COI barcode reference dataset for forensic identification of Silphidae (Coleoptera) in Korea

In forensic entomology, coleopteran evidence can provide important supplementary information when mPMI estimation based primarily on Diptera is limited; however, molecular reference data for Korean Silphidae remain scarce. This study aimed to establish a COI sequence-based reference dataset for forensically important Korean Silphidae and to support DNA barcoding-based species identification. Adult silphids were collected during pig decomposition experiments and identified morphologically. COI sequencing was performed for 38 adult specimens representing seven Silphidae species. Intra- and interspecific genetic distances were calculated using the p-distance model, and sequence similarity to NCBI reference sequences was evaluated. Phylogenetic concordance was further assessed using a neighbor-joining tree. COI sequences were successfully obtained from all 38 specimens. Intraspecific distances were low (0.00-0.57%), whereas interspecific distances were ≥ 10%, indicating sufficient divergence for species-level discrimination. Most species showed high similarity (99-100%) to NCBI reference sequences; however, Thanatophilus rugosus exhibited comparatively lower similarity (97.75-97.95%). Nicrophorus concolor also showed reduced similarity to a U.S. reference sequence (93.41%). In the neighbor-joining tree, specimens formed species-specific clusters consistent with morphological identifications. Overall, this study provides COI reference sequences for seven Korean Silphidae species, expanding the limited national DNA barcode resources and facilitating molecular identification of morphologically challenging samples such as immature stages.