Abstract
Several empirical studies have shown that variation in daily energy expenditure (DEE) and resting metabolic rate (RMR) is influenced by environmental and individual factors, but whether these shared influences are responsible for, or independent of, relationships between DEE and RMR remains unknown. The objectives of this study were to (i) simultaneously evaluate the effects of environmental and individual variables on DEE and RMR in free-ranging eastern chipmunks (Tamias striatus) and (ii) quantify the correlation between DEE and RMR before and after controlling for common sources of variation. We found that the influence of individual factors on DEE and RMR is most often shared, whereas the influence of environmental factors tends to be distinct. Both raw and mass-adjusted DEE and RMR were significantly correlated, but this correlation vanished after accounting for the shared effect of reproduction on both traits. However, within reproductive individuals, DEE and RMR remained positively correlated after accounting for all other significant covariates. The ratio of DEE to RMR was significantly higher during reproduction than at other times of the year and was negatively correlated with ambient temperature. DEE and RMR appear to be inherently correlated during reproduction, but this correlation does not persist during other, less energy-demanding periods of the annual cycle.
Original language | English |
---|---|
Pages (from-to) | 418-426 |
Number of pages | 9 |
Journal | Journal of Experimental Biology |
Volume | 216 |
Issue number | 3 |
Early online date | 16 Jan 2013 |
DOIs | |
Publication status | Published - 1 Feb 2013 |
Bibliographical note
ACKNOWLEDGEMENTSWe are grateful to the Ruiter Valley Land Trust for allowing us to conduct this research on their property. We thank J. P. Boyer, M. Descôteaux, R. Morin, A. Thomas, M. Landry-Cuerrier, and all field assistants who have helped to collect the data, P. Redman and P. Thomson for technical assistance with the isotope analysis, and two reviewers for their constructive criticism. Animals were captured and handled following the protocol approved by the Animal Welfare Committee of Université de Sherbrooke and the Ministère des Ressources Naturelles et de la Faune du Québec. We are indebted to the late Don Thomas for his invaluable contribution to this project.
FUNDING
This research was supported by a Fonds Québécois de la Recherche sur la Nature et les Technologies (FQRNT) team grant, by a Natural Sciences and Engineering Research Council of Canada (NSERC) doctoral scholarship to V.C., discovery grants to Don Thomas, M.M.H., D.R., D.G. and F.P., and by Canada Research Chair funds to D.R. and F.P.
Keywords
- Basal metabolic rate
- BMR
- Doubly labelled water
- Field metabolic rate
- Sustained metabolic scope