多物种共存系统中蜘蛛对菜田害虫的控制作用

Control Function of Predators in Coexistent System of Spiders and Two Vegetable Insect Pest

运用二次通用旋转组合设计统计方法,研究菜田生态系统中天敌优势种蜘蛛星豹蛛(X1)、草间黑蛛(X2)及主要害虫菜蚜(X3)、小菜蛾(X4)组成的多物种共存系统,探讨蜘蛛对菜田主要害虫的控制作用,分析天敌之间、害虫之间及天敌和害虫之间的相互作用关系,获得4个天敌对害虫的捕食量模型。对模型进行主效分析表明,害虫密度的大小对天敌的总捕食量影响较大,其中又以菜蚜密度对天敌的总捕食量的影响较大。天敌中对捕食量作用最大的是星豹蛛,其次是小狼逍遥蛛。分析天敌间的交互作用表明,2种天敌蜘蛛的种间和星豹蛛的种内干扰较大,主要原因是生态位重叠较大,种间、种内残杀较严重。而小狼逍遥蛛种内的干扰却不是很明显。最后讨论了天敌蜘蛛能有效控制害虫的最大密度,以及在该害虫密度下各种天敌密度的最佳组合。

It was investigated that the foraging behavior of two predators （X1-Pardosa astrigera, X2-Erigonidium graminicolum） for two major insect pests in vegetable field （X3-Vegetable apide 、X4-Plutella maculipennis Curtis） , and how the interference intra-species and interspecies occurred ,by using the rotational composite design of quadratic regression. Four models of predatory capacity was obtained in the coexistent system of two spiders and two insect pests in vegetable fields. The principal efficiency analysis on this model indicated that increased in insect pest density had significantly increased the predation of predators on the insect pests and had a great effect than any one of predators. Xa had a great effect than X4. However, Xa and X4 had little interference in these experiment＇densities; they even promoted each other and increased the greatest effect on the increase of predation. As the predator density increased the intra- and inter-species interference occurred, which were largely related to the size, activity, niche breath, niche overlap and searching efficiency of the predator. X1 had the greatest interference between different individual and with any other predator species, and X2 the second, which reduced the oredation in high predator densities.