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来提升自身的垂直传播效率，其中最典型的表现为细胞质不相容性（cytoplasmic incompatibility, CI）。此外，由于沃尔巴克氏体与其宿主之间缺乏系统发育一致性，频繁的种间水平转移现象已得到证实，但其横向转移的具体机制目前仍未完全阐明。为明确沃尔巴克氏体的潜在传播途径，我们对蜂类（Anthophila）中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，我们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。蜂类中的盗寄生-宿主关联以及其他生态联系，均无法单独作为沃尔巴克氏体传播的支撑依据。不过，协同系统发育分析（cophylogenetic analyses）与分化时间估算（divergence time estimations）结果显示，沃尔巴克氏体可在宿主谱系中存续相当长的时间尺度，且严格的垂直传播以及后续跨谱系的随机感染丢失，对沃尔巴克氏体菌株分布的影响可能比此前预估的更为显著。尽管目前尚无法得出关于节肢动物宿主间沃尔巴克氏体传播的普适性结论，但我们构建了一套研究框架，可用于建模并验证关于沃尔巴克氏体与宿主类群共享进化历史的精准假设。