Black soldier fly larvae as a model to investigate ‘hot’ vs. ‘cold’ food properties in traditional Chinese medicine with applications for pest management

Black soldier fly (BSF, Hermetia illucens) larvae are detritivores used in waste management; however, the influence of food chemical cues or traditional Chinese medicine’s “hot” and “cold” classifications on their feeding behaviour remains poorly understood. In this study, we investigated whether specific volatile compounds and Chinese medicine categories, including hot and cold foods, affect the feeding behaviour and growth performance of BSF larvae. Instar larvae were offered representative foods that were either pungent (volatile-rich) or bland (low-odour), as well as foods classified as hot or cold (without pungent additives). Key feeding metrics, including 24-hour consumption, larval weight gain, and feed conversion efficiency, were measured. Larvae consumed significantly less pungent, high-odour foods (e.g., garlic, onion), resulting in minimal weight gain, whereas bland foods were readily eaten and supported rapid growth. However, no significant differences in feeding metrics were observed between hot and cold foods in the absence of pungent cues. These results indicate that specific volatile compounds (e.g., sulphur compounds from garlic/onion) are decisive deterrents to BSF feeding, while the broad “hot/cold” classification alone has no intrinsic effect on short-term feeding performance except for meat (mutton vs. pork). This study identifies natural insect-repellent compounds in foods and has practical implications for improving BSF-based organic waste conversion and developing natural pest control strategies.