| In the recent years, a great progress has been made in the study on the physiological and biochemical regulations of parasitoids to their hosts. Calyx fluids﹑PDV﹑venom﹑ovarian proteins and teratocyes are several well-known factors responsible for regulating host's internal environments,in which more attentions has been paid to PDV.The reproductive system of pupal endoparasitoid, Tetrastichus sp does not have clear calyx region, but only reproductive tract and venom gland. Thus, venom may play important roles Ostrinia furnacalis pupae parasitized by Tetrastichus sp. This paper deals with the influence of pupal extract on parasitization behavior of the pupal parasitoid Tetrastichus sp, the encapsulation ability of Ostrinia furnacalis pupae, the immune evasion of Tetrastichus sp from Ostrinia furnacalis pupae, function of venom from Tetrastichus sp in parasitizied Ostrinia furnacalis pupae. The main results were as follows:1. Under laboratory conditions, the parasitoid Tetrastichus sp. can parasitize the pupae of both the Asian Corn Borer(Ostrinia furnacalis)and Adoxophyes orana. But the parasitism rate of the former is significantly higher than the latter.Using trichloromethane as an extract solvent, the extract of the two pupae induced the female parasitoid to increase searching,staying and antennal examination behaviors.The results were basically similar in both cases. The pupal extract increased the parasitism rate of A. orana. The parasitism rate was increased after 4 hours of learning stimulation. However when the time of stimulation of the pupae extract was increased,the parasitism rate did not show a further increasing. In the timing of oviposition activity, the parasitism rate was significantly influenced by the continual presence of the extract stimulus.The learning response of the adult parasitoid was able be further increased after continuous stimulation by the pupal extract.2. The hemocyte-mediated encapsulation towards injected Sephadex A-25 in the pupae of Ostrinia furnacalis Guenee was powerful, which indicated that pupae could recognize evading noself materials.Parasitism did not affect in vivo encapsulation response of pupae to injected Sephadex A-25 beads in the early stage, but did affect the response in the later stage. Pseudoparasitism influenced host's encapsulation in a similar way as normal parasitism.Eggs collected from lateral oviduct of Tetrastichus sp were encapsulated quickly when artificially injected into pupae of Ostrinia furnacalis Guenee, but when new-laid eggs were manually transplanted into new pupae, they could not elicit encapsulation response. This phenomenon suggests the existence of protective materials on the surface of new-laid eggs. Experimental removal of the protective layer with Proteinase K or 2%SDS caused the encapsulation of eggs after the treatment. Obviously, Eggs of Tetrastichus sp passively evade encapsulation responses by hemocytes of host pupae, Ostrinia furnacalis Guenee in the early stage of parasitism.3. Pseudoparasitism and injection of venom from Tetrastichus sp led the recipient pupae to death, suggesting a toxic action of venom to pupae of Ostrinia furnacalis Guenee. Pseudoparasitized pupae quickly died(2.87 days post-parasitism). Dead pupae in response to venom-injection did not show signs of deterioration(e.g., necrosis of desiccation) for up to 10 days after envenomation, and pseudoparasitized pupae were able to preserved about 20 days after death, indicating venom may have antimicrobial proterties and preservative ability. Venom-injected pupae remain developmentally arrested until death. Venom also prolonged the pupal stage of recipient pupae for 1-3 days and caused the fomation of abnormal adults.In addition, Venom from Tetrastichus sp may help its progeny to finish development in the host pupae. Transplanted newly-laid eggs emerged alone in 25 days beyond normal emergence times for about 8 days. But coinjection newly-laid eggs and one venom reservoir equivalent shortened the emergence times of new...
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