Influence of agricultural wastes on larval growth phases of the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae): An integrated approach

Abstract

Insects are an effective tool for converting nutrients in agricultural by-products into protein-rich biomass and compost. Black soldier fly (BSF) (Hermetia illucens) larvae are currently one of the insect species widely used as a protein source in aquafeed globally. Although much effort has been spent on the use of BSF in aquafeed, there is not much information on the biology of the insect, especially with the morphology of the BSF. This study aimed to evaluate the influence of various organic wastes, such as fruit wastes (FW) and vegetable wastes (VW), on different growth phases of BSF larva (BSFL), using morphometric and scanning electron microscopic examinations, and the composition of the compost produced, as well as a method for upscaling of larval production of BSFL. Faster growth was observed in BSFL fed with VW substrate (40 days) compared to the FW (46 days). Based on the morphometric measurements such as length, larval head length, total length etc., five larval stages, prepupal and pupal stage of BSFL were differentiated and described. In addition, SEM imaging of BSF mouth parts found that the mouth morphology of the BSF larvae and prepupal stage differed, and the BSF prepupa had reduced mouthparts. Also, the mandibular-maxillary complex was well developed than the BSF prepupa. BSFL larvae have proven to convert fruit and vegetable waste into high-quality residue fertilizer for the soil. The BSF compost showed optimum nitrogen, phosphorous, potassium, calcium and sulphur content. This research establishes a baseline knowledge and guidance on the BSF-rearing facilities.