Forensic anthropologists often rely on the state of decomposition to estimate the postmortem interval (PMI) in a human remains case. The state of decomposition can provide much information about the PMI, especially when decomposition is treated as a semi-continuous variable and used in conjunction with accumulated-degree-days (ADD). This preliminary study demonstrates a supplemental method of determining the PMI based on scoring decomposition using a point-based system and taking into account temperatures in which the remains were exposed. This project was designed to examine the ways that forensic anthropologists could improve their PMI estimates based on decomposition by using a more quantitative approach. A total of 68 human remains cases with a known date of death were scored for decomposition and a regression equation was calculated to predict ADD from decomposition score. ADD accounts for approximately 80% of the variation in decomposition. This study indicates that decomposition is best modeled as dependent on accumulated temperature, not just time.

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The black soldier fly, Hermetia illucens (L.), has been shown to be a ubiquitous inhabitant of both surface and buried human remains throughout the southern, central and western United States and Hawaii. Unlike most other species of forensically important Diptera, this species frequently dominates bodies in the dry/post decay stage of decomposition. Adults of the black soldier fly appear to initiate oviposition (egg laying) 20 to 30 days postmortem. Even at warm temperatures (27.8°C), subsequent completion of the life cycle can require an additional 55 days. Life history data for H. illucens, when used in combination with data for other cohabiting arthropod species and viewed in the context of local environmental conditions, can provide medicolegal investigators with valuable parameters for estimating the postmortem intervals for badly decomposed remains.

Comparative performance and complementarity tests of four arthropod sampling methods (aerial netting, hand collection, pitfall traps, and sticky traps), used by forensic entomologists in death investigations, training workshops, and research trials, were conducted from simultaneously placed human and porcine subjects inside the Forensic Anthropology Center at the University of Tennessee, Knoxville, TN. A secondary aim investigated the widely held claim that pig carcasses are reliable surrogates for human corpses. Over a 35-d period in summer 1989, >72,000 invertebrates from three subjects (one human, two pigs) were sampled of which 93% were members of the forensically important (FI) fauna. Performance tests revealed that hand collections, when performed by an experienced forensic entomologist, consistently yielded the largest fraction of FI arthropods from the total invertebrate catch, followed by aerial netting, sticky traps, and pitfall traps, regardless of subject. Pitfall traps and hand collections were broadly effective at sampling both fly and beetle populations, whereas aerial netting and sticky traps mostly targeted flies. The best two-method combination, based on the highest combined catches of FI taxa, were hand collections and pitfall traps, regardless of subject. Between-subject comparisons revealed negligible preference by FI arthropods for human over pig remains. Insofar as our limited comparisons allow with only three study subjects, these results validated the concept of transferability of "best practices" from one subject to another and confirmed the claim that pig carcasses (of 23-27-kg starting mass) can substitute for human corpses in research and training programs, at least for summer-exposed and unconcealed remains in the first 5 wk postmortem.

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