The evolutionary significance of long copulation duration in bumble bees

Abstract

Copulation duration - the time spent in copula - is of particular interest in social insects. Female social insects ( or queens) generally only mate during a short, initial post-emergence period, and in the absence of extensive pre- or post-copulatory mate guarding, copulation is the only point in time at which the sexes directly interact with each other. Although copulation duration is likely to be under natural selection, because queens depend upon successfully transferred sperm, longer copulation durations offer males the possibility to manipulate paternity in their own interest. Consequently, copulation duration might be one of the few traits in social insects where sexual selection has resulted in evolutionary conflict between the sexes. Here we review the available data on copulation duration in bumble bees and, by relating it to other aspects of mating in Bombus, develop a framework within which we may understand the selective forces that have shaped this enigmatic behaviour.