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为探明寄生蜂引起寄主寄生性去势的机制,本文选取携带不同多分DNA病毒(Polydnavirus,PDV)的2种内寄生蜂与共同寄主小菜蛾Plutella xylostella(L.)为寄生体系,研究不同虫龄小菜蛾被寄生后雄性生精细胞、精子束形态和精巢发育体积变化,系统比较寄生性去势程度和分别拥有2类PDV的寄生蜂在寄主精子发生和形成过程中的作用。结果表明:携带Bracovirus PDV的菜蛾盘绒茧蜂Cotesiave stalis(Haliday)或拥有Ichvovirus PDV的半闭弯尾姬蜂Diadegma semiclausum Hellén寄生对不同虫龄小菜蛾的精子发生和形成过程均产生明显的抑制作用,表现为不能产生精子束或精子束数量减少,但抑制程度以寄生低龄寄主时最明显。2种蜂寄生均能抑制小菜蛾精巢体积的增长,但对低龄寄主的抑制程度明显强于高龄寄主,寄生性去势程度取决于寄生时寄主虫龄。相比而言,寄生不同虫龄小菜蛾时,茧蜂引起小菜蛾寄生性去势的程度均强于姬蜂。
In order to elucidate the mechanism of host parasitism caused by parasitoids, two kinds of parasitoids carrying different polydnavirus (PDV) and the common host diamondback moth Plutella xylostella (L.) were selected as parasitic systems, Age-dependent changes in spermatogenic cell morphology, sperm bundle morphology, and testis development after parasitized the diamondback moth Plutella xylostella were studied systematically to compare the degree of parasitoid castration and the role of parasitoids with two types of PDV in host spermatogenesis and formation, respectively. The results showed that parasitism of Diadegma semiclausum Hellén with Brachypterus mykiss on Brachyspira PDV carrying Bradyrhizobium mongolicolabrandis (Haliday) or Ichvovirus PDV significantly inhibited the spermatogenesis and formation of Plutella xylostella at different instar stages Role, showed no sperm or sperm bundles to reduce the number, but the degree of inhibition to the parasitic host of the most obvious younger. The parasitism of both bees could inhibit the growth of the diamondback moth testis, but the inhibition to the younger hosts was significantly stronger than that of the older hosts. The degree of parasitism depends on the host insect age at parasitism. In contrast, Parasitoid had more parasitism than Plutella xylostella when parasitizing Plutella xylostella at different instar stages.