Territoriality and the origin of slave raiding in leptothoracine ants.

The slave-raiding behavior of Harpagoxenus canadensis closely resembles the territorial behavior of its host species, Leptothorax muscorum. Of primary importance is the discovery that both species of ants recruit nest mates into battle using an alarm-recruitment system which is a probable evolutionary precursor of more specialized forms of slave-raiding recruitment. The behavior of these species supports the hypothesis that slave raiding in leptothoracine ants evolved from territorial behavior.