A common belief is that body mass scaling of metabolic rate results chiefly from intrinsic body-design constraints. However, several studies have shown that multiple ecological factors affect metabolic scaling. The mechanistic basis of these effects is largely unknown. Here, we explore whether abiotic and biotic environmental factors have interactive effects on metabolic scaling. To address this question, we studied the simultaneous effects of temperature and predator cues on the ontogenetic metabolic scaling of amphipod crustaceans inhabiting two different aquatic ecosystems, a freshwater spring and a saltwater lagoon. We assessed effects of phenotypic plasticity on metabolic scaling by exposing amphipods in the laboratory to water with and without fish cues at multiple temperatures. Temperature interacts significantly with predator cues to affect metabolic scaling. Our results suggest that metabolic scaling is highly malleable in response to short-term acclimation. The interactive effects of temperature and predators show the importance of studying effects of global warming in realistic ecological contexts.

人们普遍认为，代谢率的体重缩放主要是由于内在的身体设计限制造成的。然而，一些研究表明多种生态因素影响代谢规模。这些效应的机制基础在很大程度上尚不清楚。在这里，我们探讨非生物和生物环境因素是否对代谢缩放具有交互影响。为了解决这个问题，我们研究了温度和捕食者线索对栖息在两个不同水生生态系统（淡水泉和咸水泻湖）的片脚类甲壳类动物的个体发育代谢尺度的同时影响。我们通过在实验室中将片足类动物暴露在多个温度下有或没有鱼线索的水中来评估表型可塑性对代谢规模的影响。温度与捕食者信号显着相互作用，从而影响代谢规模。我们的结果表明，代谢规模对于短期适应具有高度可塑性。温度和捕食者的相互作用表明了在现实生态环境中研究全球变暖影响的重要性。