Meeting Abstract
Bumblebees are common and charismatic pollinators that play a critical role in the ecology of northern temperate and boreal ecosystems. However, in recent decades anthropogenic environmental changes, such as increased use of pesticides, the spread of bee-specific diseases and habitat destruction, have led to declining numbers for wild bee species around the world. Neonicotinoid pesticides have been a focus of efforts to understand pollinator declines. The systemic nature of neonicotinoids or their derivatives mean they persist in the nectar and pollen of plants after application where they have been found to reduce individuals’ foraging efficiency, colony fitness, and increase susceptibility to disease. Importantly, the mechanisms by which neonicotinoids affect bumblebee immunity are not well understood. We have used high-throughput DNA and RNA sequencing to examine the affects of agriculturally relevant concentrations of imidacloprid, the most commonly used neonicotinoid, on the composition of gut microbiota and host gene expression in the common eastern bumblebee, Bombus impatiens. We find significant gene expression changes at all doses, notably associated with immune and neural functions. High doses of imidacloprid also significantly reduced the relative abundance of Acetobacteraceae, including Saccharibacter sp., which are known to promote pathogen resistance in honeybees. These results suggest that neonicotinoids such as imidacloprid may lead to disease susceptibility in bees in part via altered microbial-host interactions and resulting dysbiosis.
