In the butterfly, this phenomenon is caused by the pervasiveness of a male-killing strain of Wolbachia (more than 90 percent of A. encedon females support the parasite).

• 在非洲细蝶中，族群里渗透了一种专杀雄性的沃巴赫菌菌株才会造成这种现象（感染的雌性超过90%25）。