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The neurotoxic insecticide class of neonicotinoids has become one of the most widely used groups of pesticides globally. Their long half-lives and high water solubility increase their potential to linger and affect numerous organisms long after application. A prominent concern associated with residual contamination is the negative impact that neonicotinoids can have on beneficial arthropods such as bees and certain groups of beetles. Many studies have looked at the effects neonicotinoids have on arthropod communities in lab settings; however, comparatively few studies have looked at these groups in neonicotinoid-contaminated restored prairie habitats. These habitats are often restored from or located near agriculture and are almost ubiquitously contaminated with neonicotinoids. Our one-year manipulated field study compared native bee nesting rates and beetle community assemblages between paired clothianidin-contaminated and non-contaminated restored prairie plots. Native bee nesting probability and nesting abundance increased by 46% and 172%, respectively, in sites contaminated with clothianidin. Conversely, we observed no significant differences in beetle family assemblages, abundance, or richness between clothianidin-contaminated and control sites. These results suggest that neonicotinoid contamination of natural habitats can have numerous environmental consequences for arthropods and that these effects are not always consistent between taxa. Understanding how neonicotinoid contamination affects beneficial groups such as bees and arthropod community assemblages is crucial for characterizing the risks these chemicals pose to ecologically imperative taxa. [ABSTRACT FROM AUTHOR]

Wild and managed bees are needed to move sunflower (Helianthus annuus L.) pollen, both to create hybrid seed and to encourage high, consistent yields when those hybrids are subsequently grown. Among floral traits that influence bee preference, floret size may be critical, as the depth of the corolla affects the accessibility of nectar. Sampling and observation of inbred maintainer (HA) lines were used to assess variation in floret size, and to measure any effects of floret size on pollinator visitation. Among 100 inbreds sampled, there was significant variation among the lines, with floret lengths of 6.8–9.9 mm. Floret length, measured before anthesis, was closely related to corolla depth during anthesis and was consistent between 2 years (environments). Pollinator observations on 30 inbred lines showed floret size explained a majority (52%) of the variation in wild bee preference, with a reduction in floret length of 2 mm more than doubling pollinator activity. Though honey bee, Apis mellifera L., colonies were located ≈ 60 m from the plots, near-zero honey bee activity in the sunflowers precluded an assessment of how strongly this managed pollinator is affected by floret length. Production of inbreds and hybrids with smaller florets could enhance sunflower pollination, but genetic markers for floret size are needed to facilitate selection, and an understanding of potential trade-offs also is required. Information on variation and heritability of other traits, such as pollen and nectar rewards, could help explain residual variation in wild bee visitation to sunflowers. [ABSTRACT FROM AUTHOR]