Regional Occurrence and Integrative Characterization of Larval Parasitoids Associated With Spodoptera exigua in Korea

The beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), has expanded its geographic occurrence in Korea and causes substantial damage to a wide range of crops. Accurate documentation and identification of its associated parasitoids are important for understanding parasitoid diversity and supporting future ecological studies. In this study, larvae of S. exigua were collected from nine agricultural regions in Korea and reared to recover emerging parasitoids. To address taxonomic difficulties arising from morphological similarity among parasitoids, we combined morphological examination with molecular characterization based on the mitochondrial cytochrome c oxidase subunit I (COI) gene. Three parasitoid genera, Microplitis , Meteorus , and Campoletis , were recovered from field‐collected hosts. Genus‐level assignments were based on diagnostic morphological characters and were further supported by BLASTn similarity searches against reference sequences available in the NCBI database. The COI dataset was further examined using four complementary molecular species delimitation approaches (ABGD, ASAP, bPTP, and GMYC) to evaluate barcode‐based group structure. The recovered parasitoid assemblage showed regional variation, with Microplitis occurring most widely, whereas Meteorus and Campoletis showed more restricted occurrence. Our results provide baseline information on parasitoids associated with S. exigua in Korea and demonstrate the usefulness of combining morphology, DNA barcodes, and multiple species delimitation approaches for regional surveys of parasitoid assemblages. These findings establish a baseline faunistic, taxonomic, and molecular framework for future studies on the diversity, taxonomy, and ecology of parasitoids associated with S. exigua in Korean agroecosystems.