Meeting Abstract

32.1  Jan. 5  Seasonal variation in Resting Metabolic Rates (RMR) and Daily Energy Expenditures (DEE) SZAFRANSKA, Paulina A.*; ZUB, Karol; KONARZEWSKI, Marek; SPEAKMAN, John R.; Mammal Research Institute Polish Academy of Sicences; Mammal Research Institute Polish Academy of Sicences; Mammal Research Institute Polish Academy of Sicences and Univesity of Bialystok; University of Aberdeen pszafran@bison.zbs.bialowieza.pl

The relationship (if any) between daily energy expenditures (DEE) and RMR is still open to debate. We measured seasonal variation of DEE and RMR in the same free-ranging individual weasel males – small predator characterized by a considerable variation in body mass (range 40g � 150g). DEE and RMR varied in concert among seasons. They were lowest in winter and significantly higher in spring and summer. Most important predictor of DEE was daily activity time followed by body mass. Ambient temperature affected DEE indirectly through its positive correlation with daily activity time. On the other hand, body mass explained most of the variation in RMR, which was less affected by activity time and ambient temperature. In the whole annual cycle RMR was positively correlated with DEE. However, the correlation was not significant within seasons. We conclude that between-season variation in both RMR and DEE was high enough to resolve the correlation between them. However, within-season variation was insufficient to demonstrate the correlation.