Data from: Disassortative mating prevails in style-dimorphic Narcissus papyraceus despite low reciprocity and compatibility of morphs

Evolution to reduce inbreeding can favor disassortative (inter-morph) over assortative (intra-morph) mating in hermaphroditic sexually polymorphic plant species. Heterostyly enhances disassortative pollination through reciprocal placement of stigmas and anthers of morphs and appropriate pollinators. Stylar dimorphism in which there is not reciprocal anther placement may compromise disassortative mating, particularly when there is not intra-morph incompatibility. Variable rates of disassortative mating along with differential female fecundity or siring success among floral morphs could lead to variation in morph ratio. We investigated mating patterns, female fecundity and siring success of style-length morphs in Narcissus papyraceus, a self-incompatible but morph-compatible species with dimorphic (long- and short-styled) and monomorphic (long-styled) populations in central and north regions of its range respectively. We established experimental populations in both regions and exposed them to ambient pollinators. Using paternity analysis, we found similar siring success of morphs and high disassortative mating in most populations. Female fecundity of morphs was similar in all populations. Although these results could not completely explain the loss of dimorphism in the species’ northern range, they provided evidence for the evolutionary stability of stylar dimorphism in N. papyraceus in at least some populations. Our findings support the hypothesis that prevailing inter-morph mating is key for the maintenance of stylar dimorphism.

在雌雄同体且具有性多态性的植物物种中，为降低近交（inbreeding）而发生的演化过程更青睐异型（形态间）交配（disassortative mating）而非同型（形态内）交配（assortative mating）。
花柱异长（heterostyly）通过不同花部形态个体的柱头与花药的交互排布，以及适配的传粉者，促进异型传粉。
不具有花药交互排布特征的花柱二态性（stylar dimorphism），可能会削弱异型交配，尤其是在不存在形态内不相容性的情况下。
异型交配率的差异，加上花部形态间雌性繁殖力或父本成功率（siring success）的差异，可能导致花部形态比例的变化。

我们以纸白水仙（Narcissus papyraceus）为研究对象，该物种为自交不亲和但形态间亲和的物种，其分布区中部和北部分别具有二态（长花柱型与短花柱型）和单态（仅长花柱型）种群。
我们在两个区域分别建立实验种群，并使其暴露于自然传粉者环境中。
通过父本分析（paternity analysis），我们发现多数种群中各花部形态的父本成功率相近，且异型交配比例较高。
所有种群中各花部形态的雌性繁殖力均无显著差异。
尽管这些结果无法完全解释该物种北部分布区中二态性的丢失，但它们为至少部分种群中纸白水仙的花柱二态性演化稳定性提供了实证支持。
本研究结果支持"主流异型交配是维持花柱二态性的核心因素"这一假说。