Torpor is an energy saving strategy achieved by substantial reductions of metabolic rate and body temperature that enables animals to survive periods of low resource availability. During hibernation (multiday torpor), the frequency of periodic rewarming—characterised by high levels of oxidative stress—is associated with shortening of telomeres, a marker of somatic maintenance. In this study, we determined the impact of ambient temperature on feeding behaviour and telomere dynamics in hibernating garden dormice (Eliomys quercinus) over winter. This obligate hibernator prepares for hibernation by accumulating fat stores but can also feed during hibernation. Food intake, torpor pattern, changes in telomere length, and body mass change were assessed in animals housed at experimentally controlled temperatures of either 14 °C (i.e., a mild winter) or 3 °C (i.e., a cold winter) over 6 months. When hibernating at 14 °C, dormice experienced 1.7-fold more frequent and 2.4-fold longer inter-bout euthermia, and spent significantly less time torpid, compared to animals hibernating at 3 °C. Higher food intake enabled individuals to compensate for increased energetic costs when hibernating at milder temperatures (14 °C vs. 3 °C), to buffer body mass loss and thus increase winter survival. Interestingly, we observed a significant increase of telomere length over the entire hibernation period, irrespective of temperature treatment. We conclude that higher temperatures during winter, if associated with sufficient food availability, can have a positive effect on the individual’s energy balance and somatic maintenance. These results suggest that winter food availability might be a crucial determinant for the survival of the garden dormouse in the context of ever-increasing environmental temperatures.

中文翻译：

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食物供应对冬眠花园睡鼠（Eliomys quercinus）的生存和体细胞维持有积极影响


冬眠是一种通过大幅降低代谢率和体温来实现的节能策略，使动物能够在资源匮乏的时期生存下来。在冬眠期间（多天的休眠），周期性复温的频率（以高水平的氧化应激为特征）与端粒的缩短有关，端粒是躯体维持的标志。在这项研究中，我们确定了冬季环境温度对冬眠花园睡鼠（Eliomys quercinus）的摄食行为和端粒动态的影响。这种专性冬眠者通过积累脂肪储备来为冬眠做准备，但也可以在冬眠期间进食。在实验控制温度 14°C（即温和的冬季）或 3°C（即寒冷的冬季）饲养的动物 6 个月内，对食物摄入量、麻木模式、端粒长度的变化和体重变化进行了评估。与在 3 °C 下冬眠的动物相比，在 14 °C 下冬眠时，睡鼠经历的体温升高频率高出 1.7 倍，间歇期的体温延长了 2.4 倍，而且呆滞的时间也明显减少。较高的食物摄入量使个体能够补偿在较温和的温度（14°C 与 3°C）冬眠时增加的能量消耗，缓冲体重损失，从而提高冬季存活率。有趣的是，我们观察到在整个冬眠期间端粒长度显着增加，与温度处理无关。我们得出的结论是，冬季较高的气温如果与充足的食物供应相关，可以对个体的能量平衡和躯体维持产生积极影响。 这些结果表明，在环境温度不断升高的情况下，冬季食物的供应可能是花园睡鼠生存的关键决定因素。