Multi-generational life table responses of Neoseiulus cucumeris (Acari: Phytoseiidae) to mixed diets supplied via its factitious prey

Neoseiulus cucumeris (Oudemans) is a generalist phytoseiid predatory mite widely used as a biological control agent against phytophagous mites, including tetranychid and tarsonemiid species, as well as thrips and whiteflies. Because identifying a suitable diet is a critical first step for the mass rearing of predatory mites, this study evaluated the effects of several enriched diets of Tyrophagus putrescentiae (Schrank) as a factitious prey (alternative food) on the performance of N. cucumeris. The tested diets included bran (B) as a control; wheat flour + bran (BW); yeast + wheat + bran (BWY); dog food + wheat + bran (BWD); yeast + dog food + bran (BDY); and wheat + yeast + dog food + bran (BWDY). The results showed that the intrinsic rate of increase (r) did not differ significantly among diets compared with the control. However, total lifespan and fecundity of N. cucumeris reared on the enriched diets were higher than those reared on the control and BW diets. The predatory mite was reared on the BDY and BWDY diets for ten consecutive generations. After ten generations, females fed the BDY diet showed significant increases in fecundity, gross reproductive rate (GRR), finite rate of increase (λ), and intrinsic rate of increase (r) relative to G1. In contrast, rearing the predatory mite on the BWDY diet for ten generations resulted in significantly shorter female longevity, adult longevity, and total lifespan compared to those fed BDY at G10. Overall, the BDY diet improved the biological performance of N. cucumeris after ten generations compared with the first generation, while long-term feeding on the BWDY diet maintained stable performance. Although the combination of diets appears more costly than a single diet, the resulting stable performance justifies the additional expense. Therefore, the BWDY diet is considered the most suitable option for the long-term mass rearing of N. cucumeris.