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Physiological ecology of frillneck lizards in a seasonal tropical environment

Christian, Keith A., Griffiths, Anthony D. and Bedford, Gavin S. (1996). Physiological ecology of frillneck lizards in a seasonal tropical environment. Oecologia,106(1):49-56.

Document type: Journal Article
Citation counts: Scopus Citation Count Cited 26 times in Scopus Article | Citations

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Title Physiological ecology of frillneck lizards in a seasonal tropical environment
Author Christian, Keith A.
Griffiths, Anthony D.
Bedford, Gavin S.
Journal Name Oecologia
Publication Date 1996
Volume Number 106
Issue Number 1
ISSN 0029-8549   (check CDU catalogue open catalogue search in new window)
Scopus ID 2-s2.0-0029668497
Start Page 49
End Page 56
Total Pages 8
Place of Publication Germany
Publisher Springer
Abstract The frillneck lizard, Chlamydosaurus kingii, is a conspicuous component of the fauna of the wetdry tropics of northern Australia during the wet season, but it is rarely seen in the dry season. Previous studies have demonstrated that during the dry season the field metabolic rate (FMR) is only about one-quarter of the wet-season rate, and one factor involved in this seasonal drop is a change in the behavioural thermoregulation of the species such that lower body temperatures (Tbs) are selected during dry-season days. Here we examine other factors that could be responsible for the seasonal change in FMR: standard metabolic rates (SMR) and activity. Samples from stomach flushing revealed that the lizards in the dry season continued to feed, but the volume of food was half as much as in the wet season. SMR in the laboratory was 30% less in the dry season. During the dry season, the energy expended by the lizards is 60.4 kJ kg-1 day-1 less than during the wet season. Combining laboratory and field data, we determined the relative contribution of the factors involved in this energy savings: 10% can be attributed to lower nighttime Tb, 12% is attributable to lower daytime Tb, 12% is attributable to decreased metabolism, and the remaining 66% is attributable to other activities (including e.g. locomotion, reproductive costs, digestion). Calculations indicate that if FMR did not drop in the dry season the lizards would not survive on the observed food intake during this season. Seasonal analysis of blood plasma and urine indicated an accumulation of some electrolytes during the dry season suggesting modest levels of water stress.
Keywords Acclimatisation
Body mass changes
Chlamydosaurus kingii
Seasonal tropics
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Created: Fri, 29 Aug 2014, 20:18:22 CST by Anthony Hornby