南方小花蝽对为害蚕豆的三种蚜虫的捕食作用

Predation of Three Aphid Species on Faba Bean by Orius strigicollis

豆蚜Aphis craccivora、豌豆蚜Acyrthosiphon pisum和豌豆修尾蚜Megoura crassicauda是为害豆科作物的主要害虫。南方小花蝽Orius strigicollis是重要捕食性食蚜天敌,广泛分布于我国南方。为明确南方小花蝽对豆科作物上3种蚜虫的捕食作用和生物防治潜能,本研究在实验室条件下,测定了南方小花蝽对3种蚜虫的捕食选择性和捕食功能反应。结果表明,南方小花蝽对3种蚜虫的捕食功能反应均符合HollingⅡ模型,不同龄期南方小花蝽对3种蚜虫捕食量由大到小依次为5龄若虫,雌成虫,低龄若虫。对豆蚜的捕食量均大于对豌豆修尾蚜的捕食量,对豌豆蚜的捕食量最小,雌成虫对以上3种蚜虫的日最大捕食量分别为豆蚜63.69头/d、豌豆蚜36.23头/d和豌豆修尾蚜49.26头/d。南方小花蝽对3种蚜虫的寻找效应随蚜虫密度的增加而降低,随小花蝽龄期的增加而升高,相同龄期的南方小花蝽对3种蚜虫的寻找效应由大到小依次为豌豆修尾蚜,豆蚜,豌豆蚜。南方小花蝽对猎物的捕食作用受自身密度的干扰,当猎物密度不变时,随着小花蝽自身密度的增加,单头小花蝽平均捕食量下降,其干扰反应符合HasseⅡ模型方程。南方小花蝽对豆蚜、豌豆蚜和豌豆修尾蚜的喜好性指数分别为0.186、-0.245、0.027,对豆蚜和豌豆修尾蚜表现出正喜好性,且对豆蚜的喜好性强于豌豆修尾蚜,但对豌豆蚜表现出负喜好性。综上所述,南方小花蝽对豆科作物上的3种蚜虫具有良好的防治潜能。

Aphis craccivora,Acyrthosiphon pisum,and Megoura crassicauda are the main pests damaging leguminous crops.Orius strigicollis,a successful aphidophagous natural enemy,is widely distributed in Southern China.To determine the biological control potential of O.strigicollis on the three aphid species,this study measured the predatory selectivities and predatory functional responses of different stages of O.strigicollis in the laboratory.The results showed that the predatory functional responses of the nymphs and female adults of O.strigicollis to the three aphid species fitted well with the Holling Ⅱ functional response model.Predation capacities ranked from high to low were 5th instar nymphs,female adults,and young nymphs.Predation capacity was the highest for A.craccivora and the lowest for A.pisum.The theoretical maximum daily predation of female O.strigicollis was 63.69for A.craccivora,36.23 for A.pisum,and 49.26 for M.crassicauda.The searching efficiency of O.strigicollis decreased with increasing density of the three aphid species,whereas increased with the predator's stage.The searching efficiency with the same nymphal stage of the predator ranked from high to low were M.crassicauda,A.craccivora,and A.pisum.Predation by the female adults was affected by the predators' density,which is described by Hasse Ⅱ model equation.The preference index was positive for A.craccivora(0.186) and M.crassicauda(0.027),whereas it was negative for A.pisum(-0.245).The results show that O.strigicollis has the potential to control the three aphis species on leguminous.