Data from: Multiple endosymbiont infections and reproductive manipulations in a linyphiid spider population

In many arthropods, maternally inherited endosymbiotic bacteria can increase infection frequency by manipulating host reproduction. Multiple infections of different bacteria in a single host population are common, yet few studies have documented concurrent endosymbiont phenotypes or explored their potential interactions. We hypothesized that spiders might be a particularly useful taxon for investigating endosymbiont interactions, because they are host to a plethora of endosymbiotic bacteria and frequently exhibit multiple infections. We established two matrilines from the same population of the linyphiid spider Mermessus fradeorum and then used antibiotic curing and controlled mating assays to demonstrate that each matriline was subject to a distinct endosymbiotic reproductive manipulation. One matriline was co-infected with Rickettsia and Wolbachia and produced offspring with a radical female bias. Antibiotic treatment eliminated both endosymbionts and restored an even sex ratio to subsequent generations. Chromosomal and fecundity observations suggest a feminization mechanism. In the other matriline, a separate factorial mating assay of cured and infected spiders demonstrated strong cytoplasmic incompatibility (CI) induced by a different strain of Wolbachia. However, males with this Wolbachia induced only mild CI when mated with the Rickettsia–Wolbachia females. In a subsequent survey of a field population of M. fradeorum, we detected these same three endosymbionts infecting 55% of the spiders in almost all possible combinations, with nearly half of the infected spiders exhibiting multiple infection. Our results suggest that a dynamic network of endosymbionts may interact both within multiply infected hosts and within a population subject to multiple strong reproductive manipulations.

在诸多节肢动物（arthropods）中，母系遗传的内共生细菌可通过操纵宿主繁殖提升自身感染频率。单一宿主种群内同时感染多种不同细菌的现象十分普遍，但目前鲜有研究同时记录内共生体表型，或探究它们之间的潜在相互作用。我们提出假说：蜘蛛或许是研究内共生体相互作用的理想类群，因为它们携带有大量内共生细菌，且常出现多重感染情况。我们从同一皿蛛科蜘蛛（linyphiid spider）*Mermessus fradeorum*种群中建立了两个母系株，随后通过抗生素清除疗法与控制性交配实验，证实每个母系株均受独特的内共生繁殖操纵。其中一个母系株同时感染立克次体（Rickettsia）与沃尔巴克氏体（Wolbachia），其后代呈现出显著的雌性偏倚。抗生素处理可消除这两种内共生体，并使后续子代恢复至均等性比。染色体与繁殖力观察结果提示其作用机制为雌性化机制。在另一个母系株中，针对清菌与未感染蜘蛛的析因交配实验显示，该株感染的另一株沃尔巴克氏体可诱导强烈的细胞质不相容性（cytoplasmic incompatibility，CI）。然而，当携带该沃尔巴克氏体的雄蛛与同时感染立克次体-沃尔巴克氏体的雌蛛交配时，仅会引发轻度的细胞质不相容性。后续对*M. fradeorum*野外种群的调查显示，这三种内共生体的感染率达55%，且几乎所有可能的组合感染均被检测到，近半数受感染蜘蛛呈现多重感染状态。我们的研究结果表明，内共生体可能构成一个动态互作网络，这种互作既发生在多重感染的宿主体内，也存在于受多种强繁殖操纵作用的种群中。