不同干扰因素对斜纹猫蛛(Oxyopes sertatus)和红彩真猎蝽(Harpactor fuscipes)捕食作用的影响

斜纹猫蛛和红彩真猎蝽均是烟草上斜纹夜蛾的重要捕食性天敌。室内测定几种干扰因素对斜纹猫蛛和红彩真猎蝽捕食作用的影响,结果表明这些干扰因素对斜纹猫蛛种内、红彩真猎蝽种内和两种捕食者种间的捕食作用均有明显的干扰作用,随捕食者数量的增加,其对斜纹夜蛾捕食作用率显著降低。斜纹猫蛛种内的干扰系数和红彩真猎蝽种内的干扰系数分别为0.7278和0.6911,而两者种间的干扰系数为0.9464,说明两者种间的干扰作用要明显高于同一种捕食者种内的干扰作用。两种捕食性天敌对斜纹夜蛾的捕食量和捕食作用率随烟草茎杆数的增加而降低,表明空间异质性同样是影响两种捕食性天敌捕食作用的一个重要因素。

Effect of interference factors on predations of Oxyopes sertatus (L.) Koch (Araneae:Oxyopidae) and Harpactor fuscipes (F.) (Hemiptera:Reduviidae) on Spodoptera litura (F.)

Both Oxyopes sertatus and Harpactor fuscipes are important predators of common cutworm(Spodoptera litura)on tobacco.The effect of several interference factors on the predations of O.sertatus and H.fuscipes on the larvae of S.litura were examined in laboratory.The results indicated that there were significant mutual interferences on their predations with the existence of other individual in the same/different species.As the number of the predator increased,the predation rates decreased significantly.The interference coefficients(m)within H.fuscipes and within O.sertatus were 0.7278 and 0.6911,respectively,while the interference coefficient(m)between O.sertatus and H.fuscipes was 0.9464.These results showed that the effect of mutual interference on predation in interspecies was more obvious than that in intraspecies.The number of prey captured and the predation rate of predator dropped with increasing the number of tobacco stalks.This result suggested that spatial heterogeneity was also an important factor affecting the predation of predator on prey.