The parasitoid Aphidius gifuensis-host aphid system was used to evaluate the regulatory effects of wasp-associated factors,i.e.teratocytes,venom and calyx fluid,on the growth and development of the host larvae by means of pseudoparasitism and superparasitism.The results showed that after pseudoparasitism the host larvae were distinctly prolonged in the developmental duration.The development and immune system of normally parasitized host larvae was constantly checked as compared with that of the non-parasitized larvae.Superparasitism could strengthen the inhibition of host development,probably due to more physiological doses of teratocytes,venom and calyx fluid injected into the host larvae at wasp ovi posi ti on.It is indicated that there were many differences between the larval development and growth of the naturally parasitized and pseudoparasitized hosts,which were probably partially resulted from the functions of teratocytes.