Thermal dependence of food assimilation and locomotor performance in juvenile blue-tailed skinks, Eumeces elegans

摘要

Variation in the physiological performance and behaviour of ectotherms as a result of changes in body temperature can affect important life-history traits. Studies investigating the effects of temperature on physiological performance and behaviour have thus clear ecological significance. We captured juvenile blue-tailed skinks, Eumeces elegans, from a population in Zhejiang, eastern China, and determined the effects of temperature on their food assimilation and locomotor performance. Food intake of the juveniles generally increased with increase in temperatures within the range of 24-30 degrees C and decreased at higher temperatures. The temperature significantly affected the apparent digestive coefficient (ADC) and the assimilation efficiency (AE) of juveniles; the ADC and AE of the skinks at 32 degrees C were higher than those of skinks at other temperatures. The sprint speed increased with increase in temperature within the range of 12-32 degrees C and decreased at higher temperatures. These results suggest the patterns of thermal sensitivity may differ in various functional performances, and hence support the 'multiple optima hypothesis', which suggests that no specific temperature maximises all functional performance. In addition, this study indicates significant between-age difference in thermal physiology by comparing our data with those on adult skinks, including different thermal sensitivity of AE, and different ranges of thermal-performance breadth for food intake and locomotor performance between juvenile and adult E. elegans.