Local adaptation reduces the metabolic cost of environmental warming

Metabolism shapes the ecosystem role of organisms by dictating their energy demand and nutrient recycling potential. Metabolic theory (MTE) predicts consumer metabolic and recycling rates will rise in a warming world, especially if body size declines, but it ignores potential for adaptation. We measured metabolic and nutrient excretion rates of individuals from populations of a globally invasive fish that recently colonized a wide temperature range (19-37°C) on two continents. Fish body size declined across our temperature gradient and MTE predicted large rises in population energy demand and nutrient recycling. However, we found that the allometry and temperature dependency of metabolism varied in a countergradient pattern with local temperature in a way that offset predictions of MTE. Scaling of nutrient excretion was more variable, and did not track temperature. Our results suggest that adaptation can reduce the metabolic cost of warming, increasing the prospects for population persi...

新陈代谢通过调控生物体的能量需求与养分循环潜力，塑造其在生态系统中的功能角色。代谢理论（Metabolic Theory, MTE）预测，在气候变暖的背景下，消费者的代谢速率与养分循环速率将随之升高，尤其当生物体体型缩小时，但该理论并未考虑适应性演化的潜在影响。我们针对两大洲内新近入侵并占据19-37℃宽温度梯度生境的一种全球性入侵鱼类不同种群的个体，测定了其代谢速率与养分排泄速率。随着温度梯度升高，鱼类体型呈现下降趋势，按照MTE的预测，种群的能量需求与养分循环速率将大幅提升。然而我们发现，代谢的异速生长（allometry）关系与温度依赖性会随局地温度呈现逆梯度变化模式，这一效应抵消了MTE的预测结果。养分排泄的尺度关系则表现出更强的变异性，并未随温度变化呈现一致规律。本研究结果表明，适应性演化可降低气候变暖带来的代谢成本，提升种群存续的可能性……