Functional response of different developmental stages of Orius albidipennis Reuter feeding on the strawberry spider mite, Tetranychus turkestani (Ugarov&Nikolski)

The strawberry spider mite, Tetranychus turkestani (Ugarov & Nikolski) is one of the most important pests of agricultural crops in Iran. Orius albidipennis (Reuter) is also an active predator of spider mites in agricultural ecosystems in Iran. One of the characters which is used for the evaluation of predators is their response to the different densities of prey (functional response). Functional response of different developmental stages of this bug by feeding on adult female T. turkestani was investigated at 25 ± 1 ºC, 60 ± 5% RH and a photoperiod of 16:8 (L:D) h under laboratory condition. The experiments were carried out in a petri (10 cm diameter) on a bean leaf with the densities of 5, 10, 20, 30, 50 and 70 adult female mites. Mean maximum feeding rate of first, second, third, fourth and fifth nymphal stages as well as female and male adults of this bug were 9.6, 23, 34.8, 39.2, 48.1, 56.4 and49.1female adult T. turkestani, respectively. Functional response of all developmental stages (except for fourth nymphal stage) was of the Holling’s type II. Fourth nymphal stage showed Holling’s type III. Based on the Rojer’s equation, estimated attack rates of O. albidipennis were0.0654, 0.0678, 0.075, 0.0098, 0.1834, 0.1691 and0.165 and estimated handling times were 2.3048, 0.8259, 0.4684, 0.6585, 0.3666, 0.2484 and 0.3336 h for the first, second, third, fourth, fifth, female and male adult, respectively.