title: Phylogeography and evolution of a fungal-insect association on the Tibetan Plateau.
abstract: Parasitoidism refers to a major form of interspecies interactions where parasitoids sterilize and/or kill their hosts typically before hosts reach reproductive age. However, relatively little is known about the evolutionary dynamics of parasitoidism. Here, we investigate the spatial patterns of genetic variation of Chinese cordyceps, including both the parasitoidal fungus Ophiocordyceps sinensis and its host insects. We sampled broadly from alpine regions on the Tibetan Plateau and obtained sequences on seven fungal and three insect DNA fragments from each of the 125 samples. Seven and five divergent lineages/cryptic species were identified within the fungus and host insects, respectively. Our analyses suggested that O. sinensis and host insects originated at similar geographic regions in southern Tibet/Yunnan, followed by range expansion to their current distributions. Cophylogenetic analyses revealed a complex evolutionary relationship between O. sinensis and its host insects. Significant congruence was found between host and parasite phylogenies and the time estimates of divergence were similar, raising the possibility of the occurrence of cospeciation events, but the incongruences suggested that host shifts were also prevalent. Interestingly, one fungal genotype was broadly distributed, consistent with recent gene flow. In contrast, the high-frequency insect genotypes showed limited geographic distributions. The dominant genotypes from both the fungus and the insect hosts may represent ideal materials from which to develop artificial cultivation of this important Chinese traditional medicine. Our results demonstrate that both historical and contemporary events have played important roles in the phylogeography and evolution of the O. sinensis-ghost moth parasitoidism on the Tibetan Plateau.
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China; School of Life Sciences, Shanxi University, Taiyuan, 030006, China; Department of Biology, McMaster University, Hamilton, Ontario, Canada, L8S 4K1.
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Zhang
authors.forename: Shu
authors.initials: S
authors.lastname: Zhang
authors.forename: Yuling
authors.initials: Y
authors.lastname: Li
authors.forename: Shaoli
authors.initials: S
authors.lastname: Ma
authors.forename: Chengshu
authors.initials: C
authors.lastname: Wang
authors.forename: Meichun
authors.initials: M
authors.lastname: Xiang
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: An
authors.forename: Jianping
authors.initials: J
authors.lastname: Xu
authors.forename: Xingzhong
authors.initials: X
authors.lastname: Liu
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D002681:China; D004271:DNA, Fungal / Q000235:genetics; D051456:Gene Flow; D005838:Genotype; D006999:Hypocreales / Q000235:genetics*; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics* / Q000382:microbiology; D010802:Phylogeny; D058974:Phylogeography; D017422:Sequence Analysis, DNA
chemical_list: D004271:DNA, Fungal
keywords: Ophiocordyceps sinensis; evolution; ghost moth; parasitoidism; phylogeography; the Tibetan Plateau