Developing the gestalt: Nestmate recognition cues in the red harvester ant, Pogonomyrmex barbatus

Over the past few decades, biologists have come to a consensus that communication among eusocial insects is predominantly olfactory in nature. With the exception of unicolonial species, all social insects have some form of nestmate recognition that deters members of nearby colonies from entering a foreign colony. In ants, nestmate recognition is widely thought to occur through chemical cues found on the bodies of individuals called cuticular hydrocarbons (CHCs). Nestmate recognition cues are complex mixtures of the intrinsic chemical profiles of all workers, the queen, and the environment; the result is a gestalt odor that is generally thought to be unique from one colony to another. This gestalt nestmate odor arises, in part, from the combined contribution of each individual’s innately developed CHCs. Individual ants may distribute CHCs during grooming, trophallaxis, and direct body contact. Each of these functions help to generate a homogenized, colony-wide recognition cue. Despite such detailed studies into the roles of CHCs in eusocial insect chemical communication, however, little is known about their development at the individual level, much less about their genetic basis. In this study, we examined the CHC profiles of red harvester ant (Pogonomyrmex barbatus) adult workers. Individuals were marked within 24 hours of pupal eclosion, and placed into one of two treatment groups: (1) “colony,” or (2) “isolation” treatment. CHCs were then sampled at eight time points as they developed over the course of 30 days. The details of our findings will be presented this fall at the ESA annual meeting.