Wu Qiong, Dang Wei, Hu Ying-Chao, Lu Hong-Liang
Hangzhou Key Laboratory for Animal Adaptation and Evolution, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, Zhejiang, PR China.
Hangzhou Key Laboratory for Animal Adaptation and Evolution, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, Zhejiang, PR China.
J Therm Biol. 2018 Jan;71:136-141. doi: 10.1016/j.jtherbio.2017.11.005. Epub 2017 Nov 13.
Population differentiation in ectotherm physiological performance may be driven by adapting to different thermal environments. In this study, we measured locomotor performance in two different altitude populations of the Qinghai toad-headed lizards (Phrynocephalus vlangalii) at different test temperatures to assess between-population differences in thermal sensitivity of sprint speed. Low-elevation lizards ran faster than high-elevation lizards at most test temperatures. Sprint speed varied with test temperature similarly between populations, but the thermal sensitivity (performance breadth) differed significantly. Low-elevation lizards had a lower optimal temperature (T) for sprint speed and narrower performance breadth than high-elevation lizards as inferred from the thermal performance curves constructed for each individual. We also measured the body temperature of active lizards (T) in the field and selected temperature (T) in the laboratory. Low-elevation lizards had a lower T, and less variable T than high-elevation lizards. In both populations, T was lower than T for sprint speed, which was inconsistent with the prediction for a match between thermal preference and T. Our results suggest that lower thermal sensitivity and weaker locomotor ability for high-elevation lizards may be an adaptive response to the local environmental conditions (e.g., greater thermal variability, higher food availability, and lower predator pressure).
变温动物生理性能的种群分化可能是由适应不同的热环境所驱动的。在本研究中，我们在不同的测试温度下测量了青海沙蜥（Phrynocephalus vlangalii）两个不同海拔种群的运动性能，以评估种群间冲刺速度热敏感性的差异。在大多数测试温度下，低海拔蜥蜴比高海拔蜥蜴跑得更快。种群间冲刺速度随测试温度的变化相似，但热敏感性（性能广度）存在显著差异。根据为每个个体构建的热性能曲线推断，低海拔蜥蜴的冲刺速度最佳温度（T）较低，性能广度比高海拔蜥蜴更窄。我们还测量了野外活动蜥蜴的体温（T）和实验室中的选择温度（T）。低海拔蜥蜴的T比高海拔蜥蜴更低，且T的变化更小。在两个种群中，T均低于冲刺速度的T，这与热偏好和T之间匹配的预测不一致。我们的结果表明，高海拔蜥蜴较低的热敏感性和较弱的运动能力可能是对当地环境条件（如更大的热变异性、更高的食物可利用性和更低的捕食压力）的适应性反应。
