Ambient temperature and thermal variability play a crucial role in diverse aspects of organisms' biology. In the current context of climate change, it is critical to understand how temperature impacts traits that could affect fitness. In Phyllotis xanthopygus, a small altricial rodent inhabiting an altitudinal gradient in the Andes Mountains of Argentina, the behavioral response to temperature varies between populations from different altitudes. Animals from high altitude (cold environment) reduce their activity rate at high temperatures, in contrast to animals from low altitude (relatively warmer environment). The goal of this study was to unveil the mechanism underlying such intraspecific behavioral variability in P. xanthopygus. We characterized activity rates under different thermal treatments both for wild-reared and lab-reared animals. As we expected, the intraspecific variability shown by animals raised at different altitudes in the field disappeared in animals raised under homogenous conditions in the laboratory. Our results are indicative of ontogenetic plasticity in P. xanthopygus and suggest that the behavioral versatility of adult individuals to deal with thermal challenges is shaped by the range of environmental conditions experienced during their early life. This adds to the list of features that modulate the biological performance of individuals and could influence the relative vulnerability of populations inhabiting different elevations under the global disturbance of climate change.

中文翻译：

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发育环境影响山地啮齿动物 Phyllotis xanthopygus 的活动水平

环境温度和热变化在生物体生物学的各个方面都起着至关重要的作用。在当前气候变化的背景下，了解温度如何影响可能影响健康的特征至关重要。在 Phyllotis xanthopygus 中，一种栖息在阿根廷安第斯山脉海拔梯度的小型高地啮齿动物，对温度的行为反应在不同海拔的种群之间有所不同。与来自低海拔（相对温暖的环境）的动物相比，来自高海拔（寒冷环境）的动物在高温下会降低其活动率。本研究的目的是揭示 P. xanthopygus 中这种种内行为变异的潜在机制。我们对野生饲养和实验室饲养的动物在不同热处理下的活动率进行了表征。正如我们预期的那样，在田间不同高度饲养的动物所表现出的种内变异性在实验室同质条件下饲养的动物中消失了。我们的结果表明了 P. xanthopygus 的个体发育可塑性，并表明成年个体应对热挑战的行为多样性是由他们早期经历的环境条件范围决定的。这增加了调节个体生物性能的特征列表，并可能影响在全球气候变化干扰下居住在不同海拔的人群的相对脆弱性。我们的结果表明了 P. xanthopygus 的个体发育可塑性，并表明成年个体应对热挑战的行为多样性是由他们早期经历的环境条件范围决定的。这增加了调节个体生物性能的特征列表，并可能影响在全球气候变化干扰下居住在不同海拔的人群的相对脆弱性。我们的结果表明了 P. xanthopygus 的个体发育可塑性，并表明成年个体应对热挑战的行为多样性是由他们早期经历的环境条件范围决定的。这增加了调节个体生物性能的特征列表，并可能影响在全球气候变化干扰下居住在不同海拔的人群的相对脆弱性。