Nutritional quality ofDrosophila melanogasteras factitious prey for rearing the predatory bugOrius majusculus

The predatory bug,Orius majusculus(Reuter), is an important predator of thrips commercially produced for augmentative releases using the eggs of the Mediterranean flour mothEphestia kuehniella(Zeller). In this study, we assessed the potential for using frozen adults of fruit flies,Drosophila melanogaster(Meigen), either as nymphal rearing diet or as diet throughout the entire life-cycle. We compared life-history traits and reproduction of predators when fedD. melanogasterwith high lipid body content (lipid-rich) and with high protein body content (protein-rich), using a diet of 100%E. kuehniellaeggs as control. We also analyzed the biochemical composition of both prey and predator in order to assess the nutritional quality of each diet, which partially explained the adequacy of the different diets forO. majusculus. There were significant differences between predators fed the two types ofD. melanogaster, with the protein-rich flies as diet providing the best results in terms of mortality and fecundity. Furthermore, we show that while feedingO. majusculusthroughout their development withD. melanogasterincreases mortality and reduces reproduction, protein-richD. melanogastercan be used as nymphal diet with minimal reduction in reproductivity and minimal increase in mortality.

Automated summary

We compare the effect of fruit flies as diet on predators, and find that fruit flies with high protein content provide the best results in terms of mortality and fecundity for predators.