Wild black soldier flies, Hermetia illucens (Diptera: Stratiomyidae): Seasonal availability and life history traits in two common organic streams in Bangladesh

Abstract

The black soldier fly (BSF) Hermetia illucens (L.) (Diptera: Stratiomyidae) is a “crown jewel” in waste management because it rapidly bioconverts organic streams into nutrient-rich biomass. Bangladesh's inefficient waste management has caused serious environmental issues due to the massive amounts of organic waste, mainly livestock manures and municipal organic waste, generated daily. We need reliable BSF to maximize our organic resources. To establish a long-term, stable BSF colony, we closely examined the seasonal abundance and life cycle features of BSF raised on municipal garbage and poultry manure in a regional natural environment in the lab. This investigation lasted two years (2019–2020). Season and raising substrates affected wild BSF egg clutches and life cycles. Organic waste dumps captured the most egg clutches in rainy seasons and the fewest in cooler months. Municipal rubbish dumps consistently produced wilder BSF egg clutches than poultry manure dumpsites. The BSF larvae grew slower in winter and faster in the rainy season, independent of substrate. Winter was optimal for adult BSF longevity in all organic streams. Winter cultivated wild BSF on two organic streams exhibited fewer egg clutches per female, shorter and lighter prepupae, and lower adult ecolosion rates than wetter months. While BSF given municipal organic wastes had the highest adult ecolosion rates, BSF fed poultry manure had more variation in prepupae length and weight, adult lifespan, and egg clutches. Larval development was faster with poultry manure BSF than with municipal organic waste. The protein and ash content of prepupae rearing on poultry manure exceeded those of prepupae on urban organic waste, although fat content was equivalent. These findings indicate that both types of organic streams may be suitable substrates for BSF larvae for trash treatment.