Molting is an important developmental process in insects, usually along with synthesis and degradation of chitin.20-hydroxyecdysone (20E), an insect hormone, has been reported to contribute to many processes including molting.However, little is known about the link between the chitin biosynthesis pathway and 20E signaling.Here,we report that conserved miR-8-5p (miR-8-5p) and miR-2a-3p and their new target genes are critical for ecdysone-induced chitin biosynthesis in a hemipteran insect Nilaparvata lugens.