Data from: Sexual selection in a hermaphroditic plant through female reproductive success

Sexual selection is well accepted as a mechanism of shaping traits in animals. However, whether and how floral traits are sexually selected in hermaphroditic plants remains less clear. Here, we use Passiflora incarnata to address how floral traits that affect pollination success are selected via female function. We manipulated the ecological context by limiting pollination and adding resources to expand the phenotypic distribution and alter the intensity of sexual selection. Total sexual selection favoured lower style deflexion because of its impact on pollen receipt and subsequent seed number. However, total selection on style deflexion was not significant, indicating additional selection on style deflexion through routes other than mating. Limited pollination and enhanced resources were expected to alter the distribution of pollen deposition and seed production and therefore intensify the Bateman gradient – the relationship between pollen receipt and seed production. Indeed, the Bateman gradient was strongest when pollination was limited, suggesting potential for sexual selection to influence floral trait evolution under these conditions. Overall, we found floral traits may be shaped by sexual selection through female reproductive success in this hermaphroditic plant. These results support manipulations to enhance the variance in mating as a mechanism to understand patterns of sexual selection.

性选择（sexual selection）作为塑造动物性状的核心机制已得到学界广泛认可。然而，雌雄同体植物的花部性状是否以及如何经受性选择，目前仍不甚明晰。本研究以红花西番莲（Passiflora incarnata）为研究对象，探讨通过雌性生殖功能，影响传粉成功的花部性状如何受到选择作用。我们通过限制传粉与补充资源的方式操控实验生态背景，以扩大表型分布范围并改变性选择强度。总体性选择青睐较低的花柱弯曲度，因其可影响花粉接收量与后续结籽数；但针对花柱弯曲度的总体选择并不显著，这表明花柱弯曲度还存在除交配通路之外的其他选择途径。传粉受限与资源供给提升本应改变花粉沉积与结籽量的分布，进而强化贝特曼梯度（Bateman gradient）——即花粉接收量与结籽数之间的关联。实验结果证实，当传粉受限时，贝特曼梯度最为显著，提示在该条件下性选择具备影响该植物花部性状演化的潜在可能。总体而言，本研究发现，在这种雌雄同体植物中，花部性状或可通过雌性生殖成功受到性选择的塑造。本研究结果支持通过操控手段提升交配变异度，以此作为阐释性选择模式的有效研究路径。