Abstract

Five ILP genes were identified in Hermetia illucens. • ILP2 was crucial for the growth and lipid metabolism of Hermetia illucens larvae. • Overexpression of ilp2 significantly increased the proportion of unsaturated fatty acids and enhanced the bioconversion ability of organic waste. Insulin-like peptides (ILPs) are key regulators of insect growth and metabolism. We investigated the role of ILPs in the black soldier fly (BSF), Hermetia illucens , a species used for sustainable bioconversion and a promising alternative feed source. We identified five ilp genes in BSF and demonstrated a critical function for ilp2 in larval growth and lipid metabolism. Overexpression of ilp2 significantly increased larval biomass and bioconversion efficiency. The ilp2 overexpression ( ilp2 -OE) strain showed enhanced triglyceride and crude fat content and significantly upregulated genes related to lipid biosynthetic pathways. Low levels of unsaturated fatty acids limit the potential of BSF as a high-quality feed ingredient, but ilp2 -OE larvae also exhibited an 11.43% rise in total unsaturated fatty acids and a 28.53% increase in linoleic acid (18:2, n -6). Collectively, these findings indicate that ilp2 is a major regulator of larval lipid metabolism in BSF, providing a target for the generation of BSF strains with improved nutritional quality for animal feed. Download: Download high-res image (304KB) Download: Download full-size image