Evaluation of black soldier fly, Hermetia illucens, as food for the pink-spotted lady beetle, Coleomegilla maculata

Discovery of new and improved factitious and artificial diets are necessary to mass rear natural enemies of high quality to support augmentative biological control of plant pests in greenhouses, nurseries, and other agroecosystems. This study evaluated the utilization of Hermetia illucens black soldier fly (BSFly) as a suitable alternative food source for mass rearing the predatory coccinellid Coleomegilla maculata (Cmac), which is a predator of aphids and other small, soft-bodied insects found on crop plants. The hypothesis that BSFly larval powder was suitable food to support growth, development, and reproduction of Cmac was tested in the laboratory. When compared to a standard in-house diet containing brine shrimp egg powder plus Chlorella vulgaris algae and myristic acid (BSE+CM), the BSFly diet reduced immature growth and development. Immatures successfully reared to teneral adults were smaller when fed BSFly rather than BSE+CM. In a separate experiment, combining BSFly with an artificial diet, AD, in a 50: 50% ratio (i.e., BSFly+AD) did not improve predator growth or development, in comparison to Cmac reared on BSE+CM. Cmac oviposition (early reproduction) responses, i.e., egg clutch production, to BSFly vs BSE+CM or BSFly+AD vs BSE+CM did not differ significantly. However, females tended to require a longer pre-oviposition period when reared on BSFly rather than BSE+CM. In conclusion, BSFly has potential as food for rearing Cmac adults but not larvae. Future research could evaluate the addition of plant-derived natural compounds to BSFly to boost oviposition and reduce pre-oviposition time of Cmac over multiple generations in climate-controlled rooms.