Exploring the Potential of Isoproteinic Diets Based on Greek Agricultural Byproducts as a Nutritional Resource for Larvae of the Lesser Mealworm, Alphitobius Diaperinus (Panzer) (Coleoptera: Tenebrionidae)

Abstract The utilization of agricultural byproducts as feed substrates for insect farming offers a promising strategy to enhance sustainability and reduce production costs. This study evaluated the suitability of three isoproteinic sets of diets with 17.3, 22.5 and 27.5% protein content, composed of mixtures of lupin with three other agricultural substrates, i.e. triticale, barley and oats, for the rearing of Alphitobius diaperinus larvae. Wheat bran with baker’s yeast was used as a positive control diet. All cereals and legumes used in the study were byproducts of the seed cleaning process. Results indicated that diet composition significantly influenced larval growth, development time and feed utilization parameters. Among the tested diets, those combining the byproducts of lupin with barley or triticale yielded the best outcomes, achieving the highest individual larval weights and shortest development times, while outperforming yeast-enriched control diets in larval biomass production and economic feasibility. Conversely, diets with high oat byproduct inclusion exhibited poorer performance. Notably, the protein levels of the tested diets appeared to have no direct influence on larval development. Differentiation among diet treatments became apparent only after the first 28 days of development, irrespective of their nutritional composition. These findings underscore the potential of low-cost agricultural byproducts to serve as effective feeding substrates for A. diaperinus . Future research should identify the key nutritional components of high-performing byproducts to guide their combination and adjustment in the larval diet based on nutritional profiles that align with the specific dietary requirements of A. diaperinus larvae.