A Comparative Study on the Prevalence of Forensic Flies using Chicken Corpse

Abstract

Forensic entomology is used as evidence of crime incidents especially to a murder case using biological and ecological habits of insects. We wondered how insects can be the key to solving cases by studying insects collected at the scene, so started this study. The decay of the corpse is influenced by the environmental factors, physical conditions or conditions of corpse at the sites, therefore, in order to confirm the hypothesis that types or groups of flies will be different from the sites separately, We compared with the occurrence of flies to different sites according to decay stages of chicken. The chicken corpse was placed in cages made of wire mesh from June 16 to July 20, 2019 at four different sites in Kunsan National University, and a sticky wrap was attached to the cage lid. Sticky traps were collected and replaced daily from 14:00 to 16:00 from June 18 to June 30, and every three days from July 1 to July 20, and the temperature and humidity also were recorded. In addition, a random selection of flies on the sticky trap was carried out for molecular identification of a total of 18 flies. A total of 20 collections were performed, and a total of 1,139 flies were observed in the entire trap. Most of the areas where flies were more collected were a pine forest and a meadow. It was confirmed that the temperature were lower in the pine forest than in other regions, and the humidity in the pine forest was maintained at 70-80%. At the beginning of the trap installation, many flies were collected, and the number of flies collected thereafter decreased. After the rain, the number of flies collected briefly increased. The number of flies was estimated to be related to temperature and humidity, and the Mantel test was used to determine their correlation. As a result, it was confirmed that the number of flies varies with temperature. As a result of molecular identification using COI markers to determine which flies mainly came from, they were identified: Chrysomya pinguis, Anthomyia illocata, Hydrotaea ignava and Hydrotaea leucostoma. We confirmed that the density of flies has been found to be affected by the surrounding environment, the flies, which are known to be the first to fourth group flies that visit the corpse depending on the decay time of the corpse, were coming at the same time, supposing to affected by the decay rate and incision of the corpse. As a result of DNA identification, most of the collected flies were Chrysomya pinguis and Hydrotaea leucostoma was found unrecorded species in South Korea. The results of this study may be useful as basic data for the study of forensic insect flies in the Gunsan.