A Literature Review on the Growth Rate Experiment for Necrophagous Fly Species Commonly Observed in Korea and Consideration for Minimum Postmortem Interval Estimation / 대한법의학회지

Estimation of the minimum post-mortem interval (PMI-min) by means of forensic entomology is mainly based on the results of the growth rate studies on necrophagous flies. However, results of these studies are difficult to use because these studies have only been undertaken for a select few necrophagous flies, and experimental methods and results processing have not been standardized. In this review, we have summarized the current state of growth rate studies on necrophagous fly species that are frequently found in human cadavers. Criteria have been suggested in order to select reliable data, and the accumulated degree hours and base temperatures to be used in the calculation of PMI-min for each species have been tabulated.

A Comparison of Growth Curve Models for Forensically Important Flies Using Sigmoid Functions / 대한법의학회지

To estimate postmortem interval, it is essential to obtain information regarding fly growth. Analyzing the relationship between growth period and body length using a sigmoid function is widely accepted in animal science. However, in forensic entomology, it is difficult to find studies related to growth period and body length. Therefore, we compared growth curve models for forensically important flies using sigmoid functions. we used the data from flour fly species (Calliphora lata, Calliphora vicina, Chrysomya pinguis, and Lucilia illustris) and fited these against five sigmoid functions: quadratic-plateau model, logistic model, Gompertz model, von Bertalanffy model, and Brody model. Model evaluation criteria were, R2 mean squared error (MSE), Akaike information criterion (AIC), and Bayesian information criterion (BIC). The von Bertalanffy model yielded the highest R2 value and the lowest MSE, AIC, and BIC values for C. lata, whereas the logistic model was the best fit for the data from the other three species C. vicina, Ch. pinguis, and L. illustris.

A Forensic Entomology Case Estimating the Minimum Postmortem Interval Using the Distribution of Fly Pupae in Fallow Ground and Maggots with Freezing Injury / 대한법의학회지

Forensic entomology investigates postmortem interval (PMI) estimation using insect evidence. We estimated the minimum PMI of a putrefied male cadaver using pupae in the soil and maggots found in the body. Most of the maggots, collected during the autopsy, were postfeeding third instar larvae with empty crop contents, which developed freezing injuries when the cadaver was placed in the freezer. Pupae in the soil were collected 45 days after the discovery of the body. DNA barcoding revealed that most pupae and maggots were Chrysomya pinguis, with a few exceptions. The minimum PMI was estimated at 10 days before the discovery time based on the scene investigation, maggot developmental stage, distribution of pupae moving away from the body toward pupariation sites, DNA barcoding results, and weather information. To reduce the gap between the minimum and maximum PMI values, complete entomological evidence collection should be conducted at the time of discovery.

Molecular Species Identification of Forensically Important Flies in Korea / 대한법의학회지

To estimate the postmortem interval (PMI) by using entomological evidence, species identification of forensically important flies is mandatory. However, the traditional species identification method, which relies on the key morphological features of adult flies, is not always available to investigators and has limitations to the immature samples. Because of these limitations, species identification using DNA sequences has long been an issue in the field of forensic entomology. In this review, I have briefly described the basic principles of molecular species identification and phylogenetic analysis and their applications in forensic entomology. I also recommend an experimental and statistical method to identify unknown fly samples obtained from the field.