Contribution of Multiple Isolating Barriers to Reproductive Isolation Between a Pair of Phytophagous Ladybird Beetles
Contribution of Multiple Isolating Barriers to Reproductive Isolation Between a Pair of Phytophagous Ladybird Beetles
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DOI：
10.1111/j.1558-5646.2009.00738.x
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发表时间：
2009-10
期刊：
影响因子：
--
通讯作者：
K. Matsubayashi;H. Katakura
中科院分区：
文献类型：
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作者：
K. Matsubayashi;H. Katakura
物种间的生殖隔离通常是通过多个隔离屏障来实现的，但在动物类群中对其成分的研究很少。为了阐明多重隔离屏障的性质，我们量化了两种植食性瓢虫间的三种主要屏障的强度，包括基于生态的屏障(季节性、栖息地和性)，两种交配前-孵化障碍(降低的卵孵化率和同种精子优先[CSP])，以及一种后孵化屏障，包括四种成分的F1杂交降低适合度。我们检测到五个正障碍(生境隔离、性隔离、降低蛋孵化率、CSP和回交降低蛋孵化率)。当基因交换单独起作用时，所有这些障碍都不能完全阻止基因交换，但它们共同产生了几乎完全的生殖隔离，即使在共处的种群之间也是如此。寄主保真度对生殖隔离的贡献最大，它通过几种重要的生态隔离类型减少种间杂交，包括微空间隔离、栖息地和季节隔离。多个隔离屏障的存在可能有助于保持生殖隔离的稳定和健壮，这是对泄漏屏障强度变化的补充。多个隔离屏障的这种互补性产生了生殖隔离的稳健性概念，这在考虑共存物种对中物种边界的长期维持时是重要的。
Reproductive isolation between species may often be attained by multiple isolating barriers, but the components are rarely studied in animal taxa. To elucidate the nature of multiple isolating barriers, we quantified the strength of three premating barriers, including ecologically based ones (seasonal, habitat, and sexual), two postmating—prehatching barriers (reduced egg hatchability and conspecific sperm precedence [CSP]), and one posthatching barrier, including four components of F1 hybrid reduced fitness, between two phytophagous ladybird beetles, Henosepilachna vigintioctomaculata and H. pustulosa. We detected five positive barriers (habitat isolation, sexual isolation, reduced egg hatchability, CSP, and reduced egg hatchability in backcrosses of F1 hybrids). None of these barriers entirely prevents gene exchange when it acts alone, but jointly they generate nearly complete reproductive isolation even between sympatric populations. Host fidelity contributed most strongly to reproductive isolation by reducing interspecific hybridization through several important types of ecological isolation, including microspatial, habitat, and seasonal isolation. The existence of multiple isolating barriers likely helps keep reproductive isolation stable and robust, by complementing changes in the strength of leaky barriers. This complementarity of multiple isolating barriers yields the concept of robustness of reproductive isolation, which is important when considering the long-term maintenance of species boundaries in coexisting species pairs.