Flexibility in metabolic rate and activity level determines individual variation in overwinter performance

Auer, S. K., Salin, K., Anderson, G. J. and Metcalfe, N. B. (2016) Flexibility in metabolic rate and activity level determines individual variation in overwinter performance. Oecologia, 182(3), pp. 703-712. (doi: 10.1007/s00442-016-3697-z) (PMID:27461377) (PMCID:PMC5043002)

Abstract

Energy stores are essential for the overwinter survival of many temperate and polar animals, but individuals within a species often differ in how quickly they deplete their reserves. These disparities in overwinter performance may be explained by differences in their physiological and behavioral flexibility in response to food scarcity. However, little is known about whether individuals exhibit correlated or independent changes in these traits, and how these phenotypic changes collectively affect their winter energy use. We examined individual flexibility in both standard metabolic rate and activity level in response to food scarcity and their combined consequences for depletion of lipid stores among overwintering brown trout (Salmo trutta). Metabolism and activity tended to decrease, yet individuals exhibited striking differences in their physiological and behavioral flexibility. The rate of lipid depletion was negatively related to decreases in both metabolic and activity rates, with the smallest lipid loss over the simulated winter period occurring in individuals that had the greatest reductions in metabolism and/or activity. However, changes in metabolism and activity were negatively correlated; those individuals that decreased their SMR to a greater extent tended to increase their activity rates, and vice versa, suggesting among-individual variation in strategies for coping with food scarcity.

• Item Type: Articles
• Additional Information: This research was supported by an ERC Advanced Grant (number 322784) to NBM.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Anderson, Mr Graeme and Auer, Dr Sonya and Metcalfe, Professor Neil and Salin, Dr Karine
• Authors: Auer, S. K., Salin, K., Anderson, G. J., and Metcalfe, N. B.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Oecologia
• Publisher: Springer
• ISSN: 0029-8549
• ISSN (Online): 1432-1939
• Published Online: 26 July 2016
• Copyright Holders: Copyright © 2016 The Authors
• First Published: First published in Oecologia 182:703-712
• Publisher Policy: Reproduced under a creative commons license