Investigations into mechanisms regulating the reproductive division of labor in social insects can have wide implications regarding the evolution of social behavior. In social insects, there has been a hypothesized transition from aggressive regulation of the reproductive division of labor to pheromonal regulation of the reproductive division of labor. Bumble bees are prime candidate organisms to explore this transition because both aggression and chemical communication are used by workers and queens to regulate this competition, but the relative contributions of each mechanisms seem to vary between species. In this thesis, I investigate the physiological, behavioral and genetic mechanisms underlying the reproductive division of labor in the bumble bee species, Bombus impatiens, and compare those to the well-studied species, Bombus terrestris.
