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）常被遗传共生菌（inherited symbionts）侵染，这类共生菌有时可为雌性宿主带来适合度益处，或是操控宿主的生殖过程。部分细菌可诱导早期雄性致死（early male killing）现象：受侵染的雄性个体在胚胎发育阶段死亡，代表类群包括沃尔巴克氏体（Wolbachia）与螺原体（Spiroplasma）。研究人员从日本一处茶园采集的茶长卷蛾（Homona magnanima）种群中，观测到雌性偏性的性别比例特征。本研究针对茶长卷蛾的雄性致死性状展开探究，并鉴定出诱导其早期雄性致死的病原物。性别比例扭曲（SR）品系仅能产生雌性后代，无雄性个体，且其卵孵化率显著低于正常（N）品系。正常品系仅携带沃尔巴克氏体，而SR品系同时感染沃尔巴克氏体与螺原体。对SR品系施加0.10%浓度四环素的抗生素处理后，其性别比例恢复为1:1的雌雄平衡比例。经0.05%四环素处理的雌性个体仅携带螺原体而非沃尔巴克氏体，其后代呈现雌性偏性的性别比例；而仅携带沃尔巴克氏体的雌性个体，其后代未出现雄性致死现象。将SR品系雌性个体的匀浆物接种至仅携带螺原体的雌性个体后，这些个体的后代呈现雌性偏性的性别比例。对16S核糖体RNA基因的序列分析显示，茶长卷蛾所携带的螺原体（Spiroplasma sp.）属于ixodetis进化支。上述结果表明，螺原体是导致茶长卷蛾出现雄性致死现象的病原物。茶长卷蛾的晚期雄性致死（late male killing）现象由一类类RNA病毒诱导，这也是首个在同一宿主物种内，发现不同雄性致死因子在生命周期不同阶段发挥作用的研究案例。