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No evidence for neonicotinoid preferences in the bumblebee Bombus impatiens

Citation

Muth, Felicity (2020), No evidence for neonicotinoid preferences in the bumblebee Bombus impatiens, Dryad, Dataset, https://doi.org/10.5061/dryad.0gb5mkkxw

Abstract

Neonicotinoid pesticides can have a multitude of negative sub-lethal effects on bees. Understanding their impact on wild populations requires accurately estimating the dosages bees encounter under natural conditions. This is complicated by the possibility that bees might influence their own exposure: two recent studies found that bumblebees (Bombus terrestris) preferentially consumed neonicotinoid-contaminated nectar, even though these chemicals are thought to be tasteless and odourless. Here we used Bombus impatiens to explore two elements of these reported preferences, with the aim of understanding their ecological implication and underlying mechanism. First, we asked whether preferences persisted across a range of realistic nectar sugar concentrations, when measured at a series of time points up until 24 hours. Second, we tested whether bees’ neonicotinoid preferences were driven by an ability to associate their post-ingestive consequences with floral stimuli such as color, location, or scent. We found no evidence that foragers preferred to consume neonicotinoid-containing solutions, despite finding effects on feeding motivation and locomotor activity in line with previous work. Bees also did not preferentially visit floral stimuli previously paired with a neonicotinoid-containing solution. These results highlight the need for further research into the mechanisms underlying bees’ responses to these pesticides, critical for determining how neonicotinoid-driven foraging preferences might operate in the real world for different bee species.

Funding

U.S. Department of Agriculture, Award: 2018-67014-27543

L'Oreal USA

U.S. Department of Agriculture, Award: Postdoctoral Fellowship