Honey bee gut microbial communities are robust to the fungicide Pristine® consumed in pollen

Honey bees that consume pollen with sublethal levels of the fungicide Pristine® can have reduced pollen digestion, lower ATP synthesis, and in many ways resemble malnourished bees. Reduced nutrient acquisition in bees exposed to Pristine® might be due to the effects of this fungicide on the composition of gut microbial communities. Two experiments were conducted in two separate years to test for the effects of Pristine® on the composition and diversity of bacteria in nurse bee midguts. In the low-dose experiment, bees fed the fungicide had a reduced relative abundance of Gilliamella sp. and the number of bacterial taxa within each individual bee was lower. In the high-dose experiment, the fungicide treatment led to increased relative abundance of Lactobacillus sp. Firm 4 and Firm 5 relative to the control. Presence of the fungicide did not impact the distribution of bacteria among individuals on either the low-or high-dose experiments. Considerable differences in gut microbial communities existed between the two experiments perhaps due to environmental and dietary factors. The effects of Pristine® on the gut microbiota were inconsistent between experiments indicating that exposure rate and environmental conditions can influence the effects of this fungicide on gut microbial communities.