Resting metabolic rate (RMR), i.e. spent energy necessary to maintain basic life functions, is a basic component of energy budget in ectotherms. The evolution of RMR through natural selection rests on the premise of its non-zero repeatability and heritability, i.e. consistent variation within individual lifetimes and resemblance between parents and their offspring, respectively. Joint estimates of RMR repeatability and heritability are missing in ectotherms, however, which precludes estimations of the evolutionary potential of this trait. We examined RMR repeatability and heritability in a long-lived ectotherm, the alpine newt (Ichthyosaura alpestris). Individual RMR was repeatable over both six-month (0.28 ± 0.09 [SE]) and five-year (0.16 ± 0.07) periods. While there was no resemblance between parent and offspring RMR (0.21 ± 0.34), the trait showed similarity among offspring within families (broad-sense heritability; 0.25 ± 0.09). Similar repeatability and broad-sense heritability values in parental and offspring generations, respectively, and non-conclusive narrow-sense heritability suggest the contribution of non-additive genetic factors to total phenotypic variance in this trait. We conclude that RMR evolutionary trajectories are shaped by other processes than natural selection in this long-lived ectotherm.

静息代谢率 (RMR)，即维持基本生命功能所需的消耗能量，是变温动物能量预算的基本组成部分。RMR 通过自然选择的进化依赖于其非零重复性和遗传性的前提，即个体生命周期内的一致变异以及父母与其后代之间的相似性。然而，在变温动物中缺少对 RMR 可重复性和遗传性的联合估计，这排除了对该特性进化潜力的估计。我们检查了长寿变温动物高山蝾螈（Ichthyosaura alpestris）。个人 RMR 在六个月 (0.28 ± 0.09 [SE]) 和五年 (0.16 ± 0.07) 期间都是可重复的。虽然亲代和后代 RMR 之间没有相似性 (0.21 ± 0.34)，但该特征显示家庭内后代之间的相似性（广义遗传力；0.25 ± 0.09）。分别在亲代和后代中相似的重复性和广义遗传力值，以及非决定性的狭义遗传力表明非加性遗传因素对该性状总表型变异的贡献。我们得出的结论是，在这个长期存在的变温过程中，RMR 的进化轨迹是由自然选择以外的其他过程塑造的。