School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, United Kingdom.
Centre for Biodiversity Dynamics, Institutt for Biologi, NTNU, Trondheim, N-7491, Norway.
Evolution. 2022 Mar;76(3):636-648. doi: 10.1111/evo.14426. Epub 2022 Jan 19.
Female mating preferences for exaggerated male display traits are commonplace. Yet, comprehensive understanding of the evolution and persistence of costly female preference through indirect (Fisherian) selection in finite populations requires some explanation for the persistence of additive genetic variance (V ) underlying sexual traits, given that directional preference is expected to deplete V in display and hence halt preference evolution. However, the degree to which V , and hence preference-display coevolution, may be prolonged by spatially variable sexual selection arising solely from limited gene flow and genetic drift within spatially structured populations has not been examined. Our genetically and spatially explicit model shows that spatial population structure arising in an ecologically homogeneous environment can facilitate evolution and long-term persistence of costly preference given small subpopulations and low dispersal probabilities. Here, genetic drift initially creates spatial variation in female preference, leading to persistence of V in display through "migration-bias" of genotypes maladapted to emerging local sexual selection, thus fueling coevolution of costly preference and display. However, costs of sexual selection increased the probability of subpopulation extinction, limiting persistence of high preference-display genotypes. Understanding long-term dynamics of sexual selection systems therefore requires joint consideration of coevolution of sexual traits and metapopulation dynamics.
雌性对雄性夸张展示特征的交配偏好很常见。然而，要全面理解在有限种群中通过间接（费希尔）选择进化和维持有成本的雌性偏好，需要对性特征的加性遗传方差（V）的持久性做出一些解释，因为定向偏好预计会耗尽展示中的 V，从而停止偏好进化。然而，仅由有限基因流和空间结构种群中的遗传漂变引起的空间可变的性选择在何种程度上可以延长 V，从而延长偏好-展示的协同进化，尚未得到检验。我们的遗传和空间显式模型表明，在生态同质环境中产生的空间种群结构可以促进小亚种群和低扩散概率下有成本的偏好的进化和长期持续。在这里，遗传漂变最初在雌性偏好中产生空间变异，导致通过不适应新出现的局部性选择的基因型的“迁移偏见”在展示中保留 V，从而推动有成本的偏好和展示的协同进化。然而，性选择的成本增加了亚种群灭绝的概率，限制了高偏好-展示基因型的持续存在。因此，理解性选择系统的长期动态需要同时考虑性特征的协同进化和复合种群动态。
