Ants have been used with great success to answer sociobiological questions of communication, ecology, and phylogenetics. The use of ant models to study regulation of social behavior at the physiological level, though, has been less fruitful, at least in part due to difficulties in processing small specimens for detailed analyses. However, with recent advances in methodological techniques come opportunities to examine the physiological machineries of ant behavior. Using these improved techniques, we have acquired data that may help shed light on fundamental mechanisms of division of labor. Our study has focused on the harvester ant Pogonomyrmex californicus, an ant with obligately foraging, semiclaustral queens that go through discrete behavioral stages after mating. These changes lead from mating, through an egg laying and a foraging stage, until the queen ultimately is confined to the nest of the mature colony. Our data suggest that the distinct behavioral stages of P. californicus queens are linked to changes in endocrine signaling. The results demonstrate that ants can provide new insights into the regulatory building blocks of social insect behavior.