UC Riverside

Animal survival is dependent on the capacity to effectively find and consume nutritious food resources and avoid harmful components that may be present in food. This fundamental process operates at multiple scales in all animal species. At the organismal scale, for example, nutritional state impacts whether an individual is motivated to consume or reject food (Dethier, 1976). The goal of this dissertation research was to establish a foundation for studying feeding and foraging in bumble bees at the scales of the organism, colony, insect-plant interactions, and the environment. Although bumble bee feeding and foraging behavior have been previously studied at most of these scales, there are several substantial gaps in our knowledge that this dissertation addresses. To address these gaps, I first identified taste-related genes in Bombus impatiens and characterized the tissues in which these genes are expressed. I then examined how feeding and food-collection tasks are organized amongst workers in bumble bee colonies. Next, I tested whether pollen nutrients drive floral resource visitation in wild bumble bees. Finally, I examined what bumble bee species are present across several ecoregions in California. Together, this work provides a foundation to study the ecology and evolution of feeding and foraging in bumble bees.