Interaction between insect strain and artificial diet in diamondback moth development and reproduction

The economical production of physiologically and behaviorally competent diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is critical to most research and control programs against this insect. Although a few laboratory-adapted colonies are currently maintained on artificial diets, the establishment and adaptation of feral DBM onto semi-synthetic diets is often difficult. Understanding the interactions between insect strain and diet may be critical to the process of laboratory adaptation as well as to the successful use of laboratory-reared insects in the field. As such, the objective of this study was to investigate the interaction between several DBM colonies/strains and different natural and semi-synthetic diets. Specifically, we examined the effect of different diets on the length of development, percent survival, adult weight, female fecundity, and adult longevity for two feral and one laboratory-adapted strain of DBM. Significant interactions were observed between diet and laboratory-adapted and feral strains, and also between diet and different feral strains with respect to many of the growth and development parameters tested. Therefore, the performance of one strain of DBM on a particular diet was not necessarily predicted by the performance of another DBM strain on the same diet. However, the soy-based diet developed and reported herein performed well for all three DBM strains tested. In future efforts to colonize feral DBM, we suggest that researchers assay different diet formulations in order to identify a semi-synthetic diet that is most suitable for the particular DBM strain under consideration.