Data from: Identification of an early male-killing agent in the oriental tea tortrix, Homona magnanima

Arthropods are frequently infected with inherited symbionts, which sometimes confer fitness benefits on female hosts or manipulate host reproduction. Early male killing, in which infected males die during embryogenesis, is induced by some bacteria, such as Wolbachia and Spiroplasma. A female-biased sex ratio has been found in Homona magnanima, collected from a tea plantation in Japan. Here, we examined the male-killing trait in H. magnanima and identified the agent that induces early male killing. The sex ratio distortion (SR) strain produced only females and no males, and its egg hatch rate was significantly lower than that of the normal (N) strain. The N strain was infected with only Wolbachia, whereas the SR strain was infected with both Wolbachia and Spiroplasma. Antibiotic treatment with 0.10% tetracycline restored the 1:1 sex ratio in the SR strain. Females treated with 0.05% tetracycline were positive for Spiroplasma but not for Wolbachia and showed a female-biased sex ratio, whereas Wolbachia-positive females did not revert to male killing. When inoculated with a homogenate of the SR strain female, females infected with only Spiroplasma produced female-biased offspring. Sequence analysis of the 16S rRNA gene revealed that Spiroplasma sp. of H. magnanima belonged to the ixodetis clade. These results indicate that Spiroplasma was responsible for male killing in H. magnanima. Late male killing is induced in H. magnanima by an RNA-like virus, and therefore this is the first case in which different male-killing agents expressed at different times in the life cycle have been found within one host species.节肢动物（Arthropods）常携带遗传性共生菌，这类共生菌有时可赋予宿主雌性适合度收益，或调控宿主生殖过程。部分细菌可诱发早期雄杀现象——即受感染的雄性个体在胚胎发育阶段死亡，例如沃尔巴克氏体属（Wolbachia）与螺原体属（Spiroplasma）。研究团队在日本一处茶园采集的茶长卷蛾（Homona magnanima）种群中，观察到了雌性偏倚的性比。本研究针对茶长卷蛾的雄杀特性展开探究，并明确了诱发早期雄杀现象的病原物。性比畸变（sex ratio distortion, SR）品系仅产生雌性后代，无雄性个体，且其卵孵化率显著低于正常（normal, N）品系。正常（N）品系仅携带沃尔巴克氏体，而性比畸变品系同时感染了沃尔巴克氏体与螺原体。采用0.10%浓度的四环素进行抗生素处理后，性比畸变品系的性比恢复为1:1。经0.05%四环素处理的雌性个体仅检出螺原体而非沃尔巴克氏体，其后代仍呈现雌性偏倚的性比；而仅携带沃尔巴克氏体的雌性个体并未出现雄杀现象。用性比畸变品系雌性的组织匀浆进行接种后，仅携带螺原体的雌性个体产生了雌性偏倚的后代。对16S rRNA基因的序列分析显示，茶长卷蛾所携带的螺原体（Spiroplasma sp.）隶属于ixodetis演化支。上述结果表明，螺原体是诱发茶长卷蛾早期雄杀现象的病原物。茶长卷蛾的晚期雄杀现象则由类RNA病毒诱发，因此这是首个在同一宿主物种内，发现不同雄杀病原物于生命周期不同阶段发挥作用的案例。