Necrophagous fly occurrence and primary colonizing species in forensic entomology cases from the Yeongnam Region, South Korea.

Forensic entomology is widely used in death investigations to estimate the minimum postmortem interval (mPMI). In South Korea, however, casework-based ecological data remain limited, particularly for indoor scenes. We established a collaborative framework with investigating officers in the Yeongnam region (Gyeongsangbuk-do, Daegu, and Busan) and compiled forensic entomology cases from 2019 to 2022 to summarize the occurrence patterns of necrophagous flies. Scene information and specimens were collected using a standardized field record form, and species were identified by morphological examination and confirmed by COI DNA barcoding. Occurrence patterns were summarized by month, region, and scene type. The primary colonizing species was operationally defined as the species with the longest estimated developmental time in each case. Among the 73 cases analyzed, 66 (90.4%) were indoor and 7 (9.6%) were outdoor, yielding 17 identified species. Lucilia sericata was the most frequently detected species (n = 55, 75.3%) across most months, followed by Sarcophaga peregrina (n = 16, 21.9%), Chrysomya pinguis (n = 13, 17.8%), and Chrysomya megacephala (n = 13, 17.8%). Regarding primary colonizing species, L. sericata predominated in indoor cases (n = 41, 62.1%), whereas Calliphora calliphoroides (n = 3, 42.9%) and Calliphora nigribarbis (n = 2, 28.6%) were the most frequent in outdoor cases. Overall, the observed patterns were broadly consistent with previous Korean surveys. These findings provide a casework-based regional reference for mPMI interpretation in Korea.