Eusociality, characterized by cooperative brood care, and reproductive division of labor, evolved independently in insects. The evolution of eusociality has been hypothesized to lead to differences in the extent of both positive and negative selection. While population genomics studies of eusocial insects have so far focused on positive selection, there have been fewer studies on negative selection in social insects, and its relationship to the evolution of caste-biased genes. To address this knowledge gap, our research estimated the extent of negative selection in honey bees, bumblebees, and paper wasps. We show a significant negative correlation between increasing social complexity and negative selection, suggesting effective population size affects the strength of negative selection. We identified a significantly stronger negative selection in queen traits relative to worker traits in honey bees. Lastly, we observe stronger negative selection in drone traits relative to queen traits in honeybees, possible due to the haplodiploidy system