Metabolic heat generation in larval masses of the black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae), at different stocking rates

Abstract

The increasing global population, expected to surpass nine billion by the mid-21st century, necessitates innovative solutions for sustainable food and feed production. Insect larvae, specifically of the black soldier fly (Hermetia illucens), offer a promising alternative through bioconversion technology, wherein insects convert organic waste into valuable products like protein-rich animal feed, human food, and by-products such as frass and chitin. This study investigates the impact of stocking rate and temperature on the heat accumulation, development and growth and performance of black soldier fly larvae fed on pre-consumer fruit and vegetable waste. Larvae were reared at four stocking rates (0.5, 1, 1.5, and 2 g diet per larva) and incubated at three temperatures (27.5°C, 30°C, and 32.5°C). Results showed that increasing stocking rate led to heat accumulation in larval aggregations, which affected larval development. While survival rates were highest at 32.5°C with 0.5 g/larva (44.95%), weight gain was greatest at 30°C. Larval length was highest at 27.5°C. Bioconversion efficiency peaked at 45% with a stocking rate of 0.5 g/larva. Waste reduction efficiency remained consistently high across treatments, demonstrating the adaptability of H. illucens larvae for bioconversion in varied conditions. This research highlights the potential of black soldier fly larvae as a sustainable method for waste management and resource conversion, supporting both food and feed production.