Manipulation of species barrier with cosmopolitan species

沃尔巴克氏菌引起的细胞质强烈不亲和性被认为是菜豆象甲的物种形成机制之一。人工注射沃尔巴克氏菌和用四环素去除实验表明，沃尔巴克氏菌不能在无尾轮虫、斑点轮虫、罗氏轮虫和萨布诺特轮虫之间起到物种形成的作用。另一方面，对9个品系的沃尔巴克氏菌清除和再引入实验表明，随着弓形虫和沃尔巴克氏菌共同进化的时间延长，CI水平变得更良性。沃尔巴克氏菌诱导的CI水平是沃尔巴克氏菌与其寄主共同进化的产物。

Strong cytoplasmic incompatibility caused by Wolbachia was thought to be a speciation mechanism among bean weevils in genus Callosobruchus. Artificial Wolbachia injection and removal experiments with tetracycline showed that Wolbachia did not play a role of speciation among C. analis, C. maculatus, C. rhodesianus, and C. sabinnotetus. On the other hand, Wolbachia removal and reintroducing experiments among 9 strains of C. analis revealed that the CI level became more benign as the length of coevolution between C. analis and Wolbachia was longer. CI levels induced by Wolbachia were products of coevolution between Wolbachia and its hosts in C. analis.