Data from: Low evolutionary potential for egg-to-adult viability in Drosophila melanogaster at high temperatures

To cope with the increasing and less predictable temperature forecasts under climate change, many terrestrial ectotherms will have to migrate or rely on adaptation through plastic or evolutionary means. Studies suggest that some ectotherms have a limited potential to change their upper thermal limits via evolutionary shifts, but research has mostly focused on adult life stages under laboratory conditions. Here we use replicate populations of Drosophila melanogaster and a nested half sib/full sib quantitative genetic design to estimate heritabilities and genetic variance components for egg-to-adult viability under both laboratory and semi-natural field conditions, encompassing cold, benign and hot temperatures in two separate populations. The results demonstrated temperature-specific heritabilities and additive genetic variances for egg-to-adult viability. Heritabilities and genetic variances were higher under cold and benign compared to hot temperatures when tested under controlled laboratory conditions. Tendencies towards lower evolutionary potential at higher temperatures were also observed under semi-natural conditions although the results were less clear in the field setting. Overall the results suggest that ectotherms that already experience temperatures close to their upper thermal tolerance limits have a restricted capacity to adapt to higher temperatures by evolutionary means.

为应对气候变化下愈发频发且难以预判的温度波动，许多陆生变温动物（ectotherms）要么选择迁徙，要么通过表型可塑性或进化途径实现适应性演化。已有研究表明，部分变温动物通过进化改变其高温耐受上限的潜力有限，但现有研究大多聚焦于实验室条件下的成虫生命阶段。本研究以黑腹果蝇（Drosophila melanogaster）的重复种群为研究对象，采用巢式半同胞/全同胞数量遗传设计，分别在实验室与半自然野外条件下，估算两个独立种群在低温、适宜及高温环境下的卵至成虫存活率的遗传力与遗传方差组分。研究结果显示，卵至成虫存活率的遗传力与加性遗传方差存在温度特异性。在可控实验室条件下检测时，低温与适宜环境下的遗传力及遗传方差均高于高温环境。在半自然条件下也观察到高温环境下进化潜力降低的趋势，但野外环境中的研究结果相对不够明确。总体而言，本研究结果表明，那些已处于接近自身高温耐受上限温度环境中的变温动物，通过进化途径适应更高温度的能力较为有限。