Kin recognition via cuticular hydrocarbons shapes cockroach social life

Genetic relatedness plays a key role in the organization and the functioning of societies. A large diversity of species has developed kin recognition abilities, allowing individuals to discriminate conspecifics in relation to relatedness. In social insects, many studies showed that discrimination generally acts at the level of nestmateship and only few studies report kin recognition abilities. Our results highlight the importance of kin recognition in shaping social life in the urban cockroach Blattella germanica (L.) and present a complete description of the recognition system from expression to action components. Cockroaches of all developmental stages (nymphs and adults) discriminate siblings from nonsiblings independently of any prior social experience. Preference is context dependent so that siblings are preferred as social partners, whereas nonsiblings are preferred as mating partners. Discrimination is based on quantitative differences of cuticular hydrocarbons that are perceived through antennal contacts. As individual cuticular profiles remain stable over time, they constitute reliable discrimination cues correlated with relatedness. Our results offer interesting perspectives for the study of kin recognition and for the understanding of evolution toward sociality in insects.