应用单克隆抗体评价拟环纹豹蛛对褐飞虱的控制作用

Evaluation of the control effects of Pardosa pseudoannulata on Nilaparvata lugens (stl) with a monoclonal antibody

应用褐飞虱的单克隆抗体 4 B8研究了 1999年浙江大学华家池校区农场汕优 6 3单季晚稻田中拟环纹豹蛛对褐飞虱的捕食作用。采用盘拍法的调查结果表明 ,褐飞虱、拟环纹豹蛛种群数量高峰期均在水稻生长后期 (9月中旬 ) ,最大种群密度分别为12 6头 /丛和 1.83头 /丛。对每次捕获的每头拟环纹豹蛛样品的抗体夹心 EL ISA检测结果表明 ,拟环纹豹蛛对褐飞虱单克隆抗体的阳性反应率与田间褐飞虱的生物量及拟环纹豹蛛对褐飞虱的占有量显著相关。定量评估结果表明 ,在此密度条件下 ,拟环纹豹蛛对褐飞虱的最大捕食率仅为 2 .2 8%。拟环纹豹蛛对褐飞虱的平均捕食量、总捕食量和捕食率与田间褐飞虱的生物量显著相关。总捕食量。

Field surveys were carried out at five days interval in the single rice-growing season in Hangzhou in 1999. The rice crop were transplanted on June 23 and harvested on October 3. Using a plate inserted at the base of the plants, the numbers of Nilaparvata lugens and Pardosa pseudoannulata per hill were counted by eye. Counts were taken for 20 samples, 2 hills for each sample. Field investigation showed that the maximal densities of N. lugens and P. pseudoannulata were 126 /hill and 1.83 /hill, respectively. 10～30 individuals of P. pseudoannulata were collected from rice paddy for each survey date. They were tested for the presence of N. lugens prey remained in their guts using a double antibodies sandwich enzyme-linked immunosorbent assay (ELISA) in combination with specific monoclonal antibody, 4B8, against N. lugens. The results showed that P. pseudoannulata was active predator on N. lugens. Correlation analysis based on the field population densities and results of the ELISA indicated that the positive rates of P. pseudoannulata on N. lugens increased with the increase of the field biomass of N. lugens and the occupying prey biomass of each predator. Quantitative assessment were given based on the equation, R=Q_0×d/f(0.1526+exp(3.9716-0.1347×T)), which was established for the model system of P. pseudoannulata-N. lugens. Q_0, d, f, T and R were the prey antigen titer remained in the predator gut, predator density, coefficient of digestion of prey, temperature and total prey captured biomass, respectively. Throughout the whole rice-growing season, the largest prey biomass of N. lugens that each P. pseudoannulata predated was 0.449mg (0.33 female). The largest predation rates of them were 2.28%. This suggested that the brown planthopper could not be controlled by P. pseudoannulata. It was resulted from low population densities of P. pseudoannulata. The average prey captured biomass, the total prey captured biomass and the predation rate of P. pseudoannulata on N. lugens increased with the increase of the field biomass of N. lugens. The total predated biomass and the predation rate of P. pseudoannulata on N. lugens increased with the increase of the density of P. pseudoannulata. The advantages and limitations of the prey gut content assay (double antibodies sandwich ELISA) were discussed.