Keeping your cool: thermoregulatory performance and plasticity in desert cricetid rodents.
Keeping your cool: thermoregulatory performance and plasticity in desert cricetid rodents.
复制标题
保持冷静：沙漠仓鼠啮齿动物的体温调节性能和可塑性。
DOI：
--
复制
发表时间：
2022
影响因子：
2.8
通讯作者：
B. Wolf
中科院分区：
文献类型：
--
作者：
Richard W Ramirez;E. Riddell;S. Beissinger;B. Wolf
炎热沙漠中的小型哺乳动物通常通过夜行性和穴居来避热，并且被认为利用蒸发冷却来散热的能力有限。到目前为止，研究主要集中在对低于体温（Tb）的气温（Ta）的体温调节反应上。因此，人们对暴露在高温下的小型哺乳动物的体温调节性能了解甚少，尤其是在地理和季节尺度上的反应。我们对莫哈韦沙漠四个地点暴露在高温Ta下的四种仓鼠科啮齿动物（白喉林鼠Neotoma albigula、沙漠林鼠N. lepida、荒漠鹿鼠Peromyscus eremicus、灰鹿鼠P. crinitus）的季节性体温调节性能进行了量化。我们使用流通式呼吸测定法测量了新陈代谢、蒸发失水和体温。当暴露在Ta≥Tb的环境中时，啮齿动物的体温急剧上升，大量流涎，蒸发散热有限。大多数个体只能维持约1°C的Ta - Tb梯度，导致耐热极限（HTL）在Ta = 43 - 45°C之间。所有物种都表现出约35 - 36°C的热中性体温，体温上升到约43°C的最高水平。随着Ta接近Tb，所有物种的代谢率和蒸发失水率都急剧上升。我们还观察到，在热中性区及以上的Ta环境下，从夏季到冬季，静息代谢和蒸发失水都显著增加。相比之下，我们发现不同地点的同一物种在体温调节性能上差异不大。我们的研究结果表明，仓鼠科啮齿动物应对超过Tb的环境温度的生理能力有限，快速变暖的环境可能会越来越限制它们的夜行活动。
Small mammals in hot deserts often avoid heat via nocturnality and fossoriality and are thought to have a limited capacity to dissipate heat using evaporative cooling. Research to date has focused on thermoregulatory responses to air temperatures (Ta) below body temperature (Tb). Consequently, the thermoregulatory performance of small mammals exposed to high air temperatures is poorly understood, particularly responses across geographic and seasonal scales. We quantified the seasonal thermoregulatory performance of four cricetid rodents (Neotoma albigula, N. lepida, Peromyscus eremicus, P. crinitus) exposed to high Ta, at four sites in the Mojave Desert. We measured metabolism, evaporative water loss and Tb using flow-through respirometry. When exposed to Ta≥Tb, rodents showed steep increases in Tb, copious salivation and limited evaporative heat dissipation. Most individuals were only capable of maintaining Ta-Tb gradients of ∼1 °C resulting in heat tolerance limits (HTL) ranging from Ta=43-45°C. All species exhibited a thermoneutral Tb of ∼35-36 °C, and Tb increased to maximal levels of∼43°C. Metabolic rates and rates of evaporative water loss increased steeply in all species as Ta approached Tb. We also observed significant increases in resting metabolism and evaporative water loss from summer to winter at Tas within and above the thermoneutral zone. In contrast, we found few differences in the thermoregulatory performance within species across sites. Our results suggest that cricetid rodents have a limited physiological capacity to cope with environmental temperatures that exceed Tb and that a rapidly warming environment may increasingly constrain their nocturnal activity.
影响因子：
56.9
作者：
Riddell, E. A.;Iknayan, K. J.;Beissinger, S. R.
通讯作者：
Beissinger, S. R.