荧光物示踪法测定除草剂对食虫沟瘤蛛摄食量的影响(英文)

Quantitative measurement of influence of herbicides on food intake of Ummeliata insecticeps by the fluorescence labeling method

采用一种全新的测定方法———荧光物示踪法,以稀土元素铕作为荧光示踪物质,以“水稻白背飞虱SogatellafurciferaHorvath食虫沟瘤蛛UmmeliatainsecticepsBosenbergetStrand”这一食物链中的水稻和白背飞虱作为铕的传递者,经萃取和反萃取等一系列化学分析方法,定量地测定了3种除草剂胁迫下食虫沟瘤蛛的摄食量。结果表明:施用除草剂西草净、使它隆和高效盖草能以后,食虫沟瘤蛛的存活个体12天内平均每天捕食白背飞虱分别为1.784、2.678和2.856头,均低于对照组的平均个体摄食量3.321头d;各组12天内个体摄食量的趋势线均为开口向上的抛物线,可用二次方程进行拟合;同时除草剂的喷施亦对食虫沟瘤蛛造成一定的致死率,因而造成施药后食虫沟瘤蛛的种群摄食率减退,第2、5、8天的平均摄食率分别为对照组的52.11%、36.45%和50.27%;药后第12天3个处理组的摄食量均超过了正常值,平均摄食率达到对照组的131.84%。因此在稻田中害虫大发生或天敌群落迁移时应慎用除草剂,以免食虫沟瘤蛛药后摄食量减少导致对目标害虫控制力减弱或由于除草剂的致死力而对食虫沟瘤蛛的群落重建构成威胁。

This paper focuses on studying the influence of herbicides on the food intake of Ummeliata insecticeps （Bosenberg et Strand） by a novel quantitative method - the fluorescence labeling method. Europium, the lanthanide chosen for the experiment, was dissolved in the soil and then absorbed by the rice plants. Sogatella furcifera eats the plants and U. insecticeps preys on S. furcifera for food. Thus, by applying a series of chemical analytical methods of extracting and invert extracting onthe tested fly louse and spider samples, the food intake of U. insecticeps could be known. The results showed that each surviving spider individual sprayed with Simetryne preyed on 1. 784 S. furcifera individuals per day over the course of 12 days. If sprayed with Starane, spiders preyed on 2.678 S. furcifera individuals/d, and with Gallant-S, 2.856 individuals/d, on average. The individual food intakes of the three test groups were all less than that of the control group, which preyed on 3.321 S. furcifera individuals/d. The curves of the food intakes of the spiders in the different groups are all inverted parabolas, which can be fitted by quadratic equations. If mortality is taken into account, for the first 8 days after the application of herbicides, the population food intakes of the test groups are all much less than that of the control group. The average predatory ratios of the three test groups in the 2nd day, the 5th day and the 8th day are 52.11%, 36.45% and 50.27% of the control group＇s population food intake, respectively. In the 12th day, however, the population food intake of the test groups is 131.84% of that of the control group. It could be concluded that all of the herbicides tested do harm to the spiders＇ food intake capacity within 8 days of exposure. Therefore, it is unadvisable to apply herbicides when the paddy field is rife with pests because the herbicides would weaken the spiders＇ control over the pests. It is also unadvisable to apply herbicides during the harvest season because the spiders migrate at this time and the lethality of the herbicides will disturb the rebuilding of the spider communities.