荧光物示踪法测定重复施药胁迫下食虫沟瘤蛛的摄食量动态

定量评价农药对天敌的影响是IPM研究的重要内容之一，由于对天敌的捕食量缺乏有效的定量测量方法，农药对天敌摄食功能影响仍处于定性水平的研究，误差基数较大。本文采用一种定量的测定方法——荧光物示踪法，以稀土元素铕作为荧光示踪物质，定量地测定了食虫沟瘤蛛在重复接受噻嗪酮喷施后，其存活个体在药后13天内摄食量的变化趋势，且把药后食虫沟瘤蛛的死亡率加以考虑，计算药后整个试验食虫沟瘤蛛群体的摄食量变化。结果表明：任何浓度任何一次施药后2天左右食虫沟瘤蛛存活个体的捕食量均急剧下降；药物浓度较低时，第1次施药对食虫沟瘤蛛的影响最大；药物浓度较高时，食虫沟瘤蛛存活个体药后摄食量恢复周期较长。药后一段时间内整个食虫沟瘤蛛种群的摄食率相当低下，高浓度农药处理的食虫沟瘤蛛组3次施药后13天内的平均种群摄食率只有正常状况下的1/4左右（24.44%），推荐浓度及低于推荐浓度的食虫沟瘤蛛种群摄食率也仅为对照组的1/3左右（38.69%，36.52%）。因此在对水稻虫害防治时，应当尽可能地避免使用化学农药，充分发挥天敌对害虫数量的调控作用；当害虫数量超过经济阈值而必须施药时，也应当掌握农药用药剂量和次数的尺度，以利于食虫沟瘤蛛等稻田天敌的生理恢复和群落重建。

Quantitative measurement of the influence of repeated pesticide application on food intake of Ummeliata insecticeps by the fluorescence labeling method

By applying a patented technique, the quantitative analysis of food intake using the fluorescence tracer as it is transferred in the food chain, we studied the food intake of Ummeliata insecticeps (Bosenberg et Strand) when exposed to pesticide buprofezin repeatedly. The results showed that food intakes of the surviving spiders in all treated groups were much less than that in the control group. Food intake of surviving U. insecticeps sprayed with buprofezin for the first time was less than that of the surviving spiders sprayed with the pesticide for the second or third time when buprofezin was diluted. It took a long time for the surviving spiders to recover when sprayed with the pesticide at high concentrations. Since the applying pesticides could bring high mortality to the spider, food intake of U. insecticeps population greatly decreased in 13 days after being sprayed with buprofezin. Though the surviving spiders in the treated groups ate even more than the control individuals on the 13th day, no pesticide was worth spraying because food intake of the population in the treated groups was less than that in the control group due to the high mortality of the population.