Meeting Abstract
Honeybees are important pollinators that appear to be threatened by the widespread use of neonicotinoid pesticides such as imidacloprid. The sublethal effects of imidacloprid on adult bee foraging effort and navigational abilities are well known. Recent studies of imidacloprid-induced winterkill revealed that bioaccumulation in hive reserves affects colony survival. We hypothesized that larvae fed pollen and nectar contaminated with sublethal doses of imidacloprid may not develop normally or, if successfully metamorphosed to adults, may perform poorly in the hive. Larvae by matched queens were divided into control and imidacloprid treatments. Larvae in the imidacloprid treatment were fed 1/100 of the LD50 (0.18 ng/larvae) in 1.5 M sucrose whereas control larvae were fed only 1.5 M sucrose. Larvae were fed 5 uL daily for 5-6 days before pupation and were maintained in hive frames. We subsampled 20 larvae for HSP70 assays and the remaining larvae pupated and emerged in an incubator. Larval mortality was difficult to assess in frames but did not differ between treatments. Pupal mortality was higher in imidacloprid treatments than control treatments but emergence rates of healthy pupae were not different between them. When new nurse bees were tasked with cleaning 20-30 cells contaminated with hive dust, nurses fed imidacloprid as larvae cleaned fewer cells than nurses in the control treatment. Our preliminary results suggest that larvae exposed to sublethal doses of imidacloprid exhibit latent effects on adult performance traits important to hive maintenance and survival. If confirmed in future studies, this may inform predictive models of colony collapse disorder.
