UC Riverside

Bumble bees (genus Bombus) are an important group of bees that perform many complex behaviors and provide vital ecosystem services through plant pollination. Bumble bees, along with many other pollinators, face a variety of stressors in their environment that can lead to global population declines. A deeper understanding of bumble bee molecular biology and physiology is necessary to fill the gap in our understanding of how bumble bees can be impacted by environmental stressors and can elucidate mechanisms underlying some of the responses seen in the current literature. In this dissertation, I explore how molecular mechanisms can be influenced by external stressors, such as neonicotinoid pesticides, and starvation. I also investigate the molecular mechanisms that are involved in bumble bee foraging behavioral states, of which pollination is byproduct. Bumble bee foraging behaviors are essential for the maintenance of our ecosystems as well as their own survival. Yet environmental stressors threaten the efficiency or performance of these foraging behaviors. In order to understand how bumble bee foraging behavioral states are impacted by environmental stressors, we must understand what drives these specific behaviors. Within this dissertation, each chapter explores a different facet of bumble bee molecular and metabolic biology, with the intent to fill the gap in our comprehensive understanding of the effects, or potential effects, of external factors on different aspects of bumble bee fitness. Chapter One explores the effects of both neonicotinoid pesticide exposure and starvation stress on bumble bee energy metabolism. Chapter Two focuses on investigating the molecular mechanisms associated with foraging behavioral states in wild bumble bees. Chapter Three explores how rearing history impacts offspring starvation resilience and further examines the metabolic mechanisms that are involved in enforcing starvation resistance.