Abstract
Worldwide pollinator declines are attributed to a number of factors, including pesticide exposures. Neonicotinoid insecticides specifically have been detected in surface waters, non-target vegetation, and bee products, but the risks posed by environmental exposures are still not well understood. Pollinator strips were tested for clothianidin contamination in plant tissues, and the risks to honey bees assessed. An enzyme-linked immunosorbent assay (ELISA) quantified clothianidin in leaf, nectar, honey, and bee bread at organic and seed-treated farms. Total glycogen, lipids, and protein from honey bee workers were quantified. The proportion of plants testing positive for clothianidin were the same between treatments. Leaf tissue and honey had similar concentrations of clothianidin between organic and seed-treated farms. Honey (mean±SE: 6.61 ± 0.88 ppb clothianidin per hive) had seven times greater concentrations than nectar collected by bees (0.94 ± 0.09 ppb). Bee bread collected from organic sites (25.8 ± 3.0 ppb) had significantly less clothianidin than those at seed treated locations (41.6 ± 2.9 ppb). Increasing concentrations of clothianidin in bee bread were correlated with decreased glycogen, lipid, and protein in workers. This study shows that small, isolated areas set aside for conservation do not provide spatial or temporal relief from neonicotinoid exposures in agricultural regions where their use is largely prophylactic.
Highlights
Worldwide pollinator declines are attributed to a number of factors, including pesticide exposures
Buckwheat (Fagopyrum esculentum) and phacelia (Phacelia tanacetifolia), which start blooming within a month of germination in the spring, had significantly lower concentrations recovered in leaf tissue, ranging from 0–52 ppb and 0–33 ppb, respectively (Fig. 1)
It has been suggested that any harmful exposures resulting from non-target plant uptake of neonicotinoids would be diluted by the fact that honey bees visit numerous flowers on a single foraging expedition[54]
Summary
Worldwide pollinator declines are attributed to a number of factors, including pesticide exposures. Pollinator strips were tested for clothianidin contamination in plant tissues, and the risks to honey bees assessed. An enzyme-linked immunosorbent assay (ELISA) quantified clothianidin in leaf, nectar, honey, and bee bread at organic and seed-treated farms. Leaf tissue and honey had similar concentrations of clothianidin between organic and seed-treated farms. Widespread and prophylactic use of neonicotinoids and other pesticides in the United States[7,8] as a result of policy-driven changes in agronomic practices[9], in the Upper Midwest, has resulted in decreased access to forage[10] (with the removal of vegetation surrounding fields to maximize crop production) and increased risk of neonicotinoid exposure for the majority of the nation’s honey bees during the months of honey production. Correspondence and requests for materials should be addressed to C.L.M.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call