Schueller Sheila K
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109-1048 USA.
Am J Bot. 2004 May;91(5):672-81. doi: 10.3732/ajb.91.5.672.
Traits associated with self-pollination are common in island plants. This pattern could simply reflect the vestige of selection during colonization. Alternatively (or in addition), the ability to self-pollinate may provide a reproductive assurance benefit in established island plant populations due to inferior island pollinator service. To test these alternatives I studied an introduced plant (Nicotiana glauca; Solanaceae) on the California mainland and on two Channel Islands colonized at different times (approximately 30 and 100 yr ago). I compared these populations in terms of (1) capacity for self-pollination (self-compatibility, autogamy, stigma-anther distance, and incidence of a crumpled floral morph) and (2) current selection for the ability to self-pollinate (pollinator service by hummingbirds and the effect of emasculation on reproductive success). In general, island plants exhibited a higher capacity for self-pollination than mainland plants, especially on the most recently colonized island. However, island plants were not visited less frequently or more variably, nor did I detect current selection for selfing on islands. This supports the hypothesis that selfing traits in island plants are the product of a filter to successful establishment during colonization and not of selection for selfing in established island populations.
与自花授粉相关的性状在岛屿植物中很常见。这种模式可能仅仅反映了定殖过程中选择的遗迹。或者（或者此外），由于岛屿传粉者服务较差，自花授粉的能力可能在已建立的岛屿植物种群中提供繁殖保证益处。为了检验这些可能性，我研究了一种引入的植物（烟草；茄科），在加利福尼亚大陆以及两个在不同时间（大约30年和100年前）定殖的海峡群岛上。我从以下方面比较了这些种群：（1）自花授粉能力（自交亲和性、自动自花授粉、柱头-花药距离以及皱缩花形态的发生率），以及（2）当前对自花授粉能力的选择（蜂鸟的传粉服务以及去雄对繁殖成功的影响）。总体而言，岛屿植物比大陆植物表现出更高的自花授粉能力，尤其是在最近定殖的岛屿上。然而，岛屿植物被访问的频率并不更低或更不稳定，我也没有在岛屿上检测到当前对自交的选择。这支持了这样的假设，即岛屿植物中的自交性状是定殖过程中成功建立的一个筛选产物，而不是已建立的岛屿种群中自交选择的结果。
