Functional response of Serangium montazerii (Col.: Coccinellidae) to different densities of Dialeurodes citri (Hem.: Aleyrodidae): an open-patch approach

The functional response of a predator is the base of prey-predator dynamics. Functional response of Serangium montazerii Fürsch at different egg densities (50، 100، 150، 200 and 250) of Dialeurodes citri (Ashmead) was studied in an open-patch experiment، in a growth chamber (25 ± 1°C، 65 ± 5% RH and a photoperiod of 16:8 L: D h) on ‘Thompson’ navel orange (Citrus sinensis cv. Thompson) apical leaves. A type II functional response was obtained using logistic regression. The searching efficiency (a'') and handling times (Th) of the female adults using nonlinear least-square regression were estimated as 0. 0421 ± 0. 00945 h-1 and 0. 0896 ± 0. 0362 h، respectively. Mean times required for the female predator to settle in a patch were 121. 4، 140، 116، 83 and 78 minutes at above-mentioned prey densities، respectively. It was inversely density dependent (R2 = 0. 740). The proportion of female predators remaining in open patches at the end of the experiment was directly dependent on prey density (R2 = 0. 9). It was concluded that the type of functional response obtained here was in agreement with studies on this predator in closed patches.