttingen. Department of Crop Sciences. Agroecology. Alemania. Fil: Webber, Sean. University of Reading. School of Agriculture, Policy & Development. Centre for Agri-Environmental Research. Reino Unido. Fil: Westbury, Duncan B. University of Worcester. School of Science and Environment. Reino Unido. Fil: Westphal, Catrin. University of Göttingen. Department of Crop Sciences. Functional Agrobiodiversity. Alemania. Fil: Wickens, Jennifer B. University of Reading. School of Agriculture, Policy & Development. Centre for Agri-Environmental Research. Reino Unido. Fil: Wickens, Victoria J. University of Reading. School of Agriculture, Policy & Development. Centre for Agri-Environmental Research. Reino Unido. Fil: Winfree, Rachael. The State University of New Jersey. Department of Ecology, Evolution and Natural Resources. Estados Unidos. Fil: Zhang, Hong. Chinese Academy of Agricultural Sciences. Institute of Apicultural Research. China. Fil: Klein, Alexandra-Maria. University of Freiburg. Faculty of Environment and Natural Resources. Nature Conservation and Landscape Ecology. Alemania. While an increasing number of studies indicate that the range, diversity and abundance of many wild pollinators has declined, the global area of pollinator-dependent crops has significantly increased over the last few decades. Crop pollination studies to date have mainly focused on either identifying different guilds pollinating various crops, or on factors driving spatial changes and turnover observed in these communities. The mechanisms driving temporal stability for ecosystem functioning and services, however, remain poorly understood. Our study quantifies temporal variability observed in crop pollinators in 21 different crops across multiple years at a global scale. Using data from 43 studies from six continents, we show that (i) higher pollinator diversity confers greater inter-annual stability in pollinator communities, (ii) temporal variation observed in pollinator abundance is primarily driven by the three-most dominant species, and (iii) crops in tropical regions demonstrate higher inter-annual variability in pollinator species richness than crops in temperate regions. We highlight the importance of recognizing wild pollinator diversity in agricultural landscapes to stabilize pollinator persistence across years to protect both biodiversity and crop pollination services. Short-term agricultural management practices aimed at dominant species for stabilizing pollination services need to be considered alongside longer term conservation goals focussed on maintaining and facilitating biodiversity to confer ecological stability. .

Pollinator declines coupled with increasing demand for insect pollinated crops have the potential to cause future pollinator shortages for our most nutritious and valuable crops. Ensuring adequate crop pollination may necessitate a shift in pollination management, from one that primarily relies on the managed European honeybee (Apis melliferaL.) to one that integrates alternative pollinators. While a growing body of scientific evidence supports significant contributions made by naturally occurring, native bees for crop pollination, translating research to practice requires buy-in from growers. The intention of agricultural extension is to address grower needs and concerns; however, few studies have assessed grower knowledge, perceptions and attitudes about native pollinators. Here we present findings from questionnaire-based surveys of over 600 apple growers in New York State and Pennsylvania, coupled with ecological data from bee surveys. This hybrid sociological and biological survey allows us to compare grower knowledge and perceptions to an actual pollinator census. While up to 93% of respondents highly valued importance of native bees, 20% growersdid not knowhow much native bees actually contribute to their orchard pollination. Despite the uncertainty, a majority of growers were open to relying on native bees (up to 60% in NY and 67% in PA) and to making low-cost changes to their farm's management that would benefit native pollinators (up to 68 in NY and 85% in PA). Growers consistently underestimated bee diversity, but their estimates corresponded to major bee groups identifiable by lay persons, indicating accurate local knowledge about native bees. Grower reliance on honeybees increased with farm size; because native bee abundance did not measurably decrease with farm size, renting honeybees may be motivated by risk avoidance rather than grower perception of lower native bee activity. Demonstrated effectiveness of native pollinators and clear guidelines for their management were the most important factors influencing grower decision to actively manage orchards for native bees. Our results highlight a pressing need for an active and research-based extension program to support diversification of pollination strategies in the region.

A growing body of evidence suggests that wild bees play an important role in agricultural pollination. It is very difficult, however, to accurately quantify the contribution of wild bees relative to honeybees in most crop systems. We quantified the relative contribution of honeybees and wild bees to the pollination of an economically important, insect-pollinated crop (apple). We use an empirical dataset to identify which of three functional traits (body size, pollen load purity, and flower handling behavior) contribute significantly to seed set. We find that flower handling behavior and abundance were the only functional traits that significantly predict seed set. When we take into account flower handling behavior and abundance, wild bees contributed significantly more to seed set than honeybees in the apple orchards we surveyed. Our findings suggest that land managers may benefit from focusing on supporting communities of wild bees, rather than investing in honeybee hive rental.

Understanding the importance of biodiversity in applied settings is a central theme for ecologists. Pollination is an essential ecosystem service, which may rely on biodiversity for effectiveness and stability. Empirical examples which link functional outcomes of increased biodiversity to pollination services are rare. To investigate the importance of wild and managed pollinator communities to apple production, we assessed the effect of wild and managed bee abundance and diversity on pollen limitation and seed set on commercial farms in New York State. Seed set increased and pollen limitation decreased with increasing wild bee species richness, functional group diversity (based on nesting, sociality, and size traits), and abundance, but not with honey bee abundance. Functional group diversity explained more variation in apple seed set than species richness. Our findings demonstrate the important role of functional complementarity of wild bees, defined here as functional group diversity, to crop pollination even in the presence of large populations of managed honey bees. Therefore, our results suggest that management of diverse pollinator communities may decrease reliance on managed honey bees for pollination services and enhance crop yields.

Ancestral history matters Biodiversity is sometimes quantified purely by the number of species within a system that allow it to function to produce ecosystem services. Grab et al. show that simple species counting is too simplistic. They combined remotely sensed land-cover analyses and crop production records with an extensive 10-year pollinator community survey and a complete species-level phylogeny generated using genome-wide phylogenomic methods. They found that the equivalent of millions of years of pollinator evolution were lost in highly altered agricultural environments, which decreased pollination services above and beyond what would be expected from a simple numerical species count. Science , this issue p. 282

International audience; AbstractDeclines in honey bee health and increasing demand for pollination services highlight a need to optimize crop pollination by wild bees. Apple is an economically important crop in eastern North America, requires insect pollination, and is visited by a diverse bee fauna, but a direct assessment of wild bee pollination in apple orchards is lacking. We combined measurements of two facets of pollination service, per-visit efficiency (fruit and seed set) and relative abundance, to estimate orchard-level, pollinator importance of mining bees (Andrena subgenus Melandrena), bumble bees (Bombus), and honey bees (Apis mellifera L.). Average pollinator importance provided a relative measure that allowed comparison of pollination service among the three focal bees across the study region. On average, a wild bee visit resulted in higher pollen transfer to stigmas, but had the same probability of setting fruit and seed as a honey bee visit. Regionally, pollinator importance of Melandrena and Bombus were 32 and 14 % that of honey bees, respectively. Because per-visit performances were similar, such disparities in importance were based largely on differences in relative abundance. Although the summed pollinator importance of Melandrena and Bombus was less than that of the honey bee, these, and other, wild pollinators have a role to play in filling future pollination gaps, and thus, warrant further study and conservation.

Bees are important pollinators of agricultural crops, and bee diversity has been shown to be closely associated with pollination, a valuable ecosystem service. Higher functional diversity and species richness of bees have been shown to lead to higher crop yield. Bees simultaneously represent a mega-diverse taxon that is extremely challenging to sample thoroughly and an important group to understand because of pollination services. We sampled bees visiting apple blossoms in 28 orchards over 6 years. We used species rarefaction analyses to test for the completeness of sampling and the relationship between species richness and sampling effort, orchard size, and percent agriculture in the surrounding landscape. We performed more than 190 h of sampling, collecting 11,219 specimens representing 104 species. Despite the sampling intensity, we captured

Bees play a key role in the functioning of human-modified and natural ecosystems by pollinating agricultural crops and wild plant communities. Global pollinator conservation efforts need large-scale and long-term monitoring to detect changes in species’ demographic patterns and shifts in bee community structure. The objective of this project was to test a molecular sequencing pipeline that would utilize a commonly used locus, produce accurate and precise identifications consistent with morphological identifications, and generate data that are both qualitative and quantitative. We applied this amplicon sequencing pipeline to native bee communities sampled across Conservation Reserve Program (CRP) lands and native grasslands in eastern North Dakota. We found the 28S LSU locus to be more capable of discriminating between species than the 18S SSU rRNA locus, and in some cases even resolved instances of cryptic species or morphologically ambiguous species complexes. Overall, we found the amplicon sequencing method to be a qualitatively accurate representation of the sampled bee community richness and species identity, especially when a well-curated database of known 28S LSU sequences is available. Both morphological identification and molecular sequencing revealed similar patterns in native bee community structure across CRP lands and native prairie. Additionally, a genetic algorithm approach to compute taxon-specific correction factors using a small subset of the most concordant samples demonstrated that a high level of quantitative accuracy could be possible if the specimens are fresh and processed soon after collection. Here we provide a first step to a molecular pipeline for identifying insect pollinator communities. This tool should prove useful for future national monitoring efforts as use of molecular tools becomes more affordable and as numbers of 28S LSU sequences for pollinator species increase in publicly-available databases.

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.

Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in‐field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in‐field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes., EML and DC were supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2014‐51106‐22096. BMF was supported by the National Council for Scientific and Technological Development‐CNPq, Brasília, Brazil #305062/2007‐7. SGP and MO were supported by the Felix Trust and STEP Project (EC FP7 244090).

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

Wild bee communities provide underappreciated but critical agricultural pollination services. Given predicted global shortages in pollination services, managing agroecosystems to support thriving wild bee communities is, therefore, central to ensuring sustainable food production. Benefits of natural (including semi-natural) habitat for wild bee abundance and diversity on farms are well documented. By contrast, few studies have examined toxicity of pesticides on wild bees, let alone effects of farm-level pesticide exposure on entire bee communities. Whether beneficial natural areas could mediate effects of harmful pesticides on wild bees is also unknown. Here, we assess the effect of conventional pesticide use on the wild bee community visiting apple ( Malus domestica ) within a gradient of percentage natural area in the landscape. Wild bee community abundance and species richness decreased linearly with increasing pesticide use in orchards one year after application; however, pesticide effects on wild bees were buffered by increasing proportion of natural habitat in the surrounding landscape. A significant contribution of fungicides to observed pesticide effects suggests deleterious properties of a class of pesticides that was, until recently, considered benign to bees. Our results demonstrate extended benefits of natural areas for wild pollinators and highlight the importance of considering the landscape context when weighing up the costs of pest management on crop pollination services.

© 2015 Macmillan Publishers Limited. All rights reserved. There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.

Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch connectivity and habitat aggregation) and farm management (organic vs. conventional and local-scale field diversity), and their interactions, on wild bee abundance and richness for 39 crop systems globally. Bee abundance and richness were higher in diversified and organic fields and in landscapes comprising more high-quality habitats; bee richness on conventional fields with low diversity benefited most from high-quality surrounding land cover. Landscape configuration effects were weak. Bee responses varied slightly by biome. Our synthesis reveals that pollinator persistence will depend on both the maintenance of high-quality habitats around farms and on local management practices that may offset impacts of intensive monoculture agriculture. Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch connectivity and habitat aggregation) and farm management (organic vs. conventional and local-scale field diversity), and their interactions, on wild bee abundance and richness for 39 cropsystems globally. Bee abundance and richness were higher in diversified and organic fields and in landscapes comprising more high-quality habitats; bee richness on conventional fields with low diversity benefited most from high-quality surrounding land cover. Landscape configuration effects were weak. Beeresponses varied slightly by biome. Our synthesis reveals that pollinator persistence will depend on boththe maintenance of high-quality habitats around farms and on local management practices that may offsetimpacts of intensive monoculture agriculture.

Biological invasions change native plant communities, but theory predicting whether introductions create naturalized or invasive species is lacking. Focusing on either plant traits or interactions of introduced plants with native biota creates unreliable results, and improvements may require integration of trait- and interaction-based approaches. To assess the importance of plant traits and herbivory on invasiveness, we incorporated herbivore effects in comparisons of growth and phenology of invasive Phragmites australis and its native congener P. australis subsp. americanus. Our results were infl uenced by venue (fi eld or common garden), with extended life span and optimized leaf-age structure of introduced P. australis indicating greater potential for resource capture. Attack by introduced gallfl ies affected expression of plant traits, but we found no consistent effect of aphid attack. Origin did not affect leaf emergence or stem height, but preferential gallfl y attack stunted native P. australis and delayed senescence. Greater resource capture and lower attack by nonnative herbivores could give introduced P. australis an advantage over the native subspecies. Our results demonstrating the importance of plant traits as well as their modifi cation by interactions with natural enemies questions whether the outcome of plant introductions can be predicted.