Data from: Environmental and genetic control of cold tolerance in the Glanville fritillary butterfly

Thermal tolerance has a major effect on individual fitness and species distributions, and can be determined by genetic variation as well as phenotypic plasticity. We investigate the effects of developmental and adult thermal conditions on cold tolerance, measured as chill coma recovery (CCR) time, during the early and late adult stage in the Glanville fritillary butterfly. We also investigate the genetic basis of cold tolerance by associating CCR variation with polymorphisms in candidate genes that have a known role in insect physiology. Our results demonstrate that a cooler developmental temperature leads to reduced cold tolerance in the early adult stage, whereas cooler conditions during the adult stage lead to increased cold tolerance. This suggests that adult acclimation, but not developmental plasticity, of adult cold tolerance is adaptive. This could be explained by the ecological conditions the Glanville fritillary experiences in the field, where temperature during early summer, but not spring, is predictive of thermal conditions during the butterfly’s flight season. In addition, an amino acid polymorphism (Ala-Glu) in the gene flightin, which has a known function in insect flight and locomotion, was associated with chill coma recovery. These amino acids have distinct biochemical properties and may thus affect protein function and/or structure. To our knowledge, our study is the first to link genetic variation in flightin to cold tolerance, or thermal adaptation in general.

热耐受性（Thermal tolerance）对个体适合度及物种分布具有显著影响，其可由遗传变异与表型可塑性（phenotypic plasticity）共同决定。本研究以格纹蛱蝶（Glanville fritillary butterfly）为研究对象，探究发育阶段与成虫期的热环境对其耐寒性的影响，耐寒性以冷昏迷恢复（chill coma recovery, CCR）时长进行量化，实验分别在成虫早期与成虫晚期开展。此外，本研究通过将冷昏迷恢复时长的变异与在昆虫生理中功能已明确的候选基因多态性进行关联分析，解析耐寒性的遗传基础。研究结果显示，较低的发育温度会降低成虫早期的耐寒性，而成虫期的低温环境则可提升耐寒性。这表明成虫耐寒性的成虫冷驯化（而非发育可塑性）具有适应性价值。该现象可由格纹蛱蝶野外所处的生态环境得到解释：该物种飞行季的热环境可由初夏（而非春季）的气温进行预测。此外，在昆虫飞行与运动中功能已明确的飞行蛋白基因（flightin）中存在一处丙氨酸-谷氨酸（Ala-Glu）氨基酸多态性，该多态性与冷昏迷恢复时长存在关联。这两种氨基酸具有截然不同的生化特性，因此可能影响蛋白质的功能与/或结构。据我们所知，本研究首次将飞行蛋白基因的遗传变异与耐寒性（或广义的热适应性）建立关联。