Food, sex and predators: animal personality persists with multidimensional plasticity across complex environments

The payoffs of an individualʹs behaviour vary with changing environmental conditions. Animals often modify their behaviours according to those environmental conditions (i.e. plasticity), but also retain consistent individual differences across environmental change (i.e. personality). These patterns of behavioural variation are often measured with respect to a single environmental variable, which raises the question of how individuals respond to change in combinations of environmental variables, and whether individual differences in behaviour persist across change in multiple variables. Furthermore, an individualʹs amount of plasticity in response to a change in one environmental variable may or may not be repeatable across change in a second environmental variable. To answer these questions, we experimentally manipulated combinations of mating, foraging and predation risk to determine their effect on the antipredator behaviour of male Beldingʹs ground squirrels, Urocitellus beldingi. We found that the combination of environmental variables had an interactive effect on antipredator behaviour, but among-individual variation persisted along with within-individual variation in behaviour. The plasticity of squirrelsʹ responses to change in one environmental variable, such as change in antipredator behaviour from high to low predation risk, was repeatable when measured in a mating environment and foraging environment, and vice versa. These results demonstrate patterns of behavioural variation across complex environments such as animals encounter in nature, and point towards the benefit of addressing greater environmental complexity in studies of animal behaviour.