Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
College of Wildlife Resources, Northeast Forestry University, Harbin 150040, People's Republic of China.
Proc Biol Sci. 2023 Oct 25;290(2009):20231768. doi: 10.1098/rspb.2023.1768.
Climate change often includes increases in the occurrence of extreme environmental events. Among these, heatwaves affect the pace of life and performance of wildlife, particularly ectothermic animals, owing to their low thermoregulatory abilities. However, the underlying mechanisms by which this occurs remain unclear. Evidence shows that heatwaves alter the redox balance of ectotherms, and oxidative stress is a major mediator of life-history trade-offs. Therefore, oxidative stress may mediate the effect of extreme thermal conditions on the life histories of ectotherms. To test this hypothesis, a 2 × 2 experiment was conducted to manipulate the redox balance (through a mitochondrial uncoupler that alleviates oxidative stress) of the desert toad-headed agama () exposed to heatwave conditions. We recorded lizard growth and survival rates and quantified their redox and immune statuses. In control lizards (unmanipulated redox balance), heatwave conditions decreased growth and survival and induced oxidative damage and immune responses. By contrast, lizards with alleviated oxidative stress showed close-to-normal growth, survival, and immune status when challenged with heatwaves. These results provide mechanistic insight into the role of oxidative stress in mediating the effects of extreme temperatures on ectothermic vertebrates, which may have major eco-evolutionary implications.
气候变化通常包括极端环境事件发生频率的增加。在这些事件中，热浪会影响野生动物的生活节奏和表现，尤其是那些体温调节能力较低的变温动物。然而，其发生的潜在机制尚不清楚。有证据表明，热浪会改变变温动物的氧化还原平衡，而氧化应激是生物史权衡的主要介导者。因此，氧化应激可能介导极端热条件对变温动物生物史的影响。为了验证这一假设，我们进行了一项 2×2 的实验，通过一种缓解氧化应激的线粒体解偶联剂来操纵沙漠蟾头螈（）的氧化还原平衡，使其暴露在热浪条件下。我们记录了蜥蜴的生长和存活率，并量化了它们的氧化还原和免疫状态。在对照蜥蜴（氧化还原平衡未受干预）中，热浪条件降低了生长和存活率，并诱导了氧化损伤和免疫反应。相比之下，当受到热浪挑战时，氧化应激得到缓解的蜥蜴表现出接近正常的生长、存活和免疫状态。这些结果为氧化应激在介导极端温度对变温脊椎动物的影响方面的作用提供了机制上的见解，这可能具有重大的生态进化意义。
