Effects of hibernation temperature and duration on oxidative status in the common wall lizard (Podarcis muralis)

Abstract

Global warming is expected to alter phenology in temperate ectotherms by advancing spring arousal and delaying autumn entry into hibernation. However, the physiological consequences of such shifts remain poorly understood in reptiles, particularly with respect to oxidative balance. We investigated the effects of hibernation temperature and duration on oxidative status in the common wall lizard (Podarcis muralis). Oxidative markers were measured in the liver and tail during the pre-hibernation period and after exposure to laboratory-simulated winter regimes differing in temperature (∼2.5 °C vs. 5.5 °C) and duration (three vs. four months), representing short-cold, short-mild, long-cold, and long-mild winter scenarios. Hibernation duration exerted generally inconsistent effects on antioxidant defenses, with changes detected in liver superoxide dismutase, catalase, and glutathione, as well as in tail superoxide dismutase and glutathione. Temperature effects were modest, manifesting as upward trends in liver glutathione content and tail catalase activity, without significant interactions with hibernation duration. Cold-winter regimes were associated with increased lipid oxidative damage in the liver, although this response was not consistent across all treatments. Importantly, most oxidative parameters remained comparable to pre-hibernation values, with a significant reduction in glutathione levels observed only under short-cold conditions. Overall, the maintenance of redox homeostasis across contrasting thermal and temporal winter regimes indicates substantial physiological plasticity and resilience of P. muralis to altered thermal environments during hibernation, highlighting the capacity of reptiles to buffer oxidative challenges imposed by climate-driven changes in winter conditions.