FUNCTIONAL RESPONSE OF HIPPODAMIA VARIEGATA (GOEZE) (COLEOPTERA: COCCINELLIDAE) ON APHIS FABAE (SCOPOLI) (HOMOPTERA: APHIDIDAE) IN LABORATORY CONDITIONS

Abstract

Functional response is one of the most important behavioral characteristics that reveal different aspects of prey-predator interactions. In this study, the functional response of the amber ladybird, Hippodamia variegata (Goeze), attacking the black bean aphid, Aphis fabae (Scopoli), was investigated. Different levels of aphid densities - 20, 40, 60, 80, 100, 120, 140, 160 and 180 - were used. Each density was placed in a test cage (6 x 11 x 23 cm 3 ), and then exposed to an adult 24 hours old. The experiments were carried out at 25 ± 1 °C, 60 ± 5 % of relative humidity and 16 : 8 (light : darkness) hours photoperiod. Logistic regression was used to distinguish the shape of the functional response (type II or III). Nonlinear least-square regression was used to estimate the attack rate (a) and handling time (T h ). The Nicholson model was used to determine per capita searching efficiency. Logistic regression suggested a type II response on A. fabae adults. Searching efficiency, handling time and estimated maximum percent of consumed prey were 0.00078, 0.1774 and 135.29, respectively.