Hydrocarbon Signals Explain the Pattern of Worker and Egg Policing in the Ant Aphaenogaster cockerelli

In ant societies, worker reproduction is regulated through policing behaviors, such as physical aggression or egg eating. The information used by policing individuals is thought to be in blends of hydrocarbons present on the cuticle and the surface of eggs. These fertility signals have been studied in numerous genera. However, signaling patterns that emerge across distinct subfamilies of ants have yet to be explained. We investigated policing behavior and the chemical signaling upon which policing behaviors are informed in the ant Aphaenogaster cockerelli. We found that worker-produced eggs are not policed, and we showed that there is a lack of chemical signaling for effective egg policing to occur in this species. Furthermore, we identified the available signals that demarcate workers to be policed physically. We showed that in A. cockerelli, a species with derived social organization, workers produce fertility signals identical to the queen. This queen-like signaling may be due to workers maintaining a high level of ovarian activity, linked to trophic egg production, in the presence of the queen.