title: Shaving increases daily energy expenditure in free-living root voles.
abstract: Experimental manipulation of energy expenditure has long been recognized as an effective means for identifying causative effects and avoiding confounded interpretations arising from spurious correlations. This approach has been successfully applied mainly to studies on birds, particularly on reproducing adults, whereas manipulations in mammals have proved more problematic. Here, we tested the hypothesis that shaving off 50% of the dorsal pelage should effectively increase energy expenditure in wild root voles (Microtus oeconomus) in their natural environment. We measured daily energy expenditure (DEE), using doubly labelled water in shaved and unshaved voles at the beginning of winter. The difference in DEE (corrected for body mass and year effects) between experimental and control group fluctuated from 11.5% to 17.3%. Probability of recapture over the 3 day DEE assay was strongly dependent on body mass, but did not differ between shaved and unshaved animals; however, a prevalence of larger (heavier) shaved individuals was observed. Shaved animals lost more weight between the first and second trapping. Shaving therefore appears to be an effective method of increasing the cost of total DEE in wild endotherms in their natural environment.
authors.affiliation: Mammal Research Institute of the Polish Academy of Sciences, 17-230 Białowieża, Poland pszafran@ibs.bialowieza.pl.
authors.forename: Paulina A
authors.initials: PA
authors.lastname: Szafrańska
authors.affiliation: Mammal Research Institute of the Polish Academy of Sciences, 17-230 Białowieża, Poland.
authors.forename: Karol
authors.initials: K
authors.lastname: Zub
authors.affiliation: Mammal Research Institute of the Polish Academy of Sciences, 17-230 Białowieża, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Wieczorek
authors.affiliation: University of Białystok, 15-950 Białystok, Poland.
authors.forename: Aneta
authors.initials: A
authors.lastname: Książek
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: John R
authors.initials: JR
authors.lastname: Speakman
authors.affiliation: University of Białystok, 15-950 Białystok, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Konarzewski
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology; D001835:Body Weight / Q000502:physiology*; D017666:Deuterium Oxide; D004734:Energy Metabolism / Q000502:physiology*; D006197:Hair; D010103:Oxygen Isotopes
chemical_list: D010103:Oxygen Isotopes; D017666:Deuterium Oxide
keywords: Body mass; Doubly labelled water; Fur insulation; Mammal; Metabolic rate; Thermoregulation