Abstract Bactrocera dorsalis is a major horticultural pest. Biocontrol using parasitoids, such as Fopius arisanus, is a sustainable tool for managing this pest. However, the mechanisms enabling the successful parasitism of B. dorsalis are poorly understood. Using transcriptomic profiling, cellular bioassays, and targeted metabolite analyses, we investigated how F. arisanus modulates the immunity and metabolic activity of B. dorsalis to achieve a high parasitism rate. Our results revealed a weak