Habitat-dependent variation in consistent behavioural traits does not affect the efficiency of resource acquisition in a thermophilic ant

Consistent variation in behavioural traits among individuals is common in many species and such variation has been documented along large-scale environmental gradients across the geographic ranges of several species. However, the effect of local environmental variation on the behaviour of subpopulations and the ecological impact of such variation remain largely unexplored. In this study, we investigated the variation in activity levels and exploration among colonies of the thermophilic ant species, Aphaenogaster senilis , in two undisturbed, geographically close habitats (grassland and woodland) and the effect of this variation on their efficiency of resource acquisition. The two habitats varied significantly in canopy cover and ground temperature at the nest entrances. Colonies in the grassland were more active than those in the woodland although exploration was comparable between the two habitats. Both activity levels and exploration showed repeatability, and colonies that were more active were more exploratory. However, we did not find any clear influences of personality traits on the efficiency of resource acquisition of these colonies and, contrary to our expectations, risk-prone colonies that were more active and exploratory did not forage more efficiently than risk-averse ones. Our study indicates that colonies in different habitats use different strategies to achieve similar degrees of ecological success. Significance statement Variation in local environmental conditions can lead to variation in consistent behavioural (personality) traits of the animals occupying a particular habitat and can affect their ecological functioning. This link between personality traits and the ecological consequences of these traits, such as the effect on foraging, is not frequently studied. We investigated this link in colonies of the thermophilic ant species Aphaenogaster senilis . Colonies present in open areas that had less canopy cover and were exposed to higher temperatures were more active than those present in forest areas. However, this variation had no effect on their foraging success and colonies in both areas were equally efficient in foraging for different food items. This indicates that colonies that are exposed to different environmental conditions have different behavioural strategies to achieve the same level of foraging success.