Data from: Regulation of thermal acclimation varies between generations of the short-lived mosquitofish (Gambusia holbrooki) that developed in different environmental conditions

1. Environmental variability and perturbations can influence population persistence. It is therefore important to understand whether and how animals can compensate for environmental variability, and thereby increase resilience of natural populations. Evolutionary theory predicts that in fluctuating environments selection should favour developmental modifiers that reduce phenotypic expression of genetic variation. The expected result is that phenotypes are buffered from environmental variation across generations. 2. Our aim was to determine whether phenotypes of mosquitofish (Gambusia holbrooki) remain stable across generations in which individuals were born into different thermal environments. We predicted that the spring generation (cool environment) would acclimate by increasing the concentration of regulatory transcription factor mRNA and activities of rate-limiting enzymes (hierarchical regulation) to compensate for the negative thermodynamic effects of lower temperatures on metabolic and locomotor performance. In contrast, the summer-born generation (warm environment) would show less capacity for acclimation and hierarchical regulation. 4. We show that fish from both generations acclimated, but that there were significant differences in the phenotypic consequences of acclimation. The overall result was that sprint performance, metabolic scope, and the activities of cyctochrome c oxidase and lactate dehydrogenase were buffered from environmental change, and did not differ between spring and summer fish at their natural water temperatures of 15oC and 25oC, respectively. However, there were differences between generations in sustained swimming performance and citrate synthase activity. 5. We used metabolic control analysis to show that modes of regulation of metabolic scope and locomotor performance differed between generations. Spring fish showed primarily hierarchical regulation, but regulation in summer fish relied to a lesser extent on rate-limiting enzymes and transcription factors. 6. We suggest that developmental modifiers are favoured in fluctuating environments to maximise phenotypic fitness of each generation. We show that the interaction between developmental and reversible acclimation can render physiological performance of a natural population independent from climate variation.1. 环境变异与扰动可影响种群存续。因此，阐明动物能否以及如何补偿环境变异，进而提升自然种群的恢复力，具有重要研究意义。进化理论预测：在波动环境中，自然选择会青睐能够降低遗传变异表型表达的发育修饰因子，其预期结果为跨世代的表型可免受环境变异的影响。 2. 本研究旨在探究：出生于不同热环境的世代间，食蚊鱼（mosquitofish, Gambusia holbrooki）的表型是否保持稳定。我们预测：春季世代（所处环境温度较低）会通过提升调控型转录因子mRNA的浓度以及限速酶的活性（即层级调控），补偿低温对代谢与运动性能产生的负面热力学效应；与之相对，夏季出生的世代（所处环境温度较高）的驯化能力与层级调控能力则相对较弱。 4. 本研究发现，两个世代的食蚊鱼均发生了驯化，但驯化所带来的表型效应存在显著差异。整体结果显示：冲刺运动性能、代谢范围，以及细胞色素c氧化酶（cytochrome c oxidase）与乳酸脱氢酶（lactate dehydrogenase）的活性均免受环境变化的影响；在各自自然水温（春季世代为15℃，夏季世代为25℃）下，春、夏两世代的食蚊鱼上述指标并无显著差异。不过，两个世代在持续游泳性能与柠檬酸合酶活性方面存在差异。 5. 本研究采用代谢控制分析（metabolic control analysis）证实：代谢范围与运动性能的调控模式在两个世代间存在差异。春季世代的食蚊鱼主要采用层级调控，而夏季世代的调控对限速酶与转录因子的依赖程度相对更低。 6. 我们认为：在波动环境中，发育修饰因子更受自然选择青睐，以最大化每个世代的表型适合度。本研究证实，发育调控与可逆驯化之间的相互作用，可使自然种群的生理性能不受气候变异的干扰。