Chronic impairment of bumblebee natural foraging behaviour induced by sublethal pesticide exposure

1. Insect pollination is a vital ecosystem service that maintains biodiversity and sustains agricultural crop yields. Social bees are essential insect pollinators so it is concerning that their populations are in global decline. 2. Although pesticide exposure has been implicated as a possible cause for bee declines, we currently have a limited understanding of the risk these chemicals pose. Whilst environmental exposure to pesticides typically has non-lethal effects on individual bees, recent reports suggest that sublethal exposure can affect important behavioural traits such as foraging. However, at present we know comparatively little about how natural foraging behaviour is impaired and the relative impacts of acute and chronic effects. 3. Using Radio Frequency Identification (RFID) tagging technology we examined how the day-to-day foraging patterns of bumblebees (Bombus terrestris) were affected when exposed to either a neonicotinoid (imidacloprid) and/or a pyrethroid (λ-cyhalothrin)...