Article,
Foraging Biology of the Seed-Harvesting Ant, <i>Pogonomyrmex (Ephebomyrmex) imberbiculus</i> (Hymenoptera: Formicidae)
Sociobiology, 43 (2): 367--375 (2004)
Abstract
Competition is a central factor shaping the community structure of many desert seed-harvesting ants. Aggressively defended territories are often the manifestation of these interactions. Here we show that colonies of the harvester ant Pogonomyrmex (Ephebomyrmex) imberbiculus have greatly overlapping foraging ranges and do not defend foraging territories. Enforced encounters between foragers from 50m distant colonies resulted in considerable aggressive interactions and were typically "won" by the worker originating from the colony near which the interaction was induced. Encounters between foragers from neighboring colonies were less aggressive and their outcome was not predictable. The observed pattern of aggression suggests that P. imberbiculus defends nest territories but not foraging territories. Our finding stands in contrast to the observation of fighting among foragers in several previously studied species of trunk-trail foraging Pogonomyrmex species, which show a similar diet but have much larger colony size than P. imberbiculus.
