Am J Bot. 1997 May;84(5):641.
The influence of outcrossing and pollination biology on the maintenance of hermaphroditism was studied for Schiedea lydgatei (Caryophyllaceae: Alsinoideae), a species endemic to Molokai in the Hawaiian Islands. Schiedea lydgatei is the only hermaphroditic species in an otherwise dimorphic clade and hermaphroditism is likely the result of a reversal from a gynodioecious ancestor. Both wind and native moths in the family Pyralidae are responsible for pollination in S. lydgatei. Outcrossing rates were generally high (0.80), especially in years when the greatest number of plants were flowering. The combination of high outcrossing rates and substantial inbreeding depression indicates that at present females would not be favored in the population. Pollination by both wind and insects is consistent with the hypothesis that hermaphroditism is the result of a relatively recent reversal, as the ancestor of S. lydgatei was probably wind pollinated and gynodioecious with few females in the populations. A shift from wind to predominately insect pollination on Molokai may have resulted in increased outcrossing rates and prevented the expression of high inbreeding depression among progeny of hermaphrodites, a condition that would select against females and favor a reversal to hermaphroditism. Because few females were likely to have been present in ancestral populations that colonized Moloka`i, founder effect is another potential explanation for loss of females. In either case, current high levels of outcrossing prevent re-establishment of females in populations of S. lydgatei.
对异交和传粉生物学对雌雄同体维持的影响进行了研究，研究对象是 Schiedea lydgatei（石竹科：Alsinoideae），这是一种仅存在于夏威夷莫洛凯岛的特有种。Schiedea lydgatei 是一个形态二态种属中唯一的雌雄同体物种，雌雄同体可能是从雌性-雄性异株祖先逆转而来的结果。风和鳞翅目天蛾科的本地飞蛾都负责 S. lydgatei 的传粉。异交率通常很高（0.80），尤其是在有大量植物开花的年份。高异交率和大量近亲繁殖衰退的结合表明，目前在种群中雌性不会受到青睐。风和昆虫的授粉方式与雌雄同体是最近逆转的假说一致，因为 S. lydgatei 的祖先可能是风媒传粉和雌性-雄性异株的，种群中雌性很少。莫洛凯岛从风媒向主要昆虫授粉的转变可能导致异交率增加，并防止雌雄同体后代中近亲繁殖衰退的表达，这种情况会选择对雌性不利，并有利于向雌雄同体逆转。由于在殖民莫洛凯岛的祖先种群中可能很少有雌性存在，奠基者效应是雌性丧失的另一个潜在解释。在任何一种情况下，当前高水平的异交都阻止了 S. lydgatei 种群中雌性的重新建立。
