Gupta Anjali, Svensson Erik I, Frietsch Henrik, Tsuboi Masahito
Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali, Punjab 140306, India.
Department of Biology, Lund University, Sölvegatan 37, Lund 22362, Sweden.
J Evol Biol. 2025 Jul 21;38(6):728-743. doi: 10.1093/jeb/voaf040.
Following the development of regression-based methods to estimate natural and sexual selection, evolutionary biologists have quantified the strength, mode, and direction of selection in natural populations. Although this approach has been successful, its limitations include the lack of replication across species, which compromises the generality of the inferences beyond microevolutionary time scales. Here, we carried out a comparative study of selection on wing shape and body size across multiple populations of two closely related pond damselflies: Enallagma cyathigerum and Ischnura elegans (Odonata: Coenagrionidae). We found weak stabilizing selection on wing shape in both sexes and no evidence that selection on this trait differed between the species. In contrast, selection on body size was curvilinear in males and directional in females, with differences in form (males) and intensity (females) between the species. By analyzing selection in each local pond, we found that selection on male body size was shaped by various population characteristics that reflect local mating systems. Furthermore, the relationship between mating system characteristics and directional selection was remarkably consistent across these species. Finally, we present a graphical model that links contemporary selection with macroevolution. Based on this model, we conclude that the persistence of ecological modes of life in pond damselflies explains why varying selection in nature may still result in a stable adaptive zone lasting millions of years.
随着用于估计自然选择和性选择的基于回归方法的发展，进化生物学家已经对自然种群中选择的强度、模式和方向进行了量化。尽管这种方法取得了成功，但其局限性包括缺乏跨物种的重复验证，这损害了超出微观进化时间尺度的推断的普遍性。在这里，我们对两种亲缘关系密切的池塘豆娘（Enallagma cyathigerum和Ischnura elegans，蜻蜓目：色蟌科）的多个种群的翅形和体型选择进行了比较研究。我们发现两性对翅形的稳定选择都很弱，而且没有证据表明这两个物种在该性状上的选择存在差异。相比之下，对体型的选择在雄性中呈曲线形，在雌性中呈定向性，物种之间在形式（雄性）和强度（雌性）上存在差异。通过分析每个当地池塘中的选择情况，我们发现对雄性体型的选择受到反映当地交配系统的各种种群特征的影响。此外，交配系统特征与定向选择之间的关系在这些物种中非常一致。最后，我们提出了一个将当代选择与宏观进化联系起来的图形模型。基于这个模型，我们得出结论，池塘豆娘生态生活方式的持久性解释了为什么自然界中不同的选择仍可能导致一个持续数百万年的稳定适应区。
