Phenotypic plasticity leading to the division of labor between reproductive queen and non-reproductive worker castes forms the basis of superorganismality, one of the major transitions in evolution. A century of research on caste determination and differentiation in social insects, and in particular in honey bees, has revealed a complex picture of how these processes are regulated in different species. Advances in molecular methods have recently allowed the identification of common patterns across species, bringing us closer to a unified concept of caste development. In my talk, I will present new results on caste determination and differentiation in the emerging laboratory model ant Cardiocondyla obscurior.