Intraspecific Brood Raiding, Territoriality, and Slavery in Ants

Abstract

The possible role of intraspecific territoriality in the evolution of obligate interspecific slavery, dulosis, among ants has been debated by several authors. Recent research on the establishment of colonies in several non-dulotic, intra-specifically territorial ants provides support for and an extension of the territorial hypothesis as a general explanation for dulosis. Several ant species, regardless of dulotic tendencies, have clumped starting nests; adult colonies, nonetheless, are territorial, suggesting that, from each clump, at most a single adult colony will prevail. Territoriality among these starting colonies takes the form of reciprocal brood raiding ("intraspecific slavery" in the sense of Holldobler 1976a); colonies with the most workers, including those acquired from brood raiding, prevail. Truly dulotic species have polydomous hosts; that is, a single colony occupies several nests. Such polydomous host colonies represent a renewable resource that likely permits specialization in their procurement without resource depletion, that is, the evolution of obligate dulosis.