Abstract

Aggressiveness is a proper efficiency index of a biological control agent. Present study aimed at determining the level of Phytoseiulus persimilis aggressiveness against eggs of T. urticae after feeding on eggs of the predatory mite Neoseiulus californicus (intraguild predator). For the experiment, <1 day old adult females starved in cages for 24h before the start of the experiment. Each group was then divided to 3 subgroups: a) 5 spider mite eggs as prey, b) 5 eggs of N. californicus as prey and c) 5 eggs of each of spider mite and N. californicus (choice test). Type of prey before adulthood had not any effect on adulthood aggressiveness. Attacking to eggs of spider mite was significantly faster than intraguild predator‘s eggs, (all p<0.035). All predators attacked spider mite in both choice tests. Comparing means of attack time on spider mite in two groups and also versus choice test did not show significant differences (all p>0.05). So, it seems that type of prey before adulthood in P. persimilis does not have any effect on level of its aggressiveness on spider mites eggs in adulthood.