Data from: Evolution of pre- and post-copulatory traits in male Drosophila melanogaster as a correlated response to selection for resistance to cold stress

Background: In Drosophila melanogaster the fitness of males depends on a broad array of reproductive traits classified as pre- and post-copulatory traits. Exposure to cold stress, can reduce sperm number, male mating ability and courtship behavior. Therefore, it is expected that the adaptation to cold stress will involve changes in pre- and post-copulatory traits. Such evolution of reproductive traits in response to cold stress is not well studied. Methods: We selected replicate populations of D. melanogaster for resistance to cold shock. Over 37–46 generations of selection, we investigated pre- and post-copulatory traits such as mating latency, copulation duration, mating frequency, male fertility, fitness (progeny production) and sperm competitive ability in male flies subjected to cold shock and those not subjected to cold shock. Results: We found that post cold shock, the males from the selected populations had a significantly lower mating latency along with, higher mating frequency, fertility, sperm competitive ability and number of progeny relative to the control populations. Conclusion: While most studies of experimental evolution of cold stress resistance have documented the evolution of survivorship in response to selection, our study clearly shows that adaptation to cold stress involves rapid changes in the pre- and post-copulatory traits. Additionally, improved performances under stressful conditions need not necessarily trade-off with performance under benign conditions.背景：在黑腹果蝇（Drosophila melanogaster）中，雄性的适合度依赖于一系列被划分为交配前和交配后两类的繁殖性状。冷胁迫暴露会降低雄性的精子数量、交配能力与求偶行为表现。由此推测，对冷胁迫的适应性演化会涉及交配前与交配后繁殖性状的改变。然而，目前针对冷胁迫响应的繁殖性状演化相关研究仍较为匮乏。 方法：本研究选取黑腹果蝇的重复种群进行冷休克抗性选育。在历经37至46代的选育后，我们分别对经历冷休克与未经历冷休克的雄性果蝇，开展了交配潜伏期、交配持续时间、交配频率、雄性育性、适合度（子代产出量）以及精子竞争能力等交配前、后繁殖性状的检测。 结果：相较于对照种群，经冷休克处理后的选育种群雄性果蝇，其交配潜伏期显著缩短，同时交配频率、育性、精子竞争能力以及子代数量均显著提升。 结论：尽管多数冷胁迫抗性实验演化研究仅报道了选育响应下的存活率演化规律，本研究明确证实，对冷胁迫的适应性演化会快速改变交配前与交配后繁殖性状。此外，胁迫环境下的性状表现提升，未必会与良性环境下的表现存在适合度权衡。