Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, K1S 5B6, Canada.
Sci Rep. 2021 May 25;11(1):10876. doi: 10.1038/s41598-021-90401-5.
Species from colder climates tend to be more chill tolerant regardless of the chill tolerance trait measured, but for Drosophila melanogaster, population-level differences in chill tolerance among populations are not always found when a single trait is measured in the laboratory. We measured chill coma onset temperature, chill coma recovery time, and survival after chronic cold exposure in replicate lines derived from multiple paired African and European D. melanogaster populations. The populations in our study were previously found to differ in chronic cold survival ability, which is believed to have evolved independently in each population pair; however, they did not differ in chill coma onset temperature and chill coma recovery time in a manner that reflected their geographic origins, even though these traits are known to vary with origin latitude among Drosophila species and are among the most common metrics of thermal tolerance in insects. While it is common practice to measure only one chill tolerance trait when comparing chill tolerance among insect populations, our results emphasise the importance of measuring more than one thermal tolerance trait to minimize the risk of missing real adaptive variation in insect thermal tolerance.
来自寒冷气候的物种往往更能耐受寒冷，无论所测量的耐寒性特征如何，但对于黑腹果蝇来说，当在实验室中测量单一特征时，并非总能在种群水平上发现种群间耐寒性的差异。我们测量了复制品系的冷昏迷起始温度、冷昏迷恢复时间和慢性冷暴露后的存活率，这些复制品系来自多个配对的非洲和欧洲黑腹果蝇种群。我们的研究中的种群在慢性冷生存能力方面存在差异，据信这种差异是在每个种群对中独立进化的；然而，它们在冷昏迷起始温度和冷昏迷恢复时间方面没有以反映其地理起源的方式存在差异，尽管这些特征已知在果蝇物种中随起源纬度而变化，并且是昆虫中最常见的热耐受性衡量标准之一。虽然在比较昆虫种群之间的耐寒性时，通常只测量一个耐寒性特征，但我们的结果强调了测量多个热耐受性特征的重要性，以最大程度地降低错过昆虫热耐受性真正适应性变化的风险。
