New research: Neonicotinoid-contaminated pollinator strips adjacent to cropland reduce honey bee nutritional status


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