"The evolution and maintenance of cooperation in the face of inevitable conflicts, is regarded as one of the major questions in biology today. Answering this question requires understanding both the proximate basis of cooperative behavior and its comparative biology, but studies integrating experimental and comparative approaches are rare. Social insects are one of the pinnacles of sociality, with societies characterized by reproductive division of labour, one of the major evolutionary transitions in biological organization. While most of the research in the last century has focused on the ultimate reasons favoring cooperation, the methodological advances during the last decade has provided the tools necessary to study the genetic basis of cooperation directly. The “reproductive groundplan hypothesis” (RPGH) has emerged as one potentially powerful explanation for the proximate mechanisms for the evolution of eusociality. It postulates that conserved gene networks, which underlie the reproductive physiology and behavior of solitary insects, were co-opted and modified during the evolution of eusocial insects to generate worker division of labor. This hypothesis is potentially of fundamental and far-reaching importance for our understanding of the mechanistic basis by which eusociality evolved, but empirical evidence in support of the hypothesis is still limited to only a few species. This project will combine large scale phylogenetic tests of the RPGH, with endocrinology, state of the art molecular techniques (RNA interference) and classic behavioral analysis, to investigate if the RPGH applies to ants and therefore represents a general explanatory framework for the evolution of division of labour in social insects. The training in three cutting-edge sets of techniques will provide a step-change in the research capabilities of the applicant, and the results will provide fundamental insights into the proximate and ultimate basis for the evolution of cooperation."