The optimal combination of standard metabolic rate and aerobic scope for somatic growth depends on food availability

Auer, S. K., Salin, K., Rudolf, A. M., Anderson, G. J. and Metcalfe, N. B. (2015) The optimal combination of standard metabolic rate and aerobic scope for somatic growth depends on food availability. Functional Ecology, 29(4), pp. 479-486. (doi:10.1111/1365-2435.12396)

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Abstract

Metabolic rates can vary as much as threefold among individuals of the same size and age in a population, but why such variation persists is unclear given that they determine the energetic cost of living. Relationships between standard metabolic rate (SMR), growth and survival can vary with environmental conditions, suggesting that the fitness consequences of a given metabolic phenotype may be context-dependent. Less attention has focused on the link between absolute aerobic scope (AS, the difference between standard and maximum metabolic rate) and fitness under different environmental conditions, despite the importance of aerobic scope to an organism's total energetic capacity.<p></p> We examined the links between individual variation in both SMR and AS and somatic growth rates of brown trout (Salmo trutta) under different levels of food availability.<p></p> Standard metabolic rate and AS were uncorrelated across individuals. However, SMR and AS not only had interactive effects on growth, but these interactions depended on food level: at ad libitum food levels, AS had a positive effect on growth whose magnitude depended on SMR; at intermediate food levels, AS and SMR had interactive effects on growth, but at the low food level, there was no effect of either AS or SMR on growth. As a result, there was no metabolic phenotype that performed best or worst across all food levels.<p></p> These results demonstrate the importance of aerobic scope in explaining somatic growth rates and support the hypothesis that links between individual variation in metabolism and fitness are context-dependent.<p></p> The larger metabolic phenotype and the environmental context in which performance is evaluated both need to be considered in order to better understand the link between metabolic rates and fitness and thereby the persistence of individual variation in metabolic rates.<p></p>

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Rudolf, Ms Agata Marta and Anderson, Mr Graeme and Auer, Dr Sonya and Metcalfe, Professor Neil and Salin, Dr Karine
Authors: Auer, S. K., Salin, K., Rudolf, A. M., Anderson, G. J., and Metcalfe, N. B.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Functional Ecology
Publisher:Blackwell
ISSN:0269-8463
ISSN (Online):1365-2435
Copyright Holders:Copyright © 2014 The Authors
First Published:First published in Functional Ecology 29(4):479-486
Publisher Policy:Reproduced under a Creative Commons License

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