A recent controversy has arisen over the relative advantage of the hymenopteran sting as a defensive weapon against vertebrates or invertebrates as this relates to the origin of insect sociality (STARR 1985a, KUKUK et al. 1989, and reply by STARR 1989). These studies emphasize the value of the sting as an antipredator device, but minimize its offensive potential. Concomitant with the evolution of cooperation among hymenopteran insects has been extensive exploitation by parasitic individuals of the reproductive efforts of others. Use of the sting is a common feature of both facultative and obligate nest usurpation in the social Hymenoptera. Increases in sting size and venom gland size have occurred, presumably as a result of arms races arising out of the competing selective forces of cooperation and parasitism which underly hymenopteran sociality.