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Multigenerational exposure to increased temperature reduces metabolic rate but increases boldness
  • Emma Moffett,
  • David Fryxell,
  • Kevin Simon
Emma Moffett
The University of Auckland

Corresponding Author:[email protected]

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David Fryxell
The University of Auckland
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Kevin Simon
The University of Auckland
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Acute exposure to warming temperatures increases minimum energetic requirements in ectotherms. However, over and within multiple generations, increased temperatures may cause plastic and evolved changes that modify the temperature sensitivity of energy demand and alter individual behaviours. Here, we aimed to test whether populations recently exposed to geothermally elevated temperatures express an altered temperature sensitivity of metabolism and behaviour. We expected that long-term exposure to warming would moderate metabolic rate, reducing the temperature sensitivity of metabolism, with concomitant reductions in boldness and activity. We compared the temperature sensitivity of metabolic rate (acclimation at 20 versus 30°C) and allometric slopes of routine, standard, and maximum metabolic rates, in addition to boldness and activity behaviours, across eight recently divergent populations of a widespread fish species (Gambusia affinis). Our data reveal that warm-source populations express a reduced temperature sensitivity of metabolism, with relatively high metabolic rates at cool acclimation temperatures and relatively low metabolic rates at warm acclimation temperatures. Allometric scaling of metabolism did not differ with thermal history. Across individuals from all populations combined, higher metabolic rates were associated with higher boldness and activity. However, warm-source populations displayed relatively more bold behaviour at both acclimation temperatures, despite their relatively low metabolic rates at warm acclimation temperatures. Overall, our data suggest that in response to warming, multigenerational processes may not direct trait change along a simple “pace-of-life syndrome” axis, instead causing relative decreases in metabolism and increases in boldness. Ultimately, our data suggest that multigenerational warming may produce a novel combination of physiological and behavioural traits, with consequences for animal performance in a warming world.
01 Oct 2021Submitted to Ecology and Evolution
05 Oct 2021Submission Checks Completed
05 Oct 2021Assigned to Editor
10 Oct 2021Reviewer(s) Assigned
26 Oct 2021Review(s) Completed, Editorial Evaluation Pending
01 Nov 2021Editorial Decision: Revise Minor
04 Mar 20221st Revision Received
07 Mar 2022Assigned to Editor
07 Mar 2022Submission Checks Completed
07 Mar 2022Review(s) Completed, Editorial Evaluation Pending
08 Mar 2022Reviewer(s) Assigned
28 Mar 2022Editorial Decision: Revise Minor
31 Mar 20222nd Revision Received
01 Apr 2022Assigned to Editor
01 Apr 2022Submission Checks Completed
01 Apr 2022Review(s) Completed, Editorial Evaluation Pending
05 Apr 2022Editorial Decision: Accept