The Impacts of Maturation and Experience on Volumetric Neuroplasticity in Solitary and Social Bees

Some animals are incredibly social, living and working together as one cohesive group. Alternatively, many animals are solitary, never living with and rarely interacting with others. A large body of biological research has focused on understanding the role that brains play in promoting these behavioral differences across species. Even so, it remains unclear why some brains facilitate social behavior while others do not. My dissertation aims to advance our understanding of this concept by characterizing bees’ brains and how they change over a lifetime. Bees are beneficial for investigating relationships between the brain and social behavior because some species are solitary while others are highly social. However, sociality in bees is more dynamic than that; a blending of these two extremes can also occur. This enables us to explore how brains change with social context within a single group of organisms. My first chapter uses a solitary bee to understand how simple social interactions can impact the brain. I found that—even in a solitary bee—certain brain regions grow in size in response to the presence of other bees. This trait may have been important in the evolutionary origins of social behavior. My second chapter investigated the effects of aging in the brains of two bee species, one that is sometimes social while the other is always social. I found that the brains of these species naturally change over time, a feature common to highly social species, e.g., honey bees. This suggests that having brains that change with age may be an important feature of sociality. My final research chapter made comparisons between queen and worker bees to investigate if their colony roles and behaviors dictated the relative size of different regions of their brains. I found that queen and worker brains respond differently to removing offspring care, a trait fundamental to defining their role in the colony. This highlights a potentially unique relationship between the brain and social life. Collectively, my dissertation used bees to enhance our understanding of what it means to have a social brain