Willink Beatriz, Ho Tammy Ai Tian, Svensson Erik I
Department of Entomology, Cornell University, Ithaca, NY 14853.
Department of Biology, Aarhus University, Aarhus C 8000, Denmark.
Proc Natl Acad Sci U S A. 2025 Sep 9;122(36):e2503400122. doi: 10.1073/pnas.2503400122. Epub 2025 Sep 4.
Sexual conflict over mating has been documented in many species, both in the field and in experimental studies. In pond damselflies (family Coenagrionidae), sexual conflict maintains female-limited color polymorphisms, with one female morph typically being a male mimic. However, it is not known whether sexual conflict can also explain the evolutionary origin of novel female morphs, and if so, what ecological factors play a role in this macroevolutionary transition, by modulating the strength of the conflict. Here, we use phylogenetic comparative methods to show that female color polymorphisms are more likely to evolve in temperate regions and open landscapes, whereas region and habitat shifts are independent of female-color states. We also show that these macroecological patterns are mediated by population densities at breeding sites. Temperate and open habitats are associated with female-polymorphic lineages because they harbor higher densities of adults, promoting more frequent encounters between females and males. Finally, we found that female-limited polymorphisms typically evolve from sexually dimorphic ancestors through the addition of a male-like female morph, consistent with the hypothesis of selection for male mimicry. We conclude that female color polymorphisms evolve in a predictable fashion and are likely driven by ecological conditions that increase the rate of premating interactions and thus the intensity of sexual conflict.
在野外和实验研究中，许多物种都存在交配方面的性冲突。在池塘豆娘（色蟌科）中，性冲突维持了雌性特有的颜色多态性，其中一种雌性形态通常是雄性拟态。然而，尚不清楚性冲突是否也能解释新的雌性形态的进化起源，如果可以，在这种宏观进化转变中，哪些生态因素通过调节冲突强度发挥作用。在这里，我们使用系统发育比较方法表明，雌性颜色多态性更有可能在温带地区和开阔景观中进化，而区域和栖息地的变化与雌性颜色状态无关。我们还表明，这些宏观生态模式是由繁殖地的种群密度介导的。温带和开阔栖息地与雌性多态性谱系相关，因为它们容纳了更高密度的成虫，促进了雌性和雄性之间更频繁的相遇。最后，我们发现雌性特有的多态性通常从两性异形的祖先通过添加类似雄性的雌性形态进化而来，这与雄性拟态选择假说一致。我们得出结论，雌性颜色多态性以可预测的方式进化，并且可能由增加交配前相互作用速率从而增加性冲突强度的生态条件驱动。
