Post-mortem interval estimation based on insect evidence in a quasi-indoor habitat

Area of Science:

• Forensic entomology
• Forensic science
• Entomology

Background:

• Insect evidence from indoor cadavers is crucial for post-mortem interval (PMI) estimation.
• Investigative environments like buildings present variable conditions affecting insect access and temperature.
• Atypical indoor habitats pose unique challenges for PMI analysis.

Purpose of the Study:

• To conduct post-mortem interval (PMI) oriented analyses of insect evidence from a human cadaver in an atypical indoor habitat.
• To assess the impact of unusual environmental conditions on cadaver entomofauna and PMI estimation.
• To discuss the challenges and limitations of insect-based PMI estimations in non-standard indoor settings.

Main Methods:

• Analysis of insect evidence (entomofauna) collected from a human cadaver found in an uninhabited house with rubbish and restricted access.
• Estimation of PMI based on the developmental stages of specific insect species, including immature Necrodes littoralis and live puparium of Stearibia nigriceps.
• Corroboration of PMI estimates using empty puparia of Sarcophaga argyrostoma with traces of Nasonia sp. eclosion.
• Comparison of indoor thermal conditions with local weather station data and discussion of retrospective temperature correction needs.

Main Results:

• The cadaver entomofauna was surprisingly diverse and abundant, with several taxa not typically found on indoor cadavers.
• Immature stages of Necrodes littoralis (Coleoptera: Silphidae) and Stearibia nigriceps (Diptera: Piophilidae) were recorded.
• PMI was estimated at 37 (±7.4) days plus a 4-20 day pre-appearance interval for S. nigriceps, corroborated by other insect evidence.
• Indoor thermal conditions showed less variability than outdoor weather but more than typical indoor habitats.

Conclusions:

• Insect-based PMI estimation is feasible even in atypical indoor habitats, though challenging.
• The presence of unusual taxa highlights the adaptability of insects to diverse environments.
• Accurate PMI determination requires careful consideration of environmental factors and insect life cycles in unique settings.