Effects of mild wintering conditions on body mass and corticosterone levels in a temperate reptile, the aspic viper (Vipera aspis)
Résumé
Temperate ectotherms are expected to benefit fromclimate change (e.g., increased activity time), but the impacts
of climate warming during the winter have mostly been overlooked. Milder winters are expected to decrease
body condition upon emergence, and thus to affect crucial life-history traits, such as survival and reproduction.
Mildwinter temperature could also trigger a state of chronic physiological stress due to inadequate thermal conditions
that preclude both dormancy and activity. We tested these hypotheses on a typical temperate ectothermic
vertebrate, the aspic viper (Vipera aspis). We simulated different wintering conditions for three groups of
aspic vipers (cold: ~6 °C, mild: ~14 °C and no wintering: ~24 °C) during a one month long period. We found
that mild wintering conditions induced a marked decrease in body condition, and provoked an alteration of
some hormonal mechanisms involved in emergence. Such effects are likely to bear ultimate consequences on reproduction,
and thus population persistence. We emphasize that future studies should incorporate the critical,
albeit neglected, winter season when assessing the potential impacts of global changes on ectotherms.