Data from: Exploratory behavior undergoes genotype-age interactions in a wild bird

Animal personality traits are often heritable and plastic at the same
time. Indeed, behaviors that reflect an individual's personality can
respond to environmental factors or change with age. To date, little is
known regarding personality changes during a wild animals' lifetime
and even less about stability in heritability of behavior across ages. In
this study, we investigated age‐related changes in the mean and in the
additive genetic variance of exploratory behavior, a commonly used measure
of animal personality, in a wild population of great tits. Heritability of
exploration is reduced in adults compared to juveniles, with a low genetic
correlation across these age classes. A random regression animal model
confirmed the occurrence of genotype–age interactions (G×A) in
exploration, causing a decrease in additive genetic variance before
individuals become 1 year old, and a decline in cross‐age genetic
correlations between young and increasingly old individuals. Of the few
studies investigating G×A in behaviors, this study provides rare evidence
for this phenomenon in an extensively studied behavior. We indeed
demonstrate that heritability and cross‐age genetic correlations in this
behavior are not stable over an individual's lifetime, which can
affect its potential response to selection. Because G×A is likely to be
common in behaviors and have consequences for our understanding of the
evolution of animal personality, more attention should be turned to this
phenomenon in the future work.