Climate and host demographic cycling often shape both parasite genetic diversity and host distributions, processes that transcend a history of strict host-parasite association. We explored host associations and histories based on an evaluation of mitochondrial and nuclear sequences to reveal the underlying history and genetic structure of a pinworm, Rauschtineria eutamii, infecting 10 species of western North American chipmunks (Rodentia:Tamias, subgenus Neotamias). Rauschtineria eutamii contains divergent lineages influenced by the diversity of hosts and variation across the complex topography of western North America. We recovered six reciprocally monophyletic R. eutamii mitochondrial clades, largely supported by nuclear gene trees, exhibiting divergence levels comparable to intraspecific variation reported for other nematodes. Phylogenetic relationships among pinworm clades suggest that R. eutamii colonized an ancestral lineage of western chipmunks and lineages persisted during historical isolation in diverging Neotamias species or species groups. Pinworm diversification, however, is incongruent and asynchronous relative to host diversification. Secondarily, patterns of shallow divergence were shaped by geography through events of episodic colonization reflecting an interaction of taxon pulses and ecological fitting among assemblages in recurrent sympatry. Pinworms occasionally infect geographically proximal host species; however, host switching may be unstable or ephemeral, as there is no signal of host switching in the deeper history of R. eutamii.

中文翻译：

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时空镶嵌：深层宿主关联和浅层地理驱动因素塑造了广泛分布的蛲虫 Rauschtineria eutamii 的遗传结构。


气候和宿主人口循环通常会影响寄生虫的遗传多样性和宿主分布，这一过程超越了严格的宿主与寄生虫关联的历史。我们基于对线粒体和核序列的评估探索了宿主关联和历史，以揭示感染 10 种北美西部花栗鼠（啮齿目：Tamias，Neotamias 亚属）的蛲虫 Rauschtineria eutamii 的潜在历史和遗传结构。 Rauschtineria eutamii 包含受宿主多样性和北美西部复杂地形变化影响的不同谱系。我们恢复了六个相互单系的 R. eutamii 线粒体进化枝，主要由核基因树支持，表现出与其他线虫报道的种内变异相当的分歧水平。蛲虫进化枝之间的系统发育关系表明，R. eutamii 定殖了西方花栗鼠的祖先谱系，并且在历史隔离期间，该谱系在不同的 Neotamias 物种或物种组中持续存在。然而，蛲虫的多样化与宿主的多样化是不一致且异步的。其次，浅层分歧的模式是由地理通过偶发性殖民事件形成的，反映了分类单元脉冲的相互作用和循环同源性组合之间的生态拟合。蛲虫偶尔会感染地理上邻近的宿主物种；然而，宿主转换可能是不稳定或短暂的，因为在 R. eutamii 的更深层历史中没有宿主转换的信号。