Functional and numerical responses of Stethorus gilvifrons Mulsant feeding on strawberry spider mite, Tetranychus turkestani Ugarov and Nikolski.

Laboratory experiments were conducted to measure the functional and numerical responses of Stethorus gilvifrons Mulsant feeding on Tetranychus turkestani Ugarov and Nikolski. Adult ladybirds were isolated singly for 24 h in 8 cm petri dishes with either 4, 8, 12, 24, 48 or 96 adult females of T. turkestani. Results showed a typical type 3 functional response, with up to 65.2 preys attacked when 96 preys were provided. The rate of attack and handling time were 0.0012 and 0.415 (days), respectively. The number of eggs deposited by the predator depended on the density of the prey; up to maximum of 223.6 eggs female(-1) at prey density of 96 spider mites were recorded. No eggs were laid at densities of 4 and 8 prey/arena.