Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
J Evol Biol. 2011 Oct;24(10):2217-29. doi: 10.1111/j.1420-9101.2011.02350.x. Epub 2011 Jul 4.
Ecological speciation studies have more thoroughly addressed premating than postmating reproductive isolation. This study examines multiple postmating barriers between host forms of Neochlamisus bebbianae leaf beetles that specialize on Acer and Salix trees. We demonstrate cryptic isolation and reduced hybrid fitness via controlled matings of these host forms. These findings reveal host-associated postmating isolation, although a nonecological, 'intrinsic' basis for these patterns cannot be ruled out. Host preference and performance results among cross types further suggest sex-linked maternal effects on these traits, whereas family effects indicate their genetic basis and associated variation. Genes of major effect appear to influence these traits. Together with previous findings of premating isolation and adaptive differentiation in sympatry, our results meet many assumptions of 'speciation with gene flow' models. Here, such gene flow is likely asymmetric, with consequences for the dynamics of future ecological divergence and potential ecological speciation of these host forms.
生态物种形成研究更多地解决了交配前的生殖隔离问题，而不是交配后的生殖隔离问题。本研究考察了专性吸食槭树和柳树的 Neochlamisus bebbianae 叶甲宿主形式之间的多种交配后障碍。我们通过对这些宿主形式的控制交配证明了隐性隔离和杂种适应性降低。这些发现揭示了与宿主相关的交配后隔离，尽管不能排除这些模式的非生态的、“内在的”基础。跨类型的寄主偏好和表现结果进一步表明，这些性状存在与性别相关的母体效应，而家系效应则表明其遗传基础和相关变异。主要效应基因似乎影响这些性状。结合以前在同域中发现的交配前隔离和适应性分化，我们的结果符合“有基因流的物种形成”模型的许多假设。在这里，这种基因流可能是不对称的，这对未来生态分歧的动态和这些宿主形式的潜在生态物种形成有影响。
