Metabolism and thermoregulation in three species of rodent from Northeastern China

Metabolic rate, body temperature, and thermal conductance were determined in the gray red-backed vole (Clethrionomys rufocanus), large Japanese field mouse (Apodemus speciosus) and striped field mouse (Apodemus agrarius) at a temperature range of 5-32.5degreesC. Oxygen consumption was measured by using a closed circuit respirometer. The thermal neutral zone of gray red-backed vole, large Japanese field mouse and striped field mouse were 22.5-27.5degreesC, 25-30degreesC and 25-27.5degreesC, respectively. The mean metabolic rates within thermal zone of these species were 3.62+/-0.18, 2.69+/-0.08, and 3.29+/-0.11 ml O(2) g(-1) h(-1), respectively, which are relatively higher than the predicted values based on their body mass. Non-shivering thermogenesis of these animals were 6.76+/-0.12, 5.56+/-0.39 and 6.13+/-0.28 ml 0(2) g(-1) h(-1), respectively. Mean body temperature of the three species were 37.1+/-0.13degreesC, 36.9+/-0.2degreesC, and 37.5+/-0.2degreesC, respectively. Mean thermal conductance of the three species were 0.25+/-0.04, 0.23+/-0.00 and 0.25+/-0.00ml O(2) g(-1) h(-1)degreesC(-1), respectively. The ecophysiological properties of these species were: (1) the gray red-backed vole and large Japanese field mouse had high body temperatures and metabolic rates, median non-shivering thermogenesis, relatively wide thermal neutral zones and low lower critical temperatures, and relatively high thermal conductance. All these characteristics might constrain their distribution and extension to extreme desert, low latitudes and hot regions in China. (2) the striped field mouse had high metabolic rate, body temperature and thermal conductance, median non-shivering thermogenesis, a relatively narrow thermal neutral zone and low lower critical temperature. (C) 2004 Elsevier Ltd. All rights reserved.