Preliminary Studies On Parasitic Mechanism Of Diachasmimorpha Longicaudata To Bactrocera Dorsalis

Microstructure of venom organ and ovary from Diachasmimorpha longicaudata(Ashmead)，and affectting the melanism phenomenon of the larvae of Bactroceradorsalis（Hendel）through changing the four enzymes′avitivity of parasitic larvae wasstudied in this paper. According to the optimal enzyme activity the larvae of theparasitoid at different temperatures, the influence of physiological indices and byalternating temperature to rear the parasitoid was studied. The parasitic mechanism ofD. longicaudata and the influence of physiological indices and by alternatingtemperature to rear the parasitoid was preliminary searched.1. Through the microstructure of venom organ and ovary from D. longicaudataby microscope, the venom apparatus of D. longicaudata was composed of one venomreservoir and one gland filaments. The gland filaments joined together at the top ofthe venom reservoir. The reproductive apparatus was composed a pair of ovaries andtwo lateral oviducts which formed a common oviduct andopened into the ovipositor.The venom apparatus joined together with the common oviduct by its venom duct.2.Determinate the activity of catalase(CAT), peroxidase(POD), superoxide dismutase(SOD), phenoloxidase(PO) in4th instar larvae of B.dorsalis parasitized byD.longicaudata. The results show that after the larvae were parasitized, under theregulation of the immune system there was a great of reactive oxygen species (ROS),which increased the activity of CAT, POD, SOD comparing the parasitized-free larvae.However, the activity of PO was decreased distinctly.3. The melanism of Bactrocera dorsalis was changed by Diachasmimorphalongicaudata.It was proved that they were not influenced, because the melanism rateof the unparasitic larvaes was100%. However, the melanism rate of the parasiticlarvaes was decreased distinctly through the search of affect to the melanism by theparasitism of D. longicaudata.4. It was proved that the activity of CAT of the larvae with28℃was thehighest,the activity of POD with25℃,and the activity of SOD with25℃whenBactrocera dorsalis was parasitized by Diachasmimorpha longicaudata for4h. the activity of CAT of the larvae with25℃was the highest,the activity of POD with25℃,and the activity of SOD with25℃when Bactrocera dorsalis was parasitizedfor24h. The activity of CAT of the larvae with25℃was the highest,the activity ofPOD with31℃,and the activity of SOD with31℃when Bactrocera dorsalis wasparasitized for48h. The activity of CAT of the larvae with31℃was the highest,theactivity of POD with31℃,and the activity of SOD with31℃when Bactroceradorsalis was parasitized for72h in the study of treating the larvae with differenttemperatures in different period.5. Through four different temperature raising solutions, it was best to process thelarvaes with28℃,25℃and25℃,31℃when it was parasitic at4h,24h,48h,72h, their hatchability, pupa weight, emergence rate, lifetime and sex ratio wereoptimal.