Forensic entomology applies insect evidence to legal problems such as the estimation of minimum postmortem interval (mPMI). For this purpose, knowledge of the insect fauna that are attracted to human cadavers in each geographic region is a prerequisite. Despite many studies investigating the insect fauna attracted to meat, there has been no survey of the entomofauna on human cadavers in the East Asian temperate climate zone, particularly in Korea. Therefore, this study reports the entomofauna collected from medicolegal autopsies in northeastern Seoul and its suburbs. Insect samples were collected from 35 medicolegal autopsies in 2010, 2011, and 2013. Molecular and morphological methods were utilized for taxonomic identification. Among 1398 individual samples belonging to 3 orders, 13 families, 18 genera, and 32 species, the dominant family and species were Calliphoridae and Lucilia sericata, respectively. Despite its limited scale, this study provides a snapshot of the general entomofauna that are attracted to human cadavers in this region.

Identifying species of insects used to estimate postmortem interval (PMI) is a major subject in forensic entomology. Because forensic insect specimens are morphologically uniform and are obtained at various developmental stages, DNA markers are greatly needed. To develop new autosomal DNA markers to identify species, partial genomic sequences of the bicoid (bcd) genes, containing the homeobox and its flanking sequences, from 12 blowfly species (Aldrichina grahami, Calliphora vicina, Calliphora lata, Triceratopyga calliphoroides, Chrysomya megacephala, Chrysomya pinguis, Phormia regina, Lucilia ampullacea, Lucilia caesar, Lucilia illustris, Hemipyrellia ligurriens and Lucilia sericata; Calliphoridae: Diptera) were determined and analyzed. This study first sequenced the ten blowfly species other than C. vicina and L. sericata. Based on the bcd sequences of these 12 blowfly species, a phylogenetic tree was constructed that discriminates the subfamilies of Calliphoridae (Luciliinae, Chrysomyinae, and Calliphorinae) and most blowfly species. Even partial genomic sequences of about 500 bp can distinguish most blowfly species. The short intron 2 and coding sequences downstream of the bcd homeobox in exon 3 could be utilized to develop DNA markers for forensic applications. These gene sequences are important in the evolution of insect developmental biology and are potentially useful for identifying insect species in forensic science.

DNA extraction frequently requires destruction of whole samples. However, when the sample is very rare or has taxonomic importance, nondestructive DNA extraction is required for preservation of voucher specimens. In the case of arthropod specimens, minor anatomical structures such as a single leg or a single wing are often sacrificed instead of the whole body for DNA extraction. In an attempt to save the entire anatomical structure of specimens, several authors tried to brew the whole specimen in a lysis buffer and to extract DNA from the “soup.” We applied this nondestructive DNA extraction technique to a forensically important blowfly species,Phaenicia sericata. With nondestructive DNA extraction, a satisfactory quantity and quality of DNA for PCR amplification was obtained with only minimal anatomical disruptions that do not alter the morphologic identification. This nondestructive method may be applicable to DNA extraction of rare samples as well as vouchering of regular fly samples.

Phoridae are a family of necrophagous flies commonly found in indoor death scene. They account for approximately 19.7% of the entomofauna in human cadavers in Korea. Additionally, this taxon is an indicator of indoor hygiene, and these flies appear in environments where access by other necrophagous insects is difficult, such as enclosed rooms. Thus, they are likely to be used as forensic evidence. Despite their importance in forensic investigations and environmental hygiene, detailed studies on the taxonomy and molecular barcoding for this family are scarce, including in Korea. Because accurate taxonomic information regarding necrophagous insects collected from a death-related scene is essential during medicolegal investigations, molecular barcoding data could be useful as well as reliable. In this paper, full-length nucleotide sequences of genes coding for the cytochrome c oxidase subunit I (COI) in 79 Phoridae larvae collected from 20 medicolegal autopsy cases in Korea were phylogenetically analyzed by comparing their sequences to the foreign barcoding data of Phoridae. Six mitochondrial haplogroups were identified, which two of them matched to foreign Phoridae fly species haplotypes, Megaselia scalaris (Loew, 1866) and M. spiracularis Schmitz 1938. Taxonomies of five other haplogroups, with nucleotide distances ranging from 1.68% to 2.26% from the M. scalaris group, could not be confirmed solely based on the molecular barcoding data. Further research should be performed to determine whether these five haplogroups are diverged conspecifics of M. scalaris or a closely related sister cryptic species of M. scalaris.

Identification of insect species is an important task in forensic entomology. For more convenient species identification, the nucleotide sequences of cytochrome c oxidase subunit I (COI) gene have been widely utilized. We analyzed full-length COI nucleotide sequences of 10 Muscidae and 6 Sarcophagidae fly species collected in Korea. After DNA extraction from collected flies, PCR amplification and automatic sequencing of the whole COI sequence were performed. Obtained sequences were analyzed for a phylogenetic tree and a distance matrix. Our data showed very low intraspecific sequence distances and species-level monophylies. However, sequence comparison with previously reported sequences revealed a few inconsistencies or paraphylies requiring further investigation. To the best of our knowledge, this study is the first report of COI nucleotide sequences from Hydrotaea occulta, Muscina angustifrons, Muscina pascuorum, Ophyra leucostoma, Sarcophaga haemorrhoidalis, Sarcophaga harpax, and Phaonia aureola.