Evaluation of Artemia franciscana Cysts to Improve Diets for Mass Rearing Stethorus gilvifrons, a Predator of Tetranychus turkestani

SIMPLE SUMMARY: The ladybird beetle Stethorus gilvifrons is a native predator of spider mites in the Mediterranean region that could be mass-reared and released to control spider mite populations on crop plants. The aim of this research was to test the hypothesis that brine shrimp cysts can improve diets for mass rearing of S. gilvifrons in the absence of prey, i.e., spider mites. The diet treatments included brine shrimp cysts alone (D1), brine shrimp cysts plus a vitamin B complex (D2), brine shrimp cysts plus date palm pollen (D3), or brine shrimp cysts plus date palm pollen and Mediterranean flour moth eggs (D4). The results revealed that only two diets, D3 and D4, supported predator development to the adult stage and reproduction. The predator reproductive rate and life table estimates indicated that D4 was superior. In conclusion, only a mixed diet of brine shrimp cysts, date palm pollen, and flour moth eggs is suitable for mass rearing S. gilvifrons. ABSTRACT: Stethorus gilvifrons is an acarophagous coccinellid distributed in the Mediterranean region and could potentially be mass-reared for the augmentative biological control of Tetranychus turkestani and related species on crop plants. The hypothesis that brine shrimp Artemia franciscana cysts can improve diets for rearing of S. gilvifrons was tested in laboratory experiments. The diet treatments included A. franciscana cysts (D1), A. franciscana cysts plus a vitamin B complex (D2), A. franciscana cysts plus date palm pollen (D3), and A. franciscana cysts plus date palm pollen and Ephestia kuehniella eggs (D4). The results indicated that D1 did not support immature development. D2 supported egg–larval development but not pupal–adult development. Both D3 and D4 supported development to the adult stage and reproduction. However, D4 was the most effective diet, determined by observations of S. gilvifrons oviposition behavior and fecundity. A life table analysis corroborated these results; an intrinsic rate of increase, net and gross reproductive rates, and mean generation time were best for S. gilvifrons fed D4 rather than D3. A mixed diet composed of A. franciscana cysts, date palm pollen, and E. kuehniella eggs can be used to mass rear S. gilvifrons.