Repeatability and individual correlates of basal metabolic rate and total evaporative water loss in birds: a case study in European stonechats.
Basal metabolic rate (BMR) and total evaporative water loss (TEWL) are thought to have evolved in conjunction with life history traits and are often assumed to be characteristic features of an animal. Physiological traits can show large intraindividual variation at short and long timescales, yet natural selection can only act on a trait if it is a characteristic feature of an individual. The repeatability of a trait, a measure of the portion of variance that is caused by differences among individuals, indicates if it is a characteristic feature of an individual. We measured repeatability of BMR and TEWL of 18 captive European stonechats (Saxicola torquata rubicola) within the winter season. Repeatability was 0.56 for BMR and 0.60 for mass-specific BMR. Age and body mass had a significant effect on variation in BMR. Also after accounting for this variation, BMR remained repeatable. TEWL and mass-specific TEWL showed nonsignificant repeatabilities of 0.11 and 0.12, respectively. We conclude that BMR is a characteristic feature of an individual in our population of European stonechats, whereas TEWL is not. We discuss our results in the context of a review of currently available estimates of repeatability of BMR and TEWL for birds.
Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, P.O. Box 14, 9750 AA, Haren, The Netherlands. m.a.versteegh@rug.nl
Maaike A
MA
Versteegh
Barbara
B
Helm
Niels J
NJ
Dingemanse
B Irene
BI
Tieleman
D000222:Adaptation, Physiological; D000818:Animals; D001481:Basal Metabolism; D005075:Biological Evolution; D001834:Body Water / Q000378:metabolism; D001835:Body Weight; D004734:Energy Metabolism; D004777:Environment; D005260:Female; D008297:Male; D010101:Oxygen Consumption; D046109:Passeriformes / Q000502:physiology*; D015203:Reproducibility of Results; D013997:Time Factors; D014870:Water Loss, Insensible