作 者 ：舒霖,张群利,屈彦福,计翔*
期 刊 ：生态学报 2010年 30卷 8期 页码：2036~2042
关键词：鬣蜥科；青海沙蜥；选择体温；热耐受性；疾跑速；食物同化；
Keywords:agamidae, Phrynocephalus vlangalii, thermal tolerance, selected body temperature, sprint speed, food assimilation,
摘 要 ：研究了青海沙蜥（Phrynocephalus vlangalii）成体的选择体温、热耐受性及食物同化和运动表现的热依赖性。结果显示：选择体温、临界低温和临界高温无显著的两性差异，其平均值分别为33.3、0.9 ℃和46.9 ℃。在27-35 ℃实验温度范围内，体温显著影响日摄食量，表观消化系数（ADC）和同化效率（AE）无显著影响。停顿次数随着体温的升高而降低，至39 ℃时停顿次数最少，但与37 ℃和41 ℃处理下的停顿次数无显著差异。疾跑速在17-39 ℃范围内随体温升高而加快，在39 ℃体温下最快。体温大于39 ℃后速度减慢。在17-27 ℃体温范围内，随体温的升高持续运动距离无显著差异。持续运动距离在29-41 ℃ 体温下大于较低体温（17-27 ℃）下的测定值。
Abstract:Temperature is the single most important environmental factor affecting many biological processes in organisms. Ectotherms are viable under a wide range of body temperatures, but their physiological processes and behavioral performances are usually maximized at moderate to relatively high body temperatures. We collected Qinghai toad\|headed lizards (Phrynocephalus vlangalii; Agamidae) in August 2005 from a population in Qinghai (northwestern China) and used adults to study selected body temperature (Tsel), thermal tolerance \[critical thermal minimum (CTmin) and critical thermal maximum (CTmax)\] and the thermal dependence of food assimilation and locomotor performance. Tsel was measured on a laboratory thermal gradient ranging from 18 ℃ to 60 ℃ (20 mm above the terrarium floor); CTmin and CTmax were determined in an incubator, with lizards being cooled or heated from 28 ℃ at the rate of 0.25 ℃ per minute and more slowly when temperatures inside the incubator were lower than 5 ℃ or higher than 40 ℃. We did not find between\|sex differences in Tsel, CTmin and CTmax, and thus pooled data for both sexes. The mean values for Tsel, CTmin and CTmax were 33.3 ℃, 0.9 ℃ and 46.9 ℃, respectively. Within the range from 27 ℃ to 35℃, body temperature affected daily food intake but had no important role in influencing apparent digestive coefficient and assimilation efficiency. Thus, consistent with the results reported for a wide range of lizard taxa, our data show that digestive performance is less sensitive to variation in body temperature in P. vlangalii. The number of stops in the racetrack decreased with increase in body temperature within the range from 17 ℃ to 39 ℃, and then increased at 41 ℃. Sprint speed increased with increase in body temperature within the range from 17 ℃ to 39 ℃, and then decreased at 41 ℃. The mean values for the length of continuous locomotion were overall greater at higher body temperatures (29-41℃) than at lower temperatures (17-27 ℃). Overall, body temperatures within the range of 33-41 ℃ were optimal for locomotion. When comparing our data with those reported for temperate and warm\|climate lizards, we found that body temperatures maximizing locomotor performance are relatively high in P. vlangalii. Our data support the idea that Tsel represents the body temperature at which numerous processes function at a relatively high level, as revealed by the fact that Tsel fell within the range of temperatures optimal for locomotor performance in P. vlangalii. Inter\|specific comparisons reveal that lizards using different habitats and occupying different geographic (climatic) regions differ in both CTmin and CTmax. Overall, CTmin is greater in lizards using warmer habitats or living in warmer localities, and CTmax is greater in lizards using opened habitats. Qinghai toad\|headed lizards are typically found in open spaces in arid or semi\|arid regions covered sparse vegetation. The region occupied by P. vlangalii is climatically severe, where daily and seasonal fluctuations in ambient temperature are very pronounced. Thus, the enhanced ability to tolerate temperature extremes seen in P. vlangalii is likely determined evolutionarily as a consequence of adaptation to local thermal conditions.
全 文 ：