The impact of blowflies on pig cadaver decomposition on Yeongdo Island, Busan, South Korea

The decomposition process is an important factor in forensics, and flies play a crucial role in the decomposition of animals and humans. However, there remains limited information on the effect of flies that attend death scenes. This study assesses the effect of the presence or absence of blowflies on the rate and process of cadaver decomposition in the spring, summer, and autumn from 2016 to 2020 on Yeongdo Island, Busan, South Korea. Nine blowfly species belonging to four genera in two subfamilies were sampled. The blowflies that approached the cadavers differed between seasons, but Chrysomya pinguis (Walker) was the dominant species regardless of the season. Blowfly presence on cadavers significantly affected the duration of the decomposition stage and the pattern of weight loss in nearly all scenarios. With the presence of blowflies, the decomposition rate was four times faster in spring, three times faster in summer, and nine times faster in autumn. These results show that the presence or absence of blowflies is an essential factor in the decomposition process of cadavers. Therefore, it should be taken into account when estimating postmortem intervals in medicolegal forensic entomology.