【摘要】 <正> 草间小黑蛛Erigonidium graminicolum(Sundevall)与单种猎物的作用关系已在上文述及(李超等,1982),然而草间小黑蛛在自然情形下是一种多食性的捕食性天敌,它的捕食对象不止棉铃虫Heliothis armigera H(?)bner一种。我们在对草间小黑蛛捕食行为的观察中也发现,捕食对象除棉铃虫外还有棉蚜等,并且在棉花上主要是徘徊式地捕获猎物。这样,在草间小黑蛛-棉铃虫作用系统的动态中就必须考虑替代食物的影响。替代食物的存在使捕食者对不同种类的猎物由于有不同的相对喜好程度而产生了对食物的选择,而该相对喜好程度的更多还原

【Abstract】 This paper suggests an equation to estimate the total amount of prey capturedand a method to estimate the parameter of preferencewhereand also a simulation model under the existing of an alternative food species (cotton aphid)The results of predation experiments carried out in big cages can be described by following the modelAnd the more the prey species exist with one predator species, the lower the predation rate to a special prey species is.The research on the behaviour of the simulation model shows some different results that occured in two species interacting system as follows. (1)Themore the predator depends upon its prey which is not prefered, the more stable of the three species system is; (2)Only the slight interference within the predator species can increase the stability of the system.更多还原