Host defense reinforces host-parasite cospeciation
Host defense reinforces host-parasite cospeciation
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DOI：
10.1073/pnas.2533751100
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发表时间：
2003-12-23
影响因子：
11.1
通讯作者：
Johnson, KP
中科院分区：
文献类型：
--
作者：
Clayton, DH;Bush, SE;Johnson, KP
当相互作用的群体（如宿主和寄生虫）串联形成物种时，就会发生共物种形成，从而产生一致的共生关系。共物种形成可以是一个中性的过程，其中寄生虫的物种形成仅仅是因为它们被隔离在不同的宿主岛屿上。适应性进化也可能发挥作用，但这一点很少得到验证。我们探讨了适应性的基础上，共同物种形成的模式系统组成的羽毛虱（Columbicola）和他们的鸽子和鸽子的主机（Columbiformes）。我们通过使用细胞核和线粒体DNA序列重建了两组的遗传学。两个种族都得到了很好的解决和很好的支持。比较这些寄生虫，揭示了显着的共同物种形成和相关的主机和寄生虫的身体大小的演变。身体大小的匹配表明，适应性约束限制了虱子可以使用的宿主范围。我们通过在不同大小的主机之间转移虱子来模拟主机开关来测试这一假设。这些实验的结果表明，虱子不能建立可行的人口在新的主机，从本地主机的大小不同。为了确定为什么大小问题，我们测量了虱子健康的三个组成部分：附着，进食和逃避宿主防御（梳理）。虱子可以附着在大小不同的宿主身上，并以其为食。然而，他们无法逃避梳理新的主机，不同的大小从本地主机。总的来说，我们的研究结果表明，宿主防御通过阻止虱子在不同大小的宿主之间转换来加强鸟类和羽毛虱子的共同物种形成。
Cospeciation occurs when interacting groups, such as hosts and parasites, speciate in tandem, generating congruent phylogenies. Cospeciation can be a neutral process in which parasites speciate merely because they are isolated on diverging host islands. Adaptive evolution may also play a role, but this has seldom been tested. We explored the adaptive basis of cospeciation by using a model system consisting of feather lice (Columbicola) and their pigeon and dove hosts (Columbiformes). We reconstructed phylogenies for both groups by using nuclear and mitochondrial DNA sequences. Both phylogenies were well resolved and well supported. Comparing these phylogenies revealed significant cospeciation and correlated evolution of host and parasite body size. The match in body size suggested that adaptive constraints limit the range of hosts lice can use. We tested this hypothesis by transferring lice among hosts of different sizes to simulate host switches. The results of these experiments showed that lice cannot establish viable populations on novel hosts that differ in size from the native host. To determine why size matters, we measured three components of louse fitness: attachment, feeding, and escape from host defense (preening). Lice could remain attached to, and feed on, hosts varying in size by an order of magnitude. However, they could not escape from preening on novel hosts that differed in size from the native host. overall, our results suggest that host defense reinforces cospeciation in birds and feather lice by preventing lice from switching between hosts of different sizes.