Ambidextrous Mandibles in the Fire Ant Solenopsis invicta

Abstract

The elongation and sharp teeth of ant mandibles are considered important adaptations that have contributed to ants successful colonization of terrestrial habitats worldwide. In extant ant species, mandibles function as hunting and defense weapons, as well as multipurpose tools for excavating soil, cutting leaves, capturing and butchering prey, harvesting seeds, and transporting brood. This article reports that the mandibles in the red imported fire ant, Solenopsis invicta Buren, are functionally ambidextrous. Individuals opened and closed each mandible in synchrony or independently depending on the requirement of the task at hand. Upon completion of a task, individuals were without a preference in the orientation of mandible overlap—right overlap or left overlap. Orientation of mandible overlap before and after performing a task was also examined in nine other ant species. No overlap orientation preference was observed in any of these ant species, suggesting that ambidextrous mandibles are a universal trait in ants. These findings add an increment of knowledge to the diverse functions of ant mandibles.