Habitat structure, promiscuity and social organisation in Liopholis whitii, an experimental test

The occurrence of kin-based social organisation represents a turning point in evolution whereby local genetic relatedness can be exploited to increase gene frequencies through behavioural cooperation with relatives. Insights into the factors responsible for both the diversity and stability of social systems are therefore crucial for enhancing our understanding of key evolutionary processes. However the precise conditions that favour the origin and maintenance of sociality remain unclear. Both theoretical and empirical studies suggest that physical characteristics of the environment play a key role in mediating social complexity. This is because the structure and coordination of available habitat determines the density and dispersion of individuals, influencing mating strategies and the intensity of resource competition. These processes are fundamental to the evolution of sociality because 1) the number of males a female mates with directly affects the relatedness between individuals within a family group and 2) levels of resource competition will define the cost/benefit trade-offs of expressing social behaviors, such as tolerance and parental care. Despite this, very few studies have experimentally examined the role that habitat availability plays in underlying patterns of social behavior. Thus we have a poor understanding of the causal relationship between habitat and social organization. Using experimental techniques in a semi-natural setting, we investigated how the physical structure of habitats influenced various aspects of social behavior including aggressive interactions, pairing behavior, rates of promiscuity and parent-offspring association in the social skink, Liopholis whitii.