Spatial Aspects of Corpse Removal in the Western Harvester Ant, Pogonomyrmex occidentalis

Eusocial insects actively combat pathogen proliferation with a myriad of tactics, one of which is the removal of corpses from the nest, a behavior known as necrophoresis. Spatial patterns of corpse depositions by colonies of the western harvester ant, Pogonomyrmex occidentalis, were examined. Colonies were presented with nestmate and non-nestmate corpses to discern if each type of waste was handled differently. Specialized areas for corpse disposal were not observed. Non-nestmate corpses were carried farther from the nest than were nestmate corpses, perhaps reducing the chance of introduction of pathogens new to the colony that may be harbored by a non-nestmate. Factors external to the nest mound, such as slope and neighboring colonies, had no perceptible effect on these depositions and did not change the uniformity of dispersal of this particular waste. These findings add to our knowledge of the intricacies of corpse removal in eusocial insects and suggest that this is a more dynamic activity than previously thought.