Forensic Entomology: Insects in Crime Investigation

The minimum post mortem interval (PMI) can be estimated from the measurement of immature developmental stages of the insects that colonizes the natural and/or traumatic wound sites. Our objectives are to determine the patterns of insect succession across decomposition stages, identify primary colonizing species, and evaluate the effect of temperature and humidity on larval growth for accurate postmortem interval (PMI) estimation. Methods: This descriptive and analytical experimental study was conducted over a 30-day duration using controlled conditions simulating natural environments. A total of 100 decomposing animal tissue samples were evaluated across five stages of decay. Insect specimens (eggs, larvae, pupae, and adults) were collected and identified through morphological examination and mitochondrial cytochrome oxidase I (COI) gene sequencing. Data on temperature and humidity were recorded and analyzed using IBM SPSS version 26 via Chi-Square test and Pearson correlation analysis. Results: Active decay was the most frequent stage (30.0%), followed by bloated and advanced decay (20.0% each). Blowflies (Calliphoridae) were the dominant primary colonizers (40.0%), followed by beetles (Coleoptera, 25.0%) during later stages. A significant association was identified between decomposition stages and insect species distribution (χ2 = 18.45, p = 0.002). Temperature exhibited a strong positive correlation with larval growth rate (r = 0.72, p = 0.001), while humidity correlated with insect activity (r = 0.58, p = 0.004). Conclusion: Insect colonization follows a predictable, statistically significant succession pattern that serves as a dependable biological indicator for PMI estimation. Ambient temperature significantly accelerates larval development, highlighting the necessity of integrating regional environmental data and standardized identification protocols in forensic investigations.