淡翅小花蝽对豆大蓟马的捕食功能反应及猎物偏好性

Functional Response and Predation Preference of Orius tantillus to Megalurothrips usitatus

为评价淡翅小花蝽对豆大蓟马的控害潜能,在室内测定了淡翅小花蝽各虫态对豆大蓟马2龄若虫的捕食能力、寻找效应、捕食选择性及自身密度干扰反应。结果表明:一定的猎物密度范围内,淡翅小花蝽各虫态对豆大蓟马的捕食作用均符合HollingⅡ功能反应模型,淡翅小花蝽各虫态的捕食量均随猎物密度的增加而升高,搜寻效应均随猎物密度增加而下降。淡翅小花蝽若虫的捕食能力随龄期的增长而提高,5龄若虫的日捕食能力最强,为42.9头。淡翅小花蝽5龄若虫对豆大蓟马2龄若虫捕食率随其自身密度的增加而下降,经拟合获得的干扰模型为E=0.412P^(-0.822),分摊竞争模型为I=1.042lg P+0.071。猎物偏好性试验结果表明,淡翅小花蝽5龄若虫和成虫均对豆大蓟马2龄若虫的偏好性明显高于成虫。研究结果表明淡翅小花蝽对豆大蓟马具有较好的防控潜能。

Orius tantillus(Motschulsky) is one of the local nature enemies of thrips in Hainan province,but its predatory capacity on Megalurothrips usitatus has never been determined.In this work,the functional response,searching efficiency,predation preference and interference response of O.tantillus on M.usitatus were studied under laboratory conditions.The results showed that the predation of O.sauteri on M.usitatus followed the Holling II functional response.The predation amount of the 1^(st)―5^(th) instar nymphs and adults of O.tantillus on the 2^(nd) instar nymphs of M.usitatus were all positively correlated with the prey density,while their searching efficiency were negatively correlated with the prey density.The predation ability of the nymphs increased with increasing instar stage,reaching the highest at the 5^(th) instar nymphs with a a’/Th value of 42.9 thrips.The predation of the 5^(th) instar nymphs was strongly affected by intraspecific interference,and the average daily predation amount decreased with the increase of the predator density.The interference model was E=0.412P^(-0.822),the apportionment competition model was I=1.042lg P+0.071.The predation preference results showed that both the 5^(th) instar nymphs and adults of O.tantillus strongly preferred the 2^(nd) instar prey nymphs.These results suggest that O.tantillus is of strong control potential against the 2^(nd) instar nymphs of M.usitatus.