Animals, just like humans, differ consistently in behavioural traits such as aggressiveness, exploration, reactivity. The study of behavioural syndromes (animal personalities), defined as sets of correlated behaviours across situations, helps in explaining the evolutionary significance of individual variation. However, most studies have focussed on few model organisms with no, or relatively little, social structure. Social insects represent one of the pinnacles of social evolution. Their well-organized societies are based on an often extensive division of labour, which includes reproduction and is frequently accompanied by morphological differentiation. The extent to which this labour partitioning can be implemented depends on the efficiency of communication strategies: in particular, the communication of identity. In social insects, communication of identity involves multiple levels of recognition: inter-individual, within-colony and between-colony level. How effectively individual or group identity can be detected may depend on the behavioural type of the receiver, but this has never been explored in social insects. This project builds on the synergy between the expertise of the applicant and the host to investigate the evolutionary significance and the ontogeny of individual variation in stimulus response allowing recognition at different levels by using different species of ants, which are among the most advanced and ecologically successful animal societies. The project combines behavioural observations, chemical analysis, electrophysiology, quantitative genetics, neurobiology and cognitive studies to achieve an interdisciplinary understanding of the forces that have shaped individual behavioural variation and collective division of labour in ants. The project’s implementation will be facilitated by the applicant’s network of high-profile collaborators and will thus have a significant impact (co-operation, professional integration) and transfer of knowledge.