Journal of Comparative Physiology B

, Volume 162, Issue 3, pp 284–295

Warm-up rates during arousal from torpor in heterothermic mammals: physiological correlates and a comparison with heterothermic insects

  • Graham N. Stone
  • Andy Purvis
Article

DOI: 10.1007/BF00357536

Cite this article as:
Stone, G.N. & Purvis, A. J Comp Physiol B (1992) 162: 284. doi:10.1007/BF00357536

Summary

This study examines the relationship between warm-up rate, body mass, metabolic rate, thermal conductance and normothermic body temperature in heterothermic mammals during arousal from torpor. Predictions based on the assumption that the energetic cost of arousal has been minimised are tested using data for 35 species. The observation that across-species warm-up rate correlates negatively with body mass is confirmed using a comparative technique which removes confounding effects due to the non-independence of species data due to shared common ancestry. Mean warm-up rate during arousal correlates negatively with basal metabolic rate and positively with the temperature difference through which the animal warms, having controlled for other factors. These results suggest that selection has operated to minimise the overall energetic, cost of warm-up. In contrast, peak warm-up rate during arousal correlates positively with peak metabolic rate during arousal, and negatively with thermal conductance, when body mass has been taken into account. These results suggest that peak warm-up rate is more sensitive to the fundamental processes of heat generation and loss. Although heterothermic marsupials have lower normothermic body temperatures and basal metabolic rates, marsupials and heterothermic eutherian mammals do not differ systematically in warm-up rate. Pre-flight warm-up rates in one group of endothermic insects, the bees, are significantly higher than predictions based on rates of arousal of a mammal of the same body mass.

Key words

Mammals Torpor Arousal Warm-up rate Metabolic rate Comparative method 

Abbreviations

BMR

basal metabolic rate

ICM

independent comparisons method

MWR

mean warm-up rate

PMR

peak metabolic rate

PWR

peak·warm-up rate

Tbactivity

body temperature during activity

Tbtorpor

body temperature during torpor

ΔTarousal

increase in body temperature during arousal

Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • Graham N. Stone
    • 1
  • Andy Purvis
    • 1
  1. 1.Department of ZoologyOxford UniversityOxfordUK
  2. 2.Imperial College at Silwood ParkI.R.C. Population BiologyAscotUK