Bloated Stage Research Articles

Lime and odour: A preliminary investigation into the effect of hydrated lime on the volatiles emitted from human remains

The location of human remains is performed primarily through the aid of cadaver detection dogs, which rely on the malodour produced through decomposition of decaying bodies. Malefactors will attempt to conceal these putrefactive odours through chemical additions such as lime, which is also wrongly believed to accelerate decomposition and prevent the identification of the victim. Despite the frequency of lime in forensic applications, to date no research has been performed to determine its effect on the volatile organic compounds (VOCs) released during human decomposition. This research was therefore conducted to ascertain the effects of hydrated lime on the VOC profile of human remains. Two human donors were used in a field trial at the Australian Facility for Taphonomic Experimental Research (AFTER): one donor was covered with hydrated lime, and the other had no chemical additions acting as a control. VOC samples were collected over a period of 100 days and analysed using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS). The volatile samples were accompanied by visual observations of how decomposition progressed. The results showed that lime application decreased the rate of decomposition and decreased total carrion insect activity. Lime increased the abundance of VOCs during the fresh and bloat stages of decay, however the abundance of compounds plateaued during active and advanced decomposition and were much lower than those detected from the control donor. Despite this suppression of VOCs, the study found that dimethyl disulfide and dimethyl trisulfide, key sulfur-containing compounds, were still produced in high quantities, and can thus still be used to locate chemically altered human remains. Knowledge of the effects of lime on human decomposition can inform the training of cadaver detection dogs, and ensure a greater chance at locating victims of crimes or mass disasters.

Post-mortem interval of buried homicides in Okuku, Nigeria

BackgroundPost-mortem interval estimation of carcasses buried in shallow graves is a grey area in Nigerian forensic investigations. Most of the investigations and court decisions on the time of death of concealed homicides are based on assumptions in Nigeria. Therefore, this study investigated the post-mortem interval of buried remains in Okuku, Cross River State of Nigeria using porcine models. This study also provided a model account of the pattern and timeline of decomposition of buried remains in Nigeria.ResultsFour stages of decomposition were identified within the study period which includes fresh, bloat, active decay, and advanced decay stages. Features of bloat stage of decomposition include bloating of the animals and release of putrid odour. The active decay stage was characterized by the absence of maggots, bone exposure, and greyish discolouration of the body. The advanced decay stage of decomposition is characterized by adipocere formation, fungi activities, and bone exposure.ConclusionsBuried bodies do not completely skeletonize within 168 days in a typical Nigerian savannah region. Bloat stage started by the 7th day; the active decay stage started by the 14th day. The fresh stage of decay lasted up to 7 days; the bloat stage lasted for 14 days. The active decay stage lasted about 35 days, and the advanced decay stage started at about the 56th day and progressed until the end of the study.

Necrodes littoralis (Coleoptera: Silphidae) visiting and breeding on a carcass in Italy.

The community that progressively colonizes a decaying corpse can be considered a small ecosystem mostly composed of sarcosaprophagous arthropods belonging to the orders Diptera and Coleoptera. Studies on these species are often performed through animal models to obtain data on their succession, behaviour and life cycle, together with information on habitat, corpse conditions, season and association with other species. These data may be relevant for forensic investigations, especially concerning the estimation of Post Mortem Interval (PMI). An investigation on the sarcosaprophagous insect community in a rural area was set in Calabria (Southern Italy), using a pig, Sus scrofa Linnaeus, 1758 (Artiodactyla: Suidae) as experimental model. Analyses of the community of Diptera and Coleoptera revealed the massive presence of Necrodes littoralis (Linnaeus, 1758) (Coleoptera: Silphidae). Adults of this species reached the carcass during the bloated stage and a large amount of larvae was detected from the decay stage onwards, simultaneous to the sharp decrease in dipteran larvae and pupae. The occurrence and the activity of N. littoralis should be considered to avoid misinterpretation and errors in estimating PMI in forensic investigation.

Changes in the morphometric characteristics of tattoos in human remains

ABSTRACT Tattoos are secondary identifiers that can be used to provide a presumptive identity and provide information about a deceased individual to a case. Additional information may be available through the analysis of the visual presentation of tattoos. The aim of this study was to examine the morphological changes of tattoos during the decomposition of a human donor in an Australian environment. Using time-lapse cameras recording for 16 months, stills were extracted and tattoos were quantified using ImageJ. A full analysis was completed on three tattoos, while a fourth tattoo was partially analysed. The tattoos showed the most change in area during the bloat stage of decomposition, staying relatively constant in size for the remainder of the study. The detailed shape of the outlines showed the morphological effect of desiccation as part of decomposition and continued to change until the tattoo was no longer visible. Of the tattoos fully analysed, two became redundant as secondary identifiers on day 294, the other on day 333, all due to lack of visibility. This information is useful during investigations of unknown deceased persons; in this case, the stage of decomposition influenced the presentation of the tattoo.

An Exploratory Study of Beetles and Flies of Forensic Importance on Sheep Carrion in Kwazulu-Natal Province of South Africa

This study selected sheep as an animal model for domestic and wildlife ruminants to collect and identify arthropods of forensic importance. Two adult Merino sheep were humanely killed (each in cold and warm season) at Ukulinga Research and Training Farm of the University of KwaZulu-Natal, South Africa. Five decomposition stages were observed as fresh, bloated, active, advanced and dry stages. Calliphoridae, Muscidae and Sarcophagidae flies comprising of Chrysomya marginalis (Wiedemann), Ch. putoria (Wiedemann), Ch. albiceps (Wiedemann), Ch. chloropyga (Wiedemann.), Lucilia cuprina (Wiedemann), Musca domestica (Walker) and Sarcophaga calcifera (Boettcher) were recorded. Colonisation by coleopterans during the warm season started as early as the fresh stage with Dermestes maculatus (De Geer), Thanatophilus micans (Fabricius) and Onthophagus crassicollis (Boucomont), whilst the same species were collected from the bloated stage in the cold season. Chrysomya marginalis, M. domestica, D. maculatus, T. micans and O. crassicollis persisted on the carcass throughout the five stages of decomposition during the warm season. Results from this study generated important information on the endemic arthropod species that are attracted to sheep carcass during the warm and cold season in a locality of the KwaZulu-Natal province and their succession pattern can be further investigated as potential indicator species in estimating the post-mortem interval in this locality.

Insect Succession and Decomposition Pattern on Pig Carrion During Warm and Cold Seasons in Kwazulu-Natal Province of South Africa.

With the aim of identifying insects with potential value as indicator species in postmortem interval (PMI), the location or season of death of human or monogastric animals, two medium-sized large white pigs were used for the study during cold and warm seasons. Five stages of decomposition and their durations were observed and described in the pig carcasses during both seasons. Carcasses were first colonized by flies from seven taxa during fresh stage. Chrysomya marginalis (Wiedemann) (Diptera: Calliphoridae), Chrysomya albiceps, (Wiedemann) (Diptera: Calliphoridae) and Musca domestica (Walker) (Diptera: Calliphoridae) were recorded as the overall dominant adult flies found on the carcasses in both seasons. Colonization by beetles began during the bloated stage in the warm season and active stage in the cold season. Dermestes maculatus (De Geer) (Coleoptera: Dermestidae) and Necrobia rufipes (De Geer) (Cleridae) were the most abundant beetles in both seasons. Flies and beetles were generally abundant during the warm seasons as compared to the cold season. However, the difference was only significant for beetles. The highest number of flies were recorded in the bloated stage for both seasons, however they were reduced in the active stage which coincided with the introduction of predatory beetles. The arrival time of the different arthropod species and their association with different stages of decomposition during both seasons pointed to their value in estimating the PMI in forensic investigations in the locality of KwaZulu-Natal, South Africa. Consequently, they can potentially be useful in the estimation of PMI and other cases of criminal investigations.

A Checklist of Arthropods Recorded on Exposed Pig Carrion in Neke, Enugu State, Nigeria.

A comprehensive study of insects recovered on the decaying pig was carried out from 7th June to 7th September, 2018 to identify the arthropods connected with the pig carrions. The study revealed that Diptera, Coleoptera, Hymenoptera and Isoptera were the group of insects that were collected on the carrions. At the fresh stage, there were 78 insects and at the bloated stage there were 182 insects while at the active decay stage there were 262 and at the advanced decay stage there were 319 insects as the dry decay stage yielded only 119 insects. The Simpson index was high (0.95) in the active decay and advanced decay stages but was low (0.89) in the fresh and dry decay stages. The Dominance index was high (0.11) in the fresh and dry decay stages of but was low (0.05) in the active and advanced decay stages and the Shannon-Weiner index (H) was high (3.09) in the advanced decay stage but low (2.33) in the dry decay stage. The Evenness index (E) was high (0.95) in the fresh stage but low (0.86) in the dry decay stage. Richness index: Margalef (R) was high (4.03) in the advanced decay stag but was low (2.07) in the fresh stage as the Equitability index was high (0.98) in the fresh and bloated stages but low (0.94) in the dry decay stage. The score plot of the PCA shows a scatter plot of species distribution in carrion for components 1 and 2. Component 1 accounted for 42.3% of the variation in the dataset while component 2 accounted for 24.6% making a total of 66.9%.

Temporal variability of the rove beetle (Coleoptera: Staphylinidae) community on small vertebrate carrion and its potential use for forensic entomology

Rove beetles (Coleoptera: Staphylinidae) are one of the most important colonizers of vertebrate cadavers. We have previously investigated carrion-associated rove beetle communities across various forests and demonstrated that the study regions are the main drivers of the local rove beetle species pool that is, in turn, able to colonize a carcass. Nevertheless, little is known about their temporal variation in community composition during the decomposition process. The aim of our study has been to analyze the temporal changes of the composition of the rove beetle community and to identify new, potentially useful candidate species for forensic entomological evaluations. We determined 80 rove beetle species that were attracted to 60 piglet cadavers across various forest stands in Germany. Both the abundance and the community composition changed over the decomposition process, independently of the species-specific geographical variation across study regions. In the region Schorfheide-Chorin, species from the genus Philonthus proved to be a suitable group for future forensic entomological investigations. They appeared in markedly high numbers at piglet cadavers from the bloated stage until the advanced decay stage. For the study region Schwäbische Alb, we newly describe the species Omalium septentrionis as a member of the carrion-associated rove beetle fauna. Based on the geographical variation in rove beetle community compositions, we have filtered out several species that might contribute to advances in postmortem interval estimations or other applied fields in forensic entomological contexts.

Forensic Entomology: Arthropods collected on decomposing pig carrions in Warri, Delta State, Nigeria.

A data base of arthropods of forensic importance was collected from pig carrions from 10th June to 10th August 2017 in the Warri city, 3 pigs were killed by cervical dislocation and left to decay while the daily assemblage of arthropods were collected from it. The result showed 5 stages of the carrion decomposition; fresh, bloated, active decay, advance decay and dry decay correspondingly despite that there was only a single sequence of decomposition. Entomofauna groups from 3 orders of Diptera, Coleoptera and Hymenoptera, with ten families were collected during the study while 233 insects were collected at the fresh stage, 324 were collected at the bloat stage, and 328 were recorded at the active decay stage, 405 at the advance decay stage and only 158 at the dry decay stage. The dominance index was high (0.09) at the dry decay stage but low (0.06) at the bloat, active decay and advanced decay stages. Shannon–Wiener index (H) was high (2.91) in the advanced decay stage but was low (2.52) at the dry decay stage. Arthropod from the orders of Diptera and Coleoptera were forensically significant as they used the carcasses for feeding and oviposition and could be used in the estimation of the post mortem interval while the order Hymenoptera used the carrion as extension of their habitat and as predatory ground to the necrophagous groups, it is advocated that more studies be carried out in different seasons using different animal models to create dependable data base of forensically importance arthropods in Warri and its environs.

First record of flesh fly Sarcophaga (Liosarcophaga) aegyptica (Diptera: Sarcophagidae) from India

Accurate identification of insect specimens is an essential requirement in forensic entomology. This study aimed to collect adult sarcophagid flies and to identify them based on the male genitalic characters. Its the first report of Sarcophaga (Liosarcophaga) aegyptica from India. The fly has collected, from pig carcasses placed in indoor, outdoor, and aquatic environments during bloated & advanced decay stages of decomposition. The carcasses have placed for decomposition during winter (2015) and spring (2017) seasons in the rural area of Punjab (India). S. (L.) aegyptica belongs to subgenus Liosarcophaga of Superfamily Sarcophagidae, and Salem first reported it from Egypt in 1935. S. (L.) aegyptica is a subtropical thermophilous species that has a wide distribution in the Eastern Hemisphere. The species is infrequent and generally attracted to meat and feces. Their larvae feed and develop on vertebrates carcasses. The species show peculiarity from other species of this genus by the structure of inner forceps of genitalia, which is straight and slightly widened at the subterminal end. Another disparity is in the process of the apical plate of paraphallus, which is pointed at the end. This family has great importance in the field of forensic entomology as they visited immediately on carcasses after Calliphoridae. The fly is of medical importance as these flies are responsible for causing myiasis in humans and animals; hence, they are of medical importance and useful in the estimation of post mortem interval (PMI).

A Preliminary Forensic Entomological Study of Beetles (Coleoptera) in Interior Alaska, USA.

Forensic entomology uses knowledge of arthropod ecology to help solve crimes. There has been no published forensic entomological research in Alaska. We used one piglet carcass split in half to create two carcass plots in Fairbanks (~64.8°N, subarctic) that were sampled over a period of 59days in 2019. Four pitfall traps were placed around each carcass, and four similarly arranged pitfall traps were placed 40m distant as controls. Traps were emptied approximately weekly covering the first four stages of decomposition. We focused on adults of the larger-bodied (>9mm) families and subfamilies of Coleoptera: Staphylinidae (subfamily Staphylininae), Carabidae, and Silphidae. A total of 621 specimens were collected and processed: 29 staphylinines, 210 carabids, and 382 silphids. A one-way ANOVA showed no significant difference between the mean numbers of staphylinines or carabids caught in carcass versus control traps. Silphids showed significantly greater mean number of beetles caught in carcass traps relative to control traps. Four species of Silphidae were documented, but contrary to similar studies, the vast majority of specimens belonged to two species of Nicrophorus (N.vespilloides Herbst and N.investigator Zetterstedt). Each of the three target taxa showed a peak in the number of specimens collected during the bloat stage of decomposition despite the carabid peak being driven by a phytophagous species.

Succession study on forensically important Coleoptera from India: a preliminary study and its forensic implications

BackgroundColeoptera is the second most important group of entomofauna associated with decomposition, yet little is known about its role in decomposition and postmortem colonization of carcasses in India and other parts of the world. Consequently, a preliminary study was conducted to study the succession of forensically important Coleoptera using goat carrion as an animal model.ResultsFive decomposition stages were observed during the experiment. A total of 1174 adult coleopterans belonging to 21 species and seven families were collected during this study. Throughout faunal succession, Histeridae and Silphidae were the dominant Coleopteran families, and they occurred mainly during the bloated and decay stages of decomposition; Necrophila (Calosilpha) ioptera was the dominant species present from the bloated to dry stage of putrescence. Two species, Pachylister bellicus and Saprinus sternifossa were reported for the first time from India.ConclusionThis study provides baseline data regarding Coleopteran species associated with different decomposition stages, but more extensive studies need to be performed to develop a geographical database on arthropod succession from as many habitats as possible so that this kind of data can be used in forensic cases.

Successive waves of dipteran flies attracted to warfarin-intoxicated rabbit carcasses in Cairo, Egypt

BackgroundForensic entomology is an increasing area of research, focuses on the violent crime, and deals with the necrophagous-feeding insects that typically decompose carcasses. The present study aimed to update the baseline data of the decay process and its associated successive waves of necrophagous flies on rabbits placed in an urban city (Cairo, Egypt) in spring season.ResultsSix rabbits divided equally into two groups were used. The first group was killed by asphyxia via hanging and marked as the control (C), while the second group was intoxicated with rodenticide warfarin (WI). The fresh, bloated, active decay, advanced decay, and skeletal stages of decomposition were observed and defined in all carcasses. Out of 30 insect families collected, 3 families were more common (Calliphoridae, Muscidae, and Sarcophagidae). Thirteen insect families were collected of which Calliphoridae, Muscidae, and Sarcophagidae were common. A total of 10,121 individuals (immature and adult stages) of 26 species were collected, of which Chrysomya rufifacies was the most common species on both types of carcasses (14.7%) followed by Musca domestica, Chrysomya megacephala, Chrysomya albiceps, Muscina stabulans, Sarcophaga hertipes, Calliphora vicina, Musca sorbens, Lucilia cuprina, Sarcophaga argyrostoma, and Lucilia sericata (2.0–12.4%). The other 15 species were represented by small numbers (cumulatively 2.9%). Among the collected flies, Scathophaga litorea (Scathophagidae) was reported for the first time as a new report in Egypt. Unexpectedly, significantly more adults and immatures were attracted to WI than to C carcasses (P < 0.05).ConclusionThis study investigated the rabbit carrion dipteran necrophagous fauna as a model which may be of value for medico-legal cases.

Seasonality of Insect Succession and Dog Carcass Decomposition in Different Habitats

The different collected insect species were distributed on the carcasses according to the decomposition stages or postmortem intervals (PMI). In the winter season, the insect succession showed that carcasses placed outdoor attracted the greatest numbers and highest diversity of insect species. The calliphorid fly; Chrysomya albiceps was first attracted to the bloated and decay stages. In both habitats (outdoor and indoor), the numbers and diversity of insect species on carcasses were decreased during the advanced decay stage and then increased again during the dry stage. In the spring season, Chrysomya albiceps was the first fly attracted to the fresh or bloated stage of dog carcass in both habitats. Moreover, calliphorid flies were disappeared during the advanced decay stage in both habitats. While Coleopteran insects appeared during the decay and advanced decay stages. In the summer season, the forensic insect species showed nearly the same distribution of the different decomposition stages. Also, Chrysomya albiceps was the first fly attracted to the early stages of decomposition. In general, it appeared that the diversity and numbers of forensic insect species, which colonize dog carcass, were increased outdoor and decreased indoor. In the autumn season, carcasses placed outdoor attracted the greater numbers and higher diversity of forensic insects. The calliphorid fly, Chrysomya albiceps,and housefly, Musca domestica were first attracted to the fresh and bloated stages, especially of carcasses placed outdoor. The adult beetles, Dermestes maculatus, Necrobia rufipes and Hister sp.were early seen during bloated, decay and advanced decay stages.

Social wasps (Vespidae: Polistinae) on carcasses of Rattus norvegicus (Mammalia: Muridae) in the Central Amazonia, Brazil: possible forensic implications

We evaluated the occurrence of social wasps in the decomposition process in tropical rainforest in central Amazonia (Ducke Reserve, Manaus, Brazil), using cadavers of rats as attractants, exposed in suspended cages. Ten species, in three genera, of social wasps were collected only in the initial stages of decay (fresh and bloated). Five species were collected, mainly in the fresh stage, feeding on flesh: Agelaia angulata, Agelaia constructor, Agelaia fulvofasciata, Agelaia pallipes and Angiopolybia pallens. Five species were collected, mainly in the bloated stage, feeding on flesh and eggs and first instar larvae of dipteran: Agelaia testacea, Angiopolybia obidensis, Apoica arborea, Apoica pallens and Apoica thoracica. Due to the aspect of the injuries caused by the wasps to the carcass, they may be mistaken as skin ulcers, burns or abrasions, which may mislead a forensic investigation.

Temperature Influence on Prevailing Necrophagous Diptera and Bacterial Taxa With Forensic Implications for Postmortem Interval Estimation: A Review.

The decomposition process of human (and other mammalian) remains is influenced by numerous factors such as the environmental temperature, relative humidity, precipitation, geographical location of the remains, as well as the medical conditions of and any injuries sustained by the deceased person. The decomposition process generally follows a consistent pattern (fresh, bloat, active decomposition, advanced decomposition, and dry stage). Understanding the time-span of each stage of decomposition and the influence of the biotic and abiotic factors involved is imperative when trying to estimate the time elapsed since death (postmortem interval [PMI]). Over the course of decomposition, the tissues are gradually consumed by necrophagous insects and bacteria. The environmental temperature and its variations influence how insects colonize the remains, having a significant impact on their presence and developmental cycle. Additionally, the bacterial community colonizing decomposing tissues is also greatly affected by variations in environmental temperature. Because both the rate of decomposition of human remains and the relative abundance of certain insects and bacterial species are all temperature-dependent, insect and bacterial colonization data are useful as key points for the PMI estimation. This article reviews the current literature documenting the data collected on the occurrence and development cycles of predominant necrophagous Diptera (Calliphoridae, Muscidae, Sarcophagidae) and bacterial taxa involved in the decomposition of various carcasses at different temperatures. This review will impact the forensic community by providing an overview on the temperature, insect and bacterial records for the PMI estimation, seeking to aid forensic entomologists, microbiologists, pathologists, and the legal community.

Ants (Hymenoptera: Formicidae) Attracted to Rabbit Carcasses in Three Different Habitats

This study reports the ant species that were attracted to rabbit carcasses in three different habitats (agricultural, desert, urban) in the city of Riyadh, Saudi Arabia from May to July 2014. Rabbit carcasses were used as a model for decomposition. Carcasses were categorized as exposed, clothed, shaded and burnt. A total of 726 ants belonging to three subfamilies and 14 species were collected during the decomposition process. Trichomyrmex mayri (Forel) was the only ant species attracted to the carcasses placed in the desert site. At the agricultural site, there was one ponerine species, five formicine species, and three myrmicine species were attracted, while at the urban site, five formicine species and one myrmicine species were recorded. The agricultural site attracted the highest number of ants. In contrast, the desert site attracted the lowest number of ants. Tr. mayri was the most prevalent species occurring in both the agricultural and desert sites. The bloated stage of decomposition attracted the highest number of ants followed by the decay, fresh and dry stages, respectively. Clothed carcasses attracted the highest number of ants followed by the exposed and burnt carcasses, respectively. The shaded carcasses attracted the fewest number of ants. This study found that ants are attracted to carcasses at all stages of decomposition and are common components of the necrofauna of central Saudi Arabia.

Chrysomya chani Kurahashi (Diptera: Calliphoridae), a blow fly species of forensic importance: morphological characters of the third larval instar and a case report from Thailand

ABSTRACTBlow flies are worldwide the most important insects from a forensic point of view. In Thailand, aside from the two most common species, Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart), Chrysomya chani Kurahashi was also found to be of forensic importance. We present a case of a human female cadaver in its bloated stage of decomposition, discovered at Pachangnoi Subdistrict, northern Thailand. Entomological sampling during the autopsy displayed an assemblage of numerous dipteran larvae. Macroscopic observations showed the coexistence of third instar larvae of the three blow flies C. megacephala, Chrysomya villeneuvi Patton, an unknown blow fly species and one muscid, Hydrotaea sp. The minimum post-mortem interval was estimated to be six days, based on the developmental rate of C. megacephala. The ID of the unknown larva, which is the focus of this report, was revealed later as C. chani by DNA sequencing, using a 1205 bp of cytochrome c oxidase subunit I (COI). The occurrence of C. chani on a human body revealed the need to analyse and describe the morphology of its immature stage, to enable forensic entomologists to identify this fly species in future cases. The morphological examination of the third instar was performed, revealing peculiar characteristics: protuberant tubercles encircling abdominal segments; 9–11 lobes on the anterior spiracle; six prominent pairs of tubercles along the peripheral rim of the eighth abdominal segment; a heavily sclerotized complete peritreme of the posterior spiracles. A key to differentiate the third instar of blow flies of forensic importance in Thailand is provided.

The importance of Saprinus semistriatus (Coleoptera: Histeridae) for estimating the minimum post-mortem interval.

In forensic science, the use of entomological evidence to estimate the minimum post-mortem interval can be crucial. However, not all cadaver-visiting insects are equally useful. Our focus is on the histerid beetle Saprinus semistriatus (Scriba 1790) (Histeridae; Coleoptera). Histeridae are common predators that feed mainly on dipteran larvae on carrion and dung. We review 23 publications mentioning this species and provide new experimental data on its temporal pattern beneath and on hanging pig cadavers. In a field experiment near Neuchâtel, Switzerland, we recorded the abundance of S. semistriatus on ten decomposing pig cadavers (Sus scrofa) over a 32-day period in summer 2013 (July, 01- August; 02). Five cadavers were placed on the ground and five cadavers were hung one metre above the ground. Insects were collected from pitfall traps and by manual sampling. The abundance of S. semistriatus was significantly higher during the active stage than during the fresh and the bloated stages of decomposition in both, ground and hanging pigs. However, S. semistriatus was more abundant on the ground than on the hanging cadavers. The literature and our new data show that S. semistriatus is present on cadavers during a relatively short period of time (approximately two weeks), mainly during the active decay stage, but it may also occasionally occur in the bloated stage. Identifying key indicators such as S. semistriatus can help optimise forensic research by focusing on the most informative taxa. A few key indicators for each decomposition stage may constitute an optimal toolbox for forensic entomologists.

Insect succession on pig carcasses using different exposure time - A preliminary study in Guangzhou, China

The exposure time of carcasses in insect succession studies are generally not consistent and more than 40% studies start in the morning. How such an arrangement affects the succession of insects is worth evaluating. In this study, six piglet carcasses (15–17 kg) were exposed at 6 time points during the day: 11:00, 15:00, 19:00, 23:00, 03:00 and 07:00 on July 20th-July 21st 2006 in Guangzhou, China to investigate the potential effects of the time of day of carcass exposure on body decomposition and insect succession, and also to provide fundamental data on insect succession in summer for this area. The results showed that there were negligible differences in the decay process among the carcasses. We found the carcasses synchronized their decay stage after entering the bloated stage on July 21st. All 6 carcasses entered the remains stage on August 3rd (approximately 14 d after carcass placement). The carcasses yielded 30 species of arthropods, representing 3 orders and 12 families, and no obvious differences were found in species composition between the carcasses. However, we found that there were significant differences in the arrival and colonization of Calliphoridae. We found two batches of Chrysomya megacephala (Fabricius) larvae with significant differences in body length and instar on the carcasses placed at the site at 11:00, 15:00 and 19:00. By contrast, there was only one batch of C. megacephala larvae having similar body length and instar on the carcasses placed at the site at 23:00, 03:00 and 07:00. These observations have potential use for estimating the postmortem interval in forensic entomology.