低剂量农药作用下拟环纹豹蛛对褐飞虱的功能反应及搜寻行为

Functional response and searching behavior to the brown planthopper, Nilaparvata lugens by the wolf spider, Pardosa pseudoannulata under low-dose chemical pesticides

在室内研究了低剂量农药作用下拟环纹豹蛛对褐飞虱的功能反应及搜寻行为。结果表明,拟环纹豹蛛对褐飞虱的功能反应均符合HollingⅡ模型,且在最适的低剂量农药(V药∶V水为2∶5000甲胺磷,12∶5000杀虫双和1∶20烯丙菊酯)刺激下,蜘蛛捕食褐飞虱的数量是最多的,蜘蛛用于对1头褐飞虱进行制服和取食等活动所需的时间(处理猎物时间,Th)短,仅分别为未经农药处理的蜘蛛所需时间的0.45、0.32和0.35倍;而施用较高剂量8∶5000的甲胺磷、28∶5000的杀虫双和6∶20的烯丙菊酯的蜘蛛,处理猎物时间长得多,依次是经最适低剂量3种农药作用的蜘蛛所用时间的9.70、13.60和13.62倍。拟环纹豹蛛在稻株上的搜寻行为属非随机搜索型,在相同的低剂量农药作用下,蜘蛛的搜寻效应随飞虱密度的增加而下降;但在相同的猎物密度下,蜘蛛的搜寻效应与使用的农药浓度有密切的关系,在上述最适低剂量农药作用下,豹蛛对猎物的寻找效应最佳,其在稻株上的总滞留时间依次是未施药情形的1.56、1.49、1.48倍,总搜寻距离依次是未施药情形的1.36、1.42、1.39倍。据此,进一步证实了低剂量农药增强了稻田蜘蛛的控虫效能和对害虫的相对活力。

The functional response and searching behavior to the brown planthopper （BPH）, Nilaparvata lugens by its predator, the wolf spider Pardosa pseudoannulata treated with the fittest low-dose concentration of 3 chemical pesticides were studied in the laboratory. The results showed that the predating number of the predator to the prey was significantly higher under the fittest low-dose pesticides （volume ratio of pesticide to water is 2：5 000 for methamidophos, 12：5 000 dimehypo, and 1：20 d-allethrin, respectively） than those without treatment of pesticide or treated by high-dose pesticides. Although all predating functional responses were in accordance with the Holling Ⅱ model, the functional response of the spiders treated by low-dose chemical pesticides was obviously stronger than those without treatment of pesticide or treated by high-dose pesticides. The time spent in handling and/or killing a brown planthopper （ Th ） by the spiders treated by the fittest low-dose pesticides were 0.45, 0. 32 and 0. 35 times, respectively, less than that by the spiders without treatment of pesticide. The time consumed by the spiders treated under the high-dose pesticides （volume ratio of pesticide to water is 8 ： 5 000 for methamidophos, 28 ： 5 000 dimehypo, and 6 ： 20 d-allethrin, respectively） were 9.70, 13.60 and 13.62 times, respectively, as much as that by the spiders treated under the fittest low-dose pesticides. The searching pattern of the spiders to BPH over rice plant was non-random. The searching efficiency decreased with the increase of prey density under the same chemical pesticide concentration. In the same BPH density, the searching efficiency of the predator varied more under different concentrations of pesticide. Under the influence of the fittest low-dose pesticides, the searching efficiency of the predator was the highest, and the total staying time and searching distance of the spiders were 1.56, 1.49, 1.48 times and 1.36, 1.42, 1.39 times as much as those under no pesticides, respectively. The results further proved that application of low-dose chemical pesticides might enhance spiders＇ efficiency of controlling pests and their relative activities to insect pests.