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Time series data on crop yields for two main wind-pollinated crops (barley and wheat) and for three crops benefitting from insect pollination (turnip rapeseed, caraway, and black currant), were compiled from official agricultural statistics. In Finland, these statistics are available at aggregate national level, and at the level of each of the 15 provinces of the country. Yields of wind-pollinated crops have steadily increased in Finland, while yields of insect-pollinated crops have been highly variable. The largest crop benefitting from insect pollination is turnip rapeseed, which shows first a clear tendency to increased yields from 1980 to 1993, after which there has been a continuous decline in yields at the national average level. Regionally, the trends in turnip rapeseed yield show large variation, so that in six provinces of Finland, the trend has been significantly decreasing; in five provinces, there has been no significant trend; and in two provinces, there has been a significant linear increase in yields. Yield trends in the two other insect-pollinated crops, caraway and black currants, show similar trend variations. However, at the national average level, caraway yields show no significant trend, while black currant yields have increased during the past 6 years. The possible impact on the trends of insect-pollinated crops of three explanatory variables was analyzed. Significant linear correlation was found between the yield trends (slope of the trends) in rapeseed, and the extent of using neonicotinoid seed dressing in the provinces; the magnitude of yield decline in turnip rapeseed increased, as the use of neonicotinoid seed dressing increased. Similar significant linear correlation was found for the magnitude of yield decline in turnip rapeseed and the complexity of the agricultural landscape in each province; yield trend changed from negative to positive as the proportion of agricultural land of the total terrestrial land area declined from 28% to below 10%. The availability of honey bee colonies with respect to the growing area of crops benefitting from insect pollination also had a linear, significant impact on turnip rapeseed yield trends: yields tended to decline in provinces, where the supply of managed pollinators with respect to demand was low, but tended to increase in provinces, where the number of honey bee colonies were over 30% of the estimated demand. As neither the landscape complexity (proportion of arable land of total terrestrial land area), nor the number of honey bee colonies for pollination have changed significantly over the past 10–20 years, these factors cannot explain the observed differences in the yield trends of the examined insect-pollinated crops. It appears that only the uptake of neonicotinoid insecticide seed dressing about 15 years ago can explain the crop yield declines in several provinces, and at the national level for turnip rapeseed, most likely via disruption of pollination services by wild pollinators.

A significant portion of world food supply depends on the action of pollinators, which for most crops are primarily domesticated and “wild” bees. Over 75% of pollinator value in the USA accrues through the actions of domesticated honey bees. However, the number of commercial honey bee colonies in the USA has been declining for seven decades due to parasitic arthropods, diseases, and various stresses. The recognition that honey bees, and the crops they service, are vulnerable has accelerated the search for alternative species of bees for pollination of selected crops. Foremost among potential alternatives are native solitary species such as Osmia lignaria propinqua, the “Blue Orchard Bee” (BOB), whose use as a pollinator of almonds, cherries, and apples is increasing. The BOB occurs on public lands managed by the USDA Forest Service, and the USDI Bureau of Land Management and National Park Service. BOBs are targets of “trappers” who place mostly unauthorized “trap-nests” of various designs on public lands. Several problems result from this “Tragedy of the Commons” situation: (1) the unsupervised removal of target bee species from their role in maintaining healthy ecosystems as pollinators of native plants; (2) the removal, as bycatch, of many nontarget species of bees and wasps that also employ trap-nests to rear their progeny; and (3) the shipping of these bees into areas where they do not occur naturally. We argue that unauthorized trap-nesting on public lands should be prohibited and offer several proposals to legalize commercial trap-nesting at a reduced level.

The unique benefits of wild pollinators to the productivity of agricultural crops have become increasingly recognized in recent decades. However, declines in populations of wild pollinator species, largely driven by the conversion of natural habitat to agricultural land and broad-spectrum pesticide use often lead reductions in the provision of pollination services and crop production. With growing evidence that targeted pollinator conservation improves crop yield and/or quality, particularly for pollination specialist crops, efforts are increasing to substitute agriculturally intensive practices with those that alleviate some of the negative impacts of agriculture on pollinators and the pollination services they provide, in part through the provision of suitable pollinator habitat. Further, similarities between the responses of some pollinators and predators to habitat management suggest that efforts to conserve pollinators may also encourage predator densities. We evaluated the effects of one habitat management practice, the addition of cacao fruit husks to a monoculture cacao farm, on the provision of pollination services and the densities of two groups of entomophagous predators. We also evaluated the impacts of cacao fruit husk addition on pollen limitation, by crossing this habitat manipulation with pollen supplementation treatments. The addition of cacao fruit husks increased the number of fruits per tree and along with hand pollination treatments, increased final yields indicating a promotion of the pollination ecosystem service provided by the specialist pollinators, midges. We also found that cacao fruit husk addition increased the densities of two predator groups, spiders and skinks. Further, the conservation of these predators did not inhibit pollination through pollinator capture or deterrence. The findings show that, with moderate habitat management, both pollinator and predator conservation can be compatible goals within a highly specialized plant-pollinator system. The effectiveness of this habitat manipulation may be attributable to the increased availability of alternative habitat and food resources for both pollinators and predators. The results exemplify a win-win relationship between agricultural production and biological conservation, whereby agricultural practices to support vital pollinators and pollination services can increase production as well as support species conservation.

Honey bees play a vital role in the pollination of flowers in many agricultural systems, while providing honey through well managed beekeeping activities. Managed honey bees rely on the provision of pollen and nectar for their survival and productivity. Using data from field plot inventories in natural mistbelt forests, we (1) assessed the diversity and relative importance of honey bee plants, (2) explored the temporal availability of honey bee forage (nectar and pollen resources), and (3) elucidated how plant diversity (bee plant richness and overall plant richness) influenced the amount of forage available (production). A forage value index was defined on the basis of species-specific nectar and pollen values, and expected flowering period. Up to 50% of the overall woody plant richness were found to be honey bee plant species, with varying flowering period. As expected, bee plant richness increased with overall plant richness. Interestingly, bee plants' flowering period was spread widely over a year, although the highest potential of forage supply was observed during the last quarter. We also found that only few honey bee plant species contributed 90 percent of the available forage. Surprisingly, overall plant richness did not significantly influence the bee forage value. Rather, bee plant species richness showed significant and greater effect. The results of this study suggest that mistbelt forests can contribute to increase the spatial and temporal availability of diverse floral resources for managed honey bees. Conservation efforts must be specifically oriented towards honey bee plant species in mistbelt forests to preserve and enhance their potential to help maintain honey bee colonies. The implications for forest management, beekeeping activities and pollination-based agriculture were discussed.

Bumble bees are important pollinators of native flowers and crop plants. Consequently, declines in bumble bee populations in many regions around the globe are cause for concern. We monitored abundance of 22 bumble bee species at multiple elevations over 5 years in Boulder County, Colorado. While no declines in abundance of any species were apparent over the course of the study, such a finding does not preclude prior declines in abundance. This study provides current baseline abundance data that can be used for future monitoring projects.

Insect pollination is an important ecosystem service for the production of many economically valuable crops. Managed honeybees as well as wild bees provide a pollination service for most pollinator dependent crops. Because of intensified agriculture, fragmentation of landscapes, increased use of pesticides, climate change, habitat loss etc. the abundance and species richness of wild bees has decreased and the pollination service is in jeopardy. The decline of pollinators has a direct impact for farmers because the yield of insufficiently pollinated plants decreases. In this chapter we highlight the widespread concerns about pollinator declines and thus the potential loss of pollination services. The public and scientists have realized that the naturally cost-free pollination services like they were available a century ago and not a topic of concern, must today be compensated by providing cost-intensive pollination services in many cases.

Evidence for pollinator declines largely originates from mid-latitude regions in North America and Europe. Geographical heterogeneity in pollinator trends combined with geographical biases in pollinator studies can produce distorted extrapolations and limit understanding of pollinator responses to environmental changes. In contrast with the declines experienced in some well-investigated European and North American regions, honeybees seem to have increased recently in some areas of the Mediterranean Basin. Because honeybees can have negative impacts on wild bees, it was hypothesized that a biome-wide alteration in bee pollinator assemblages may be underway in the Mediterranean Basin involving a reduction in the relative number of wild bees. This hypothesis was tested using published quantitative data on bee pollinators of wild and cultivated plants from studies conducted between 1963 and 2017 in 13 countries fromthe European, African and Asian shores of the Mediterranean Sea. The density of honeybee colonies increased exponentially and wild bees were gradually replaced by honeybees in flowers of wild and cultivated plants. The proportion of wild bees at flowers was four times greater than that of honeybees at the beginning of the period, the proportions of both groups becoming roughly similar 50 years later. The Mediterranean Basin is a world biodiversity hotspot for wild bees and wild bee-pollinated plants, and the ubiquitous rise of honeybees to dominance as pollinators could in the long run undermine the diversity of plants and wild bees in the region.

International audience; Identifying environmental drivers which structure wild bee species assemblages appears essential in a context of worldwide pollinator decline. During a two-year survey, we studied wild bee species assemblages in an 85km 2 protected area dominated by Mediterranean scrubland, the Calanques National Park, located in southern France. Our objectives were (i) to assess the composition of the wild bee species assemblages, and (ii) to explore the effect of a) land cover composition (anthropogenic zone, low scrubland, forest and rocky land cover), b) local plant community composition, and c) honeybee colony density on wild bee species assemblages. On 17 circular 100m 2 plots, we collected 541 specimens belonging to 87 wild bee species. We found that large bee species were significantly influenced by land cover composition within a 1000m radius. More specifically, we observed that the presence of a diversified land cover composition within a 1000m radius maximized large wild bee species richness, whereas large bee abundance and richness were negatively affected by honeybee colony density. Small wild bee species were structured by the local plant community composition within 100m 2 plots and by land cover composition within a 1000m radius. Their occurrence were related to the local composition of plants growing on deep soils in scrublands. The Calanques National Park, which is the only European park located at the interface with a large city and consequently suffers from anthropic pressure, encompasses several types of land cover which are beneficial for a wide diversity of bees. However, we would like to raise awareness among park managers regarding beekeeping activities within this territory which includes diverse types of land cover favorable for wild bee species.

Author(s): Guzman, Aidee; Chase, Marissa; Kremen, Claire | Abstract: Agricultural practices can either contribute to pollinator decline or provide opportunities to support pollinator communities. At the landscape-scale, agriculture can have negative impacts on pollinators, especially pollinators that specialize on limited floral or nesting resources. While increasing floral resources at the field-scale is positive for pollinator communities, little is known about how it affects specialist bees that depend on a specific pollen source (oligoleges). We studied pollinators on small-scale farms that contrasted in crop diversity (monocultures vs. polycultures), embedded in the intensively managed agriculture region of the San Joaquin Valley in California, to understand how wild bee communities and specialist bees would respond to field-scale diversification practices. We used squash (Cucurbita pepo) as our focal crop, because it is visited by both specialist pollinators, “squash bees” in the genera Peponapis and Xenoglossa, and by generalist bees like those in the genera Apis and Agapostemon. We hypothesized that there would be a greater number of squash bees on monoculture farms, which have abundant squash flowers, than on polyculture farms. Contrary to our predictions, we found that increasing the number of non-squash floral resources at the field-scale in agroecosystems supports a greater abundance of squash bees but has no effect on the diversity of bees visiting squash flowers. This pattern of increased abundance was consistent for other wild bees and the total number of bees (i.e., including honey bees), but not for honey bee abundance alone. Further, the abundance of pollinators increased or remained the same on polyculture farms throughout the morning while decreasing on monoculture farms, suggesting that as squash flowers start to close in midmorning, bees on the monocultures go elsewhere because no other floral resources co-occur. However, they remain on the polycultures where other resources co-occur. Thus, on-farm diversification may be an important refuge for both specialist bees and other pollinator species that are vulnerable to floral resource simplification as a result of development, especially through monoculture agriculture.

As pollinator decline is increasingly reported in natural and agricultural environments, cities are perceived as shelters for pollinators because of low pesticide exposure and high floral diversity throughout the year. This has led to the development of environmental policies supporting pollinators in urban areas. However, policies are often restricted to the promotion of honey bee colony installations, which resulted in a strong increase in apiary numbers in cities. Recently, competition for floral resources between wild pollinators and honey bees has been highlighted in semi-natural contexts, but whether urban beekeeping could impact wild pollinators remains unknown. Here, we show that in the city of Paris (France), wild pollinator visitation rates is negatively correlated to honey bee colony densities present in the surrounding (500m – slope = −0.614; p = 0.001 – and 1000m – slope = −0.489; p = 0.005). More particularly, large solitary bees and beetles were significantly affected at 500m (respectively slope = −0.425, p = 0.007 and slope = - 0.671, p = 0.002) and bumblebees were significantly affected at 1000m (slope = - 0.451, p = 0.012). Further, lower interaction evenness in plant-pollinator networks was observed with honey bee colony densities within 1000 meter buffers (slope = −0.487, p = 0.008). Finally, honey bees tended to focus their foraging activity on managed rather than spontaneous plant species (student t-test, p = 0.001) whereas wild pollinators equally visited managed and spontaneous species. We advocate responsible practices mitigating the introduction of high density of hives in urban environments. Future studies are needed to deepen our knowledge about the potential negative interactions between wild and domesticated pollinators.

Widespread reports of declining populations of pollinators have raised concerns that plant populations may be incurring increasing shortfalls in pollination, but few studies have measured pollination deficits over enough seasons to detect such changes. I have conducted pollen-supplementation experiments in a wild population of the glacier lily (Erythronium grandiflorum, Liliaceae) from 1993 to 2018. Pollination deficits were estimated by comparing the fruit set of hand-pollinated, single-flowered plants to that of open-pollinated controls. For a subset of years, seed set data were also available. A previous publication reported a significant deterioration of pollination in this population from 1993 to 2009, and suggested phenological dislocation as a possible cause. That deterioration is no longer evident in the longer-term data set. Very long time series may be necessary to detect temporal trends in pollination service. This population consistently experiences stronger pollination deficits before its flowering peak than after. This heterogeneity suggests caution in characterizing a population as pollination-limited or not, even within a single season.

Pathogens are one of the factors driving pollinator declines. Diet can play an important role in mediating pollinator health and resistance to pathogens. Sunflower pollen ( Helianthus annuus ) dramatically reduced a gut pathogen ( Crithidia bombi ) of Bombus impatiens previously, but the breadth of this effect was unknown. We tested whether pollen from nine H. annuus cultivars, four wild H. annuus populations, H. petiolarus, H. argophyllus and two Solidago spp., reduced Crithidia in B. impatiens compared to mixed wildflower pollen and buckwheat pollen ( Fagopyrum esculentum ) as controls. We also compared hand- and honeybee-collected pollen (which contains nectar) to assess whether diet effects on pathogens were due to pollen or nectar. All Helianthus and Solidago pollen reduced Crithidia by 20–40-fold compared to buckwheat pollen, and all but three taxa reduced Crithidia compared to wildflower pollen. We found no consistent differences between hand- and bee-collected pollen, suggesting that pollen alone can reduce Crithidia infection. Our results indicate an important role of pollen diet for bee health and potentially broad options within the Asteraceae for pollinator plantings to manage bee disease.

Industrial agriculture (IA) has been recognized among the main drivers of biodiversity loss, climate change, and native pollinator decline. Here we summarize the known negative effects of IA on pollinator biodiversity and illustrate these problems by considering the case of Chile, a “world biodiversity hotspot” (WBH) where food exports account for a considerable share of the economy in this country. Most of Chile’s WBH area is currently being replaced by IA at a fast pace, threatening local biodiversity. We present an agroecological strategy for sustainable food production and pollinator conservation in food‐producing WBHs. In this we recognize native pollinators as internal inputs that cannot be replaced by IA technological packages and support the development of agroecological and biodiversity restorative practices to protect biodiversity. We suggest four fundamental pillars for food production change based on: (1) sharing the land, restoring and protecting; (2) ecological intensification; (3) localized knowledge, research, and technological devel-opment; and (4) territorial planning and implementation of socio‐agroecological policies. This approach does not need modification of native pollination services that sustain the world with food and basic subsistence goods, but a paradigm changes where the interdependency of nature and human wellbeing must be recognized for ensuring the world’s food security and sovereignty., SCOPUS: re.j, info:eu-repo/semantics/published

Conservation initiatives carried out by informed, enthusiastic participants can be highly effective in conserving biodiversity, including the biodiversity of insect pollinators. It is important to understand how the public perceives insect pollinators, as it may have implications for the success of conservation initiatives and the initiation of protective policies. We used Ireland as a case study to determine how insect pollinators, pollination services, and pollinator decline are currently perceived by the public in an effort to understand the links between public knowledge and perceptions of pollinators, the implementation of insect pollinator conservation actions, and engagement with existing conservation initiatives. We designed a survey that was available to the Irish public for three months, distributed primarily through social media, and was taken by 613 participants. Findings indicate that people are aware of insect pollinator decline and of the main causes and are willing to participate in pollinator conservation, but that there are still some key gaps in the overall understanding of pollinators, their role, and their ecology. Most participants were able to identify charismatic pollinators, such as bumblebees and honeybees, and were aware of their importance to the pollination of crops and wildflowers. Fewer participants were able to identify other common pollinators, such as flies and solitary bees, and many were not aware of the importance of non-bee pollinators to pollination. While engagement with Ireland's national pollinator conservation initiative was linked with increased knowledge of Irish pollinators, less than 50 % of participants, particularly urban dwellers and those without post-secondary education, had heard of the initiative. To ensure a more inclusive approach to insect pollinator conservation, we recommend that future engagement measures highlight the importance of underrepresented non-bee insects to pollination services and target certain demographic groups that are currently not as actively engaged in pollinator conservation as others.

Pollination by insects is key for the productivity of many fruit and non-graminous seed crops, but little is known about the response of pollinators to landscapes dominated by small-holder agriculture. Here we assess the relationships between landscape context, pollinator communities (density and diversity) and pollination of oilseed rape in 18 landscapes with proportions of small-holder farming ranging from 10% to 70% in southern China. To quantify the contribution of pollinators to oilseed rape yield, we manipulated pollinator access in a focal oilseed rape field in each landscape using open and closed cages. The pollinator communities in the focal fields were sampled using pan traps. The abundance of wild pollinators increased significantly with the proportion of cultivated land, but the diversity of the wild pollinator communities declined. The responses of pollinator abundance and diversity to cultivated land were best explained at scales of around 1000 m. The abundance of the unmanaged honey bee Apis cerana was positively associated with the proportion of cultivated land, whereas the abundance of the managed A. mellifera was not. A pollination services index (PSI) was calculated by comparing the reproductive investment in seeds between plants with or without pollinator access. PSI was positively correlated with wild pollinator abundance, but not with the abundance of honeybee species. PSI was also not significantly correlated with the area proportion of cultivated land. Our results indicate that crop dominated landscapes with numerous small fields supported an abundant, but relatively species poor bee community that delivered pollination services to oilseed rape. Conservation of (semi-)natural habitats, however, is important for maintaining the diversity of wild pollinators.

Summary Whilst most studies reviewing the reliance of global agriculture on insect pollination advocate increasing the ‘supply’ of pollinators (wild or managed) to improve crop yields, there has been little focus on altering a crop's ‘demand’ for pollinators.Parthenocarpy (fruit set in the absence of fertilization) is a trait which can increase fruit quantity and quality from pollinator‐dependent crops by removing the need for pollination.Here we present a meta‐analysis of studies examining the extent and effectiveness of parthenocarpy‐promoting techniques (genetic modification, hormone application and selective breeding) currently being used commercially, or experimentally, on pollinator‐dependent crops in different test environments (no pollination, hand pollination, open pollination).All techniques significantly increased fruit quantity and quality in 18 pollinator‐dependent crop species (not including seed and nut crops as parthenocarpy causes seedlessness). The degree to which plants experienced pollen limitation in the different test environments could not be ascertained, so the absolute effect of parthenocarpy relative to optimal pollination could not be determined. Synthesis and applications. Parthenocarpy has the potential to lower a crop's demand for pollinators, whilst extending current geographic and climatic ranges of production. Thus, growers may wish to use parthenocarpic crop plants, in combination with other environmentally considerate practices, to improve food security and their economic prospects., Parthenocarpy has the potential to lower a crop's demand for pollinators, whilst extending current geographic and climatic ranges of production. Thus, growers may wish to use parthenocarpic crop plants, in combination with other environmentally considerate practices, to improve food security and their economic prospects.

Summary The effect of climate change on wild bee communities is of major concern since the decline of bee species could imperil the provision of pollination services. Additionally, habitat loss and fragmentation are major threats to wild bee populations, but improvements to the landscape structure could also improve the general conditions for wild bees. However, potential interactive effects of climate change and landscape structure on wild bee communities remain unknown. In this study, we assessed the potential of semi-natural areas to maintain robust communities under changing weather conditions. We used bee monitoring data from six 4 × 4 km field sites across Germany. Almost 30 000 bee specimens were collected from 2010 to 2012 in 16 local communities per site at six sampling occasions per year. Following a multimodel inference approach, we identified the most important weather and landscape variables as well as interaction terms that affect wild bee species richness and total abundance. Correcting for overall phenology, we found a strong negative relationship between bee species richness and temperature, indicating that future increasing temperatures will lead to a decrease in species richness. However, a high proportion of semi-natural habitats can considerably decrease the detrimental effect of warmer temperatures on bee species richness and abundance. Synthesis and applications. Semi-natural areas and green infrastructure elements within agricultural landscapes become even more important under changing temperature conditions to mitigate the negative effects of increasing temperatures on wild bee species richness and total abundance. This has important implications for conservation decision making, suggesting that maintaining or restoring a fair amount of semi-natural areas could serve as a countermeasure against climate change for wild bees.

Year round availability of foraging resources is the key for ensuring diversity and abundance of pollinators, which is crucial for maintaining production of pollinator dependent crops. However, most often, this aspect remains ignored while defining management needs of crop pollinators. Realizing this knowledge gap, extensive surveys were conducted in Nana Kosi watershed of Kumaun west Himalaya, India, and monthly datasets on diversity of foraging plants generated. Among various forage species Cirsium verutum (D. Don) Sprengel, was found as important forage that attracts diverse pollinators and supports to maintain viable population of pollinators during lean period with minimum resource availability. The study recommends C. verutum as an important plant species for pollination management and ensuring sustained flow of pollination services in agricultural landscapes.

This paper considers the potential for beekeepers' knowledges to be incorporated into participatory policy processes addressing current challenges to pollinator health. Pollinator decline is a serious issue for future food security and wider environmental resilience, with important implications for rural land use governance. The precipitous decline in global pollinator populations over recent years has resulted in a range of government initiatives to tackle the causes identified. In the UK this includes a National Pollinator Strategy in England and Pollinator Action Plan in Wales. These plans are notable for their introduction of a more participatory approach, incorporating ‘lay-knowledge’ and citizen science from beekeeping practitioners alongside scientific data. This paper presents evidence from interviews and participant observation with key stakeholders within the beekeeping community in the UK, alongside archival material from the Bee Farmers' Association, to assess the knowledge controversies arising from this strategy. Specifically, the paper considers the distinction of beekeepers' knowledges from typically acknowledged expert sources, whilst also reflecting upon aspects of plurality and tension within the beekeeping community. The paper concludes by outlining some areas of contestation between beekeepers and the wider policy and scientific community, which could impact on the future success of more participatory forums. This includes, firstly, evidence of hierarchies and exclusions in the forms of knowledge considered, when insights from professional scientists are privileged above those from beekeepers and when some beekeepers knowledges are given more credit than others. Secondly, we consider limitations resulting from policy makers' evidence requirements for peer-reviewed science, which can further exacerbate the exclusion of beekeepers' insights and lead to scenarios whereby policy only engages with a narrow set of criteria that may not be beneficial when advanced in isolation from the broader system changes. Finally, aspects of policy clash are outlined between pollinator conservation and wider agricultural strategies that seek to maintain a productivist agenda.

Over the past decades, both wild and domesticated insect pollinators are in dramatic decline, which puts at stake the existence of species, ecosystem resilience and global food security. Globally, 87 of major food crops depend on animal pollination. Together these account for 35 % of the world food production volume. Pollinator mediated crops are indispensable for essential micronutrients in the human diet. Many ornamental plants as well as crops for fibre, fodder, biofuels, timber and phytopharmaceuticals also depend on insect pollinators. This article aims to map the current situation of pollinators worldwide, with a focus on the critical role of pollinators in the human food chain and ecosystem sustainability, their intrinsic and extrinsic value, as well as the causes of their declines and the interventions needed to conserve them, in order to develop an argument for the importance of conserving and restoring pollinator populations and diversity. The present pollinator crisis threatens global and local food security, can worsen the problems of hidden hunger, erodes ecosystem resilience, and can destabilise ecosystems that form our life support system. An integrated approach that simultaneously addresses the key drivers is needed. This includes creation and restoration of floral and nesting resources, a global phase out of prophylactic use of neonicotinoids and fipronil, improvement of test protocols in authorisation of agrochemicals, and restoration and maintenance of independence in regulatory science. The authors argue that an international treaty for global pollinator stewardship and pollinator ecosystem restoration should be initiated in order to systemically counteract the current crisis.

Recent efforts to evaluate the contribution of neonicotinoid insecticides to worldwide pollinator declines have focused on honey bees and the chronic levels of exposure experienced when foraging on crops grown from neonicotinoid-treated seeds. However, few studies address non-crop plants as a potential route of pollinator exposure to neonicotinoid and other insecticides. Here we show that pollen collected by honey bee foragers in maize- and soybean-dominated landscapes is contaminated throughout the growing season with multiple agricultural pesticides, including the neonicotinoids used as seed treatments. Notably, however, the highest levels of contamination in pollen are pyrethroid insecticides targeting mosquitoes and other nuisance pests. Furthermore, pollen from crop plants represents only a tiny fraction of the total diversity of pollen resources used by honey bees in these landscapes, with the principle sources of pollen originating from non-cultivated plants. These findings provide fundamental information about the foraging habits of honey bees in these landscapes., The extent to which non-crop plants may be contaminated by insecticides is not known. Here, the authors show that pollen collected by honey bees living in areas of intensive maize production is contaminated by a wide range of pesticides throughout the growing season, with the principle pollen source being non-crop plants.

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.

Pollinating insects are in decline throughout the world, driven by a combination of factors including the loss of forage resources. The maize (Zea mays L.)– and soybean [Glycine max (L.) Merr.]–dominated agriculture of the Central and Midwestern United States produces a landscape relatively devoid of nectar and pollen resources. Introducing specialty oilseeds into current crop rotations could provide abundant floral resources for pollinating insects as well as a high-value crop for growers. We investigated the nectar sugar resources and insect visitation throughout flower anthesis of nine specialty oilseed crops in west-central Minnesota and eastern South Dakota during the 2013 and 2014 growing seasons. Total sugar produced over anthesis (TS) was highest for echium (Echium plantagineum L.) at 472 kg ha⁻¹. Canola (Brassica napus L.), crambe (Crambe abyssinica Hochst.), echium, borage (Borago officinalis L.), and cuphea (Cuphea viscosissima Jacq. × Cuphea lanceolata W. T. Aiton) produced enough sugar in one hectare to supply the annual sugar needs of a least one managed honey bee (Apis mellifera L.) colony. Pollinators visited flowers of all crops, with as many as 90 insects min⁻¹ observed. Our study is unique as we measured nectar sugar production, flower density, and insect visitation throughout anthesis for multiple specialty oilseed crops, providing a seasonwide perspective of the flux of nectar resources for pollinators. Adding specialty oilseed crops into current crop rotations could aid in reversing pollinator decline by providing forage resources that are lacking in the current agricultural landscape.

Honey bees are the most important managed pollinator worldwide and are vital to the success of modern agriculture. Native, wild bees are also important pollinators in both natural and agricultural systems, and are highly sensitive to habitat in the surrounding landscape. Few studies, however, have considered how managed honey bees, and their effectiveness as crop pollinators, may be influenced by variation in the surrounding landscape. If honey bees are influenced by areas outside of the crop fields in which they are placed, their effectiveness as crop pollinators could be diminished. The goal of this study was to determine whether the relationship between honey bee hive density and crop yield varies with the composition of the surrounding landscape. We collected historical (2000–2011) data on yield and honey bee hive stocking density from 38 commercial cranberry growers in central Wisconsin. Using mixed-model regression analyses we found that cranberry yield was strongly, positively correlated with hive density but this effect diminished as the proportion of the surrounding landscape in woodland increased. Thus, at cranberry marshes in low-woodland landscapes (e.g.

Agricultural intensification is a widespread driver of global pollinator decline that subsequently threatens the associated provisioning of ecosystem services. In North America's Prairie Pothole Region, wetlands surrounded by grassland were once abundant on the landscape, but now generally exist within a matrix of agriculture. We assessed whether restoration of these grassland-wetland complexes from cropland could be used as a potential tool for mitigating wild bee decline, using a 25-year restoration chronosequence. We also monitored the development of bee nesting and food resources to better establish the mechanisms that drive return to a restored habitat. Our objective was to assess whether restoration of grassland-wetland complexes can return bee communities to a reference state (i.e. remnant native grassland-wetland habitats), and to ascertain the timeline over which these changes occur. We found bee diversity increased following restoration and approximated reference sites after 1–4 years, while the diversity of non-Bombus species analyzed separately resembled reference sites after around 5–10 years. Floral diversity also increased following restoration from cropland but remained slightly lower than reference sites through time. Changes to bee species composition were driven more by floral species composition than time since restoration. Our results suggest that restored grassland-wetland complexes are able to provide food and nesting resources to bees within agriculturally dominated landscapes, and that restoration can recover wild bee communities to a reference state. On a broader scale, they underscore the utility of retaining patches of non-cropped and restored land within agroecosystems as a pathway for mitigating pollinator decline.

Insect pollination is a globally important ecosystem service, contributing to crop yields, production stability and the maintenance of wild plant populations. Ironically, agriculture is one of the major global drivers of wild insect pollinator decline. At the same time, increasing human population is driving ever greater demands on crop production. Agroforestry (AF) – a more diverse farming system integrating woody and agricultural crops – can theoretically reconcile high production with provision of ecosystem services such as pollination. However, empirical studies of pollination in temperate AF systems are almost entirely lacking. We sought to fill this knowledge gap by assessing whether AF can provide increased pollination service compared to monoculture (MC) systems. Six UK sites, each containing an AF and a MC system, were studied over three years. Wild pollinator abundance and diversity were used as proxies for the magnitude and stability, respectively, of the pollinating community. We also directly measured pollination service as seed set in a wild plant phytometer. We found that temperate AF systems can provide greater pollination service than MC: AF treatments had twice as many solitary bees and hoverflies, and in arable systems 2.4 times more bumblebees, than MC treatments. AF also had 4.5 times more seed set compared to MC in one of the two years. At 40% of site-by-year sampling units, species richness of solitary bees was on average 10.5 times higher in AF treatments. This provides evidence in favour of the expectation that AF systems can support higher pollinator richness, and therefore greater potential stability, of pollination service. For the other sampling units, and for bumblebees (Bombus spp.), there was no treatment effect on species richness. Further work is needed to investigate the effect of AF on species richness and its mechanistic basis. Our results also highlight the importance of AF system design, ensuring that ecosystem services outcomes are explicitly planned at the design stage. We suggest that AF has a role to play in improving the sustainability of modern farming and in mitigating the ongoing loss of wild pollinating insects, which is strongly driven by prevailing agricultural practices.

Agricultural pesticides are key contributors to pollinator decline worldwide. However, methods for quantifying impacts associated with pollinator exposure to pesticides are currently missing in comparative risk screening, chemical substitution and prioritization, and life cycle impact assessment methods. To address this gap, we developed a method for quantifying pesticide field exposure and ecotoxicity effects of honey bees as most economically important pollinator species worldwide. We defined bee intake and dermal contact fractions representing respectively oral and dermal exposure per unit mass applied, and tested our model on two pesticides applied to oilseed rape. Our results show that exposure varies between types of forager bees, with highest dermal contact fraction of 59 ppm in nectar foragers for lambda-cyhalothrin (insecticide), and highest oral intake fractions of 32 and 190 ppm in nectar foragers for boscalid (fungicide) and lambda-cyhalothrin, respectively. Hive oral exposure is up to 115 times higher than forager oral exposure. Combining exposure with effect estimates yields impacts, which are three orders of magnitude higher for the insecticide. Overall, nectar foragers are the most affected forager type for both pesticides, dominated by oral exposure. Our framework constitutes an important step toward integrating pollinator impacts in chemical substitution and life cycle impact assessment, and should be expanded to cover all relevant pesticide-crop combinations. Keywords: Honey bees, Pesticide residues, Exposure modelling, Chemical prioritization, Chemical substitution, Life cycle impact assessment

Background and Aims To predict the evolutionary consequences of pollinator declines, we need to understand the evolution of delayed autonomous self-pollination, which is expected to evolve as a mechanism of reproductive assurance when cross-pollination becomes unreliable. This involves estimating the costs of increased levels of selfing as well as those associated with floral senescence. Methods We studied the mechanisms and costs of delayed self-pollination in the mixed-mating vine Dalechampia scandens (Euphorbiaceae) by first assessing among-population variation in herkogamy and dichogamy, which together determine the rate and timing of autonomous self-pollination. We then tested whether floral longevity responds plastically to delayed pollination. Finally, we assessed the costs of delayed self-pollination in terms of seed number and size, explicitly separating inbreeding depression from effects of floral senescence. Key Results Herkogamy varied extensively, while variation in dichogamy was more limited. Unpollinated blossoms increased their longevity, but seed quantity and quality decreased with increasing delays in pollination, independently of inbreeding depression. Conclusions In D. scandens, earlier autonomous selfing is facilitated by reduced herkogamy rather than reduced protogyny, providing reproductive assurance while maintaining the possibility for outcrossing events. Effective early autonomous self-pollination may evolve under reduced cross-pollination reliability in response to costs associated with floral senescence.

Insect pollinators contribute to agricultural crop yield and beekeeping provides a major source of livelihoods for farmers in Nigeria. This study developed two survey questionnaires and collected data from beekeepers, researchers and government officials to generate quantitative indicators for the purpose of description as a guide to action. Evaluation and characterization of colony bee loses by beekeepers were assessed. The surveys conducted between October 2015 and March 2016 consisted of questions related to: the importance of pollinators, including managed honeybees (Apis mellifera), in agriculture and observations on factors associated with pollinator declines; and management of bee mortality. Evaluation and characterization of colony bee loses by beekeepers in Osun State was conducted. Responses were received from 31 beekeepers and 20 policy makers and researchers. 81% of beekeepers reported a reduction in number of colonies. The results inform policy action on pollinator benefits for increasing crop yield and helping smallholder farmers adapt to a decline in insect pollinators. This study emphasizes pollination and insect pollinators as drivers of agricultural crop production with a view to providing guidance for sustainable management of pollinators and achievement of green growth objectives.

Conserving and restoring semi-natural habitat, i.e. enhancing landscape complexity, is one of the main strategies to mitigate pollinator decline in agricultural landscapes. However, we still have limited understanding of how landscape complexity shapes pollinator communities in both crop and non-crop habitat, and whether pollinator responses to landscape complexity vary with their association with mass-flowering crops. Here, we surveyed pollinator communities on mass-flowering leek crops and in nearby semi-natural habitat in landscapes of varying complexity. Surveys were done before and during crop bloom and distinguished between pollinators that visit the crop frequently (dominant), occasionally (opportunistic), or not at all (non-crop). Forty-seven per cent of the species in the wider landscape were also observed on leek flowers. Crop pollinator richness increased with local pollinator community size and increasing landscape complexity, but relationships were stronger for opportunistic than for dominant crop pollinators. Relationships between pollinator richness in semi-natural habitats and landscape complexity differed between groups with the most pronounced positive effects on non-crop pollinators. Our results indicate that while dominant crop pollinators are core components of crop pollinator communities in all agricultural landscapes, opportunistic crop pollinators largely determine species-richness responses and complex landscapes are local hotspots for both biodiversity conservation and potential ecosystem service provision.

There is a growing concern about the status and trends of animal pollinators worldwide. Pollinators provide a key service to both wild plants and crops by mediating their reproduction, so pollinator conservation is of fundamental importance to conservation and to food production. Understanding of the extent of pollinator declines is constrained by the paucity of accessible data, which leads to geographically- and taxonomically-biased assessments. In addition, land conversion to agriculture and intensive agricultural management are two of the main threats to pollinators. This is paradoxical, as crop production depends on pollinators to maximize productivity. There is a need to reconcile conservation and ecosystem service provision in agroecosystems. These challenges require coordinated transdisciplinary research infrastructures. Specifically, we need better research infrastructures to (i) describe pollinator decline patterns worldwide, (ii) monitor current pollinator trends, and (iii) understand how to enhance pollinator numbers and pollination in agroecosystems. This can be achieved, first, by redoubling the efforts to make historical data on species occurrences, interactions and traits openly available and easy to integrate across databases. Second, by empowering citizen science to monitor key pollinator species in a coordinated way and standardizing, consolidating and integrating long term collection protocols both in natural and agricultural areas. Finally, there is a need to develop multi-actor, localised research infrastructures allowing integration of social, economic and ecological approaches in agriculture. We illustrate how decentralized infrastructures can accelerate the process of co-producing research and integrating data collection across scientists, managers, members of the public, farmers and disciplines. The time is ripe to harness the power of coordinated research infrastructures to understand and mitigate pollinator declines.

Imagine I told you there was a product that could dramatically reduce the incidence of four of the top seven causes of death in the United States,1 lift thousands of Americans out of poverty, and fight climate change—all while slowing the growth of marine dead zones and reversing pollinator decline.

Pollinator Decline One aspect of climate change is an increasing number of days with extreme heat. Soroye et al. analyzed a large dataset of bumble bee occurrences across North America and Europe and found that an increasing frequency of unusually hot days is increasing local extinction rates, reducing colonization and site occupancy, and decreasing species richness within a region, independent of land-use change or condition (see the Perspective by Bridle and van Rensburg). As average temperatures continue to rise, bumble bees may be faced with an untenable increase in frequency of extreme temperatures. Science , this issue p. [685][1]; see also p. [626][2] [1]: /lookup/doi/10.1126/science.aax8591 [2]: /lookup/doi/10.1126/science.aba6432

Bumble bee pollinators can be exposed to pathogens when foraging on flowers previously visited by infected individuals. Infectious cells may be deposited in floral nectar, providing a site for pathogens to interact with nectar secondary compounds prior to infecting bees. Some nectar secondary compounds can reduce pathogen counts in infected bumble bees, but we know less about how exposure to these compounds directly affects pathogens prior to being ingested by their host. We exposed the trypanosomatid gut pathogen, Crithidia bombi (Lipa & Triggiani 1988) (Trypanosomatida: Trypanosomatidae), to six different compounds found in nectar (aucubin, catalpol, nicotine, thymol, anabasine, and citric acid) for 1-h prior to ingestion by Bombus impatiens (Cresson 1863) (Hymenoptera: Apidae) workers that were then reared for 1 wk on a control diet. All of these compounds except citric acid reduce pathogen levels when consumed in hosts after infection, and citric acid is a common preservative found in citrus fruits and some honeys. We found that both citric acid and aucubin reduced Crithidia cell counts compared with controls. However, catalpol, nicotine, thymol, and anabasine did not have significant effects on Crithidia levels. These results suggest that Crithidia exposure in some floral nectars may reduce cell viability, resulting in a lower risk to visiting pollinators, but this effect may not be widespread across all flowering species.

Non-pathogenic microbes can provide multiple benefits to their hosts, including pathogen inhibition. Gut symbionts can augment resistance to pathogens by stimulating host immune responses, competing for space and nutrients, or producing antimicrobial metabolites. The gut microbiota of social bees, which pollinate many crops and wildflowers, has demonstrated benefits against diverse infections and might help protect against pathogen-related declines. The bumble bee gut microbiota, consisting chiefly of five taxa common to corbiculate bees, has been shown to enhance resistance to the trypanosomatid parasiteCrithidia bombi. Specifically, infection intensity was negatively correlated with abundance ofLactobacillus“Firm-5” bacteria. However, the mechanism underlying this relationship remains unknown. We tested the hypothesis that the Firm-5 bacteriumLactobacillus bombicola, which produces lactic acid, inhibitsC. bombivia a pH-mediated effect.Consistent with our hypothesis,Lactobacillus bombicolaspent medium inhibitedC. bombigrowth via a reduction in pH that was both necessary and sufficient for inhibition. Inhibition of all parasite strains occurred within the pH range previously observed in honey bee guts, though sensitivity to acidity varied among parasite strains. Spent medium was slightly more potent than HCl, D-, and L-lactic acids for a given pH, suggesting that other metabolites also contribute to inhibitory effects. Our results implicate symbiont-mediated reduction in gut pH as a key determinant of trypanosomatid infection in bees. Future investigation intoin vivoeffects of gut microbial composition on pH and infection intensity would help determine the relevance of these findings for bees threatened by trypanosomatids.ImportancePollinators such as honey and bumble bees provide services to plants in agricultural and wild ecosystems, but both wild and managed bees are threatened by infection-related declines. The symbiotic gut microbiota of bees provides a naturally occurring defense against infection. For example, the bumble bee microbiota reduces infection with trypanosomatid parasites, but how inhibition occurs remains unknown. We show that the acidic spent medium from a common bumble bee gut symbiont,Lactobacillus bombicola,inhibitsin vitrogrowth of the trypanosomatid gut parasite,Crithidia bombi.The acidity of the spent medium was both necessary and sufficient for parasite inhibition. Inhibitory pH values were within the range documented in honey bee guts, suggesting that pH-mediated parasite inhibition is plausible in live bees. Results suggest that production of acids by sugar-fermenting symbionts confers pH-mediated resistance to infection in bees, whereas depletion of core microbiota could result in low-acid conditions that favor parasite growth.

Honey bees forage across a large area, continually scouting the local landscape for ephemeral food resources. Beekeepers often rely on flowering plants in and around irrigated farmland to maintain their colonies during dry seasons, despite the potential risk of pesticide exposure. Recent declines in pollinator abundance and diversity have focused attention on the role of pesticides and their effects on honey bee health. This investigation examined two types of landscapes within a two-mile (3.2 km) radius of honey bee colonies: an intensive agricultural setting and a rural setting without intensive agriculture. More than 10,000 acres of agricultural land was surveyed to quantify the area of cultivated crops and the area treated with pesticides, including seed treatments and foliar applications of insecticides. Samples of honey, bee bread (stored pollen), beeswax, and adult bees were collected from hives in both landscape types and screened for pesticide residues to determine if foraging bees were transporting pesticides to hives. Some samples of bee bread and honey did contain pesticide residues, but these were below known lethal dose (LD50) levels for honey bees. Beeswax samples contained the highest levels of contamination, but most were still relatively low. Samples were screened for 174 common agricultural pesticides and metabolites, but only 26 compounds were detected during the two-year study. These included one defoliant, one insect growth regulator, five herbicides, six fungicides, six insecticides never used in beekeeping, and five insecticides/miticides and their metabolites, which are used in beekeeping and for various other agricultural purposes, as well as two miticides exclusively used by beekeepers to control Varroa destructor. Bee colonies foraging in agricultural landscapes are potentially exposed to numerous pesticide applications. While the residues detected in this study did not pose an acute lethal risk to adult honey bees, this study did not measure sublethal effects on bee colony health or performance, which merit further investigation.

Pollinators have been declining worldwide, affecting plants that depend on them for pollination. In order to persist in the presence of declining pollinators, plants may evolve floral traits that facilitate either pollinator-mediated outcrossing or autonomous self pollination. Whether outcrossing or selfing traits are selected can also be affected by herbivory. To determine whether herbivores can affect pollinator-mediated selection for outcrossing or selfing in the mixed-mating plant Impatiens capensis, I measured phenotypic selection on plants in three treatments: ambient pollinator access and ambient herbivory (P/H), reduced pollinator access and ambient herbivory (–P/H), and reduced pollinator access and increased herbivory (–P/+H). When pollinator access was reduced, plants experienced selection for a floral trait that facilitates autonomous selfing. This pollinator-mediated selection was intensified by herbivory. Plant populations may respond to selection by shifting their mating system towards selfing, which may affect their ability to adapt to environmental stressors in the future.

With global biodiversity in decline, there is now an urgent requirement to take ameliorative action for endangered species in the form of re-introductions. For the highly diverse orchid family, many species face imminent extinction. Successful re-introductions that result in self-sustaining populations require not only an understanding of existing threats, but an in-depth understanding of species ecology. Increasingly, translocations, ranging from re-introductions to assisted colonisation, are being adopted as recovery actions. Do these translocations mitigate threatening processes and account for the two key ecological attributes for orchid survival; pollinator and mycorrhizal presence? Here, we conducted a literature review identifying the known threats to orchid survival and their necessary mitigation strategies. Next, we evaluated the success of 74 published international orchid translocations on 66 species against a consideration of orchid ecological attributes. Lastly, we empirically tested an additional 22 previously unpublished re-introductions on 12 species undertaken since 2007 against a re-introduction process that accounts for identified threats and orchid ecological attributes. We identified habitat destruction, weed invasion, herbivory, illegal collection, pollinator decline, pathogens and climate change as critical threats to orchid survival. In our global review based on published translocations, the average survival rate, 1-year post translocation was 66 % yet only 2.8 % of studies reported natural recruitment in field sites. Although survival of translocated orchids is clearly being achieved, these programmes did not relate orchid growth and development to key ecological requirements of orchid population resilience, pollinator and mycorrhizal ecology. Ensuring pollinator and mycorrhizal presence shows that these two factors alone are key factors influencing survival and persistence in an Australian review of 22 previously unpublished orchid re-introductions. In the Australian review flowering in the year following, out-planting was observed for 81 % of the re-introductions with seed set occurring in 63 % of re-introductions within the length of the study. Recruitment was observed in 18 % of the Australian re-introduced populations indicating a degree of population resilience. As orchid re-introductions will be a major strategy for wild orchid conservation in the future, we present a framework for orchid re-introductions, including criteria for success. We recommend symbiotic propagation and, for specialised pollination syndromes, the study of pollinator interactions prior to site selection and re-introduction of plants.

Successful conservation of pollination services depends upon an understanding of the processes that influence pollinator diversity within the landscape, as well as the relationship between pollinator community composition and the provision of services. In this study, the influence of landscape simplification on the composition of pollinator communities and the provisioning of pollination services to cultivated strawberry was evaluated (Fragaria × ananassa). Additionally the relative pollination efficiency for the five most common bee genera visiting strawberry flowers was measured. Pollinators were collected during bloom with pan traps on 14 commercial farms all growing the same strawberry variety in the Finger Lakes Region, NY, USA. The farms were chosen to represent a gradient in the proportion of agricultural land uses in the surrounding landscape from 0.09 to 0.60. Landscapes with greater proportions of agricultural area had lower pollinator abundances and species richness. While yield was positively correlated with pollinator abundance, species richness had little effect on the level of pollination services. This conclusion was supported by the finding that visitor identity did not explain pollination efficiency in strawberry. Our results show that a high proportion of agricultural land in the landscape negatively impacts wild pollinators and pollination services to strawberry.

High levels of honey bee colony losses were recently reported from Canada, China, Europe, Israel, Turkey and the United States, raising concerns of a global pollinator decline and questioning current land use practices, in particular intense agricultural cropping systems. Sixty-seven crops (data from the years 2010–2012) and 66 mid-term stable land cover classes (data from 2007) were analysed for statistical relationships with the honey bee colony losses experienced over the winters 2010/11–2012/13 in Luxembourg (Western Europe). The area covered by each land cover class, the shortest distance between each land cover class and the respective apiary, the number of plots covered by each land use class and the size of the biggest plot of each land cover class within radii of 2 km and 5 km around 166 apiaries (2010), 184 apiaries (2011) and 188 apiaries (2012) were tested for correlations with honey bee colony losses (% per apiary) experienced in the winter following the season when the crops were grown. Artificial water bodies, open urban areas, large industrial facilities including heavy industry, railways and associated installations, buildings and installations with socio-cultural purpose, camping-, sports-, playgrounds, golf courts, oilseed crops other than oilseed rape like sunflower or linseed, some spring cereals and former forest clearcuts or windthrows were the land cover classes most frequently associated with high honey bee colony losses. Grain maize, mixed forest and mixed coniferous forest were the land cover classes most frequently associated with low honey bee colony losses. The present data suggest that land covers related to transport, industry and leisure may have made a more substantial contribution to winter honey bee colony losses in developed countries than anticipated so far. Recommendations for the positioning of apiaries are discussed.

International audience; Growing human footprint on the environment rapidly modifies the living conditions of natural populations. This could lead to phenotypic changes through both plasticity and evolution. Therefore, distinguishing the role of evolution in the phenotypic response to global change is a major challenge. In this study, we benefited from past and recent seeds from a population of the annual self-compatible weed Adonis annua. Seeds were sampled from the same locality at an 18 years interval and close to a region where reduction of bee pollinators’ density has been reported. We used a common garden experiment to investigate evolutionary changes, between the old (1992) and the recent (2010) sample, for some reproductive traits expected to be under selection in the context of climate warming and pollinator decline. Plants of the recent sample flowered earlier, had larger flowers, but also evolved a shorter floral longevity. The capacity of plants to reproduce autonomously (autonomous selfing) was similar in the two samples. These results are consistent with adaptation of flowering phenology to climate warming and in part consistent with the evolution of increased pollinator attraction under pollinator decline. Together with other recent studies, this study provides evidence that short-term evolution is a frequent phenomenon accompanying global change.

As pollinator decline continues, the need to provide high value forage for insects increases. Finding agricultural crops to diversify the landscape and provide forage is one way to improve pollinator health. Three winter industrial oilseed crops (pennycress, winter camelina, and winter canola) were grown in Morris, Minnesota, and Brookings, South Dakota, during the winters of 2012–2013 and 2013–2014. Each of the three crops has pollinator-friendly flowers and value as winter cover crops and cash seed crops. The crops were evaluated for pollinator use, nectar production, green cover, and yield. Pennycress, camelina, and canola flowers had high insect activity with maximum visitation rates of 67 ± 11.5, 22 ± 3.1, and 61 ± 6.8 insects min−1. Cumulative nectar produced by pennycress, camelina, and canola was 13, 100, and 82 kg of sugar ha−1 during the 2014 anthesis period, providing an important food resource to pollinators during early spring when there is little else on the agricultural landscape that is blooming. Green cover in early spring ranged from 0 to 60% amongst the three crops, with camelina providing >25% green cover across all four site-years. Maximum seed yields were 1.1 ± 0.04, 1.4 ± 0.05, and 1.2 ± 0.19 Mg ha−1 for pennycress, camelina, and canola, respectively, which are economically viable harvests. Of the three crops, winter camelina provided the highest combined agroecosystem value through pollinator resources, green cover, and seed yields.