短翅蚜小蜂对桃蚜的取食和寄生功能反应

Feeding and parasitic functional responses of the parasitoid Aphelinus asychis Walker to green peach aphid Myzus persicae(Sulzer)

为评估短翅蚜小蜂对桃蚜的搜寻及控害潜能,采用叶碟法研究了短翅蚜小蜂对甘蓝和辣椒2种植物上桃蚜2龄若虫的取食与寄生行为。结果表明,短翅蚜小蜂对甘蓝桃蚜和辣椒桃蚜的取食和寄生功能反应均符合Holling II及Holling III型方程。短翅蚜小蜂的取食和寄生搜寻效应均随蚜虫密度的增加而降低,当桃蚜密度小于35头时,短翅蚜小蜂对甘蓝桃蚜的取食搜寻效应大于辣椒桃蚜,而当桃蚜密度大于35头时,短翅蚜小蜂对辣椒桃蚜的取食搜寻效应大于甘蓝桃蚜;短翅蚜小蜂在所有密度下对辣椒桃蚜的寄生搜寻效应均大于甘蓝桃蚜。短翅蚜小蜂取食甘蓝桃蚜的瞬间攻击率a'为0.3289,处理时间T_h为0.2597,均大于辣椒桃蚜,寄生甘蓝桃蚜的瞬时攻击率a'为0.8213,小于辣椒桃蚜,而处理时间T_h为0.0275,大于寄生辣椒桃蚜;短翅蚜小蜂对甘蓝桃蚜的理论最大取食量和寄生量均小于辣椒桃蚜。研究表明,短翅蚜小蜂对不同密度的桃蚜均有一定的控制能力,且对辣椒桃蚜的控制作用大于甘蓝桃蚜。

In order to evaluate the potential abilities of the parasitoid Aphelinus asychis Walker in searching and controlling green peach aphid Myzus persicae（Sulzer）,the feeding and parasitic function responses of A.asychis to 2nd-instar nymphs of M.persicae infesting cabbage and pepper were studied using the leaf disc method.The results showed that the functional responses of A.asychis to M.persicae feeding on cabbage and pepper fitted well with Holling II and Holling III models.Both feeding and parasitic search effects of A.asychis to M.persicae infesting cabbage and pepper decreased as aphid density increased.When the density of M.persicae nymphs was less than 35,the feeding search effect of A.asychis on M.persicae infesting cabbage was greater than that on M.persicae infesting pepper.The feeding search effect on cabbage and pepper showed the inverse results when the density of nymphs was more than 35.The parasitic search effects of A.asychis on M.persicae infesting pepper were greater than that on M.persicae infesting cabbage at all densities.In the feeding functional response,the instantaneous attack rate and handling time of A.asychis preying on M.persicae on cabbage（a＇ =0.3289,Th= 0.2597） was greater than on pepper（a＇ = 0.2335,T_h= 0.1954）.In the parasitic functional response,the instantaneous attacking rate of A.asychis feeding on M.persicae on cabbage（a＇ = 0.8213） was less than that on pepper（a＇ = 0.8956）,but the handling time showed contraryresults（cabbage：T_h= 0.0275,pepper：T_h= 0.0255）.In addition,the feeding and parasitism upper limits pepper were greater than to M.persicae infesting cabbage.The results indicated that A.asychis could partly control M.persicae at all host densities,and the control efficiency pepper was greater than on M.persicae damaging cabbage.