南方小花蝽对西花蓟马和蚕豆蚜的捕食作用

南方小花蝽Orius similis是多种小型害虫的重要天敌昆虫,为了掌握其控制潜能,本文研究了南方小花蝽对西花蓟马Frankliniella occidentalis和蚕豆蚜Aphis craccivora的捕食作用。研究结果表明南方小花蝽3～5龄若虫和雌成虫对西花蓟马和蚕豆蚜的功能反应均符合HollingⅡ型方程,南方小花蝽3～5龄若虫和雌成虫对西花蓟马2龄若虫的瞬时攻击率均高于蚕豆蚜。南方小花蝽5龄若虫对蚕豆蚜的控制能力比雌成虫强,而对西花蓟马的控制能力比雌成虫差。南方小花蝽5龄若虫对西花蓟马2龄若虫和蚕豆蚜的捕食率（E）随着捕食者自身的密度（P）的增加而下降,其干扰反应方程分别为E=0.412P-1.623和E=0.416P-1.639。南方小花蝽5龄若虫对西花蓟马2龄若虫和蚕豆蚜有明显的选择性,5龄若虫喜欢取食西花蓟马2龄若虫,但前期取食的猎物对其选择性有明显的影响,更喜欢选择前期取食过的猎物。

The predation of Orius similis to Frankliniella occidentalis and Aphis craccivora

Orius similis is an important natural enemy of many small insect pests.Predation of O.similis on two common pests,Frankliniella occidentalis and Aphis craccivora,was studied.The functional responses of 3rd to 5th instars and adults of O.similis to F.occidentalis could be described by Holling Ⅱequations.Both instars and female adults of O.similis displayed higher instantaneous attack rates on F.occidentalis than on A.craccivora,however,adults had a lower instantaneous attack rate on the 2nd instar of F.occidentalis compared to that of A.craccivora.The 5th instar nymph of O.similis had a better ability to control A.craccivora than female adults,however,the reverse was true with respect to F.occidentalis.Predation rates were density-dependent;predation efficiency （E） decreased with increasing O.similes density （P）.Regression equations of the predation efficiency of 5th instar O.similes nymphs on 2nd instar larva of F.occidentalis and A.craccivora were E=0.412P-1.623 and E=0.416P-1.639 respectively.5th instar nymphs had a positive preference for 2nd instar larva of F.occidentalis over those of A.craccivora,however,previous experience had a significant influence on prey preference;O.similis prefers to prey on which it has previously fed.