Adaptive significance of affiliative behaviour differs between sexes in a wild reptile population

In recent years, we have begun to appreciate that social behaviours might exhibit repeatable among-individual variation. Such behavioural traits may even covary and have critical evolutionary implications. Importantly, some social behaviours such as aggressiveness have been shown to provide fitness benefits, including higher reproductive success and survival. However, fitness consequences of affiliative behaviours, especially between or among sexes, can be more challenging to establish. Using a longitudinal behavioural dataset (2014-2021) collected on eastern water dragons (Intellagama lesueurii), we investigated whether various aspects of affiliative behaviour (1) were repeatable across years, (2) covaried with each other at the among-individual level, and (3) influenced individuals’ fitness. In particular, we considered affiliative behaviours towards opposite-sex and same-sex conspecifics separately. We found that social traits were repeatable and covaried with each other similarly fo..., Data collection
We used data collected as part of an ongoing behavioural study that started in 2010 of an urban population of Eastern water dragons inhabiting Roma Street Parkland (RSP), Brisbane, Australia (27°27’46’S, 153°1’11’E). The RSP population has an estimated size of 336 individuals which are highly habituated to human presence. The parkland spans approximately 16 hectares and is composed of various habitats differing in size, complexity and heterogeneity of structure, vegetation and access to water.
Behavioural data
We carried out behavioural surveys twice a day (0730-1030 and 1300-1600), by following a transect which covers approximately 85% of the known population, three days a week from September to April (when dragons are most active) each year. For each individual, we took a photo of their left and/or right profile, along with their GPS location which was later used to calculate spatial proximity and define social associations (see ‘Social traits’ section). An individual’..., Excel