Data from: Foraging bumblebees acquire a preference for neonicotinoid-treated food with prolonged exposure

Social bees represent an important group of pollinating insects but can be
exposed to potentially harmful pesticides when foraging on treated or
contaminated flowering plants. To investigate if such exposure is
detrimental to bees, many studies have exclusively fed individuals with
pesticide spiked food, informing us about the hazard but not necessarily
the risk of exposure. Whilst such studies are important to establish the
physiological and behavioural effects on individuals they do not consider
the possibility that exposure may change over time. For example, many
pesticide assays exclude potential behavioural adaptations, such as a
rejection of harmful compounds by choosing to feed on an uncontaminated
food source, which would behaviourally lower the risk of exposure. Here we
conducted an experiment over 10 days in which bumblebees forage on an
array of sucrose feeders containing a range of concentrations (0, 2
& 11 parts per billion) of the neonicotinoid pesticide
thiamethoxam. We more closely mimic pesticide exposure in the wild by
allowing foraging bees to experience i) a range of pesticide
concentrations across a chronic exposure period, ii) repeated interactions
with the pesticide, and iii) allowing foraging bees to retain the social
cues associated with foraging by using whole colonies. We found that the
proportion of visits to pesticide-laced feeders increased over time,
resulting in the consumption of more pesticide-laced sucrose. After
changing the spatial position of each feeder, foragers continued to
preferentially visit the pesticide-laced food, indicating that workers can
detect thiamethoxam and alter their behaviour to continue feeding from it.
The increasing preference for consuming the neonicotinoid treated food,
therefore increases the risk of exposure for the colony during prolonged
pesticide exposure. Our results highlight the need to incorporate
attractiveness of field relevant concentrations of pesticides to foraging
bees (and other insect p