Crowley Shawn R
Department of Biology, University of New Mexico, 87131, Albuquerque, N Mex, USA.
Oecologia. 1985 May;66(2):219-225. doi: 10.1007/BF00379858.
The thermal sensitivity of sprint-running ability was investigated in two populations of Sceloporus undulatus that occupy thermally distinct habitats. Integration of field and laboratory data indicates that lizards inhabiting a cool, high-elevation habitat are frequently active at body temperatures that retard sprint-running velocity, which could affect adversely their ability to evade predators and to capture prey. These negative effects might be expected to select for local adaptation of thermal physiology. No differences in thermal physiology (optimal temperature for sprinting, critical thermal limits) were found, however, between lizards from the two habitats.Preferred body temperature of Sceloporus undulatus is lower than the body temperature that maximizes sprint velocity but is still well within an 'optimal performance range' where lizards can run at better than 95% of maximum velocity. Analysis of data from other studies shows a similar concordance of preferred body temperature and temperatures that maximize sprint velocity for some, but not all lizard species studied.Low diversity of predators and high levels of food may compensate in part for the reduced sprinting ability of highelevation lizards active at low body temperatures. The lack of population differentiation supports the view that lizard thermal physiology is evolutionarily conservative.
在两种栖息于热环境不同的栖息地的西部强棱蜥种群中，研究了短跑能力的热敏感性。野外和实验室数据的整合表明，栖息在凉爽、高海拔栖息地的蜥蜴，在体温会减缓短跑速度的情况下仍频繁活动，这可能会对它们躲避捕食者和捕获猎物的能力产生不利影响。这些负面影响可能会促使热生理学产生局部适应性变化。然而，在来自这两种栖息地的蜥蜴之间，并未发现热生理学方面的差异（短跑的最佳温度、临界热极限）。西部强棱蜥偏好的体温低于使短跑速度最大化的体温，但仍处于“最佳表现范围”内，在此范围内蜥蜴能够以超过最大速度95%的速度奔跑。对其他研究数据的分析表明，对于一些（但并非所有）所研究的蜥蜴物种，偏好体温和使短跑速度最大化的体温之间存在类似的一致性。低水平的捕食者多样性和丰富的食物资源，可能会部分弥补高海拔蜥蜴在低体温下活动时短跑能力的下降。种群分化的缺乏支持了蜥蜴热生理学在进化上较为保守的观点。
