Abstract
Despite a growing body of literature reporting developmental changes in personality, few studies have adopted a lifetime perspective to study age-related changes in personality traits. Since most personality traits are heritable and linked with fitness, ontogenetic changes can have evolutionary implications. In this paper, we explore age-related changes in two behavioral responses to handling, both of which are heritable and associated with fitness, in wild blue tits. We find that one of these responses (handling aggression), which is positively correlated with fitness, declines with age. We show that this age-related decline is not due to selective disappearance, but occurs also within individuals, which confirms that this personality trait undergoes a senescent decline in the wild. We further find that individuals differ significantly in their rate of ageing but found no statistical support for the presence of genotype-age interactions on personality. Future research on personality would benefit from a more explicit lifetime perspective.
Barbara Class
Researcher
I am a researcher interested in among-individual differences in wild vertebrate populations.