Data from: Assortative mating counteracts the evolution of dispersal polymorphisms

Polymorphic dispersal strategies are found in many plant and animal species. An important question is how the genetic variation underlying such polymorphisms is maintained. Numerous mechanisms have been discussed, including kin competition or frequency-dependent selection. In the context of sympatric speciation events genetic and phenotypic variation is often assumed to be preserved by assortative mating. Thus, recently, this has been advocated as a possible mechanism leading to the evolution of dispersal polymorphisms. Here, we examine the role of assortative mating for the evolution of trade-off driven dispersal polymorphisms by modelling univoltine insect species in a metapopulation. We show that assortative mating does not favour the evolution of polymorphisms. On the contrary, assortative mating favours the evolution of an intermediate dispersal type and a uni-modal distribution of traits within populations. As an alternative mechanism dominance may explain the occurrence of two discrete morphs.许多动植物物种均存在多态扩散策略（polymorphic dispersal strategies）。一个核心科学问题是，此类多态性背后的遗传变异是如何得以维持的。学界已讨论过诸多维持机制，包括亲缘竞争（kin competition）与频率依赖选择（frequency-dependent selection）等。在同域物种形成（sympatric speciation）的研究语境中，遗传与表型变异通常被认为可通过选型交配（assortative mating）得以保留。因此，近期有研究提出，选型交配可能是驱动扩散多态性演化的潜在机制。本文以集合种群（metapopulation）框架下的一化性昆虫（univoltine insect）为模型，探讨了选型交配在权衡驱动的扩散多态性演化中的作用。研究结果表明，选型交配并不会促进多态性的演化；相反，其更倾向于促使种群内演化出中等扩散类型，并形成单峰的性状分布。作为替代机制，显性效应或许可以解释两种离散形态的出现。