Evolutionary Impact of Cytoplasmic Sex Ratio Distorters on Host Reproductive Biology

许多动物体内的细菌生活在它们的细胞内；一些是无害的，但另一些被称为生殖寄生虫，它们自私地操纵宿主的生殖系统。这个项目调查了一种广泛传播的生殖寄生虫沃尔巴克氏菌在多大程度上塑造了一种常见的热带蝴蝶Hypolimas Bolina的生殖生物学。在一些南太平洋岛屿，沃尔巴克氏菌选择性地杀死雄性蝴蝶，因此在沃尔巴克氏菌感染水平较高的岛屿上，雄性博林纳蝴蝶较为罕见。这项研究通过比较不同性别比例岛屿上的蝴蝶种群，研究了沃尔巴克氏菌感染是否导致了新的性特征的进化。这项工作将(I)使用遗传标记确定蝴蝶的种群历史；(Ii)描述不同岛屿上蝴蝶性特征的特征；以及(Iii)测试Wolbachia感染是否解释了H.Bolina性特征的进化。最近的证据表明，生殖性寄生虫在昆虫中广泛存在，并且在自然种群中出现的频率极高。鉴于感染对宿主的重要影响(杀死男性就是一个戏剧性的例子)，生殖寄生虫可以在生殖系统的设计中发挥重要作用。Wolbchia-Hypolimas的案例研究为这一假说提供了有力的检验。

Many animals house bacteria that live inside their cells; some are harmless but others, termed reproductive parasites, selfishly manipulate the host's reproductive system. This project investigates the extent to which a widespread reproductive parasite named Wolbachia has shaped the reproductive biology of a common tropical butterfly Hypolimnas bolina. In some South Pacific islands, Wolbachia selectively kills male butterflies and consequently male H. bolina are rarer on islands with high levels of Wolbachia infection. The study addresses whether new sexual traits have evolved as a result of Wolbachia infection by comparing butterfly populations on islands with different sex ratios. The work will (i) determine the population history of the butterfly using genetic markers; (ii) characterize butterfly sexual characteristics on different islands; and (iii) test whether Wolbachia infection explains the evolution of sexual characters in H. bolina. Recent evidence indicates that reproductive parasites are widespread in insects and that they can reach extremely high frequencies in natural populations. Given the important impact of infection on the host (male-killing being a dramatic example), reproductive parasites could play a major role in the design of reproductive systems. The Wolbachia-Hypolimnas case study provides a powerful test for this hypothesis.