Abstract: To evaluate the suitability of stage-specific combined preys for rearing Orius similis, we investigated the developmental rate and fecundity of O. similis by feeding them on three diet regimes: single prey (Aphis fabae Scopoli), stage-specific combined preys (Frankliniella occidentalis for the first instar nymphs, A. fabae for the 2nd－5th instar nymphs and F. occidentalis for adults), and mixed preys (the mixture of F. occidentalis, A. fabae and Tetranychus urticae). The harvest rate of O. similis adults was only 34.2%, the lowest for the single prey regime. For the regime of stage-specific combined preys, the harvest rates were about 80% when the diet regime was used for two generations. The developmental durations of immature O. similis of the first and second generations fed on stage-specific combined preys were relatively longer (15.30 d and 15.28 d, respectively) in relative to that on mixed preys (14.71 d), but were significantly shorter than those fed on the single diet (21.48 d). The net reproductive rate R₀ (27.85 and 40.13) and intrinsic increase rate r_m (0.16 and 0.18) of the first and second generations fed on the stage-specific combined preys were not significantly different from those fed on mixed preys (R₀=31.38 and r_m=0.16), but were higher than those fed on single prey (R₀=4.27 and r_m=0.06). Our results suggested that the stage-specific combined preys were suitable for O. similis reproduction and development and could produce satisfactory efficacy for rearing the predator.

Key words: Orius similis, Frankliniella occidentalis, Aphis fabae, Tetranychus urticae, stage prey combinations, mixed preys