Functional response of two native species Typhlodromus khosrovensis and Euseius amissibilis (Acari: Phytoseiidae) feeding on eggs of Tetranychus urticae (Acari: Tetranychidae)

Typhlodromus (Anthoseius) khosrovensis and Euseius amissibilis are two native phytoseiidae species in different parts of Tehran city, Iran, which were recorded from white mulberry trees, for the first time. The studies about the predator-prey dynamics of native phytoseiids are rare. Thus, this investigation aimed to determine the predatory efficiency of both species against eggs of Tetranychus urticae. Under constant conditions (27 °C, 65% RH, and a photoperiod of 16:8 h L/ D), six egg prey densities (2, 4, 8, 16, 32, and 64) were separately offered to each predator to record its predation rates for 24h. According to the results, T. khosrovensis, and E. amissibilis represented a type II functional response. In T. khosrovensis, the attack rate coefficient (α) was 0.0213 h<sup>-1</sup>, and the handling time (T<sub>h</sub>) was 2.8013 h. These values in E. amissibilis were recorded as 0.0204 h<sup>-1</sup> and 2.3018 h, respectively. The maximum attack rate (T/T<sub>h</sub>) on eggs of T. urticae was estimated to be 8.57 h<sup>-1</sup> for T. khosrovensis, and 9.98 h<sup>-1</sup> for E. amissibilis. Therefore, both native predators illustrated a highly efficient biological control against eggs of T. urticae, although field studies are needed to show their ability as promising predators on mulberry trees in the future.