Document Detail


Heterothermic responses in the speckled mousebird (Colius striatus).
MedLine Citation:
PMID:  11585263     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We investigated normothermic thermoregulation and heterothermic responses to restricted food in the speckled mousebird Colius striatus, in the context of the widely accepted distinction between normothermia, rest-phase hypothermia, and torpor. Normothermic thermoregulation differed from typical endothermic patterns in that rest-phase body temperature (Tb) was not maintained with respect to a constant setpoint. Instead, Tb decreased during the course of the rest-phase, with the highest cooling rates observed at moderate ambient temperatures (Ta). Restricted food was associated with significant reductions in rest-phase Tb and metabolic rate. The lowest Tb recorded in a bird which was able to arouse spontaneously, was 18.2 degrees C. However, we were unable to clearly discern between normothermic, hypothermic and torpor Tb ranges. Furthermore, heterothermic responses did not accord with the patterns typically observed in birds and mammals. Metabolic suppression normally associated with entry into torpor and the defence of a torpor Tb setpoint was largely absent. The mousebirds significantly reduced their energy expenditure when heterothermic at moderate TaS only. We suggest that the observed patterns of thermoregulation in C. striatus, as well those previously reported in Colius colius, are associated with plesiomorphic clustering behaviour in the Coliiformes, and the tandem evolution of behavioural and metabolic thermoregulation.
Authors:
A E McKechnie; B G Lovegrove
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology     Volume:  171     ISSN:  0174-1578     ISO Abbreviation:  J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol.     Publication Date:  2001 Aug 
Date Detail:
Created Date:  2001-10-04     Completed Date:  2002-02-12     Revised Date:  2009-06-08    
Medline Journal Info:
Nlm Unique ID:  8413200     Medline TA:  J Comp Physiol B     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  507-18     Citation Subset:  IM    
Affiliation:
School of Botany and Zoology, University of Natal, Scottsville, South Africa. mckechnie@nu.ac.za
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MeSH Terms
Descriptor/Qualifier:
Animals
Birds / anatomy & histology,  physiology*
Body Temperature / physiology
Body Temperature Regulation / physiology*
Body Weight
Eating / physiology
Energy Metabolism
Oxygen Consumption

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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