Integrating mortality risks and theadaptiveness of hibernation

Théo Constant (1) , Sylvain Giroud (2) , Vincent Viblanc (1) , Mathilde Tissier (3) , Patrick Bergeron (3) , F Stephen Dobson (4) , Caroline Habold (1)

1 DEPE-IPHC - Département Ecologie, Physiologie et Ethologie
2 Vetmeduni - University of Veterinary Medicine [Vienna]
3 Bishop's University
4 AU - Auburn University

Low mortality rate is often associated with slow life history, and so far, has mainly been assessed through examinations of specific adaptations and lifestyles that limit mortality risk. However, the organization of activity time budgets also needs to be considered, since some activities and the time afforded for performing them may expose animals to higher mortality risks such as increased predation and/or increased metabolic stress, including oxidative stress. We examined the extent of activity time budgets contribution to explaining variation in life history traits in mammals. We specifically focused on hibernating species because of their marked seasonal cycle of activity/inactivity associated with very different mortality risks. Hibernation is considered a seasonal adaptation to prolonged periods of food shortage and cold. This inactivity period may also reduce both extrinsic and intrinsic mortality risks, by decreasing exposure to predators and drastically reducing metabolic rate. In turn, reduction in mortality may explain why hibernators have slower life history traits than non-hibernators of the same size. Using phylogenetically controlled models, we tested the hypothesis that longevity was positively correlated with the hibernation season duration (the time spent between immergence and emergence from the hibernaculum or den) across 82 different mammal species. We found that longevity increased significantly with hibernation season duration, an effect that was particularly strong in small hibernators (< 1.5kg) especially for bats. These results confirm that hibernation not only allows mammals to survive periods of energy scarcity, but further suggest that activity time budgets may be selected to reduce mortality risks according to life history pace.

Mots clés: Life History; activity pattern; time and energy allocation; Trade off; hibernator; temporal organization of activity; predation; Size

Domaines: Sciences de l'environnement

Théo Constant, Sylvain Giroud, Vincent Viblanc, Mathilde Tissier, Patrick Bergeron, et al.. Integrating mortality risks and theadaptiveness of hibernation. Frontiers in Physiology, 2020. ⟨hal-02732950⟩