Recognition and Aggression of conspecific and heterospecific worker in Acromyrmex subterraneus subterraneus (Forel) (Hymenoptera: Formicidae)

Aggressive behavior is important for social insects because it makes possible for the colony to defend itself and the offspring from the action of invasive species. We studied the recognition and aggressiveness of the leaf-cutting ant Acromyrmex subterraneus subterraneus (Forel) to co-specific workers from other nest and heterospecific workers of Acromyrmex subterraneus molestans Santschi, Acromyrmex subterraneus brunneus (Forel) and Acromyrmex niger (Smith); and queens of their social parasite Acromyrmex ameliae De Souza, Soares and Della Lucia. Workers of other species were placed in contact with those of A. subterraneus subterraneus for three minutes and during this period the behavioral interactions were quantified. The aggressiveness index (AI) for each agonistic encounter was obtained. Acromyrmex subterraneus subterraneus workers exhibited greater aggressiveness against heterospecific than against conspecific competitors. Aggressiveness is connected to differences in the chemical profiles, which are larger in heterospecifics colonies.