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  • UC Riverside
  • College of Natural and Agricultural Sciences

IVR-D12w 76.  Koteja, P., J. G. Swallow, P. A. Carter, and T. Garland, Jr. In press. Individual variation and repeatability of maximum cold-induced energy assimilation in house mice. Acta Theriologica.


Maximum cold-induced rate of food consumption in cold-acclimated laboratory house mice (Mus domesticus) averaged 10.4 g/d in females (body mass before cold exposure = 25.2 g) and 10.7 g/d in males (body mass = 31.7 g); corresponding maximum rates of energy assimilation were 139 kJ/d in females and 144 kJ/d in males. The traits were highly repeatable: the intraclass correlation coefficient for three trials at -10 C was greater than 0.7 for absolute values and greater than 0.6 for values independent of the initial body mass (residuals from ANCOVA). The estimate of repeatability of the mass-independent traits depends on which estimate of body mass (initial or after cold exposure) is used as a covariate in the regression or ANCOVA model. We conclude that the values of maximum cold-induced food consumption and energy assimilation are reliable estimates of the performance of individuals under a specific set of environmental conditions (low ambient temperature, but not limited access to food) and hence may be subject to phenotypic natural or artificial selection.