Ontogeny of recognition in social insects.

The ability to discriminate between friends and foes is a central feature of social life. In social insects, nestmate recognition is mediated by colony specific cuticular hydrocarbons (label) that are perceived by an individual and compared with its neural representation of the colony odour (template). Although numerous advances have been made in understanding the identity, origin and production of recognition cues in social hymenoptera, relatively little is known about the ontogeny of nestmate recognition, and the learning processes that might be involved. It appears that wasps and bees learn the recognition cues necessary for template formation from their nest/comb odour, while ants learn principally from their nestmates. In general, the referent template is learned during the early stages of adult life, although pre-imaginal learning might play a role. Cuticular hydrocarbons blend can change over time; cues-exchange among nestmates is therefore needed to reduce chemical variability among individuals and to integrate environmental compounds into the colony odour. As a result of this process, the referent template is updated during life. This relative plasticity of the recognition system can be exploited by insect social parasites to integrate themselves within the host colonies and to fool host workers about their real identity. By studying social parasites chemical integration strategies new insights on the ontogeny of nestmate recognition in social insects could be acquired. However, further studies are required on the neural substrates implicated in learning and memory at different stages of social insect life to better understand how and when template formation occurs.