Mother knows worst? Fungal infection enhances corn flavonoid of wogonin to inhibit Conogethes punctiferalis larval growth.

Pathogen infection in host plants can alter the attraction and adaptability of herbivorous insects. Female adult insects often exhibit selective behaviours based on their environmental experiences, enabling their offspring to avoid adverse conditions and ensuring healthy growth and development. However, comprehensive studies integrating both the perspectives of offspring fitness and host plant to validate the selective significance of such parental 'Mother knows worst' experiences remain limited. Building on our previous findings that female Conogethes punctiferalis (Yellow peach moth, YPM) adults exhibit oviposition avoidance behaviour towards corn infected with Trichoderma asperellum, we further confirmed that corn infected by T. asperellum significantly inhibits the growth and development of YPM larvae. Feeding on infected corn decreases larval gut microbiota diversity, core microbiota abundance and led to differential expression of key genes in juvenile hormone metabolic pathway. Moreover, the content of flavonoid wogonin, a secondary metabolite, was significantly increased in infected corn. In vitro feeding experiments revealed that wogonin negatively impacts YPM larval growth by causing the juvenile hormone accumulation and suppressing the abundance of core gut microbial strains. This study validates the adaptive significance of parental empiricism from the perspective of offspring, while further elucidating the mechanisms by which microbial-mediated plant resistance against insects, as well as for exploring and utilizing effective biocontrol resources against YPMs.