Size-structured flavonoid distribution in Salix babylonica branches modulates Anoplophora glabripennis feeding...

Asian longhorned beetle (Anoplophora glabripennis) has caused significant economic and ecological damage. However, environmentally friendly control strategies remain limited. Elucidating the adult's feeding preference is critical for developing effective and sustainable pest management approaches. Therefore, we firstly compared the feeding preference of adults on the Salix babylonica branch with diameters of 0.5-cm, 2-cm, 4-cm, 8-cm, 16-cm. The results showed that both female and male significantly preferred 2-cm branches over the others. Subsequently, we analyzed metabolites allocation patterns across these branch types, identifying a total of 2216 metabolites. Further analyses showed that 1500 differentially accumulated metabolites (DAMs) in branches with diameters of 0.5-cm, 4-cm, 8-cm, 16-cm compared to 2-cm samples. These DAMs were significantly enriched in flavonoid, flavone and flavonol biosynthesis pathways when comparing the 2-cm branches to others. The contents of 10 DAMs in flavonoid, flavone and flavonol biosynthesis pathways showed a significant negative correlation with feeding consumptions. To evaluate the antifeeding effects of flavonoid-related metabolites, four economically viable and practically flavonoid-related metabolites (+)-taxifolin, naringenin, kaempferol, and phlorizin were selected for feeding bioassays. They significantly inhibited feeding consumption, with (+)-taxifolin, naringenin, and phlorizin reducing by up to 70 %. Dose-response experiments confirmed varying concentrations of these compounds significantly suppressed feeding consumption. Our findings demonstrate that the allocation patterns of flavonoid compounds in branches of different diameters regulate the feeding preferences of A. glabripennis. This study explores a metabolomics-driven approach that centers on size-structured flavonoid reprogramming in S. babylonica branches, aiming to establish a sustainable strategy for disrupting A. glabripennis's feeding preference.