菜蛾盘绒茧蜂主要寄生因子对寄主小菜蛾生长发育的调控

研究了菜蛾盘绒茧蜂的主要寄生因子(多DNA病毒、毒液和畸形细胞)对寄主小菜蛾生长和发育的影响.通过利用结合假寄生和过寄生方法,证明寄生蜂寄生因子对寄主生长和发育有明显影响.结果显示,假寄生初期,寄主体重降低;但到后期,当未寄生寄主正常化蛹后,假寄生寄主继续取食、发育,寄主末龄幼虫期显著延长,不能化蛹,成为超重幼虫,最大体重可达10.52mg.正常寄生后,寄主的发育与未寄生寄主相比,始终处于抑制状态.过寄生对寄主生长、发育的抑制程度加剧.研究结果表明,假寄生与正常寄生后寄主的生长和发育有明显差异,这种差异的部分原因可能是由畸形细胞引起的.

Effects of wasp-associated factors of Cotesia plutellae on growth and development of Plutella xylostella larvae

The parasitoid Cotesia plutellae(Hymenoptera:Braconidae)-host Plutella xylostella(Lepi- doptera:Plutellidae) system was used to evaluate the regulatory effects of wasp-associated factors,i.e. PDV,venom and teratocytes,on the growth and development of the host larvae by means of pseudopara- sitism and superparasitism.The results showed that after pseudoparasitism the last-instar host larvae were distinctly prolonged in the developmental duration and eventually failed to pupate.At the beginning of pseudoparasitism host larvae increased in body weight more slowly than non-parasitized host larvae.How- ever,at the final period of pseudoparasitism the pseudoparasitized host larvae could continue to feed and develop,and finally became extra-weight larvae (up to 10.52 mg/per larva) when the non-parasitized host larvae had already pupated.The development of normally parasitized host larvae was constantly checked as compared with that of the non-parasitized larvae.Super-pseudoparasitism could strengthen the inhibition of host development,probably due to more physiological doses of PDV and venom injected into the host larvae at wasp oviposition.It is indicated that there were many differences between the larval de- velopment and growth of the naturally parasitized and pseudoparasitized hosts,which were probably par- tially resulted from the functions of teratocytes.