Social bees play a central role in our understanding of group-decision processes in animal societies. This special issue of Apidologie synthesizes research on the mechanisms of information flow and group-decision making, and how these mechanisms lead to emergent patterns of self-organization in colonies of honey bees, stingless bees and bumblebees. Reviews are presented on the physiological, sensory and communication mechanisms used to regulate the actions of individual workers, and how these actions are integrated into group-level decisions about foraging, nest construction, colony growth, nest-site selection and colony movement, queen production, and colony reproduction. The special issue brings the reader up to date on current findings in these areas, and the hope of the editorial board is that it will spark interest and provide insights for future studies.