Studies On Life-history Characteristics Of Plagiodera Versicolora And Clostera Anastomosis And Their Behavioral Response To The Alkaloids From Sophora Alopecuroids

Two poplar insect pests, Clostera anastomosis and Plagiodera versicolora, which life history characteristics were compared in lab conditions with those of field populations, and alkaloids from a leguminous weed, Sophora alopecuroids, were used to study their effects on the behavioral responses after feeding on poplar leaves treated with these alkaloids.The main results are the following:1. Food quality significantly influenced larval development and adult oviposition of Plagiodera versicolora. After feeding on old leaves, the larval developmental rates decreased, the instar duration prolonged, and it had small pupa sizes and lower pupation rates, along with the completing inhibition of ovipostion.2. Oviposition pheromone on egg surface was observed. The surfaces of egg masses of Plagiodera versicolora were washed by organic chemicals and water. It indicated that the chemical extracts were most attractive, but the water extract was repellent, for female oviposition.3. Alkaloids from Sophora alopecuroids were antifeedants against the tested two insect pests, and the antifeeding effects increased with alkaloid concentrations.4. Treated with alkaloid mixture, the growth and development of Clostera anastomosis larvae were inhibited, and the efficiency of food consumption and utilization were decreased significantly.5. The inhibited effects of alkaloids on oviposition of Plagiodera versicolora oviposition were observed. Treated with sophoramine sophocarpine, and alkaloid mixture, the egg number laid were fewer than those of controls.6. Sophoramine sophocarpine, and matrine were toxic to Plagiodera versicolora, and in non-choice tests, the mortality was higher than 90%7. Alkaloid mixture and its monomers from Sophora alopecuroids have important effects on the activities of protective enzymes of Plagiodera versicolora and Clostera anastomosis. The activities of protective enzymes tended to be enhanced in prophase andthen inhibited in anaphase. The detoxification ability of Plagiodera versicolora larvae was largely dependent upon the activities of esterase.The innovations of the dissertation:1. Detailed studies on the life-history characteristics of Plagiodera versicolora and Clostera anastomosis were conducted for the first time, and some errors on the life-history characteristics were corrected: l)It was reported that Clostera anastomosis copulated only one time in one life cycle; but we found that it could copulate more than one times; 2)It was reported that Plagiodera versicolora larvae have 4 instars in one life cycle, but only 3 instars were found in this study.2. Strong attractive effects of organic solvent crude extracts of surfaces of the egg masses on the oviposition of Plagiodera versicolora were first studied. This is important in understanding Plagiodera versicolora-poplar interactions.3. The effects of alkaloid mixture and its monomers on the behavioral responses and on the activities of digestive, protective, and esterase enzymes, of the tested three insects, were studied for the first time.