Résumé
Environmental heterogeneity can result in spatial variation in selection
pressures that can produce local adaptations. The pace-of-life syndrome
hypothesis predicts that habitat-specific selective pressures will favor
the coevolution of personality, physiological, and life-history
phenotypes. Few studies so far have compared these traits simultaneously
across different ecological conditions. In this study, we compared 3
personality traits (handling aggression, exploration speed in a novel
environment, and nest defense behavior) and 1 physiological trait (heart
rate during manual restraint) across 3 Corsican blue tit (Cyanistes
caeruleus) populations. These populations are located in contrasting
habitats (evergreen vs. deciduous) and are situated in 2 different valleys
25 km apart. Birds from these populations are known to differ in
life-history characteristics, with birds from the evergreen habitat
displaying a slow pace-of-life, and birds from the deciduous habitat a
comparatively faster pace-of-life. We expected personality to differ
across populations, in line with the differences in pace-of-life
documented for life-history traits. As expected, we found behavioral
differences among populations. Despite considerable temporal variation,
birds exhibited lower handling aggression in the evergreen populations.
Exploration speed and male heart rate also differed across populations,
although our results for exploration speed were more consistent with a
phenotypic difference between the 2 valleys than between habitats. There
were no clear differences in nest defense intensity among populations. Our
study emphasizes the role of environmental heterogeneity in shaping
population divergence in personality traits at a small spatial scale.