Data from: Latitudinal and voltinism compensation shape thermal reaction norms for growth rate

Latitudinal variation in thermal reaction norms of key fitness traits may inform about the response of populations to climate warming, yet their adaptive nature and evolutionary potential is poorly known. We assessed the contribution of quantitative genetic, neutral genetic and environmental effects to thermal reaction norms of growth rate for populations of the damselfly Ischnura elegans. Among populations, reaction norms differed primarily in elevation suggesting that time constraints associated with shorter growth seasons in univoltine, high-latitude as well as multivoltine, low-latitude populations selected for faster growth rates. Phenotypic divergence among populations is consistent with selection rather than drift as QST was greater than FST in all cases. QST estimates increased with experimental temperature and were influenced by genotype by environment interactions. Substantial additive genetic variation for growth rate in all populations suggests that evolution of trait means in different environments is not constrained. Heritability of growth rates was higher at high temperature, driven by increased genetic rather than environmental variance. While environment-specific non-additive effects also may contribute to heritability differences among temperatures, maternal effects did not play a significant role (where these could be accounted for). Genotype by environment interactions strongly influenced the adaptive potential of populations, and our results suggest the potential for microevolution of thermal reaction norms in each of the studied populations. In summary, the observed latitudinal pattern in growth rates is adaptive and results from a combination of latitudinal and voltinism compensation. Combined with the evolutionary potential of thermal reaction norms, this may affect populations’ ability to respond to future climate warming.关键适合度性状（fitness traits）的热反应规范（thermal reaction norms）的纬度变异，可为预测种群应对气候变暖的响应提供科学依据，但其适应性本质与进化潜力目前仍所知甚少。本研究以豆娘（damselfly）长叶异痣蟌（Ischnura elegans）的多个自然种群为研究对象，评估了数量遗传（quantitative genetic）、中性遗传（neutral genetic）与环境效应对其生长速率热反应规范的贡献。种群间的热反应规范主要在截距（高度）上存在差异，这表明：一化性（univoltine）高纬度种群与多化性（multivoltine）低纬度种群均面临生长季时长受限的选择压力，进而筛选出更快的生长速率。种群间的表型分化符合自然选择而非遗传漂变的预期，因为所有实验处理下数量遗传分化系数（QST）均大于遗传分化系数（FST）。QST估计值随实验温度升高而增加，且受基因型×环境互作（genotype by environment interactions）的显著影响。所有种群的生长速率均存在可观的加性遗传变异（additive genetic variation），这意味着不同环境下的性状均值进化并未受到遗传约束。高温环境下生长速率的遗传力更高，这一现象由遗传方差而非环境方差的增加所驱动。尽管环境特异性的非加性效应或许也会导致不同温度下的遗传力差异，但在可被评估的范围内，母体效应（maternal effects）并未发挥显著作用。基因型×环境互作强烈影响种群的适应性进化潜力，本研究结果表明，在所研究的每个种群中，热反应规范均存在微进化（microevolution）的潜力。综上，观测到的生长速率纬度分布格局具有适应性，其源于纬度梯度与化性（voltinism）补偿的共同作用。结合热反应规范的进化潜力，这一结果或可影响种群应对未来气候变暖的能力。