Feeding Rate Impacts on Hermetia Illucens Growth and Bioconversion Efficiency When Using Low-Value Organic Wastes

The growing generation of organic solid waste from small-scale agriculture poses major environmental challenges in developing countries like Ecuador, where rural areas often lack waste management infrastructure. Residues from livestock rearing and traditional brewing such as poultry manure (PM), bovine manure (BM), and barley by-product (BB) are often discarded untreated. This study evaluated the bioconversion potential of Hermetia illucens (black soldier fly larvae (BSFL), using a local Ecuadorian strain reared on these substrates under natural conditions and three feeding rates (50, 100, and 150 mg·larva−1·day−1). Larval growth and process efficiency were analyzed on a dry-matter basis. Both substrate and feeding rate significantly influenced performance (p < 0.05). PM and BB produced the highest larval dry weights (37.4 and 35.9 mg, respectively) at 100 mg·larva−1·day−1, with development completed in 35 days. BM-fed larvae reached only 17.6 mg and required up to 91 days. Bioconversion peaked at 4.6% (PM100) and 4.2% (BB50), while all BM treatments showed very low efficiency (<0.8%). Waste reduction was highest in BB100 (52.9%) and PM100 (43.5%). These results demonstrate the potential of BSFL as a biological treatment option for rural organic waste streams; however, performance strongly depended on substrate quality and feeding rate, indicating that not all locally available residues are equally suitable for larval bioconversion.