Polygyny and Polydomy in Three North American Species of the Ant Genus Leptothorax Mayr (Hymenoptera: Formicidae)

This paper deals with certain behavioral and ecological factors which may be relevant to the evolution and maintenance of social parasitism in ants.We will argue that some of the same factors which might predispose one species to evolve into a social parasite might make resistance to parasitism difficult for a closely related species.After their mating flight, the queens of most nonparasitic ant species found new colonies alone.A queen of such a species finds a suitable nesting place, excavates a small cavity, and seals herself inside.She then lays a clutch of eggs and feeds her first larvae a special "baby food" derived metabolically from the degeneration of her wing muscles and fat body.These larvae mature to become female workers which forage for food, enlarge the nest, feed the queen, and rear subsequent broods of workers and reproductives.Mature ant colonies usually occupy only one nest (monodomy).However, the number of queens in typical mature colonies varies.Colonies of some species never contain more than one functional queen (monogyny), while colonies of other species often have multi- ple queens (polygyny) (Buschinger 1974).However, the queens of all known obligatory slave-making, in- quiline, and temporary-parasite species found colonies non-inde- 1.This research was supported by grants to Thomas Alloway