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.Pedigree_AGE_ESMPedigree used for quantitative genetic analyses of exploratory behavior in great titsPheno_data_AGE_ESMPhenotypic data used for quantitative genetic analyses of exploratoy behavior (LOCOM) in great tits.TESTAGE = age (in months) at which individuals are tested. June days= date (in june days) on which individuals are testedScript_Character_State_ESMScript for the character state approach (bivariate animal model)Script_Random_Regression_ESMScript for the random regression animal model approachScript_Figure1_ESMScript for producing Figure 1pin_RRScript of the pin_RR function to derive age-specific quantitative genetic estimates from random regression models (asreml)Script_Simulations_ESMScript for simulations (no GxA) and analysis of simulated data (RRAM)Results_Sim_No_GXAResults of the simulationScript_Survival_Young_ESMScript for the test of selective disappearanceSurvival_Young_ESMData for the test of selective disappearancePedigree_SEX_ESMpedigree used for sex-specific quantitative genetic analysesPheno_data_SEX_ESMphenotypic data used for sex-specific quantitative genetic analysesScript_Test_Sexes_ESMScript used for sex-specific quantitative genetic analyse