Performance of <i>Amblyseius swirskii</i> (Acari: Phytoseiidae) on different astigmatid prey: life history traits and multi-generational stability

Optimizing trophic interactions within factitious prey chains is critical for the sustainable mass production of biological control agents. We investigated the developmental and demographic performance of Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) when fed on four storage mite species, Tyrophagus putrescentiae (Schrank) (Acari: Acaridae), Carpoglyphus lactis L. (Acari: Carpoglyphidae), Lepidoglyphus destructor (Schrank) (Acari: Glycyphagidae), Rhizoglyphus robini Claparede (Acari: Acaridae), and a mixed-prey treatment (equal ratio of C. lactis and L. destructor). Additionally, a previously optimized dry diet, composed of wheat bran, baker's yeast, dog food, cat food, mixed pollen, and a vitamin supplement, was directly offered to A. swirskii to assess its suitability as a non-prey artificial diet. Life table parameters were quantified under controlled laboratory conditions, and two prey treatments representing contrasting performance levels among those supporting complete development were further evaluated across 20 consecutive predator generations to assess demographic stability. Among the prey treatments, C. lactis supported the highest intrinsic rate of increase (r), net reproductive rate (R0), and fecundity, maintaining consistent demographic performance. Although T. putrescentiae was the least favorable prey among those permitting full development, it still supported population persistence, whereas R. robini failed to sustain survival beyond the protonymphal stage. Mixed-prey treatment did not enhance predator performance compared to C. lactis alone. Direct feeding on the dry diet resulted in reduced demographic performance compared to prey-based diets. The findings demonstrate that prey identity strongly influences both short-term and long-term performance, and that carefully selected astigmatid prey, particularly C. lactis can improve the efficiency of A. swirskii mass-rearing system.