BEMISIA TABACI)HOMOPTERA: ALEYRODIDAE( به تراكم جمعيت عسلك پنبه COLEOPTERA: COCCINELLIDAE واكنش تابعي سه گونه كفشدوزك شكارگر

Functional Responses of Three Species of Predatory LadybirdsColeoptera: Coccinellidae) to Population Densities of Bemisia tabaci (Homoptera: Aleyrodidae)

The functional response of ladybirds, Coccinellu septempunctata L., Hippodamiu variegata Goeze, and Clitostethus arcuatus Rossi (Coleoptera: Coccinellidae) was evaluated on different densities of Bemisia tabaci Gennadius in the laboratory, at 25+2 °C. 75 - 90% RH, and 16: 8 (L: D) photoperiod. All data fitted well to the type H model of the Honing disc equation. The predators consumed larger numbers of early than late instars of B. tabaci within the same exposure time. Adult C. arcuatus had a lower instantaneous searching efficiency and handling time and could also consume larger numbers of B. tabuci than could mature larvae. Overall, the predation efficiency of C. septempunctata on B. tabaci was higher than other ladybirds, thus it can control the aleyrodidsʹ population effeiciently.