Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala, México.
Sable Systems International, Las Vegas, Nevada, USA.
Integr Zool. 2020 Sep;15(5):363-374. doi: 10.1111/1749-4877.12434. Epub 2020 May 23.
Individuals that inhabit broad elevational ranges may experience unique environmental challenges. Because temperature decreases with increased elevation, the ectotherms living at high elevations have to manage limited activity time and high thermoregulatory effort. The resting metabolic rate (RMR) of a postabsorptive animal is related to its total energy requirements as well as many other fitness traits. Mesquite lizards (Sceloporus grammicus) living on La Malinche Volcano, Mexico, inhabit a wide elevational range with some populations apparently thriving above the tree line. We measured the RMR of lizards from different elevations (i.e., 2,600, 3,200, and 4,100 m) at four ecologically relevant temperatures (i.e., 15, 25, 30, and 35 °C) and found that RMR of mesquite lizards increased with temperature and body mass. More importantly, lizards from the high-elevation population had mass specific RMR that was higher at all temperatures. While the higher RMRs of high-elevation populations imply higher metabolic costs at a given temperature these lizards were also smaller. Both of these traits may allow these high elevation populations to thrive in the face of the thermal challenges imposed by their environment.
生活在广泛海拔范围内的个体可能会经历独特的环境挑战。由于温度随海拔升高而降低，生活在高海拔地区的变温动物必须管理有限的活动时间和高体温调节努力。吸收后动物的静止代谢率（RMR）与其总能量需求以及许多其他适应特征有关。生活在墨西哥拉马林切火山的刺尾蜥（Sceloporus grammicus）栖息在一个很宽的海拔范围内，一些种群显然在树线以上茁壮成长。我们在四个生态相关的温度（即 15、25、30 和 35°C）下测量了来自不同海拔（即 2600、3200 和 4100 米）的蜥蜴的 RMR，并发现刺尾蜥的 RMR 随温度和体重而增加。更重要的是，来自高海拔种群的蜥蜴在所有温度下的比 RMR 都更高。虽然高海拔种群的更高 RMR 意味着在给定温度下代谢成本更高，但这些蜥蜴的体型也更小。这两个特征都可能使这些高海拔种群在面对环境带来的热挑战时茁壮成长。
