Changes in social regulation across colony development in the ant Camponotus floridanus

Just as juveniles contend with different challenges than adults of the same species, a social insect colony faces different ecological and organizational challenges as it grows from a solitary foundress to a complex society with thousands of members. Key features of sociality, such as the regulation of worker reproduction, have been studied extensively in mature colonies, but virtually nothing is known about their maintenance in incipient colonies. In mature colonies of the ant Camponotus floridanus, worker sterility is enforced by the destruction, or "policing," of worker-laid eggs. We found that workers from incipient colonies, in contrast, do not exhibit policing behavior, and instead tolerate all conspecific eggs. The absence of egg policing in incipient colonies is consistent with the hypothesis that ants use differences in egg surface hydrocarbons to distinguish worker- and queen-laid eggs. Eggs laid by incipient queens lack the distinguishing hydrocarbons found on the surface of eggs laid by mature queens and are chemically indistinguishable from worker-laid eggs. At the proximate level, our results show that mechanisms of social regulation, such as the response to egg surface hydrocarbons, are not hard-wired and change dramatically over a colony’s life cycle. At the ultimate level, our results suggest the benefits of regulating worker reproduction are not constant across colony development.