Targeting the <scp>20E</scp> ‐responsive <scp>miR</scp> ‐2788–Treh1 axis disrupts chitin biosynthesis and ovarian development in the grassland pest <i>Galeruca daurica</i>

BACKGROUND: 20-hydroxyecdysone (20E) coordinates insect reproductive development through extensive metabolic reprogramming. However, the post-transcriptional mechanisms linking hormonal signaling to carbohydrate metabolism during reproductive maturation remain poorly understood in insect pests. RESULTS: We identified a novel 20E-miR-2788-Treh1 regulatory axis in Galeruca daurica. Developmental profiling revealed an inverse relationship between miR-2788 and Treh1 expression. Overexpression of miR-2788 or RNA interference (RNAi)-mediated silencing of Treh1 caused trehalose accumulation, reduced expression of chitin biosynthesis genes, and impaired ovarian development. In females, 20E treatment suppressed miR-2788 expression and increased Treh1 expression, thereby promoting ovarian maturation. Similar reproductive defects were induced by the trehalase inhibitor validamycin. CONCLUSION: These findings suggest that 20E- reproductive miR-2788-Treh1 module contributes, at least in part, to the regulation of reproductive maturation through the -mediate control of trehalose metabolism. The 20E-miR-2788-Treh1 axis represents an important metabolic checkpoint linking endocrine signaling with reproductive development and provides potential molecular targets for environmentally friendly pest management strategies. © 2026 Society of Chemical Industry.