Exploration behavior and parental effort in wild great tits: partners matter

摘要

The extended pace-of-life syndrome (POLS) hypothesis suggests that variation in boldness-like behaviors has co-evolved with variation in life-history strategies within populations, yet both theoretically driven experiments and evidence for phenotypic correlations between boldness-like behaviors and reproduction-related activities are scarce. Here we test the prediction that more exploratory individuals should be willing to provide more effort into current reproduction than less exploratory ones by investigating the association between exploration behavior and parental effort in wild great tits (Parus major). To this end, we assessed exploration behavior following a standardized assay. Then, we estimated individual willingness to provide parental effort into brood provisioning as (1) individual increase in nest visit rate after the brood had been artificially enlarged and (2) individual latency to return to the nest after this manipulation. Fast male explorers were quicker than slow explorers to return to the nest after the manipulation. Males paired with a partner of similar exploration score—either a fast or slow female explorer —increased their nest visit rate more than males paired with a partner of dissimilar exploration score. The relationship between exploration and parental effort then depended on one’s partner’s behavior. Our test thus provides only partial support for the extended POLS hypothesis and highlights the potential importance of the social environment in shaping the relationship between boldness-like behaviors and fitness-maximizing traits.