南方小花蝽对三种蚜虫的捕食能力和喜好性

Predation Capacity and Preferences of Orius similis Zheng for Three Aphid Species

南方小花蝽Oriussimilis是我国南方农田生态系统中一种对小型害虫极具控害潜力的重要捕食性天敌昆虫。为了明确天敌南方小花蝽对云南小春作物上常见蚜虫的捕食能力和喜好性,本文在实验室条件下研究了南方小花蝽5龄若虫、雌雄成虫对不同组猎物的捕食喜好性。选取云南小春作物上3种主要蚜虫种类:烟蚜Myzus persicae、甘蓝蚜Brevicoryne brassicae、豌豆蚜Acyrthosiphon pisum组成的混合猎物(A组);烟蚜低日龄寄生蚜,烟蚜僵蚜和烟蚜健蚜(B组);不同发育阶段烟蚜混合共存(C组),测定南方小花蝽的捕食选择性。结果表明:南方小花蝽对烟蚜和甘蓝蚜(A组)、烟蚜僵蚜和健蚜(B组)、烟蚜低龄若蚜和高龄若蚜(C组)的捕食量高于同组其他蚜虫,表现出正喜好性(Ci>0);而对豌豆蚜(A组)、低日龄寄生烟蚜(B组)、烟蚜成蚜(C组)表现出负喜好性(Ci<0)。3种混合猎物环境下南方小花蝽的日总捕食量为6.71~15.08头/d,对各组混合猎物的日总捕食量从大到小依次为A组,C组,B组。南方小花蝽对蚜虫具有较强的捕食能力,能利用其控制小春作物上的蚜虫。但南方小花蝽对烟蚜茧蜂Aphidius gifuensis寄生烟蚜后形成的僵蚜存在较大误食风险,在利用南方小花蝽控制蚜虫时应在僵蚜形成和子代蚜茧蜂羽化高峰期过后释放。此外,混合猎物条件下,南方小花蝽日捕食总量受混合猎物蚜虫种类和类型的复杂程度影响。

Orius similis Zheng(Hemiptera: Anthocoridae) is an important predatory natural enemy against tiny pest insects in agro-ecosystems in south China. The predation capacity and preference of O. similis to main aphid species on winter crops in Yunnan province were determined in 5 th instar nymphs, male adults, and female adults of O.similis using different mixed aphids groups under laboratory conditions. Three main aphid species Myzus persicae(Hemiptera: Aphididae), Brevicoryne brassicae(Hemiptera: Aphididae) and Acyrthosiphon pisum(Hemiptera:Aphididae) on winter crops in Yunnan province were selected as mixed prey A(hereinafter called MA), M. persicae parasitized by Aphidius gifuensis(Hymenoptera: Aphidiidae) in three different parasitic status were selected as mixed prey B(MB), and young nymphs, old nymphs and adults of M. persicae were used as mixed prey C(MC).The O. similis predated more preys of M. persicae and B. brassicae(MA), mummified aphids and healthy aphids M.persicae(MB), and low-instar nymphs and high-instar nymphs of M. persicae(MC) than those of the other aphids in the same group, showing a positive preference(Ci>0);while showed a negative preference for A. pisum(MA),low-instar parasitic aphids M. persicae(MB) and adults M. persicae(MC)(Ci<0). The total daily predation ranged between 6.71—15.08 and ranked as MA>MC>MB. O. similis had great predation capacity to aphids and can be used to control aphids on winter crops. However, O. similis stands a high risk to predate mummified M. persicae,therefore O. similis should be released after peak formation period of mummified and eclosion of offspring A.gifuensis. Meanwhile, under the coexistence of mixed preys, the total daily predation of O. similis is affected by the complexity of aphid species and types of mixed prey.