Decomposition chemistry refers to the biochemical degradation processes which occur in soft tissue as decomposition proceeds. This study aims to investigate the relationship between the release of decomposition fluids into contrasting soil environments and their potential correlation with the presence of a decomposing carcass. Soil from two different carcass decomposition trials was utilized to determine if seasonal and soil variation altered the soils reaction to a carcass. The reaction was determined by investigating the soil available phosphorus, extractable lipid-phosphate, pH, moisture and fatty acid content. A significant increase in the relative concentration of extractable lipid-phosphate, soil available phosphorus, and fatty acid content was identified, confirming the flux in the microbial biomass in the soil. Contrary to these nutrients, there were no notable changes in the soil pH and moisture content. The findings of this study were able to highlight the future forensic potential of these techniques and demonstrate a need for further research.

In homicide cases, suitcases provide concealment and ease of transport of a body and reduce the likelihood of detection. When estimating a minimum postmortem interval (mPMI), it is necessary to understand the taphonomic processes that occur when a body is concealed within a suitcase. In this study, the experimental carcasses consisted of pig (Sus scrofa Linnaeus) heads concealed within either hard shell or fabric suitcases whereas control pig heads were decomposed naturally. All control pigs heads attracted blowflies (Calliphoridae) immediately and mummified within days, whereas the experimental pigs heads had an oviposition delay of approximately 72 hours and decomposed resulting in skeletonization. Differences in the arthropod species present varied between the experimental and control pigs heads. Temperature comparisons revealed significant (p <0.001) differences between the experimental and control pigs heads. How a corpse decomposes when a suitcase is used for body disposal must be considered when estimating the mPMI.

The development and improvement of methods used for the estimation of the postmortem interval (PMI) is a common area of research in forensic science. This research was conducted to physically and chemically analyze pig carcass decomposition on a soil surface using conventional and newly developed methods for the potential use in estimating the PMI. Photographs of pig carcasses decomposing on forested and open land were scored using a decomposition scoring system and decomposition scores were related to accumulated degree days (ADD). Overall, the ADD values were significantly different for the two groups of carcasses; however, the ADD values for the onset of each score demonstrated more similarity between groups. Decomposition scoring results also indicated that refinements must be made to the calculation of ADD to allow for a meaningful comparison of pig and human decomposition. The decomposition of pig carcasses altered the water content, pH and fatty acid content of soil. The fatty acids, myristic, palmitic, palmitoleic, stearic and oleic acids were successfully extracted and analyzed from decomposition soil. Palmitic, stearic and oleic acids were the most abundant fatty acids detected whilst the levels of myristic and palmitoleic acids were negligible in comparison. A three peak fatty acid cycle was also observed for each fatty acid. Variations in soil pH and fatty acid content of decomposition soil have the potential to indicate the presence of a decomposition site. Furthermore, a nonlinear diffusion model was developed to predict the development of the cadaver decomposition island (CDI) in soil over time. The simulation of the model indicated that the diffusion model has the potential to generate PMI estimations for early stages of decomposition by corresponding the effective radius of the CDI to a particular time point. The general findings of this research indicate that more accurate methods for PMI estimations can potentially be developed with further research. / UOIT

Studies were conducted on the effects of alcohol and opioids on the development of forensically important flies. In addition different methods of degree-day calculations and development thresholds were used to determine the effects on PMI estimates. The first study determined the effects of ethanol on the development of Phormia regina in vitro. Ground pork loin was treated with a 1, 5, or 10% ethanol solution to give an equivalent Blood Alcohol Concentration (BAC) of 0.01, 0.04, and 0.8 % w/v. A significant difference in the time for second instars to complete the stage was seen between the 1% treated and control. Significant differences were also found among pupal and adult weights between all treatments and the control. A significant difference was shown between growth curves of the 5% treated and control for third instar larvae using the Kolmogorov-Smirnov test. The ethanol content of Phormia regina in migrating third instar larvae that fed on treated meat was examined using headspace-gas chromatography (HSGC). All larvae had a content of 0.01% w/v, including the control. The effects of ante-mortem injection of oxycodone in pigs were examined with respect to insect succession patterns and the development rates of Phormia regina. Pigs were given a subcutaneous injection of oxycodone hydrochloride (3 mg/kg by weight) and antemortem blood samples were collected prior to and following drug injection. Shortly after death the carcasses were placed at an open field site and allowed to decompose in a field cage. Insect samples were collected from carcasses for seven days post-mortem and the collected data were used to develop occurrence matrices. The Simple Matching Coefficient showed that successional patterns were similar between treated and untreated animals. Loin and liver from the carcasses were used as rearing media for in vitro development studies of Phormia regina. Kolmogorov-Smirnov test showed that third instar P. regina maggots from treated loin tissue were significantly longer in length than maggots feeding on untreated loin tissue. A significant difference in time was found among larvae on loin for the time from eclosion to completion of the second instar. Significant differences were seen in the weight of adults reared on liver and loin. A chi-square for homogeneity showed that adults were biased towards males (2:1) from untreated loin tissue. A final study compared weather data sources, Accumulated Degree-Day (ADD) methods, and postmortem interval (PMI) estimations based on threshold and developmental data source. Four pigs were used for statistical comparisons. Pigs were taken to a test site and allowed to decompose in an experimental cage. Probes recorded ambient temperatures and body temperatures. Maggot sampling was completed every day for each pig. A three way factorial linear fit model was used to test for statistical differences. Significant differences were seen in the calculated ADD based on probe location and the development threshold used. The ADD calculated from local weather station locations: Kentland Farm, Moore Farm, and Blacksburg Airport were also compared. A significant difference in ADD was found in the main effects among locations (Airport 44.1 ADD, Kentland 37.5 ADD, Moore 48.6 ADD), as well as among the thresholds used (10,12.2, and 14°C). Different PMI estimations also resulted when using development data from different development studies on Phormia regina. / Ph. D.

Forensic entomology has become synonymous with medico-legal entomology and involves the use of insects in legal and criminal investigations.  Insects have been used as evidence in cases of wrongful death of humans and in wildlife poaching cases for many years.  The first jail time sentence for wildlife poaching in Manitoba, Canada was awarded after insect evidence was used to create a timeline for the crime.  In the interest of advancing the science of forensic entomology, insect faunal succession was studied on four white-tailed deer carcasses in southwest Virginia in the summers of 2009 and 2010.  The patterns of insect succession between the summers of 2009 and 2010 were similar at ± = 0.05.  Necrophagous insects arrived in a successional pattern as has been observed on other animal models (e.g. pigs) during past studies conducted in southwest Virginia.  To further explore the role of wildlife specific variables to forensic entomology, larvae of Phormia regina, Meigen, were reared on pork and venison in a laboratory at Virginia Tech.  Environmental rearing conditions were 30" C, 75% RH and 14:10 hour light dark cycle.  Significant differences in lengths of 3rd instar and combined overall maggot lengths were found for maggots reared on the different meat sources.  Mean adult weights and wing lengths of venison-reared flies were significantly greater than those reared on pork at ±=0.05. / Master of Science in Life Sciences

Determining the postmortem interval (PMI) remains one of the most important but challenging factors to establish in a suspicious death investigation. Unfortunately, as time passes current methods lose accuracy and only allow investigators to approximate how long ago death occurred. Bodies interred in clandestine graves prove particularly challenging due to an abundance of variables that need to be taken into consideration. Due to the problems associated with determining the PMI of buried remains this study will utilise macroscopic, microscopic, molecular, chemical and microbiological analyses to systematically document the decompositional changes to human hair and porcine cartilage and bone in a burial environment. The aim was to correlate decompositional changes with time and develop new methods for estimating the PMI of remains found in this context. Whole trotters (from which the cartilage was harvested) exhibited decompositional changes including darkening of the dermis, skin slippage, liquefaction of soft tissues and complete skeletonisation. The decompositional changes to cartilage included a loss of cartilage covering articular facets, changes in colour and texture, formation of orthorhombic crystals, a change in surface pH and colonisation by bacteria. The bacteria found on the cartilage surface were in close proximity to the crystals and when cultured on a B-41 medium were found to precipitate crystals of the same morphology and chemical composition to those found on the cartilage surface. Three species of bacteria (Acinetobacter calcoaceticus, Acinetobacter iwoffii and Grimontia hollisae) were identified based on gas chromatography–mass spectrometry (GC-MS) of their fatty acids and one species (Comamonas sp.) was identified by DNA analysis. Formation of crystals on goat and cow cartilage proved that this was not a porcine specific phenomenon. Human hair exhibited a gradual degradation over time but this was dependent on the characteristics of the burial environment. Decompositional changes included colonisation by fungi, erosions to the cortical surface and formation of tunnels and breaks to the hair shaft. Two fungal species (Aspergillus fumigatus and Penicillium sp.) were identified based on DNA analysis of fungal ribosomal (rDNA) internally transcribed spacer (ITS) regions. The Penicillium sp. was linked with fungal tunnelling of hair. Bone exhibited little modification over time but changes were observed. These included a change in colour of the cortical surface, a change in colour and gradual loss of bone marrow and erosions, cracking and flaking of the cortical bone. Fungi were found to colonise both the bone marrow and bone surface. Whole piglets were buried to document the time period taken to reach skeletonisation. This data was used as a correction factor and combined with the bone results to give an overall time period for the decomposition changes observed. The results of this study suggest that the decompositional changes to cartilage could be used to determine the postmortem interval of buried remains. However, the degradation of hair and bone was too variable to be of use in this context.

The University of Tennessee Anthropology Research Facility (ARF) is well known for its unique history as a site of human decomposition research in a natural environment. It has been integral to our understanding of the processes of human decomposition. Over the last 30 years 1,089 bodies have decomposed at this 1.28 acre facility, producing a density of 850 corpses per acre of land. This project evaluated the abiotic and biotic characteristics of the soil exposed to various levels of human decomposition in order to determine the effect on the physicochemical properties and the indigenous bacterial communities. Specifically, 75 soil samples were taken to determine abiotic properties. A biological matrix was generated for the 40 samples inside the facility based on sequencing of the 16S rDNA gene. The identified taxonomy was evaluated for differences among decomposition bins and taxa. Results of the abiotic soil properties demonstrated few differences among the predefined bins of decomposition density. Significant differences were observed between samples inside the facility to the negative control, and to those samples taken below actively decomposing corpses. When taken together, the abiotic data demonstrated a temporal shift away from control, with the greatest deviation at 18 to 24 months. After which time, the samples became more similar to control samples. Similarly, the biotic data remained concordant with the abiotic data, but demonstrated significant differences between the areas of high decomposition to those with no history of decomposition. The high decomposition bins were marked by high levels of chemoorganotrophic and sulfate-reducing bacteria, and a reduction in Acidobacteria, indicating a change in the community of underlying bacteria in response to carcass enrichment and ammonification of the soil. Thirty years of decomposition research at the ARF has forced a shift in the underlying bacterial community in response to the enrichment of the soil with increased nitrogen and carbon-containing compounds. The baseline data presented in this work provides a control dataset for further exploration regarding the biogeochemical relationships among microbial organisms, soil characteristics, and cadaver decomposition. Within this relationship exists the potential for developing new models relating to postmortem interval estimation and clandestine grave location.

[Truncated abstract] A common application of forensic entomology is the estimation of post-mortem interval (PMI). This is most frequently estimated from the age of calliphorid specimens collected from a corpse, and in many cases it is the immature stages that are encountered. A critical step in the estimation of PMI is the accurate identification of insects to species level, with misidentification potentially resulting in the application of unsuitable developmental data and therefore inaccuracy in the resulting estimate. Identification has long been attempted on a morphological basis, but complicated by the lack of larval keys to the Calliphoridae, limited diagnostic features in immature stages and the poor preservation of specimens. Standard practice in forensic entomology is the rearing of immatures collected from the corpse through to the more distinctive adult stages, however this process is time-consuming and may be hindered where specimens die during rearing. Furthermore, many cases are presented for forensic entomologist as an afterthought and specimens are already preserved. Consequently, a new approach to the identification of calliphorids is sought which will overcome the problems of the morphological and rearing methods. ... The culmination of this study is the consideration of applications of molecular data to forensic entomology. A sequence-specific priming (SSP) technique is presented for the identification of the forensically significant calliphorids of Australia and New Zealand, along with a new method for the extraction and storage of calliphorid DNA samples using Whatman FTA cards. These techniques will potentially improve the efficiency and accuracy of identification in the estimation of PMI using calliphorids. The use of calliphorid DNA is not limited to PMI estimation, but may also be applied to museum studies. DNA was extracted from pupal casings from 300 year old mummified corpses, however difficulty was encountered in amplifying the DNA reproducibly. This illustrates however, the wide-ranging implications of the calliphorid sequence data gathered in this study. This thesis makes a significant contribution to the consideration of the status of some global calliphorid species. The new technique presented for identification of Australian and New Zealand species is the culmination of an important body of data that will ultimately contribute to the strong foundation of forensic entomology and our future accuracy, efficiency and utility as a routine investigative tool.

Orientador: Arício Xavier Linhares / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T03:37:18Z (GMT). No. of bitstreams: 1 Rezende_Fabio_M.pdf: 2094464 bytes, checksum: d1870c6b30f983e3d34cc084165c6f12 (MD5) Previous issue date: 2012 / Resumo: O aumento no número de óbitos relacionados ao uso de drogas justifica o interesse por estudos entomotoxicológicos. Estes estudos devem focar a obtenção de dados diversos sobre a entomofauna necrófaga que contribuam para a formação de um banco de dados que auxilie em investigações criminais, principalmente quando a estimativa do intervalo pós-morte (IPM) é baseada na idade do inseto, visto que a mesma pode sofrer alteração quando uma dada substância interfere no ciclo de insetos que tenham se alimentado dos tecidos cadavéricos onde tais substâncias estão presentes. Assim, no presente estudo objetivou-se verificar o efeito de diferentes concentrações de Cloridrato de Metilfenidato isolado e associado ao Fenobarbital na taxa de desenvolvimento, sobrevivência e longevidade de imaturos de Chrysomya putoria (Wiedemann), Chrysomya albiceps (Wiedemann) e Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae), quando acrescidos em dieta artificial oferecida como único substrato para seu desenvolvimento. Os imaturos foram obtidos a partir de colônias de moscas adultas mantidas em condições controladas de temperatura e umidade em laboratório. Foram feitas seis réplicas para cada grupo experimental, com 150 espécimes de cada espécie em questão, perfazendo um total de 900 larvas por espécie. Além disso, um grupo controle (sem adição da droga) foi mantido sob as mesmas condições de criação. Os imaturos foram pesados individualmente a cada 12h, sendo retirados 10 espécimes de cada grupo, desde as 12 horas após a eclosão até a pupariação. ANOVA de um fator foi realizada para comparar o efeito dos tratamentos no desenvolvimento dos imaturos, usando como resposta o ganho de massa larval. O teste de comparações múltiplas de Duncan também foi realizado para comparar as médias e apontar possíveis diferenças entre os grupos. As duas substâncias alteraram a taxa de desenvolvimento de todas as espécies estudadas, ampliando em até dois dias o tempo total de desenvolvimento dos imaturos. Desse modo seria recomendável que exames toxicológicos para a detecção de drogas em larvas fossem realizados invariavelmente para evitar erros quanto à estimativa do IPM, quando este for baseado no ciclo de desenvolvimento de insetos / Abstract: The increase on the number of deaths related to drug abuse justifies the interest in entomotoxicological studies. These studies are focused on obtaining data on the necrophagous insect fauna which contribute to the formation of a database to help in criminal investigations, especially when the estimate of the postmortem interval (PMI) is based on the age of immature necrophagous insect, since it can be altered when a given substance interferes with the larval development of insects that have fed on tissues containing this substance. The present study was aimed to evaluate the effect of different concentrations of methylphenidate hydrochloride isolated and associated with phenobarbital on the developmental rate, survival and longevity of immatures of Chrysomya putoria (Wiedemann), Chrysomya albiceps (Wiedemann) and Chrysomya megacephala (Fabricius ) (Diptera: Calliphoridae), reared in artificial diets with different concentrations of the drugs and offered as substrate for their development. The immatures were obtained from colonies of adult flies maintained under controlled temperature and humidity in the laboratory. Six replicates were performed for each experimental group, with 150 specimens of each species of blowfly, comprising a total of 900 larvae per group. In addition, a control group was maintained under the same conditions established for the other groups. Ten specimens of each group were removed and individually weighed every 12 hours, from 12 hours after hatching to pupariation. One-way ANOVA was performed to compare the effect of treatment on development of immatures, using larval weight as response variable. The Duncan Multiple Comparison Test was also performed to compare the means and to identify possible differences among the groups. The two substances were responsible for altering the rate of development of all species studied, retarding up to two days the total developmental time of the immatures. Thus, it is recommended that toxicological tests should be performed to detect drugs eventually present on larvae collected from corpses, in order to prevent errors in the estimation of IPM, when it is based on the developmental cycle of immature saprophagous insects / Mestrado / Parasitologia / Mestre em Parasitologia

The accurate estimation of the postmortem interval (PMI) is one of the most important determinations in a forensic investigation of decomposing human remains. Forensic entomology has gained popularity in death investigation due to its reliability and precision in the estimation of the minimum postmortem interval (mPMI). Forensically significant insects are mainly necrophagous species, which feed only on decomposing animal matter, and the most common necrophagous insects are the blowflies (Diptera: Calliphoridae). Estimations of the mPMI by entomological methods are made using the known developmental rates of various species of blowfly and via the successional patterns of the carrion insect community in a given region. It is generally assumed that blowflies oviposit quickly after death, so in many cases this time may equate to the time since death. The precision of mPMI estimations based on the developmental rates of blowflies often relies on this assumption. Rainfall may effect decomposition by inhibiting access of insects to the cadaver or carcass for oviposition. The current study investigated the effects of rainfall on blowfly activity, behavior, and overall decomposition of decaying animal material in an outdoor environment in the northeastern United States, conducted at the Boston University Outdoor Research Facility (ORF). It was hypothesized that natural rainfall, typically light to moderate in the geographic area of study, will disturb initial blowfly activity by acting as a physical barrier, diminishing access to the remains, and creating a delay in colonization and subsequent larval development. This hypothesized delay would result in an underestimation of the mPMI by entomological methods when rainfall has occurred. Also examined were several questions about the nocturnal behavior of blowflies and their activity in heavy rain. In the experimental trial 12 pig (Sus scrofa) heads were exposed under normal conditions (N; no rain controls), and 15 pig heads were exposed under rainy conditions (R; rain treatment), split into uncovered (N, n=6; R, n=5), covered (NC, n=5; RC, n=5), and covered partially (RCP, n=5) treatments. Additionally, there were three pig heads used in a preliminary trial and three pig heads exposed in an active rain trial. Generally, the results show that while a negative correlation exists between the amount of rainfall experienced and the coded number of flies observed, the light to moderate rainfall typical of many rainy days in the northeastern Unites States will not totally inhibit blowfly activity or disturb established maggot masses. A one-way analysis of variance (ANOVA) determined that there was no statistically significant difference (p > 0.05) between the N, NC, R, RC, and RCP treatments in the number of days it took to reach the advanced decomposition stage. While constant, heavy rainfall may inhibit blowfly activity; the results suggest that the irregularity of natural rainfall would rarely produce the conditions necessary for this to make a significant impact estimation of the PMI by entomological methods, although further studies are needed to confirm this conclusion. The results show a positive correlation between solar radiation and the coded number of flies observed. Time of day as a function of the coded number of flies observed during the first 48 hours of exposure forms a bimodal bell curve, confirming that blowflies are diurnal in their natural environment. Additionally, evidence of scavenging by turkey vulture (Cathartes aura) and some unknown animal(s) was observed. The results of this study illustrate the complicated, multivariable nature of the process of decomposition. This study provides preliminary data on the effect of rainfall on blowfly activity and overall decomposition, while future studies will be required to determine the effects of the duration and the intensity of rainfall.