The influence of metabolic heat production on body temperature of a small lizard,Anolis carolinensis

摘要

Little is known about the impact of increased metabolism on body temperatures of small ectotherms.We found that postprandial metabolic rates of 5 g Anolis carolinensis lizards were elevated by factorial increases of 2.3±1.0 (mean±S.E.) at 26 °C and 3.8±2.1 at 30 °C over their fasting rates. Cloacal body temperatures exceeded environmental temperatures by a small amount in fasted individuals (26 °C: 0.3±0.02 °C, 30 °C: 0.3±0.02 °C), and by a significantly largeramount in fed individuals (26 °C: 1.0±0.06 °C, 30 °C: 0.8±0.08 °C).We conclude that an increased metabolic rate due to specific dynamic action leads to a small but significant elevation of body temperature in this species. Comparisons with thermal increments reported for a large (750 g) varanid lizard suggest that body size has only a minor influence on body–air temperature differentials of ectotherms. This is consistent with theoretical predictions. Finally, endogenous heat production could help elevate body temperatures in the wild and therefore play a minor role in thermoregulation.