| Vitellogenesis and its endocrine regulation in insects are always the key problems of insect reproductive physiology, which had been researched in about 60 species of 10 orders. However, they have been studied in few species of Hymenoptera parasitoids, especially, were undefined in ectoparasitic wasps. In this paper, the ovarian development, oogenesis, vitellogenin molecular characteristic, vitellogenin synthesis and uptake, and vitellin degradation in Nasonia vitripennis (Hymenoptera: Pteromalidae), are studied. The detailed results are shown as follows:83% of ovaries were found to be composed of eight ovarioles with four on each side and 17% of ones to be composed of six ovarioles with three on each side. Ovarioles appeared on the 10th day after parasitization, which were transpearant and had no egg chambers. On the same ovariole, the development of egg chambers could be divided into three grades, namely, the 1st grade was yolkless, the 2nd was imcomplete with yolk protein, and the 3rd was full with yolk protein. Egg chambers with the 1st grade appeared on the 11th day after parasitization (the pupa was white, and its eyes were scarlet), egg chambers with the 2nd grade appeared on the 12th day after parasitization ad egg chambers with the 3rd grade occurred on the 1st day after emergence. Feeding adults of this parasitoid with 20% honey solution showed no marked effects on the ovarian development except significantly prolonging their life span (most adults can survive for half a month and even to about a month). In contrast, feeding with nothing or only water, the wasps only survived for four days. No difference in ovariole lengh of female adults was found among different feedig treatments. For each fedding treatment, the longitude and latitude of the root egg, the number of egg chambers with each developmental grade all changed in a parabola model.The results from native PAGE indicated that there were two specific protein i.e. vitellogenin (Vg) or vitellin (Vn) in the female wasp of N. vitripennis. The Vg or Vn was composed of two proteins with molecular weight of 181 KD and 136 KD. The results from SDS-PAGE presented that there were three female specific protein subunits with molecular weights of 123 KD, 120 KD and 91 KD, respectively. We can conclude the higher molecular compose of two subunits; The results from two dimension electrophoresis showed the isoelectric points of two female-specificspots with molecular weight of about 120KD were 5.5 and 5.7. Immunodiffusion reactions demonstrated that Vg existed both in female fat body and hemolymph, which as Vn was deposited in the ovary, while not in the male.Temporal patterns of vitellogenin (Vg) synthesis and uptake as well as vitellin (Vn) degradation in N. vitripennis, were studied using the method of enzyme-linked immunosorbent assay (ELISA). The results were showed as follows: the synthesis and uptake of Vg of this parasitic wasp respectively initiated since the 10th and 13th day after parasitism, which were equivalent to the first pupal stage and the pharate adult stage of this parasitic wasp. The degradation of Vn in eggs of this parasitic wasp was simultaneous with their embryo development in their hosts. The Vn thoroughly degraded on the 3rd day after parasitism, just being at the end of embryo development of this parasitic wasp. In addition, the temporal pattern in the levels of soluble proteins in hemolymph, ovaries or eggs of this parasitic wasp was also defined during the processes of Vg synthesis and uptake as well as Vn degradation.
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