Meeting Abstract
18.4 Tuesday, Jan. 4 Energetics, thermoregulation, and energy expenditure during winter in the subtropical hibernating bat Hipposideros terasensis LIU, J.-N*; KARASOV, WH; University of Wisconsin-Madison, Taiwan Endemic Species Research Institute; University of Wisconsin-Madison jliu22@wisc.edu
The 60-g subtropical free-ranging Formosan leaf-nosed bat, Hipposideros terasensis, enters hibernation at warm roost (and hence body) temperature of up to 22 °C. For small hibernators, torpid metabolic rate is temperature dependent and thus hibernation in warm hibernacula is energetically costly. This species, however, rarely feeds during the hibernation season to offset the expected high energetic costs. In this study we used a respiratory system to quantify physiological characteristics of euthermic and torpid H. terasensis in winter. We tested the hypothesis that H. terasensis exhibits metabolic inhibition during torpor. Our results showed that H. terasensis saved 94.6 % and 84.1 % energy by using torpor at air temperatures of 15 °C and 20 °C, respectively. Torpid bats started thermoregulation and defended their body temperature at air temperature of 10-14 °C. A Q10 value of 3.6 for metabolic rate at body temperatures ranging from 13.8 °C to 27.2 °C suggests that, in addition to temperature effects, H. terasensis exhibited metabolic inhibition during torpor. A model used to evaluate energy expenditure of H. terasensis showed that at 20 °C a 55 g bat needs 203 KJ (5.2 g fat) to survive a 70-day hibernation period and each arousal costs 5.4 KJ (2.7% of total energy expenditure). Total energy expenditure increases to 325 KJ (8.2 g fat) when temperature increases to 24 °C. There is a need to understand the effects of climatic change on the geographical distribution and hibernation ecology of H. terasensis. Supported by Taiwan Endemic Species Research Institute.
