Food preference of Amblyseius swirskii (Acari: Phytoseiidae) on different stages of Tetranychus urticae (Acari: Tetranychidae) and Bemisia tabaci (Hemiptera: Aleyrodidae)

The prey preference of polyphagous predators plays an important role in suppressing different species of herbivorous mites and insects. Prey stages preference of the predatory mite, Amblyseius swirskii Athias-Henriot was investigated among egg, protonymph and deutonymph of Tetranychus urticae Koch and egg, first and second instar nymphs of Bemisia tabaci Gennadius. All experiments were conducted using bean (cultivar: Alamoti) leaf discs in Petri dishes (9 cm in diameter) under laboratory condition with 25±2 °C, 70 ± 5% RH and 16 L: 8 D photoperiod. The preference for female predator was calculated with Manly’s preference index (β). Comparison of the preference indices using a t-test showed that A. swirskii consumed significantly more eggs than protonymphs and deutonymphs of T. urticae. There was also a significant difference between consumed protonymphs and deutonymphs of T. urticae. A. swirskii consumed significantly more eggs than second instar nymphs of B. tabaci. There was a significant difference between first instar nymphs and second instar nymphs of B. tabaci and between eggs and first instar nymphs of B. tabaci. Our findings suggest that prey stages had effect on the prey selection of A. swirskii.