Expanding black soldier fly (BSF; Hermetia illucens; Diptera: Stratiomyidae) in the developing world: Use of BSF larvae as a biological tool to recycle various organic biowastes for alternative protein production in Nepal

Abstract

The growing global demand for food, particularly animal protein, is intensifying challenges related to food security and environmental sustainability. The increase in organic waste generation, coupled with inefficient waste management, is further deteriorating living conditions by negatively impacting the environment and public health, especially in developing nations. This study investigated the potential of black soldier fly larvae (BSFL) to recycle major daily organic waste fractions in Nepal. BSFL were exposed to seven different biowaste-based substrates locally sourced from fruit and vegetable markets, farms, and food industries. Additionally, the study evaluated rapeseed cake as a supplement to enhance BSFL growth and nutritional content. BSFL survival rates exceeded 80 % on food industry waste but dropped to 63 % on high-moisture substrates like vegetable waste. Mixed vegetable waste (14.7 mg/day) and bakery waste (11.5 mg/day) supported higher average daily weight gain, likely due to their better nutrient values (soluble carbohydrates and proteins). Although rapeseed cake alone hindered larval growth, its supplementation to biowastes improved growth, survival, and bioconversion rates, increased larval protein content up to 32 %, and reduced fat by 36 %. These findings indicate BSFL can effectively recycle diverse, locally available organic wastes in developing countries like Nepal, providing a sustainable source of domestic protein and contributing to feed security. As this is the first BSFL study in Nepal, further research is needed to elucidate the chemical and microbial safety of BSFL reared on biowastes and to develop technical solutions for commercial BSFL production in countries with a low-income economy.