The “minimal boundary curve for endothermy” as a predictor of heterothermy in mammals and birds: a review
MetadataShow full item record
According to the concept of the “minimal boundary curve for endothermy”, mammals and birds with a basal metabolic rate (BMR) that falls below the curve are obligate heterotherms and must enter torpor. We examined the reliability of the boundary curve (on a double log plot transformed to a line) for predicting torpor as a function of body mass and BMR for birds and several groups of mammals. The boundary line correctly predicted heterothermy in 87.5% of marsupials (n = 64), 94% of bats (n = 85) and 82.3% of rodents (n = 157). Our analysis shows that the boundary line is not a reliable predictor for use of torpor. A discriminate analysis using body mass and BMR had a similar predictive power as the boundary line. However, there are sufficient exceptions to both methods of analysis to suggest that the relationship between body mass, BMR and heterothermy is not a causal one. Some homeothermic birds (e.g. silvereyes) and rodents (e.g. hopping mice) fall below the boundary line, and there are many examples of heterothermic species that fall above the boundary line. For marsupials and bats, but not for rodents, there was a highly significant phylogenetic pattern for heterothermy, suggesting that taxonomic affiliation is the biggest determinant of heterothermy for these mammalian groups. For rodents, heterothermic species had lower BMRs than homeothermic species. Low BMR and use of torpor both contribute to reducing energy expenditure and both physiological traits appear to be a response to the same selective pressure of fluctuating food supply, increasing fitness in endothermic species that are constrained by limited energy availability. Both the minimal boundary line and discriminate analysis were of little value for predicting the use of daily torpor or hibernation in heterotherms, presumably as both daily torpor and hibernation are precisely controlled processes, not an inability to thermoregulate.
The original publication is available at: http://www.springerlink.com
Showing items related by title, author, creator and subject.
Barker, Justine; Cooper, Christine; Withers, Philip; Cruz-Neto, A. (2012)We examine here the thermal physiology of the ash-grey mouse, as there is a paucity of data to explain how Australian rodents meet thermoregulatory demands. Most ash-grey mice remained normothermic over a range of ambient ...
Fleming, P.; Bateman, Bill (2018)Â© 2018 The Association for the Study of Animal Behaviour Novel ecosystems (â€˜emerging ecosystemsâ€™) result when species occur in combinations and relative abundances that have not occurred previously within a given ...
Potentiometric Investigation of Protonation Reactions at Aqueous-Aqueous Boundaries within a Dual-Stream Microfluidic StructureStrutwolf, J.; Collins, C.; Adamiak, W.; Arrigan, Damien (2010)The laminar flow regime prevailing in pressure-driven flow through a Y-shaped microfluidic channel was utilized to create a stable boundary between two aqueous liquids. Transverse transport of ions between these two liquids ...