The use of entomological samples as potential odor biomarkers for decomposition stages
Blanar, Katie E.
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Forensic Entomology is a growing discipline with very little scientific research regarding insects found on a dead body and how they can provide vital information that may not be found anywhere else. Along with the little research that has been done, there are also few experts in this discipline who look at odor profiles in connection with these insects. Emerging research has been looking at odor profiles of different animal cadavers as well as the odor emitted from beetles placed on a corpse. However, there are no studies that are specifically looking at the odor emitted by maggots feeding on a cadaver. The purpose of this study is to investigate the volatile odor profile within maggots found on decaying piglet cadavers as a function of decomposition stage and compare with previous literature the results obtained to see how an insect’s volatile odor profile compares to human/animal decomposition models. With this information from the maggots, the utilization of insects as a sample matrix can potentially be implemented by forensic scientists using volatile biomarkers as indicators of postmortem intervals. Knowing the volatile organic compounds emitted from the cadaver insect populations will also give cadaver canine teams more information to better their training procedures in hopes of enhancing and standardizing those procedures. This study used eight piglet cadavers: two for a pilot study, two for a summer sampling period, two for a fall sampling period, and two for a winter sampling period. Instrumental evaluation utilized Divinylbenzene/Carbon/Polydimethylsiloxane (DVB/CAR/PDMS) coated Solid Phase-Microextraction (SPME) fibers that were injected into a Gas Chromatography-Mass Spectrometry (GC-MS) system for the identification of extracted volatile odor profiles of maggots at the different stages of decomposition. The pilot study recorded and sampled the decomposition process every twenty-four hours until the process was complete. The piglet cadavers from the summer, fall, and winter sampling periods were sampled once a day for optimum sampling. Decomposing tissue samples from the piglet cadavers were also collected to provide a correlation between the odors emitted from the maggots and the pig cadavers themselves. The findings include an assortment of chemical compounds emitted from each of the maggots collected exhibiting distinctive odor profiles as a distinction of the stage of decomposition. The benefit of this study is enhanced knowledge in the realm of optimal odor profiling of maggots from the different stages of decomposition. This research will fundamentally bridge the gap in knowledge regarding the odor profiles emitted by maggots at various decomposition stages and how this profile impacts criminal investigations, which may be lacking evidence, and provide it with a new upcoming technique.