Evolution of basal metabolic rate in bank voles from a multidirectional selection experiment

A major theme in evolutionary and ecological physiology of terrestrial vertebrates\udencompasses the factors underlying the evolution of endothermy in\udbirds and mammals and interspecific variation of basal metabolic rate\ud(BMR). Here, we applied the experimental evolution approach and compared\udBMR in lines of a wild rodent, the bank vole (Myodes glareolus),\udselected for 11 generations for: high swim-induced aerobic metabolism\ud(A), ability to maintain body mass on a low-quality herbivorous diet (H)\udand intensity of predatory behaviour towards crickets (P). Four replicate\udlines were maintained for each of the selection directions and an unselected\udcontrol (C). In comparison to C lines, A lines achieved a 49% higher maximum\udrate of oxygen consumption during swimming, H lines lost 1.3 g\udless mass in the test with low-quality diet and P lines attacked crickets\udfive times more frequently. BMR was significantly higher in A lines than\udin C or H lines (60.8, 56.6 and 54.4 ml O2/h, respectively), and the values\udwere intermediate in P lines (59.0 ml O2/h). Results of the selection experiment\udprovide support for the hypothesis of a positive association between\udBMR and aerobic exercise performance, but not for the association of adaptation\udto herbivorous diet with either a high or low BMR