Effects of dietary protein and carbohydrate on life-history traits and body protein and fat contents of the black soldier fly Hermetia illucens

We investigate how the black soldier fly Hermetia illucens L. (Diptera: Stratiomyidae) responds to dietary protein (P) and carbohydrate (C) contents and the P:C ratio in terms of both immature and adult life-history traits, as well as effects on larval body composition. Nine chicken-feed based diets varying in their P:C ratio are formulated. We test three protein concentrations (10%, 17% and 24%) and three carbohydrate concentrations (35%, 45% and 55%) and their combinations. All nine diets support the complete development and reproduction of this species. Survival is high on all diets. Development time, larval yield, larval crude fat and egg yield are more influenced by P and C contents than by the P:C ratio. Low contents result in a shorter development time. Larval yield is higher on diets with higher C-contents. Pupal development is faster on a low dietary P-content for all three C-contents. Egg yield only increases when P-content increases, although it also varies with the P:C ratio. Larval crude protein content is similar on all nine diets but increases when C-content is low (10%) in P10 and P17. Larval crude fat content is high at P24-diets irrespective of C-content. We conclude that a high macronutrient content combined with a low P:C ratio positively affects H. illucens performance. The diet P17:C55 supports the highest larval and adult performance and results in a high larval body protein content and an intermediate crude fat content.