Data from: Limited dispersal in an ectoparasitic mite, Laelaps giganteus, contributes to significant phylogeographic congruence with their rodent hosts, Rhabdomys

To explore how biogeography, parasite life history and host vagility influences evolutionary codivergences, we followed a comparative phylogeography approach using a host specific non-permanent mite, Laelaps giganteus that occurs on four rodent species within the genus Rhabdomys. A mtDNA COI haplotype network derived for 278 parasite specimens showed marked phylogeographic congruence with host distributions. Analysis of the less variable nuclear intron Tropomyosin was in part consistent with these results. Although distance-based cophylogenetic analyses in AXPARAFIT failed to support significant mtDNA codivergences (P ≥ 0.02), event-based analyses revealed significant cophylogeny between sampling localities of Rhabdomys and Laelaps using CORE-PA (P = 0.046) and JANE (P = 0.026; P = 0.00). These findings, in conjunction with the weak congruence previously reported among the permanent ectoparasitic lice Polyplax and Rhabdomys, suggest that host-parasite intimacy is not the most important driver of significant codivergence in our study system. Instead the more restricted dispersal ability of L. giganteus, when compared to Polyplax, resulted in stronger spatial structuring and this could have resulted in significant codivergence. Host switching occurred predominantly on the edges of host distributions and was probably facilitated by climate-induced range shifts. When host ranges shift, the phylogeographic structure of L. giganteus is not reflecting the host movements since most of the nest bound parasites do not disperse with the host (they miss the boat) and the genetic contribution of the few dispersing mite individuals is often overwhelmed by the large number of individuals already present in nests within the new environment (causing them to drown on arrival).为探究生物地理学（biogeography）、寄生虫生活史与宿主移动性如何影响进化共分化，我们采用比较系统地理学（comparative phylogeography）方法，以寄生于刺毛鼠属（Rhabdomys）4种啮齿动物宿主的宿主专性非永久性螨类巨厉螨（Laelaps giganteus）为研究对象。对278份寄生虫标本构建的线粒体DNA细胞色素氧化酶亚基I（mtDNA COI）单倍型网络显示，其与宿主分布存在显著的系统地理学一致性。针对变异性较低的核内含子原肌球蛋白（Tropomyosin）的分析结果，在一定程度上与上述发现相符。尽管基于距离的共系统发育分析（distance-based cophylogenetic analyses）在AXPARAFIT软件中未检测到显著的mtDNA进化共分化（P≥0.02），但基于事件的共系统发育分析显示，利用CORE-PA（P=0.046）与JANE（P=0.026；P=0.00）两种工具分析时，刺毛鼠属宿主与巨厉螨的采样点之间存在显著共系统发育关系。结合此前关于永久性外寄生虱Polyplax与刺毛鼠属之间较弱共分化一致性的报道，本研究结果表明，宿主-寄生虫的亲密程度并非本研究体系中显著进化共分化的最关键驱动因素。相较Polyplax，巨厉螨的扩散能力更为受限，这使其空间结构更强，进而可能促成了显著的进化共分化。宿主转换主要发生在宿主分布的边缘地带，大概率由气候驱动的分布范围变动所促成。当宿主分布范围发生变动时，巨厉螨的系统地理学结构并不会随宿主移动同步改变：绝大多数巢居寄生虫并不会随宿主一同扩散（它们错失了“搭乘宿主的航班”），而少数扩散的螨类个体的遗传贡献，往往会被新环境中巢穴内已存在的大量螨类个体所掩盖，即它们在抵达后被“淹没”。