Effects of two host plants on the functional response of adult Orius albidipennis (Hem.: Anthocoridae) to different densities of the second instar larvae of Thrips tabaci (Thys.: Thripidae)

Thrips tabaci Lindeman، is one of the most important pests of vegetables and ornamental plants across the world. The functional response of Orius albidipennis Reuter was studied in relation to different densities of second instar larvae of T. tabaci. Laboratory experiments were conducted to evaluate the effect of two different host plants (cucumber and bean plantlets) on the functional response and its parameters (attack rate and handling time) using different densities of 2، 5، 10، 20، 30 and 40 thrips. The cucumber and bean plantlets، in relatively small pots with a diameter of 4 cm and 7 cm high were supplied to the predators to feed on the thrips in a 24-hour-period. Each density was repeated 10 times. The experiment was carried out at 25-29°C، 60 ± 5% R. H. and photoperiod of 16:8 L: D hours. The logistic regression suggested a type II functional response on two host plants. The Roger’s random predator equation was compatible with the results. The type of functional response was not affected by the host plants. Attack rate (a)، handling time (Th) and maximum predation of O. albidipennis were 0. 073 ± 0. 013، 1. 67 ± 0. 12 and 14. 37 on the cucumber and 0. 095 ± 0. 02، 1. 51 ± 0. 11 and 15. 89 on the bean plantlets، respectively. There was no significant difference among estimated parameters in both plantlets.