Imperial College London, Ascot, Berkshire, UK.
New Phytol. 2010 Oct;188(2):426-36. doi: 10.1111/j.1469-8137.2010.03438.x. Epub 2010 Aug 25.
• Pollinators, as gene flow vectors and selection agents, play a central role in the origin and maintenance of floral variation in natural populations. However, it is debatable whether pollination alone can complete the speciation process in sympatry. • Mating patterns and phenotypic selection on floral traits were characterized over two flowering seasons for sympatric corolla tube length morphs of the hawkmoth-pollinated iris Gladiolus longicollis. A mating model with genetic and spatial-temporal predictors was developed to identify seed paternity. A multivariate analysis was used to estimate selection on correlated floral traits based on maternal and paternal fitness. • Mating patterns among floral morphs were density dependent, resulting in assortative mating at low plant densities, and random mating among morphs at high densities. Weak disruptive selection on tube length was detected in one season for maternal fitness. Plant height was under opposing directional selection for maternal (+) and paternal (-) fitness functions. • These results indicate that G. longicollis morphs will introgress rather than diverge towards speciation. The lack of strong assortative mating, particularly at high densities, is predicted to result in the loss of rare morphs within populations, and indicates that spatial and temporal co-occurrences of floral morphs are evolutionarily unstable.
• 传粉媒介作为基因流载体和选择因子，在自然种群中花部变异的起源和维持中起着核心作用。然而，传粉是否单独就能完成同域物种形成过程仍存在争议。 • 在两个开花季节中，对蜂鸟传粉的鸢尾属植物长距鸢尾的同域管状花冠长度形态进行了交配模式和对花部特征的表型选择研究。建立了一个具有遗传和时空预测因子的交配模型，以确定种子的亲子关系。使用多元分析根据母本和父本适合度来估计相关花部特征的选择。 • 花部形态之间的交配模式依赖于密度，导致在植物密度低时表现出同型交配，而在密度高时表现出随机交配。在一个季节中，检测到对管长的弱破坏性选择对母本适合度有利。株高在母本（+）和父本（-）适合度函数下受到相反的定向选择。 • 这些结果表明，长距鸢尾的形态将趋同而不是趋异进化。缺乏强烈的同型交配，特别是在高密度时，预计会导致稀有形态在种群内的丧失，并表明花部形态的时空共存在进化上是不稳定的。
