In-nest ethology and mating strategies of the carpenter bees Xylocopa spp. (Hymenoptera: Apidae)

Large carpenter bees (the genus Xylocopa), as an important group of bees (Apidae), play an important role in studying early stages of insect social evolution. This article reviewed the research progress on nesting habits, social behaviors, and mating strategies of Xylocopa. Investigations in recent years showed that nest architecture is linked to numerous life history elements including the distribution of nesting events such as constructing cells and laying brood, brood size, provisioning efficiency, and susceptibility to parasitism. Competition among conspecific females at nesting sites increases as the population becomes larger, which is reflected by more intensive guarding of nests, especially during the late spring and summer. Nest guarding is not only against conspecific females but also against other species. This insect group presents the evolution tendency from solitary to eusociality, and exhibits subsocial, communal, semisocial and eusocial forms. Xylocopa is found to be socially polymorphic with b