Functional response of mirid egg predators, Cyrtorhinus lividipennis Reuter and Tytthus chinensis Stal (Hemiptera : Miridae), to brown planthopper (Nilaparvata lugens Stal, Homoptera : Delphacidae)

摘要

The mirid bugs, Cyrtorhinus lividipennis Reuter and Tytthus chinensis Stal (Hemiptera : Miridae) are important egg predators and effective for controlling brown planthopper, Nilaparvata lugens Stal (Homoptera : Delphacidae). This study reports the functional responses of these two predators under laboratory conditions, provided with brown planthopper eggs as prey. Functional response to prey density of C. lividipennis and T. chinensis were fitted to Holling's Type II functional response. Predationrates of the third instar, fifth instar, male and female were increased at a decreasing level with increasing prey density until a plateau was reached. The handling time (T_h) and the attack rate (a) of female C. lividipennis over 24 h were higher than the third instar, fifth instar and male. However, over 48 h the handling time (T_h) and the attack rate (a) of the fifth instar were higher than the other stages. The handling time (T_h) and the attack rate (a) of male T. chinensis over 24 h were higher than the third instar, the fifth instar and the female. Over 48 h the handling time (T_h) and the attack rate (a) of the females were higher than the other stages.