Effect of refuge on the functional response of Coccinella septempunctata L. feeding on Myzus persicae (Sulzer)

Author of the article:WANG Jue YOU Xiu-Feng LI Hui-Ling SUN Shu-Jun

Author's Workplace：College of Plant Protection, Henan Agricultural University

Key Words：Coccinella septempunctata, Myzus persicae, refuge, functional response, Holling disc equation, random predation equation

Abstract：Predation generally occurs on plants in nature. The author studied the effect of pure physical factor (prey refuge) on the functional response of Coccinella septempunctata L. feeding on Myzus persicae (Sulzer) using artificial plant model in the environment. The results show that the presence of prey refuge caused dramatic decrease in the prey consumption and the predation rate, and this effect is more prominent on males than that on females. The refuge effect exhibited maximium when moderate densities of preys were offered. The logistic regression indicates that the presence of refuge did not alter the type of functional response. In the absence of refuge, the Holling disc equations of females and males were Na = 1.0259 N0 /（1 + 0.003078 N0）and Na = 0.9246 N0 /（1 + 0.002127 N0）, respectively; and which were Na = 0.9500 N0 /(1 + 0.00342 N0) and Na = 0.6463 N0 /(1 + 0.002262 N0) in the presence of refuge, respectively. The refuge caused significant decrease of the instantaneous attack rates of both sexes, while only the handling time of the males significantly prolonged, suggesting that the males of predatory coccinellids were more difficult in capturing preys under complex habitats than the females.