Data from: Colder environments did not select for a faster metabolism during experimental evolution of Drosophila melanogaster

The effect of temperature on the evolution of metabolism has been the subject of debate for a century; however, no consistent patterns have emerged from comparisons of metabolic rate within and among species living at different temperatures. We used experimental evolution to determine how metabolism evolves in populations of Drosophila melanogaster exposed to one of three selective treatments: a constant 16°C, a constant 25°C, or temporal fluctuations between 16 and 25°C. We tested August Krogh's controversial hypothesis that colder environments select for a faster metabolism. Given that colder environments also experience greater seasonality, we also tested the hypothesis that temporal variation in temperature may be the factor that selects for a faster metabolism. We measured the metabolic rate of flies from each selective treatment at 16, 20.5, and 25°C. Although metabolism was faster at higher temperatures, flies from the selective treatments had similar metabolic rates at each measurement temperature. Based on variation among genotypes within populations, heritable variation in metabolism was likely sufficient for adaptation to occur. We conclude that colder or seasonal environments do not necessarily select for a faster metabolism. Rather, other factors besides temperature likely contribute to patterns of metabolic rate over thermal clines in nature.温度对代谢演化的影响已争论百年，但针对不同温度下生活的物种内部及物种间代谢率的比较研究，始终未能得出一致结论。本研究采用实验演化方法，探究黑腹果蝇（Drosophila melanogaster）种群在三种选择性培育处理下的代谢演化特征：分别为恒定16℃、恒定25℃，以及16℃与25℃的周期性温度波动。我们检验了奥古斯特·克罗（August Krogh）颇具争议的假说——低温环境会选择偏好更快代谢的个体；同时鉴于低温环境往往伴随更强的季节性温度波动，我们还验证了另一假说：温度的时间变异才是驱动代谢速率提升的选择压力。我们分别在16℃、20.5℃与25℃三个测定温度下，对各处理组果蝇的代谢速率进行了检测。尽管代谢速率随测定温度升高而显著加快，但各选择性处理组的果蝇在同一测定温度下的代谢速率并无显著差异。基于种群内不同基因型间的代谢性状差异，代谢相关性状的可遗传变异足以支撑适应性演化的发生。本研究结论为：低温或季节性温度环境未必会选择偏好更快代谢速率的个体。换言之，除温度外，其他潜在因素共同塑造了自然界中沿温度梯度分布的代谢率格局。