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Physiology at near-critical temperatures, but not critical limits, varies between two lizard species that partition the thermal environment

Telemeco, Rory S.; Gangloff, Eric J.; Cordero, Gerardo A. LU ; Polich, Rebecca L.; Bronikowski, Anne M. and Janzen, Fredric J. (2017) In Journal of Animal Ecology 86(6). p.1510-1522
Abstract

The mechanisms that mediate the interaction between the thermal environment and species ranges are generally uncertain. Thermal environments may directly restrict species when environments exceed tolerance limits (i.e. the fundamental niche). However, thermal environments might also differentially affect relative performance among species prior to fundamental tolerances being met (i.e. the realized niche). We examined stress physiology (plasma glucose and corticosterone), mitochondrial performance and the muscle metabolome of congeneric lizards that naturally partition the thermal niche, Elgaria multicarinata (southern alligator lizards; SALs) and Elgaria coerulea (northern alligator lizards; NALs), in response to a thermal challenge to... (More)

The mechanisms that mediate the interaction between the thermal environment and species ranges are generally uncertain. Thermal environments may directly restrict species when environments exceed tolerance limits (i.e. the fundamental niche). However, thermal environments might also differentially affect relative performance among species prior to fundamental tolerances being met (i.e. the realized niche). We examined stress physiology (plasma glucose and corticosterone), mitochondrial performance and the muscle metabolome of congeneric lizards that naturally partition the thermal niche, Elgaria multicarinata (southern alligator lizards; SALs) and Elgaria coerulea (northern alligator lizards; NALs), in response to a thermal challenge to quantify variation in physiological performance and tolerance. Both NAL and SAL displayed physiological stress in response to high temperature, but neither showed signs of irreversible damage. NAL displayed a higher baseline mitochondrial respiration rate than SAL. Moreover, NAL substantially adjusted their physiology in response to thermal challenge, whereas SAL did not. For example, the metabolite profile of NAL shifted with changes in key energetic molecules, whereas these were unaffected in SAL. Our results indicate that near-critical high temperatures should incur greater energetic cost in NAL than SAL via an elevated metabolic rate and changes to the metabolome. Thus, SAL displace NAL in warm environments that are within NAL's fundamental thermal niche, but relatively costly. Our results suggest that subcritical thermal events can contribute to biogeographic patterns via physiological differences that alter the relative costs of living in warm or cool environments.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
corticosterone, OCLTT, pejus temperatures, reactive oxygen species, state III respiration
in
Journal of Animal Ecology
volume
86
issue
6
pages
13 pages
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • scopus:85031736766
  • wos:000413406700022
ISSN
0021-8790
DOI
10.1111/1365-2656.12738
language
English
LU publication?
yes
id
da5ad22d-0287-4c3c-ba96-e68223f8c715
date added to LUP
2017-11-28 09:57:17
date last changed
2018-01-16 13:26:38
@article{da5ad22d-0287-4c3c-ba96-e68223f8c715,
  abstract     = {<p>The mechanisms that mediate the interaction between the thermal environment and species ranges are generally uncertain. Thermal environments may directly restrict species when environments exceed tolerance limits (i.e. the fundamental niche). However, thermal environments might also differentially affect relative performance among species prior to fundamental tolerances being met (i.e. the realized niche). We examined stress physiology (plasma glucose and corticosterone), mitochondrial performance and the muscle metabolome of congeneric lizards that naturally partition the thermal niche, Elgaria multicarinata (southern alligator lizards; SALs) and Elgaria coerulea (northern alligator lizards; NALs), in response to a thermal challenge to quantify variation in physiological performance and tolerance. Both NAL and SAL displayed physiological stress in response to high temperature, but neither showed signs of irreversible damage. NAL displayed a higher baseline mitochondrial respiration rate than SAL. Moreover, NAL substantially adjusted their physiology in response to thermal challenge, whereas SAL did not. For example, the metabolite profile of NAL shifted with changes in key energetic molecules, whereas these were unaffected in SAL. Our results indicate that near-critical high temperatures should incur greater energetic cost in NAL than SAL via an elevated metabolic rate and changes to the metabolome. Thus, SAL displace NAL in warm environments that are within NAL's fundamental thermal niche, but relatively costly. Our results suggest that subcritical thermal events can contribute to biogeographic patterns via physiological differences that alter the relative costs of living in warm or cool environments.</p>},
  author       = {Telemeco, Rory S. and Gangloff, Eric J. and Cordero, Gerardo A. and Polich, Rebecca L. and Bronikowski, Anne M. and Janzen, Fredric J.},
  issn         = {0021-8790},
  keyword      = {corticosterone,OCLTT,pejus temperatures,reactive oxygen species,state III respiration},
  language     = {eng},
  month        = {10},
  number       = {6},
  pages        = {1510--1522},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {Journal of Animal Ecology},
  title        = {Physiology at near-critical temperatures, but not critical limits, varies between two lizard species that partition the thermal environment},
  url          = {http://dx.doi.org/10.1111/1365-2656.12738},
  volume       = {86},
  year         = {2017},
}