Social behaviour lies in the genes
Social behaviour and the existence of complex societies are not phenomena restricted to the human race, being frequently encountered in the animal kingdom too. Insects constitute important model systems for studying social evolution, behaviour and complex social phenotypes. Social interactions influence many aspects of life in insect societies including colony-level (nest architecture) and individual-level traits (body size and caste). However, the limited information currently available on the genetic basis of such social phenotypes hampers the interpretation of how these traits respond to selection during evolution. Seeking to address this issue, the EU-funded ‘Quantitative genetics of caste in social insects’ (Genetics OF CASTE) project was designed to study the evolution of social insect phenotypes from a genetic angle. By using a genetic model of ants, project scientists succeeded in studying the first ever artificial selection of a trait central to complex insect societies known as the caste ratio. This refers to the proportion of individuals reared as reproductive queens versus sterile workers. Researchers developed an evolutionary genetic theory to provide insight into the genetic basis and evolution of complex social traits. This theory would help explain why genetic variation for caste ratio is maintained in social systems, how genetic variation for kin recognition and cooperation is maintained, and how social interactions influence the maintenance of genetic sequence variation. Although the strength of the genetic component could be influenced by the environment, caste determination relied on the evolution and expression of certain genes. The Genetics OF CASTE project results clearly demonstrated the importance of the genetic component in social behaviour and society formation. The interest in the work extends beyond evolutionary biology, with potential extrapolation of the findings to other social organisms including humans.
