Center for Insect Science, University of Arizona, Tucson, 85721, USA.
Mol Ecol. 2009 Dec;18(24):4988-90. doi: 10.1111/j.1365-294X.2009.04429.x.
Coevolutionary interactions between plants and their associated pollinators and seed dispersers are thought to have promoted the diversification of flowering plants (Raven 1977; Regal 1977; Stebbins 1981). The actual mechanisms by which pollinators could drive species diversification in plants are not fully understood. However, it is thought that pollinator host specialization can influence the evolution of reproductive isolation among plant populations because the pollinator's choice of host is what determines patterns of gene flow in its host plant, and host choice may also have important consequences on pollinator and host fitness (Grant 1949; Bawa 1992). In this issue of Molecular Ecology, Smith et al. (2009) present a very interesting study that addresses how host specialization affects pollinator fitness and patterns of gene flow in a plant host. Several aspects of this study match elements of a seminal mathematical model of plant-pollinator codivergence (Kiester et al. 1984) suggesting that reciprocal selection for matched plant and pollinator reproductive traits may lead to speciation in the host and its pollinator when there is strong host specialization and a pattern of geographic subdivision. Smith et al.'s study represents an important step to fill the gap in our understanding of how reciprocal selection may lead to speciation in coevolved plant-pollinator mutualisms.
植物与其相关的传粉者和种子散布者之间的协同进化相互作用被认为促进了开花植物的多样化（Raven 1977；Regal 1977；Stebbins 1981）。传粉者如何能够驱动植物物种多样化的实际机制尚未完全理解。然而，人们认为传粉者的宿主专化性可以影响植物种群生殖隔离的进化，因为传粉者对宿主的选择决定了其宿主植物中基因流动的模式，而宿主选择也可能对传粉者和宿主的适应性产生重要影响（Grant 1949；Bawa 1992）。在本期《分子生态学》中，Smith 等人（2009）发表了一项非常有趣的研究，探讨了宿主专化性如何影响植物宿主中的传粉者适应性和基因流动模式。这项研究的几个方面与植物-传粉者协同进化的开创性数学模型的要素相匹配（Kiester 等人，1984），表明当宿主专化性强且存在地理细分模式时，对匹配的植物和传粉者生殖特征的相互选择可能导致宿主及其传粉者的物种形成。Smith 等人的研究代表了在理解相互选择如何导致协同进化的植物-传粉者共生关系中物种形成方面迈出的重要一步。
