Regional and seasonal patterns of blowfly distribution in southern Korea: implications for forensic entomology

Blowfly species, which play a crucial role in forensic investigations as primary colonizers of cadavers, are influenced by environmental factors. However, most research conducted on blowfly species in South Korea remains limited to a single province. We investigated the spatiotemporal distribution of forensically relevant blowflies (Diptera: Calliphoridae) in the southern provinces of South Korea to enhance forensic entomology databases and improve postmortem interval (PMI) estimation. Overall, 3,934 adult blowflies representing 14 species across 5 genera were collected from 4 regions (Changnyeong, Pohang, Yeosu, and Jeju) over a 1-yr period using baited traps. The dominant species included Chrysomya megacephala (Fabricius), Lucilia illustris (Meigen), Lucilia caesar (Linnaeus), and Lucilia sericata (Meigen); Ch. megacephala exhibited a significantly higher abundance in Jeju than in the other regions, particularly during the warmer seasons. A self-organizing map (SOM) and principal component analysis (PCA) were employed to visualize and validate the spatiotemporal clustering of blowfly populations, confirming that seasonal factors strongly influence distribution patterns. The combination of SOM and PCA effectively distinguished seasonal and regional clustering patterns, demonstrating the influence of environmental factors on species-specific distributions. These findings emphasize the importance of considering regional and seasonal variations in forensic casework and the need to expand entomological databases to reflect geographic differences. Furthermore, the observed regional differences in species dominance underscore the need to incorporate environmental variability into forensic models to improve the accuracy of PMI estimates. This study provides fundamental data for improving forensic applications based on insect evidence, particularly PMI estimation and crime scene reconstruction.