Data from: Ecological influences and morphological correlates of resting and maximal metabolic rates across teleost fish species

Rates of aerobic metabolism vary considerably across evolutionary lineages, but little is known about the proximate and ultimate factors that generate and maintain this variability. Using data for 131 teleost fish species, we performed a large-scale phylogenetic comparative analysis of how interspecific variation in resting and maximum metabolic rates (RMR and MMR, respectively) is related to several ecological and morphological variables. Mass- and temperature-adjusted RMR and MMR are highly correlated along a continuum spanning a 30- to 40-fold range. Phylogenetic generalized least squares models suggest RMR and MMR are higher in pelagic species and that species with higher trophic levels exhibit elevated MMR. This variation is mirrored at various levels of structural organization: gill surface area, muscle protein content, and caudal fin aspect ratio (a proxy for activity) are positively related with aerobic capacity. Muscle protein content and caudal fin aspect ratio are also positively correlated with RMR. Hypoxia-tolerant lineages fall at the lower end of the metabolic continuum. Different ecological lifestyles are associated with contrasting levels of aerobic capacity, possibly reflecting the interplay between selection for increased locomotor performance on one hand and tolerance to low resource availability, particularly oxygen, on the other. These results support the aerobic capacity model of the evolution of endothermy, suggesting elevated body temperatures evolved as correlated responses to selection for high activity levels.

不同演化支系（evolutionary lineage）间的有氧代谢（aerobic metabolism）速率差异悬殊，但目前学界对催生并维持这种变异的近因与远因（proximate and ultimate factors）仍知之甚少。本研究依托131种硬骨鱼（teleost fish）的数据，针对静止代谢率（resting metabolic rate, RMR）与最大代谢率（maximum metabolic rate, MMR）的种间变异（interspecific variation）与多项生态及形态学变量间的关联，开展了大规模的系统发育比较分析（phylogenetic comparative analysis）。经质量与温度校正后的RMR与MMR在跨度达30至40倍的连续区间内呈现高度相关。系统发育广义最小二乘模型（phylogenetic generalized least squares models）结果显示，中上层鱼类（pelagic species）的RMR与MMR水平更高，且营养级（trophic level）更高的物种其MMR也显著升高。这种变异在多个结构组织层次均有体现：鳃表面积（gill surface area）、肌肉蛋白含量（muscle protein content）与尾鳍长宽比（caudal fin aspect ratio，活动水平的替代指标（proxy for activity））均与有氧能力（aerobic capacity）呈正相关；肌肉蛋白含量与尾鳍长宽比同样与RMR呈正相关。耐低氧演化支系（hypoxia-tolerant lineage）则位于代谢连续区间的下端。不同的生态生活型（ecological lifestyle）对应着迥异的有氧能力水平，这可能反映了两类选择的相互作用：一方面是对更高运动性能的选择，另一方面是对低资源（尤其是低氧）耐受能力的选择。本研究结果支持恒温演化（evolution of endothermy）的有氧能力模型，表明体温（body temperature）升高是对高活动水平选择的协同响应。