Metabolism and thermoregulation between Mrs Hume's Pheasant (Syrmaticus humiae) and Elliot's Pheasant (S. ellioti).

Abstract

To understand metabolic adaptations, the basal metabolic rate (BMR) of Mrs Hume's Pheasant (Syrmaticus humiae) and Elliot's Pheasant (Syrmaticus ellioti) were investigated. Metabolic rate (MR), body temperature (T(b) ) and thermal conductance (C) were determined in both species at a temperatrue range of 5-35 Degrees Celsius, respectively. Oxygen consumption was measured with a closed circuit respirometer. The thermal neutral zones (TNZ) were 24.5-31.6 Degrees Celsius, and 23.0-29.2 Degrees Celsius, respectively. With a temperature range of 5-35 Degrees Celsius, Mrs Hume's Pheasant and Elliot's Pheasant could maintained stable T(b) at a mean of (40.47 ± 0.64) and (40.36 ± 0.10) Degrees Celsius, respectively. Mean BMRs within TNZs were (1.36 ± 0.84) mLO₂/(g.h) for Mrs Hume's Pheasant and (2.03 ± 0.12) mLO₂/(g.h) for Elliot's Pheasant, which were 77% and 86% of the expected value based on their body mass, respectively. Thermal conductance of Mrs Hume's Pheasant and Elliot's Pheasant were (0.12 ± 0.01) and (0.17 ± 0.01) mLO₂/(g.h.Degrees Celsius), below the lower critical temperature, respectively, which were 119% and 124% of the expected value based on their body mass, respectively. The ecophysiological characteristics of these species were low metabolic rate, high body temperature, and high thermal conductance, which allow both species to better adapt to the warmer climate environment in south China.