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.节肢动物常携带遗传共生菌，这类共生菌有时会为雌性宿主带来适合度益处，或调控宿主生殖过程。部分细菌可诱导早期雄性致死现象——即受感染的雄性个体在胚胎发生期死亡，这类细菌包括沃尔巴克氏体 (Wolbachia) 和螺原体 (Spiroplasma)。研究人员在日本茶园采集的茶长卷蛾 (Homona magnanima) 种群中，发现了雌性偏倚的性别比例。本研究针对茶长卷蛾的雄性致死性状展开探究，并鉴定出诱导早期雄性致死的病原体。性别比例失衡（SR）品系仅能产生雌性后代，无法繁育雄性个体，且其卵孵化率显著低于正常（N）品系。正常（N）品系仅感染沃尔巴克氏体，而SR品系同时感染了沃尔巴克氏体与螺原体。使用0.10%浓度四环素进行抗生素处理后，SR品系的性别比例恢复为1:1。经0.05%浓度四环素处理的雌性个体，螺原体检测呈阳性而沃尔巴克氏体检测呈阴性，其后代仍呈现雌性偏倚的性别比例；而仅携带沃尔巴克氏体的雌性个体并未出现雄性致死现象。将SR品系雌性个体的匀浆接种后，仅感染螺原体的雌性个体所产后代呈现雌性偏倚的性别比例。对16S核糖体RNA (16S rRNA) 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早期雄性致死现象的病原体。茶长卷蛾还可被类RNA病毒诱导晚期雄性致死，因此本研究首次在同一宿主物种中发现了两种在生命周期不同阶段发挥作用的雄性致死病原体。