Behavioural syndromes and structural and temporal consistency of behavioural traits in a social lizard

Understanding how behavioural traits co-vary within and between individuals is a major aim of behavioural ecologists working across a wide range of taxa. Here we attempted to measure five key behavioural traits (aggression, boldness, exploration, activity and sociability) in a native Australian social skink, Egernia whitii. Specifically, we documented the temporal consistency of trait structural definition, the temporal consistency of trait expression and the relationships between behavioural traits (i.e. behavioural syndromes). We found (1) that the structural consistency of some traits (boldness), but not others (aggressiveness and exploration), changed across time and according to sex (i.e. the relationship between the raw behaviours that were measured in the boldness assay was different for males and females); (2) that three of the five behavioural traits exhibited moderate-to-high adjusted repeatability while two were not repeatable; (3) covariances between behavioural traits were weak to non-existent and did not support the presence of any behavioural syndromes. These results indicate that structural consistency of traits or the behavioural definition' of an aggregate score is potentially variable over time. This may limit inference on any subsequent estimates of repeatability of behavioural traits, as well as estimates of potential syndromes. Repeatability of behavioural traits may reflect underlying ecological importance, or measurement processes, and lack of behavioural syndromes may reflect lack of selection pressure for trait covariance. Studies examining multiple behavioural traits under a measurement as well as an ecological framework are crucial to make meaningful inferences regarding the ecological and evolutionary significance of behavioural traits.