三突花蛛和T纹豹蛛对豇豆荚螟幼虫的捕食作用

三突花蛛和T纹豹蛛对豇豆荚螟2～3龄幼虫的捕食功能反应为HollingⅡ型,三突花蛛的捕食上限(Namax)和a/′Th值均高于T纹豹蛛。这两种蜘蛛的寻找效应均随豇豆荚螟密度的增加而下降,且T纹豹蛛下降幅度较大。随着猎物密度增加和寻找效应降低,二者的捕食量均有提高,而三突花蛛提高较多。三突花蛛的寻找效应仅在豇豆荚螟密度为4头/皿时低于T纹豹蛛,当其寻找效应高于T纹豹蛛时,其捕食量(捕食上限)高于同密度下T纹豹蛛的捕食量。用汪世泽等(1988)的模型来模拟,求出了二者的日最大捕食量和最佳寻找密度,田间应用这两种蜘蛛控制豇豆荚螟时,益害比可分别设为15∶和11∶.3。

Predation of Misumenops tricuspidatus and Pardosa T-insignita to Maruca testulatis Larvae

The predatory functional response of Misumenops tricuspidatus and Pardosa T-insignita on Maruca testulatis 2～3 instar larvae fitted the model of Holling type well.Namax and a′/ Th of Misumenops tricuspidatus were higher than that of Pardosa T-insignita.The efficiency of the two kinds of spiders decreased with the increment of the prey density.And that of Pardosa T-insignita decreased much more.The attack number increased with the decrement of searching efficiency and the increment of prey density.And that of Misumenops tricuspidatus increased much more.Only when the pray density was 4 population per utensil,the searching efficiency of Misumenops tricuspidatus was lower than that of Pardosa T-insignita.When its searching efficiency was bigger than that of Pardosa T-insignita and its attack number(include Namax) was higher than that of Pardosa T-insignita.Through WANG Shi-Ze model,the largest consumption per day and the perfect density of the two kinds of spider were gained.When Misumenops tricuspidatus and Pardosa T-insignita were applied to control Maruca testulatis,the benefit and harm ratio could be 1∶5 and 1∶1.3,respectively.