LAUSR

BACKGROUND The Asian lady beetle Harmonia axyridis is an important predator of several agricultural pests, including aphids and whiteflies, and thus can contribute to pest management. Commercial viability as a pest control method requires that the beetle can be mass-reared, and that workable conditions for extended shelf-life can be guaranteed. One of the features of Harmonia's life cycle is that it enters diapause in the adult stage when the length of the photophase starts shortening in late summer. Reduction of Juvenile hormone (JH) titer has been demonstrated to be the common endocrine mechanism inducing reproductive diapause in insects. However, whether H. axyridis enters diapause dependent on JH shutdown and how the JH level is regulated before diapause remains unknown. RESULTS Like in other insects, the absence of JH triggers the induction and maintenance of reproductive diapause in H. axyridis, indicated by JH measurements and the knockdown of an intracellular JH receptor Methoprene-tolerant (Met). Methoprene, a JH analog, significantly reversed diapause into reproduction via Met. Combined with RNA-seq and RNAi, we also demonstrated that JH biosynthesis rather than the JH degradation pathway determines the reduction of JH titer in diapausing females. CONCLUSION Our results reveal the vital role of JH in regulating reproductive diapause in female H. axyridis. H. axyridis diapause could thus be manipulated by targeting JH production and JH signaling This article is protected by copyright. All rights reserved.