Data from: Selection and genetic variation in plasticity drive age-related decreases in among-individual behavioural correlations

Among-individual correlations between labile traits arise due to genetic or developmental plasticity correlations. While among-individual trait correlations have been extensively studied in behavioural ecology over the past two decades, the mechanisms underlying age-related changes in among-individual trait correlations remain unclear. Here, using field cricket Gryllus bimaculatus males from a pedigreed population as the study organisms, we investigated how age-related changes in (1) genetic and (2) nongenetic bases of among-individual aggression-exploration correlations, as well as (3) selection, explain age-related variation in an aggression-exploration correlations. Our findings indicate that the magnitudes of both the positive among-individual and genetic correlations were maintained across nymph and young adult stages, but significantly decreased with age during adulthood. This decrease was due to both selection and genetic variation in age-related behavioural plasticity. Selection favoured less explorative males at the young adult stage, which may have eroded the genetic correlations. In addition, genetic variation in age-related plasticity in exploration contributed to a decrease in the magnitude of genetic correlations during the adult stage. The similarity of age-related changes in among-individual and genetic correlations resulted from the absence of short-term permanent environmental correlations. Therefore, the findings of this study suggest that age-related changes in among-individual behavioural correlations are not caused by a single mechanism, but rather a combination of mechanisms, such as genetic variation in age-related behavioural plasticity and selection.