Data from: Loss of reproductive parasitism following transfer of male-killing Wolbachia to Drosophila melanogaster and Drosophila simulans

Wolbachia manipulates insect host biology through a variety of means that result in elevated fitness of infected females, enhancing its own transmission. A Wolbachia strain (wInn) naturally infecting D. innubila induces male-killing, while native strains of D. melanogaster and D. simulans usually induce cytoplasmic incompatibility (CI). In this study, we transferred wInn to D. melanogaster and D. simulans by embryonic microinjection, expecting conservation of the male-killing phenotype to the novel hosts, which are more suitable for genetic analysis. In contrast to our expectations, there was no effect on offspring sex ratio. Furthermore, no CI was observed in the transinfected flies. Overall, transinfected D. melanogaster lines displayed lower transmission rate and lower densities of Wolbachia than transinfected D. simulans lines, in which established infections were transmitted with near-perfect fidelity. In D. simulans, strain wInn had no effect on fecundity and egg to adult development. Surprisingly, one of the two transinfected lines tested showed increased longevity. We discuss our results in the context of host-symbiont co-evolution and the potential of symbionts to invade novel host species.

沃尔巴克氏体（Wolbachia）可通过多种途径调控昆虫宿主的生物学特性，借此提升感染雌性宿主的适合度，从而增强自身的传播效率。天然感染Innubila果蝇（Drosophila innubila，缩写为D. innubila）的沃尔巴克氏体菌株wInn可诱导杀雄表型，而黑腹果蝇（Drosophila melanogaster）与拟果蝇（Drosophila simulans）的本土沃尔巴克氏体菌株通常会引发细胞质不相容（cytoplasmic incompatibility, CI）。本研究通过胚胎显微注射技术，将wInn菌株转入黑腹果蝇与拟果蝇体内，预期可在这两种更适用于遗传分析的新宿主中保留杀雄表型。但与预期相悖的是，该菌株并未对子代性别比例产生任何影响，且在转感染的果蝇中未观测到细胞质不相容现象。总体而言，转感染的黑腹果蝇品系的沃尔巴克氏体传播率与菌株密度均低于转感染的拟果蝇品系，后者的稳定感染可实现近乎完美的传播保真度。在拟果蝇体内，wInn菌株对宿主的繁殖力以及卵到成虫的发育周期均无影响；令人意外的是，所测试的两个转感染品系之一呈现出寿命延长的表型。本研究将结合宿主-共生体共进化以及共生体入侵新宿主物种的潜力这一语境，对上述实验结果展开讨论。