Insect diets as mixtures: Optimization for a polyphagous weevil

Development or improvement of artificial insect diets can be tedious, convoluted and often under-appreciated. Using n-dimensional mixture designs, we identified a set of response-optimized meridic diets that contain fewer ingredients than the current commercial diet for Diaprepes abbreviatus, a polyphagous weevil pest of the Caribbean and southern U.S. A diet blend optimized to produce maximum adult weight was predicted to produce adult D. abbreviatus that weigh 28% more compared with adults reared on the standard commercial diet. Diet blends that produced greater individual adult weights resulted in lower survival compared with those blends that yielded adults of more modest proportions. In contrast, a simplified high cottonseed meal blend produced smaller adults more similar to field-collected individuals, and produced the greatest number of adults and the greatest biomass at relatively low cost compared with diets that yielded adult weevils of greater weight. We think that many insect-rearing programs would benefit from application of mixture design methods to situations where diet optimization is desired for researcher-selected criteria. This approach is broadly applicable to any problem that can be conceptualized as a mixture problem.