拟环纹豹蛛和前凹豹蛛对小菜蛾的捕食作用

[目的]探讨拟环纹豹蛛和前凹豹蛛对小菜蛾幼虫的捕食作用。[方法]研究不同温度下2种蜘蛛对小菜蛾幼虫捕食量和不同空间条件下拟环纹豹蛛对小菜蛾的捕食效应，利用三因子五水平二次通用回归旋转组合分析2种蜘蛛对小菜蛾幼虫的联合控制作用和拟环纹豹蛛对小菜蛾、斜纹夜蛾幼虫的控制作用。[结果]2种蜘蛛对小菜蛾捕食量随温度增加先增加后降低。拟环纹豹蛛对小菜蛾的捕食作用大于前凹豹蛛，2种蜘蛛对小菜蛾四龄幼虫捕食功能反应符合 Holling-Ⅱ型，但 Holling-Ⅲ型能完善2种蜘蛛对小菜蛾幼虫的捕食作用评价。不同体积对拟环纹豹蛛的取食作用影响较大，瞬时攻击能力 a′、处理1头猎物所用的时间 Th和捕食作用 a′/Th在小体积要高于大体积。2种蜘蛛对小菜蛾幼虫联合捕量与三者密度正相关，总体平均效应为：小菜蛾幼虫密度＞前凹豹蛛密度＞拟环纹豹蛛密度。小菜蛾和斜纹夜蛾密度显著影响拟环纹豹蛛的取食量，但拟环纹豹蛛对小菜蛾幼虫和斜纹夜蛾幼虫没有偏嗜性。[结论]该研究结果可为评价这2种蜘蛛对田间小菜蛾的控制作用提供参考。

Predation of Pardosa pseudoannulata and Pardosa procurva Against Plutella xylostella

Objective] This study was conducted to explore the predation of Pardosa pseudoannulata and Pirata procurva_ on Plutela xylostela larvae. [Method] The quantities of P. xylostela larvae predated by the two spider species at different temperatures and the quantities of P. xylostela larvae predated by P. pseudoannula-ta_in different volumes were analyzed. Based on three factors at five levels, the quadratic general regression rotation combination design was used to study the combined control effect of the two spider species on P. xylostela_larvae and the control effect of P. pseudoannulata on the larvae of P. xylostela and Spodoptera litura. [Result] The quantities of P. xylostela_ larvae predated by the two spider species increased first and then decreased with the increase of temperature, and the functional predation response of P. pseudoannulata and P. procurva_ on the fourth instar larvae of P. xylostela_fitted the Hol ing-Ⅱ model, and the Hol ing-Ⅲmodel could perfect the evaluation on the predation effect. Volume had great effect on the feeding of P. pseudoannulata. lnstantaneous attack ability (a’), the time to handle one prey (Th) and predation function (a’/Th) in a smal er volume were al higher than that in a larger volume. The predation of the two spider species on P. xylostela_larvae was positively correlated with their densities. The overal effect of the three factors was: the density of P. xylostela>the density of P. procurva>the density of P. pseudoannulata. The densities of P. xylostela and S. litura larvae could affect the feeding amount of P. pseudoannulata. But there was no predation preference for P. pseudoannulata on the larvae of P. xylostela and S. litura. [Con-clusion] The results wil provide a reference for the evaluation of control effect of_P. xylostela_by P. pseudoannulata_and P. procurva in the field.