Wild bees, such as bumblebees (Bombus spp.), are important pollinators of both crops and wildflowers, yet many species are in decline. Intensive agriculture reduces floral resources and increases pesticide exposure in agricultural environments. Synergistic interactions between pesticides and poor nutrition may exacerbate individual effects; diets with low concentrations of sucrose may lower pesticide resistance, or increase sucrose consumption, and consequently, pesticide intake. However, our understanding of the effects of environmental stressors across the whole bumblebee life cycle is limited. Here, we assessed the impact of lower carbohydrate intake and exposure to a novel insecticide, flupyradifurone on colony initiation and ovary development of wild-caught bumblebee (Bombus terrestris) queens. Using a fully crossed experimental design, queens were provided with field-realistic concentrations of flupyradifurone (1.6ppm) at high (50% (w/w)) or low (15% (w/w)) sucrose concentrations, representing good or poor-quality diets respectively. We found that bees in the low nutrition groups produced no eggs or larvae. They also developed smaller ovaries and performed less brood-caring behaviours. There was no individual impact of flupyradifurone exposure on brood production, although pesticide exposure and low nutrition synergistically reduced the likelihood of brood-caring behaviour. These results demonstrate the importance of carbohydrate intake during the spring when queens are founding colonies, highlighting a need to consider not only landscape floral diversity but also nutritional quality when developing strategies for wild bee conservation.
Assessing the impacts of pesticide exposure and poor nutrition on bumblebee (Bombus terrestris) colony initiation
Couper Coombs, E. M. (Author). 30 Sept 2025
Student thesis: Master's Thesis › Master of Science by Research (MScR)