Multigenerational exposure to elevated temperatures leads to a reduction in standard metabolic rate in the wild

Pilakouta, N. , Killen, S. S. , Kristjánsson, B. N., Skúlason, S., Lindström, J. , Metcalfe, N. B. and Parsons, K. J. (2020) Multigenerational exposure to elevated temperatures leads to a reduction in standard metabolic rate in the wild. Functional Ecology, 34(6), pp. 1205-1214. (doi: 10.1111/1365-2435.13538) (PMID:32612318) (PMCID:PMC7318562)

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Abstract

In light of global climate change, there is a pressing need to understand and predict the capacity of populations to respond to rising temperatures. Metabolic rate is a key trait that is likely to influence the ability to cope with climate change. Yet, empirical and theoretical work on metabolic rate responses to temperature changes has so far produced mixed results and conflicting predictions. Our study addresses this issue using a novel approach of comparing fish populations in geothermally warmed lakes and adjacent ambient‐temperature lakes in Iceland. This unique ‘natural experiment' provides repeated and independent examples of populations experiencing contrasting thermal environments for many generations over a small geographic scale, thereby avoiding the confounding factors associated with latitudinal or elevational comparisons. Using Icelandic sticklebacks from three warm and three cold habitats, we measured individual metabolic rates across a range of acclimation temperatures to obtain reaction norms for each population. We found a general pattern for a lower standard metabolic rate in sticklebacks from warm habitats when measured at a common temperature, as predicted by Krogh's rule. Metabolic rate differences between warm‐ and cold‐habitat sticklebacks were more pronounced at more extreme acclimation temperatures, suggesting the release of cryptic genetic variation upon exposure to novel conditions, which can reveal hidden evolutionary potential. We also found a stronger divergence in metabolic rate between thermal habitats in allopatry than sympatry, indicating that gene flow may constrain physiological adaptation when dispersal between warm and cold habitats is possible. In sum, our study suggests that fish may diverge toward a lower standard metabolic rate in a warming world, but this might depend on connectivity and gene flow between different thermal habitats.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Metcalfe, Professor Neil and Pilakouta, Dr Natalie and Lindstrom, Dr Jan and Killen, Professor Shaun and Parsons, Dr Kevin
Authors: Pilakouta, N., Killen, S. S., Kristjánsson, B. N., Skúlason, S., Lindström, J., Metcalfe, N. B., and Parsons, K. J.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Functional Ecology
Publisher:Wiley
ISSN:0269-8463
ISSN (Online):1365-2435
Published Online:29 January 2020
Copyright Holders:Copyright © 2020 British Ecological Society
First Published:First published in Functional Ecology 34(6):1205-1214
Publisher Policy:Reproduced under a Creative Commons licence

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
172724The predictability and limits of evolution to increased temperature: insights from a natural 'experiment'Kevin ParsonsNatural Environment Research Council (NERC)NE/N016734/1Institute of Biodiversity, Animal Health and Comparative Medicine
167015The Influence of Individual Physiology on Group Behaviour in Fish SchoolsShaun KillenNatural Environment Research Council (NERC)NE/J019100/1Institute of Biodiversity, Animal Health and Comparative Medicine