Epigenetics is the study of changes in gene expression caused by mechanisms other than changes in the underlying DNA sequence. One of the most important forms of epigenetic modifications is the methylation of DNA. Contrary to vertebrates, DNA methylation is not present in all insect species and is relatively sparse in insect genomes. In insects, DNA methylation is mostly found in gene bodies and at exon/intron boundaries, as opposed to vertebrates, where it mostly occurs in promoter regions. Taken together, this suggests that DNA methylation has a different role in insects, but its precise function is currently not understood. The fundamental feature of social insects (ants, bees, wasps and termites) is sophisticated division of labor, whereby different reproductive and behavioral castes coexist in insect societies. In this project I propose to use the parthenogenetic army ant Cerapachys biroi as a model species to investigate the role of DNA methylation in the regulation of reproduction and behavior. This project, jointly supervised by Prof. Daniel Kronauer (Rockefeller University, USA) and Prof. Laurent Keller (University of Lausanne, Switzerland), will be divided in two parts. First, I will use whole-genome bisulfite sequencing to identify genes for which changes in methylation status are associated with changes in reproduction and behavior. Second, I will use these candidate genes to investigate the causal relationship between DNA methylation, gene expression, alternative splicing and the regulation of reproduction and behavior. This project, which combines an elegant experimental design and state-of-the-art molecular techniques, will provide important information on the mode of action of DNA methylation and its role in the regulation of division of labor in insect societies.