Repeatability and heritability of social reaction norms in a wild agamid lizard

In the evolutionary transition from solitary to group living, it should be adaptive for animals to respond to the environment and choose when to socialise to reduce conflict and maximise access to resources. Due to the associated proximate mechanisms (e.g. neural network, endocrine system), it is likely that this behaviour varies between individuals according to genetic and non-genetic factors. We used long-term behavioural and genetic data from a population of eastern water dragons (Intellagama lesueurii) to explore variation in plasticity of social behaviour, in response to sex ratio and density. To do so, we modelled individual variation in social reaction norms, which describe individuals’ mean behaviour and behavioural responses to changes in their environment, and partitioned variance into genetic and non-genetic components. We found that reaction norms were repeatable over multiple years, suggesting that individuals consistently differed in their behavioural responses to changes ...