Data from: Tracing horizontal Wolbachia movements among bees (Anthophila): a combined approach using multilocus sequence typing data and host phylogeny

The endosymbiotic bacterium Wolbachia enhances its spread via vertical transmission by generating reproductive effects in its hosts, most notably cytoplasmic incompatibility (CI). Additionally, frequent interspecific horizontal transfer is evident from a lack of phylogenetic congruence between Wolbachia and its hosts. The mechanisms of this lateral transfer are largely unclear. To identify potential pathways of Wolbachia movements, we performed multilocus sequence typing of Wolbachia strains from bees (Anthophila). Using a host phylogeny and ecological data, we tested various models of horizontal endosymbiont transmission. In general, Wolbachia strains seem to be randomly distributed among bee hosts. Kleptoparasite-host associations among bees as well as other ecological links could not be supported as sole basis for the spread of Wolbachia. However, cophylogenetic analyses and divergence time estimations suggest that Wolbachia may persist within a host lineage over considerable timescales and that strictly vertical transmission and subsequent random loss of infections across lineages may have had a greater impact on Wolbachia strain distribution than previously estimated. Although general conclusions about Wolbachia movements among arthropod hosts cannot be made, we present a framework by which precise assumptions about shared evolutionary histories of Wolbachia and a host taxon can be modelled and tested.

内共生细菌沃尔巴克氏体（Wolbachia）通过对宿主产生生殖效应以提升自身的垂直传播效率，其中最具代表性的便是胞质不相容性（cytoplasmic incompatibility, CI）。鉴于沃尔巴克氏体与其宿主之间缺乏系统发育一致性，可见其频繁发生种间水平传播。这类水平传播的具体机制目前仍尚未完全明晰。为探明沃尔巴克氏体传播的潜在路径，本研究对采自蜂类（Anthophila）的沃尔巴克氏体菌株开展了多位点序列分型（multilocus sequence typing）分析。结合宿主系统发育与生态学数据，本研究对多种内共生菌水平传播模型进行了检验。总体而言，沃尔巴克氏体菌株在蜂类宿主中呈现随机分布的特征。蜂类间的盗寄生-宿主关联及其他生态联系，均无法单独作为沃尔巴克氏体传播的依据。然而，共系统发育分析与分歧时间估算结果表明，沃尔巴克氏体可在宿主谱系中持续存在相当长的时间；且相较于此前的预估，严格的垂直传播以及后续各谱系间感染的随机丢失，对沃尔巴克氏体菌株分布的影响可能更为显著。尽管目前尚无法就沃尔巴克氏体在节肢动物宿主间的传播模式得出普适性结论，但本研究提出了一套研究框架，可用于建模并检验关于沃尔巴克氏体与某一宿主类群共享演化历史的精准假设。