Natural Use of Heterothermy by a Small, Tree-Roosting Bat during Summer

Title
Natural Use of Heterothermy by a Small, Tree-Roosting Bat during Summer
Publication Date
2003
Author(s)
Turbill, Christopher
Koertner, Gerhard
( author )
OrcID: https://orcid.org/0000-0001-8230-0709
Email: gkoertne@une.edu.au
UNE Id une-id:gkoertne
Geiser, Fritz
( author )
OrcID: https://orcid.org/0000-0001-7621-5049
Email: fgeiser@une.edu.au
UNE Id une-id:fgeiser
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
University of Chicago Press
Place of publication
United States of America
UNE publication id
une:3492
Abstract
Little is known about the use of heterothermy by wild bats during summer, especially for tree-roosting species. Because thermal conditions within tree roosts can fluctuate widely with ambient temperature, which affects thermoregulatory energy expenditure during diurnal roosting, we measured skin temperatures of free-ranging male 'Nyctophilus geoffroyi' (8 g) to quantify the relation between summer torpor use and roost thermal conditions. Bats roosted under bark on the northern (sunny) side of trees and entered torpor every day, usually near sunrise. Bats exhibited two bouts of torpor on most days: the first occurred in the morning, was terminated by partially passive rewarming, and was followed by a period of normothermy during the warmest part of the day; a second torpor bout occurred in the late afternoon, with arousal near sunset. On the warmest days, bats had only a single, short morning bout. On the coolest days, bats remained torpid throughout the day, and one 2-d bout was observed. Thus, presumably owing to their poorly insulated roosts and the high energetic cost of normothermy at temperatures below 300C, the extent and timing of heterothermy was closely related to the cycle of diurnal temperatures. Our study indicates that torpor use is important for energy maintenance during summer diurnal roosting of 'N. geoffroyi' and likely of other small, tree-roosting bats.
Link
Citation
Physiological and Biochemical Zoology, 76(6), p. 868-876
ISSN
1537-5293
1522-2152
Start page
868
End page
876

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