Emerging Themes from the ESA Symposium Entitled “Pollinator Nutrition: Lessons from Bees at Individual to Landscape Levels”

Pollinator populations are declining (Biesmeijer et al., 2006; Brodschneider et al., 2018; Cameron et al., 2011; Goulson, Lye, & Darvill, 2008; Kulhanek et al., 2017; National Research Council, 2007; Oldroyd, 2007), and both anecdotal and experimental evidence suggest that limited access to high quality forage might play a role (Carvell, Meek, Pywell, Goulson, & Nowakowski, 2007; Deepa et al., 2017; Goulson, Nicholls, Botias, & Rotheray, 2015; Potts et al., 2003, 2010; Vanbergen & The Insect Pollinators Initiative, 2013; Vaudo, Tooker, Grozinger, & Patch, 2015; Woodard, 2017). Multiple researchers are earnestly addressing this topic in a diverse array of insect-pollinator systems. As research continues to be published, increased communication among scientists studying the topic of nutrition is essential for improving pollinator health

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies

PACT Meeting: Applicator Certification and Training, Antimicrobial/Disinfectants, COVID-19 and Beyond (Session 3 of 11)

This video is part of a series of webinars from the National Pesticide Safety Education Center. In the video, Mary Centrella talks about the American Association of Pesticide Safety Educators Antimicrobials Workgroup, its major goals, topics the workgroup explores, and outreach efforts. Following Centrella's presentation, a panel of state pesticide regulators from various regions of the United States discuss how certification and training for application of antimicrobial products are handled in their respective states in response to COVID-19. The video recording runs 1:06:24 minutes in length

REGIONAL AND LOCAL DRIVERS OF MASON BEE (GENUS OSMIA) DECLINE ACROSS THE EASTERN SEABOARD

Though there has been much focus on honey bee (Apis mellifera L.) decline, wild bees, which are essential to both ecosystem functioning and crop pollination, are also facing declines across Europe and North America. Potential drivers of theses declines include competition with non-native species, landscape simplification, increased pesticide risk, and reduced diet diversity. Here, I ask 1. how an introduced wild bee impacts a closely related, native congener at a regional scale, 2. how landscape simplification, diet diversity, and pesticide risk interact to impact wild bee populations in apple agroecosystems, and 3. how pesticide risk levels compare between wild bees and honey bees in the same apple orchards during bloom. To assess the impact of non-native Osmia cornifrons on the decline of native O. lignaria across the Eastern Seaboard, Ie used historical specimen records from 36 insect collections over 120 years. I found no evidence that O. cornifrons influenced O. lignaria decline; instead, their abundance (relative to other bees) has been decreasing since 1890, long before the 1977 introduction of O. cornifrons. Next, I was interested in exploring the drivers of Osmia performance in agroecosystems. Due to limited availability of O. lignaria, I assessed the response of nesting female O. cornifrons to landscape simplification, pesticide risk, and floral diet diversity in 17 NY apple orchards in 2015. In simplified landscapes, O. cornifrons produced fewer female offspring that weighed less, via reduced diet diversity and increased fungicide risk levels from Rosaceae (likely apple) pollen. Reductions in female offspring number and weight could lead to O. cornifrons population decline over time, as smaller-bodied bees produce fewer offspring and have shorter life-spans, suggesting that further studies of wild bee declines should focus on landscape simplification, pesticide risk, and floral diet diversity as potential drivers. To assess whether the historic use of honey bees as models for wild bee decline is adequate, I directly compared one driver of bee decline, pesticide risk levels, in O. cornifrons and A. mellifera pollen in 14 apple orchards during bloom in 2015. For O. cornifrons, increasing apple land cover resulted in increased pesticide risk levels in their pollen provisions, via increased Malus (crop) pollen collected. However, these relationships were not significant for honey bees, suggesting that their use as a model for all bee species may lead to inaccurate assessments of pesticide risk to some wild bee populations in agroecosystems. My results show that Osmia lignaria decline is not necessarily exacerbated by Osmia cornifrons at the regional scale. At the local scale, I show that landscape simplification, increased pesticide risk, and reduced diet diversity could potentially lead to O. cornifrons population decline, via reduced offspring number and size. Finally, I show that it is essential to continue studying the drivers of wild bee decline, as honey bees do not provide an adequate model with which to assess health of all bee species. By continuing to research the underlying causes of wild bee decline at both the regional and local scales, we can better preserve these important pollinators

Diet diversity and pesticide risk mediate the negative effects of land use change on solitary bee offspring production

Threats to bee pollinators such as land use change, high pesticide risk and reduced floral diet diversity are usually assessed independently, even though they often co-occur to impact bees in agroecosystems. We established populations of the non-native mason bee Osmia cornifrons at 17 NY apple orchards varying in proportion of surrounding agriculture and measured floral diet diversity and pesticide risk levels in the pollen provisions they produced. We used path analysis to test the direct and indirect effects of different habitats, diet diversity and pesticide risk on emergent female offspring number and weight. High proportions of agricultural habitat surrounding bee nests indirectly reduced the number of female offspring produced, by reducing floral diet diversity in pollen. When the proportion of agriculture surrounding bee nests was high, bees collected increased proportions of Rosaceae in their pollen provisions, which marginally (0.05 < p < 0.1) increased fungicide risk levels in pollen. This, in turn, marginally reduced female offspring weight. In contrast, female offspring weight increased as proportions surrounding open habitat (wildflowers, grassland and pasture) increased, but this effect was not influenced by proportion Rosaceae or fungicide risk levels in pollen. Synthesis and applications. Threats to bee health such as land use change, pesticide exposure and changes in pollen diet composition are often studied in isolation. However, our results suggest that these threats can simultaneously influence one another to impact bee populations in the agroecosystems where we rely on them for pollination. By replacing surrounding agricultural habitats with more natural habitats, such as grasslands and pastures, we can increase floral diet diversity and reduce pesticide exposure in bee-collected pollen, resulting in healthier mason bee populations in apple orchards.</p

Emerging Themes from the ESA Symposium Entitled “Pollinator Nutrition: Lessons from Bees at Individual to Landscape Levels”

Pollinator populations are declining (Biesmeijer et al., 2006; Brodschneider et al., 2018; Cameron et al., 2011; Goulson, Lye, & Darvill, 2008; Kulhanek et al., 2017; National Research Council, 2007; Oldroyd, 2007), and both anecdotal and experimental evidence suggest that limited access to high quality forage might play a role (Carvell, Meek, Pywell, Goulson, & Nowakowski, 2007; Deepa et al., 2017; Goulson, Nicholls, Botias, & Rotheray, 2015; Potts et al., 2003, 2010; Vanbergen & The Insect Pollinators Initiative, 2013; Vaudo, Tooker, Grozinger, & Patch, 2015; Woodard, 2017). Multiple researchers are earnestly addressing this topic in a diverse array of insect-pollinator systems. As research continues to be published, increased communication among scientists studying the topic of nutrition is essential for improving pollinator health

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition.

The idea that noncrop habitat enhances pest control and represents a win-win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win-win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies