Repeated independent evolution of obligate pollination mutualism in the Phyllantheae-Epicephala association
Repeated independent evolution of obligate pollination mutualism in the Phyllantheae-Epicephala association
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DOI：
10.1098/rspb.2008.1226
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发表时间：
2009-02-07
影响因子：
4.7
通讯作者：
Kato, Makoto
中科院分区：
文献类型：
--
作者：
Kawakita, Atsushi;Kato, Makoto
著名的无花果-无花果黄蜂和丝兰-丝兰蛾互利共生是经过数百万年共同进化形成的专性互利共生的典型例子。涉及专性种子寄生虫的授粉系统预计只会在极少数情况下进化，在这种情况下，其积极影响不会被丰富的共同传粉者和种子破坏造成的沉重成本所淹没。在这里，我们表明，在叶下珠科中，由顶头蛾授粉的特化至少进化了五次，涉及到这种专性关联中的 500 多个叶下珠属物种。在寄主植物最初分化后 10-20 Myr，Epicephala 就进化出了一次活跃的授粉行为。因此，授粉的顶头蛾辐射到已经分化的寄主谱系上，并相继殖民新的叶下珠属寄主，从而引起叶下珠科专门授粉系统的重复独立进化。该协会目前的进化成功完全取决于头头虫的主动授粉，这使其成为进化关键创新的独特例子。总体而言，我们的研究结果清楚地证明了进化创新和伙伴转变的结合如何促进共同进化物种相互作用中互利共生的传播。
The well-known fig-fig wasp and yucca-yucca moth mutualisms are classic examples of obligate mutualisms that have been shaped by millions of years of coevolution. Pollination systems involving obligate seed parasites are only expected to evolve under rare circumstances where their positive effects are not swamped by abundant co-pollinators and heavy costs resulting from seed destruction. Here, we show that, in Phyllantheae, specialization to pollination by Epicephala moths evolved at least five times, involving more than 500 Phyllantheae species in this obligate association. Active pollination behaviour evolved once in Epicephala, 10-20 Myr after the initial divergence of their host plants. The pollinating Epicephala moths thus radiated on an already-diverged host lineage and successively colonized new Phyllantheae hosts, thereby giving rise to repeated independent evolution of the specialized pollination system in Phyllantheae. The present evolutionary success of this association rests entirely upon active pollination by Epicephala, making this a distinct example of an evolutionary key innovation. Overall, our findings provide a clear empirical demonstration of how a combination of evolutionary innovation and partner shifts facilitates the spread of mutualism in a coevolving species interaction.