Rhodes Matthew K, Fant Jeremie B, Skogen Krissa A
Division of Plant Science and Conservation, Chicago Botanic Garden, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA.
Program in Plant Biology and Conservation, Northwestern University, 2205 Tech Drive, O.T. Hogan Hall, Room 2-144, Evanston, IL, 60208, USA.
Mol Ecol. 2017 Aug;26(16):4296-4308. doi: 10.1111/mec.14115. Epub 2017 Apr 12.
The occurrence and extent of multiple paternity is an important component of variation in plant mating dynamics. However, links between pollinator activity and multiple paternity are generally lacking, especially for plant species that attract functionally diverse floral visitors. In this study, we separated the influence of two functionally distinct floral visitors (hawkmoths and solitary bees) and characterized their impacts on multiple paternity in a self-incompatible, annual forb, Oenothera harringtonii (Onagraceae). We also situated pollinator-mediated effects in a spatial context by linking variation in multiple paternity to variation in plant spatial isolation. We documented pronounced differences in the number of paternal sires as function of pollinator identity: on average, the primary pollinator (hawkmoths) facilitated mating with nearly twice as many pollen donors relative to the secondary pollinator (solitary bees). This effect was consistent for both isolated and nonisolated individuals, but spatial isolation imposed pronounced reductions on multiple paternity regardless of pollinator identity. Considering that pollinator abundance and pollen dispersal distance did not vary significantly with pollinator identity, we attribute variation in realized mating dynamics primarily to differences in pollinator morphology and behaviour as opposed to pollinator abundance or mating incompatibility arising from underlying spatial genetic structure. Our findings demonstrate that functionally distinct pollinators can have strongly divergent effects on polyandry in plants and further suggest that both pollinator identity and spatial heterogeneity have important roles in plant mating dynamics.
多重父本现象的发生及其程度是植物交配动态变化的一个重要组成部分。然而，传粉者活动与多重父本现象之间的联系普遍缺乏，尤其是对于那些吸引功能多样的访花者的植物物种。在本研究中，我们区分了两种功能不同的访花者（天蛾和独居蜂）的影响，并描述了它们对一种自交不亲和的一年生草本植物——哈氏月见草（柳叶菜科）多重父本现象的影响。我们还通过将多重父本现象的变化与植物空间隔离的变化联系起来，将传粉者介导的效应置于空间背景中。我们记录了作为传粉者身份函数的父本数量的显著差异：平均而言，主要传粉者（天蛾）促进与花粉供体交配的数量几乎是次要传粉者（独居蜂）的两倍。这种效应在隔离和非隔离个体中都是一致的，但无论传粉者身份如何，空间隔离都会显著降低多重父本现象。考虑到传粉者丰度和花粉传播距离不会随着传粉者身份而显著变化，我们将实际交配动态的变化主要归因于传粉者形态和行为的差异，而不是传粉者丰度或由潜在空间遗传结构引起的交配不亲和性。我们的研究结果表明，功能不同的传粉者对植物的一妻多夫制可能有强烈不同的影响，并进一步表明传粉者身份和空间异质性在植物交配动态中都起着重要作用。
