Characterization of the volatile odor profile from larval masses in a field decomposition setting

Abstract

By studying insect populations and subsequent larval stages, forensic examiners can use entomology as a tool to estimate time of death, evaluate trauma present in body, and even determine if the corpse was moved based on the types of insects found. Due to the close contact between insect and decomposition source, this study aimed to investigate whether a larval mass sample could yield an odor profile distinctive of the various stages of decomposition using pig cadavers as models.Instrumental evaluation utilized Solid Phase-Microextraction (SPME) coupled with Gas Chromatography-Mass Spectrometry (GC–MS) for the identification of extracted volatile odor profiles of maggots. There were 107 compounds detected in larvae samples. Of these, a total of 10 compounds were selected as frequently occurring in the larvae matrix. Sulfurs and ketones were observed in the early stages of decomposition, followed by alcohols such as phenol and indole in later stages. Based on the analysis of released volatile organic compounds, it is feasible to use a larval odor sample to detect previously reported decomposition odor volatiles and through continuous sampling, the odor profile changes as a function of decomposition. Principal component analysis depicted a preliminary decomposition stage clustering of larvae odor profiles using only the selected volatile array pattern. More research is therefore needed to confirm this trend over longer longitudinal and temperature perspectives. This study, however, provides an initial foundation as to how these larval mass odor profiles could provide a preliminary path for a new tool in PMI determination.