Shah Alisha A, Bacmeister Eva M S, Rubalcaba Juan G, Ghalambor Cameron K
Department of Biology, Colorado State University, Fort Collins, CO, 80526, USA.
Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA.
Curr Zool. 2020 Oct;66(5):555-564. doi: 10.1093/cz/zoaa040. Epub 2020 Jul 21.
Environmental temperature variation may play a significant role in the adaptive evolutionary divergence of ectotherm thermal performance curves (TPCs). However, divergence in TPCs may also be constrained due to various causes. Here, we measured TPCs for swimming velocity of temperate and tropical mayflies (Family: ) and their stonefly predators (Family: ) from different elevations. We predicted that differences in seasonal climatic regimes would drive divergence in TPCs between temperate and tropical species. Stable tropical temperatures should favor the evolution of "specialists" that perform well across a narrow range of temperatures. Seasonally, variable temperatures in temperate zones, however, should favor "generalists" that perform well across a broad range of temperatures. In phylogenetically paired comparisons of mayflies and stoneflies, swimming speed was generally unaffected by experimental temperature and did not differ among populations between latitudes, suggesting a maintenance of performance breadth across elevation and latitude. An exception was found between temperate and tropical mayflies at low elevation where climatic differences between latitudes are large. In addition, TPCs did not differ between mayflies and their stonefly predators, except at tropical low elevation. Our results indicate that divergence in TPCs may be constrained in aquatic insects except under the most different thermal regimes, perhaps because of trade-offs that reduce thermal sensitivity and increase performance breadth.
环境温度变化可能在变温动物热性能曲线（TPCs）的适应性进化分歧中发挥重要作用。然而，由于各种原因，TPCs的分歧也可能受到限制。在这里，我们测量了来自不同海拔的温带和热带蜉蝣（科： ）及其石蝇捕食者（科： ）游泳速度的TPCs。我们预测，季节性气候模式的差异会导致温带和热带物种之间TPCs的分歧。稳定的热带温度应该有利于在狭窄温度范围内表现良好的“ specialists”的进化。然而，温带地区季节性变化的温度应该有利于在广泛温度范围内表现良好的“ generalists”。在蜉蝣和石蝇的系统发育配对比较中，游泳速度通常不受实验温度的影响，不同纬度种群之间也没有差异，这表明在海拔和纬度范围内性能广度得以维持。在低海拔地区的温带和热带蜉蝣之间发现了一个例外，那里纬度之间的气候差异很大。此外，除了热带低海拔地区外，蜉蝣与其石蝇捕食者之间的TPCs没有差异。我们的结果表明，除了在最不同的热状态下，水生昆虫TPCs的分歧可能受到限制，这可能是由于权衡降低了热敏感性并增加了性能广度。
