A preliminary study of forensic entomology in Medellín, Colombia

A preliminary study of carrion insects in Greece and their attraction to three animal baits: a forensic entomology perspective

The current study provides data on the composition of the dipteran and coleopteran fauna attracted to three different animal baits (chicken stomach, beef liver, fish) in the urban ecosystem of Athens, Greece. An additional objective was to examine the effect of bait choice by the collected taxa. Three trap locations were established within the Agricultural University of Athens. At each location two different types of baited traps were used to capture and record the local dipteran and coleopteran biodiversity. During the sampling period, a total of 2416 dipteran and coleopteran specimens representing 43 species were collected and identified. The three most abundant dipteran taxa were Sarcophaga sp. (Diptera: Sarcophagidae), Calliphora vicina Robineau-Desvoidy, Lucilia sericata (Meigen) (Diptera: Calliphoridae). The results showed that the structure of the local insect community associated with the decomposition of animal baits depends on the bait used for sampling. This study reinforced the feasibility of using animal tissues as attractants to a wide diversity of medical, parasitological and forensically important taxa. Overall, beef liver attracted the most insects with Diptera preferring beef liver and Coleoptera preferring chicken stomach. Furthermore, this study revealed that baits of one animal tissue did not attract all species but in combination a much better understanding of this biodiversity was achieved. Finally, from a forensic entomology perspective this study highlights the lack of understanding of the value of entomological data related to case work in Greece.

Seasonal diversity and dynamics of entomofauna associated with the decomposition of pig (Sus scrofa domesticus L.) carcasses in a Peri-urban area of Central Burkina Faso, West Africa

This study aimed to determine the effects of seasons on the diversity and dynamics of insects associated with pig carrion in Gampela, Plateau Central Region, Burkina Faso, West Africa. Pig carcasses (Sus scrofa domesticus L.) were exposed in an open area to monitor their decomposition process and their colonization by insects during a warm and dry period (March-April 2015), a warm and wet period (August-September 2015) and a cool and dry period (December 2015-January 2016). Monitoring and entomological data collection occurred for 60 days for each study period. The decomposition process always included five stages (fresh, bloating, putrefaction, postputrefaction, and skeletal), which varied in duration depending on the study period. In sum, 118,761 insects belonging to 4 orders, 12 families, 17 genera, and 21 species were collected during the three study periods, with approximately 61% of the individuals collected during the warm and wet period. The dynamics of insect populations associated with the pig carcasses included two peaks at each study period. Formicidae was the most abundant insect family in each study period, but Musca domestica was the most abundant species. The listed species were found to belong to four trophic groups with a predominance of predators/carnivores followed by necrophagous insects. The orders, families, and trophic groups reported in this study were significantly more abundant during the warm and wet period. The results show prospects for the use of Calliphoridae, Muscidae, and Dermestidae in criminal investigations, depending on seasonal variations in Sudano-Sahelian areas.

A synthesis of carcass decomposition studies conducted at a tropical (Aw) taphonomy facility: 2013-2022

Decomposition studies have been conducted in several regions of the world, but relatively few have investigated taphonomy in tropical environments. Even fewer have explored carcass decomposition during multiple tropical seasons, leaving the relationships between season and decomposition in tropical environments poorly understood. Ten decomposition studies using 30 carcasses were conducted in Honolulu, Hawaii, USA to start addressing this knowledge gap. These studies show that some postmortem processes were observed regardless of season. Carcass temperature and chemistry were spatiotemporally variable. Fly larval masses were consistently observed within 3 days (∼75 ADD) postmortem and carcasses lost 60%-90% of mass by 10 days (∼250 ADD) postmortem (Total Body Score ∼26). Season had a significant effect on decomposition, yet the warmest and most humid seasons did not always result in the most rapid and extensive decomposition. Seasonal variation appears to be less pronounced than at other tropical decomposition sites.

Beetles associated with buried carcasses: potential forensic importance in Riyadh, Saudi Arabia

Burial has a special influence on carrion fauna, which may change the rate of decomposition and so affect postmortem estimates. This study aimed to identify species and succession of beetles on buried remains. From 28 January to 31 May 2021, we examined the Coleoptera on buried and exposed rabbit carcasses, on the campus of the University of King Saud in an area measured around 175 m by 250 m. The area is almost entirely devoid of flora, except for a few acacia trees and some common wild herbs. It is about 1 km away from residential neighborhoods. In total, 165 specimens belonging to 4 families were collected. The Tenebrionidae was the most abundant family, where it formed 52% at a depth of 20 cm and 78% at a depth of 40 cm in the buried carcasses, while the family Dermestidae was the most abundant in the surface carcasses, as it formed 53% of the insects sampled. Type Mesostena puncticollis Solier, 1835 (Tenebrionidae) predominated at exposed carcasses as well as at depths of 20, 40 cm and while type Dermestes frischii Kugelann, 1792 (Dermestidae), predominated at depth of 40 cm and exposed carcasses, and type Saprinus chalcites (Illiger, 1807) (Hisiteridae) at depth of 20 only. These findings are possibly useful in forensic investigations involving buried bodies in Riyadh, Saudi Arabia.

Temperature-Dependent Development of Nitidula rufipes (Linnaeus, 1767) (Coleoptera: Nitidulidae) and Its Significance in Estimating Minimum Postmortem Interval

Coleoptera, including the family Nitidulidae, are valuable for estimating long-term postmortem intervals in the late stage of body decomposition. This study showed that, under seven constant temperatures of 16, 19, 22, 25, 28, 31, and 34 °C, the developmental durations of Nitidula rufipes (Linnaeus, 1767) from oviposition to eclosion were 71.0 ± 4.4, 52.9 ± 4.1, 40.1 ± 3.4, 30.1 ± 2.1, 24.2 ± 2.0, 21.0 ±2.3, and 20.8 ± 2.4 days, respectively. The morphological indexes of body length, the widths of the head capsules, and the distance between the urogomphi of the larvae were measured in vivo. The regression model between larval body length and developmental durations was simulated for larval aging, and the head capsule width and the distance between the urogomphi at different instars were cluster-analyzed for instar discrimination. Based on the developmental durations, larval body length and thermal summation data were obtained, and the isomorphen diagram, isomegalen diagram, linear thermal summation models, and curvilinear Optim SSI models were established. The lower developmental threshold and thermal summation constant of N. rufipes evaluated by the linear thermal summation models were 9.65 ± 0.62 °C and 471.40 ± 25.46 degree days, respectively. The lower developmental thresholds, intrinsic optimum temperature, and upper lethal developmental threshold obtained by Optim SSI models were 10.12, 24.15, and 36.00 °C, respectively. The study of the immature stages of N. rufipes can provide preliminary basic developmental data for the estimation of minimum postmortem interval (PMI_min). However, more extensive studies are needed on the effects of constant and fluctuating temperatures on the development of N. rufipes.

High-throughput sequencing to evaluate the effects of methamphetamine on the succession of the bacterial community to estimate the postmortem interval

In forensic medical examinations, estimating the postmortem interval (PMI) is an important factor. Methamphetamine (MA) is a synthetic stimulant that is commonly abused, and estimation of the PMI after MA abuse has become one of the main tasks in forensic investigation. Microorganisms play a vital role in carrion decomposition. Analysing the bacterial succession patterns can be used as a forensic tool to estimate the PMI. The present study aimed to analyse bacterial succession changes during the decomposition of MA to estimate the PMI. We analysed bacterial communities in rabbits treated with three different concentrations of MA (0, 22.5, and 90 mg/kg) under the natural conditions of 20 °C and 70% humidity by sequencing 16S rRNA gene amplicons using the Illumina MiSeq system. We obtained 2 374 209 high-quality sequences and 2 937 operational taxonomic units (OTUs). The relative abundances of the bacterial communities varied markedly in response to different MA concentrations. Interestingly, in response to the different concentrations of MA, Bacteroidetes became disparate in the rectum in the late PMI. Increased numbers of bacterial taxa were identified in the rectum and buccal cavity samples, except at the highest concentration of MA in the rectum samples when PMI was 0-h, than were present in live rabbits. Meanwhile, the PMI correlated significantly with bacterial succession at different taxonomic levels. Our results suggested that bacterial community succession could be used as a "microbial clock" to estimate the PMI in cases of MA-related death; however, further study is required to gain a deeper understanding of this concept.

Molecular identification and diversity of adult arthropod carrion community collected from pig and sheep carcasses within the same locality during different stages of decomposition in the KwaZulu-Natal province of South Africa

The current study aimed at molecular identification and comparing the diversity of arthropods communities between pig and sheep carcasses during the cold and warm season in KwaZulu-Natal province of South Africa. Adult arthropods found on and around the carcasses were collected using either fly traps or forceps. Molecular analyses confirmed the identification of twelve arthropod species collected from both sheep and pig carcasses during the cold season. Results showed that 11 of 12 arthropod species were common in both sheep and pig carcasses, with exception to Onthophagus vacca (Coleoptera: Scarabaeidae) (Linnaeus, 1767) and Atherigona soccata (Diptera: Muscidae) (Rondani, 1871) species which were unique to sheep and pig carcasses respectively. However, during the warm season, the sheep carcass attracted more arthropod (n = 13) species as compared to the pig carcass. The difference in the obtained arthropod was due to the presence of O. vacca which was also unique to the sheep carcass during this season. Furthermore, there was an addition of a beetle species Hycleus lunatus (Coleoptera: Meloidae) (Pallas, 1782), which was collected from both sheep and pig carcasses but unique to the warm season. The pig carcass attracted more dipteran flies during both warm (n = 1,519) and cold season (n = 779) as compared to sheep carcass during the warm (n = 511) and cold season (n = 229). In contrast, coleopterans were more abundant on the sheep carcass during the warm season (n = 391) and cold season (n = 135) as compared to the pig carcass in both warm season (n = 261) and cold season (n = 114). In overall, more flies and beetles were collected on both sheep and pig carcasses during the warm season, and this further highlight that temperature influenced the observed difference in the abundance of collected arthropod between seasons.

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.

The impact of the decomposition process of shallow graves on soil mite abundance

Burial of a cadaver results in a slower decomposition rate, due to more stable below‐ground temperatures and restricted access to necrophagous insects. In such circumstances, analysis of the soil mesofauna, with emphasis on mites (Acari) may be more valuable in time‐of‐death estimations. The production of volatile organic compounds of cadaveric decay results in changes, especially in the soil pH, which in turn would affect the abundance and diversity of the associated mites. In general, the effects of decomposition and the consequently altered pH levels on the abundance of mites in shallow graves, as well as the effects of fluctuating above‐ground environmental parameters (temperature, relative humidity, and precipitation) remain unknown. Here, we found that the decay of three pig cadavers buried in shallow graves (<30 cm below) caused a significant increase in the soil pH throughout decomposition, from neutral to alkaline. Cadaver decay attracted an abundance of mites: with 300 mites collected from the three pig cadavers compared to 129 from the control soil samples at the same depth. Mites rapidly became more abundant in cadaver‐associated soils than in control soils after the fresh stage. Increasing soil pH had a positive impact on the abundance of mites in graves and there was a significant interaction between cadaver body temperature and soil pH. Above‐ground fluctuations in temperature, relative humidity, and precipitation were found to have no significant direct effect on mite abundance in grave or control soils.

An Investigation of the Variations in Complete Mitochondrial Genomes of Lingula anatina in the Western Pacific Region

Lingula anatina is a brachiopod widely distributed in the western Pacific region. Even though L. anatina has been targeted for a number of biological studies, there is still limited information on intraspecific genetic variations of L. anatina. In this study, L. anatina specimens were collected from Korea and Vietnam, and complete mitochondrial genome (mitogenome) sequences were analyzed and compared with previous records. The total mitogenomes of L. anatina were 24,875 bp and 25,305 bp in size for Korean and Vietnamese specimens, respectively. Those mitogenomes are extraordinarily longer than the typical mitogenome size for an animal but shorter than the previous record from Yanagawa (Japan) for this species. The gene orders and the sizes of the protein-coding genes are also different from those for the Japanese specimen. Furthermore, the nonsynonymous (Ka) and synonymous (Ks) substitution rates in protein-coding genes (PCGs) were calculated to test the idea of evolutionary rate differences in mitochondrial genomes. The analyses showed relatively low Ka and Ks for the complete mitogenomes from Buan (Korea), Doson (Vietnam) and Yanagawa (Japan). The Ka/Ks ratio was less than 1 in comparisons of three localities, indicating the existence of purifying selection in this species. The phylogenetic analyses showed that L. anatina diverged among localities in the western Pacific region.

The Forensic Entomology Case Report-A Global Perspective

Forensic practitioners analyzing entomological evidence are faced with numerous challenges when presenting their findings to law practitioners, particularly in terms of terminology used to describe insect age, what this means for colonization time of remains, and the limitations to estimates made. Due to varying legal requirements in different countries, there is no standard format for the entomological case report prepared, nor any guidelines as to the sections that are required, optional or unnecessary in a case report. The authors herein propose sections that should be considered when drafting an entomological case report. The criteria under which entomological evidence is analyzed are discussed, as well as the limitations for each criterion. The concept of a global, standardized entomological case report is impossible to achieve due to national legislative differences, but the authors here propose a basic template which can be adapted and changed according to the needs of the practitioner. Furthermore, while the discussion is fairly detailed, capturing all differences between nations could not be accomplished, and those initiating casework for the first time are encouraged to engage other practicing forensic entomologists or professional associations within their own nation or region, to ensure a complete report is generated that meets lab or national requirements, prior to generating a finalized report.

Modeling the Invasion of the Large Hive Beetle, Oplostomusfuligineus, into North Africa and South Europe under a Changing Climate

Simple Summary

Large Hive Beetles (LHBs) are common pests of honeybee colonies, especially in the African continent. The ability of this pest to invade new regions in North Africa and Europe is highlighted in the present study using a species distribution modeling technique in current and future climate change scenarios in 2050 and 2070. In brief, this pest will be a new burden on the beekeeping sector outside Africa, and therefore the development of early monitoring strategies is recommended.

Abstract

Some beetle species can attack honeybee colonies, causing severe damage to beekeeping. These pests include Oplostomus fuligineus, which is also known as the Large Hive Beetle (LHB). This beetle is native to Sub-Saharan Africa and has recently also been recorded in some parts of North Africa. It feeds mainly on young bee larvae and stored food within the colonies, causing severe damage to weak colonies. The present work sheds light on the current and future distribution (from 2050 to 2070) of this beetle in Africa and South Europe using species distribution modeling. Maxent was used to model the invasion of LHB. The Shared Socioeconomic Pathways (SSPs) 126 and 585 were used to model the future distribution of LHB. The Maxent models showed satisfactory results with a high Area Under Curve (AUC) value (0.85 ± 0.02). Furthermore, the True Skill Statistics (TSS) value was equal to 0.87. The current and future maps showed a high risk of invasion because of temperature variation in most of the parts of North Africa and South Europe. The maps also predicted the future invasion of LHB into other countries, mainly through southern Europe. These predictive risk maps will help quarantine authorities in highly relevant countries to prevent the expansion of this pest outside of its natural range.

Role of Chrysomya albiceps (Diptera: Calliphoridae) and Musca domestica (Diptera: Muscidae) Maggot Crop Contents in Identifying Unknown Cadavers

Forensic entomology focuses on the analysis of insect larvae present at crime scenes to help identify unknown cadavers. Carrion-feeding maggots store food in a crop located at the anterior end of the gut. DNA recovered from the crop can be amplified, sequenced, and identified to determine the origin of the food. This information could help investigators to identify a missing victim if maggots are discovered at a crime scene in the absence of a corpse. Chrysomya albiceps (Wiedemann) and Musca domestica (Linnaeus) are primary forensic species. Little or no information on the identification of unknown cadavers using C. albiceps and M. domestica larvae is available, and we aimed to compare the effectiveness of using the crop contents of instars of C. albiceps and M. domestica larvae to identify corpses at different time intervals. Two hundred and forty larvae of both species were reared on rat and/or mouse liver, and DNA from crop contents was extracted after different time intervals from different instar larvae. DNA was amplified using specific primers that match the mitochondrial cytochrome oxidase subunit I (mt COI) gene of the food source. Results showed that food provided to larvae affected life span and the ability to be used to identify unknown cadavers. Chrysomya albiceps larvae proved more useful than M. domestica larvae. Moreover, crop contents of third instar larvae of both species fed for 24 h are more useful than contents from other time intervals in identifying unknown tissues. Results are promising and may help investigators to identify unknown/missing victims.

Tafonomía forense: estudio experimental del proceso de descomposición cadavérica en un Bosque seco tropical costero

El conflicto armado y la delincuencia común son las principales fuentes de homicidios en Colombia, lo que confronta a las autoridades con cadáveres abandonados y sin identificar; esta situación plantea la necesidad de recrear escenas del crimen como herramienta para estimar el Intervalo Post Mortem. Se utilizó un cadáver de cerdo para estudiar su proceso de descomposición bajo condiciones de exposición al sol en un fragmento de bosque seco del cerro Ziruma en la ciudad de Santa Marta, Colombia. El cerdo es considerado como un buen biomodelo, debido a las similitudes biológicas con el ser humano. Se evidenciaron cinco fases de descomposición, las cuales fueron descritas durante 10 días, teniendo en cuenta los cambios físicos y la temperatura ambiental. Se documentó la actividad de insectos necrófagos, la cual, junto a las altas temperaturas presentadas en el lugar de estudio, jugaron un papel importante en el aceleramiento del proceso de descomposición. El empleo de este tipo de biomodelos permitirá a futuro el desarrollo de herramientas forenses y la ejecución de protocolos de muestreos, para esclarecer investigaciones médico-legales, al contar con información útil para estimar los tiempos de muerte en cadáveres encontrados en avanzado estado de descomposición en ecosistemas similares.

Biological, Ecological, and Distributional Aspects of Two Native Species of Lucilia Genus (Diptera: Calliphoridae) of Forensic Interest in Yungas Environments of Argentina

This study determined the spatial and temporal dynamics of two native neotropical species flies of forensic interest, belonging to the Lucilia (Robineau-Desvoidy) genus. The study focused on their abundance and reproductive behaviors associated with different habitats and phenological parameters. In the Province of Salta, Argentina, monthly samplings were performed over 1 yr in urban, rural, and native habitats, at morning, mid-day, and afternoon periods, controlling the oviposition of captured specimens. Environmental variables were also assessed: cloudiness, precipitation, relative humidity, temperature, and tree cover. Lucilia purpurascens (Walker) appeared to be associated with native habitats, whereas Lucilia ochricornis (Wiedemann) was mainly associated with rural habitats, exhibiting distinct habitat preferences. Two ecotones were also identified: rural-urban and rural-native, suggesting rural habitats promoted habitable conditions at its margins. Both species were recorded at the end of winter to the middle of autumn, with an initial peak in early spring, and a second peak at late summer. These peaks were associated with the highest numbers of laid eggs. Lucilia purpurascens preferred high tree coverings, whereas L. ochricornis resisted areas with intermediate sun, suggesting limited sun exposure was important. The latter was also associated with daily flight activities; during the warm season, the densest catches occurred at morning and afternoon periods, whereas during the cold season, they occurred at mid-day. Climatic variables explained 77% of variability in terms of abundance and oviposition. Synergistic effects were observed between these variables, suggesting that these variables conditioned insect distribution and reproduction, and not just temperature per se.

Contribution to the knowledge of the clown beetle fauna of Lebanon, with a key to all species (Coleoptera, Histeridae)

The occurrence of histerids in Lebanon has received little specific attention. Hence, an aim to enrich the knowledge of this coleopteran family through a survey across different Lebanese regions in this work. Seventeen species belonging to the genera Atholus Thomson, 1859, Hemisaprinus Kryzhanovskij, 1976, Hister Linnaeus, 1758, Hypocacculus Bickhardt, 1914, Margarinotus Marseul, 1853, Saprinus Erichson, 1834, Tribalus Erichson, 1834, and Xenonychus Wollaston, 1864 were recorded. Specimens were sampled mainly with pitfall traps baited with ephemeral materials like pig dung, decayed fish, and pig carcasses. Several species were collected by sifting soil detritus, sand cascading, and other specialized techniques. Six newly recorded species for the Lebanese fauna are the necrophilous Hister sepulchralis Erichson, 1834, Hemisaprinus subvirescens (Ménétriés, 1832), Saprinus (Saprinus) externus (Fischer von Waldheim, 1823), Saprinus (Saprinus) figuratus Marseul, 1855, and Saprinus (Saprinus) niger (Motschulsky, 1849) all associated with rotting fish and dung, and the psammophilous Xenonychus tridens (Jacquelin du Val, 1853). With the exception of Hister sepulchralis, all these taxa belong to the Saprininae subfamily. A most likely undescribed species of Tribalus (Tribalus) (Tribalinae) has also been collected in detritus at wet places near rivers in Lebanon. Because of the complexity of the genus Tribalus, with possible numerous new species present in the circum-Mediterranean area, the Lebanese species is not described herein, pending a revision of the genus. This study advocates further research aimed at improving taxonomic and ecological knowledge of this coleopteran family in Lebanon. The number of Histeridae species currently known from Lebanon stands at 41; a key to all species including images is included.

A mummified human corpse and associated insects of forensic importance in indoor conditions

We report, for the first time from Poland, the presence of Dermestes haemorrhoidalis (Coleoptera: Dermestidae) on a mummified human corpse found in a flat (Lower Silesia province, south-western Poland). Different life stages of D. haemorrhoidalis were gathered from the cadaver, and the signs of activity of these beetles (i.e. frass) were observed. On the basis of these facts, we concluded that the decedent, whose remains were discovered in the flat on 13 December 2018, died no later than the summer of 2018, with a strong probability that death occurred even earlier (2016 or 2017). A case history, autopsy findings, and entomological observations are provided. The presence of larvae of Dermestidae in the empty puparia of flies is reported for the first time. A list of the invertebrate species found in the corpse is provided, compared with available data, and briefly discussed.

Calliphoridae (Diptera) in Human-Transformed and Wild Habitats: Diversity and Seasonal Fluctuations in the Humid Chaco Ecoregion of South America

A temporal study of the Calliphoridae fauna was conducted in five different types of habitats in the Humid Chaco ecoregion: an urban settlement, a cattle farm, an alfalfa crop, a savanna, and a forest. Research was carried out to analyze 1) how the species composition of blow fly communities changes across different types of human-modified and wild environments, 2) their seasonal fluctuations, and 3) the influence of climatic factors (relative humidity, temperature, and precipitations) on the temporal dynamics of these communities. In each habitat, five sites were selected for the collection of blow flies using bait traps, and flies were collected for 1 yr. In total, 32,100 blow flies were collected, distributed in five genera and 11 species. The native species Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae) was the most abundant, followed by the exotic Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae). The abundance of exotic species represented 59.9% of the total sample, showing a reduction toward less disturbed sites. The Calliphorid communities were compared in terms of species richness, composition, and abundance between habitats and seasons. Our results showed that the habitat type and season affect the composition of blow fly communities. The alfalfa crop and the forest showed the highest diversity of species. In general, there was a decrease in blow fly activity during winter in all habitats. The climatic factors did not greatly affect the diversity of these flies. This study provides a first understanding of several ecological aspects of the Calliphoridae assemblages of the previously unsurveyed Humid Chaco ecoregion of South America.

Evaluation of Insect Succession Patterns and Carcass Weight Loss for the Estimation of Postmortem Interval

This study assesses the succession of insects on rabbit carcass. The study was conducted in sunny and shaded sites in the west of Iran during four seasons in 2016 and 2017. Based on the results of this study, various factors such as body size, carcass location, and carcass injury could affect the pattern of insect succession on carcass. In this study, we estimated the elapsed time since death (R2 > 0.98, P = 0.00) based on carcass weight loss during the stages of decomposition and the cubic method. Jaccard analysis was performed to determine the similarity of insect taxa during decomposition of rabbit carrion in two different sites during a period of four seasons. Succession pattern analysis for necrophagous insects in both habitats showed a similarity between bloat and decay stages for each habitat. On the other hand, pairwise similarities in taxa were low at the fresh and dry stages, however increased at bloat and decay stages of decomposition. This study shows that succession has some limitations in determining the elapsed time of death. Therefore, the use of source of information such as a weight loss model seems to be essential.

Identification of Muscidae (Diptera) of medico-legal importance by means of wing measurements

Cadavers attract numerous species and genera of Muscidae, both regular elements of carrion insect assemblages, and accidental visitors. Identification of adult Muscidae may be considered difficult, particularly by non-experts. Since species identification is a vital first step in the analysis of entomological material in any forensic entomology orientated experiment and real cases, various alternative methods of species identification have been proposed. We investigated possibility of semiautomated identification by means of wing measurements as an alternative for classic morphology and DNA-based approaches. We examined genus-level identification success for 790 specimens representing 13 genera of the most common European cadavers visiting Muscidae. We found 99.8% of examined specimens correctly identified to the genus-level. Without error, the following were identified: Azelia, Eudasyphora, Graphomya, Hydrotaea, Musca, Muscina, Mydaea, Neomyia, Polietes, Stomoxys and Thricops. Genus-level misidentifications were found only in Helina and Phaonia. Discrimination of examined material on the species level within Hydrotaea (318 specimens representing eight species) and Muscina (163 specimens representing four species) showed lower, yet still high average identification success, 97.2 and 98.8%, respectively. Our results revealed relatively high success in both genus and species identification of Muscidae of medico-legal importance. Semiautomated identification by means of wing measurements can be used by non-experts and does not require sophisticated equipment. This method will facilitate the identification of forensically relevant muscids in comparison to more difficult and more time-consuming identification approaches based on taxonomic keys or DNA-based methods. However, for unambiguous identification of some taxa, we recommend complementary use of identification keys.

Muscidae (Diptera) of forensic importance-an identification key to third instar larvae of the western Palaearctic region and a catalogue of the muscid carrion community

The Muscidae is one of the main dipteran families recognized as important for medico-legal purposes. Although an association of adult flies with decomposing human and animal bodies is documented for about 200 taxa worldwide, cadavers and carrion represents a breeding habitat for considerably fewer species. Species that do colonize dead human bodies can do so under diverse environmental conditions and, under certain circumstances, Muscidae may be the only colonizers of a body. Because of difficulties in identification, many studies have identified immature and/or adult muscids only to the genus or family level. This lack of detailed species-level identifications hinders detailed investigation of their medico-legal usefulness in carrion succession-oriented experiments. Identification to species level of third instars of Muscidae of forensic importance and the utility of larval morphological characters for taxonomic purposes were subjected to an in-depth revision. A combination of characters allowing for the discrimination of third instar muscids from other forensically important dipterans is proposed. An identification key for third instar larvae, which covers the full set of cadaver-colonising species of Muscidae from the western Palaearctic (Europe, North Africa, Middle East), is provided. This key will facilitate more detailed and species-specific knowledge of the occurrence of Muscidae in forensic entomology experiments and real cases. The carrion-visiting Muscidae worldwide are catalogued, and those species breeding in animal carrion and dead human bodies are briefly discussed with regard to their forensic importance.

ITS2 para la identificación de Califóridos (Diptera: Calliphoridae) de importancia forense en Colombia

La entomología forense es una disciplina que utiliza insectos para obtener información útil en la determinación del intervalo postmortem (IPM). Las moscas de la familia Calliphoridae son muy utilizadas en entomología forense, sin embargo, su identificación a nivel de especie puede dificultarse cuando el individuo se encuentra incompleto o en estadio inmaduro. En el presente trabajo, se evaluó el potencial de la región ITS2 del genoma nuclear para la identificación de especies de Calliphoridae en Colombia utilizando tres aproximaciones: comparando distancias genéticas utilizando la metodología de códigos de barra, haciendo una reconstrucción filogenética, y con enzimas de restricción (PCR-RFLPs). Se secuenciaron un total de 520 pb en 44 individuos pertenecientes a 16 especies. Se calcularon los valores de distancia intraespecífica e interespecíficas utilizando el modelo K2P. Los valores de distancia intraespecífica oscilaron entre 0 y 0,252 %, mientras que las distancias interespecíficas fluctuaron entre 3,6 y 18,9 %, evidenciándose que esta técnica puede ser utilizada como código de barras genético en la identificación de especies de la familia Calliphoridae. Tanto en los análisis de Neighbour-Joining como en los análisis bayesianos el 90 % de los géneros presentan una monofilia sustentada en probabilidad posterior de 0,89 a 1. En todos los casos la especie Blepharicnema splendens agrupa con el género Lucilia. Con base en las secuencias obtenidas se utilizó la aplicación NEBCutter para identificar cuatro enzimas de restricción las cuales se probaron en el laboratorio y se comprobó su utilidad para la identificación rápida de especies de Calliphoridae en Colombia.

Potential use of bacterial community succession for estimating post-mortem interval as revealed by high-throughput sequencing

Decomposition is a complex process involving the interaction of both biotic and abiotic factors. Microbes play a critical role in the process of carrion decomposition. In this study, we analysed bacterial communities from live rats and rat remains decomposed under natural conditions, or excluding sarcosaphagous insect interference, in China using Illumina MiSeq sequencing of 16S rRNA gene amplicons. A total of 1,394,842 high-quality sequences and 1,938 singleton operational taxonomic units were obtained. Bacterial communities showed notable variation in relative abundance and became more similar to each other across body sites during the decomposition process. As decomposition progressed, Proteobacteria (mostly Gammaproteobacteria) became the predominant phylum in both the buccal cavity and rectum, while Firmicutes and Bacteroidetes in the mouth and rectum, respectively, gradually decreased. In particular, the arrival and oviposition of sarcosaphagous insects had no obvious influence on bacterial taxa composition, but accelerated the loss of biomass. In contrast to the rectum, the microbial community structure in the buccal cavity of live rats differed considerably from that of rats immediately after death. Although this research indicates that bacterial communities can be used as a “microbial clock” for the estimation of post-mortem interval, further work is required to better understand this concept.

A Biological and Procedural Review of Forensically Significant Dermestes Species (Coleoptera: Dermestidae)

The analyses of the insect species found on decomposing remains may provide useful information for the estimation of the minimum time elapsed since death and other parameters, such as causes and circumstances of death. The majority of research has focused on the early colonizing species, typically blowflies, while research concerning late colonizing insects is currently sparse. Dermestid beetles of the genus Dermestes L. (Coleoptera: Dermestidae) are one of the predominant insect species associated with decomposing remains during dry decay and skeletal stages of decomposition. In some dry environments, Dermestes species are likely to be the only necrophagous insects feeding on the decomposing remains. Furthermore, Dermestes species (immature and adults), their remains (cast skins and fecal material), and their artifacts (pupal chambers) are frequently found associated with ancient remains (e.g., mummies, fossils). Dermestes species have a worldwide distribution and are considered important in decomposition processes, forensic investigations, and economically as a known pest of stored products. Despite their recognized forensic importance, there is limited data documenting the ecology, biology, and the growth rates of the forensically relevant species. The aim of this review is to provide a comprehensive synopsis on the available literature concerning Dermestes species associated with forensic cases. In particular, aspects of colonization behavior, growth rates for forensic taxa and potential best practice guidelines for forensic casework encompassing late colonizing Dermestes species are discussed.

Blowfly Larval Tissues as a Secondary Detector for Determining Paraquat-Related Death in Rabbit Carcass

Paraquat poisoning is commonly associated with suicide or homicide in Malaysia. In a case involving advanced body decomposition, pathological analysis regarding the cause of death may become difficult or almost impossible. Insects serve as common alternative matrix for poison detection in forensic analysis. Paraquat detection via secondary bioaccumulation in fly larvae tissue has never been reported. In this study, tissues from blowfly larvae collected from a rabbit carcass with paraquat poisoning were analyzed for secondary bioaccumulation. Larvae samples were collected and analyzed using liquid-liquid extraction. The detection was performed via reduction of quaternary ammonium presence in paraquat and analyzed using gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring mode (SIM mode). GC-MS showed the elution of reduced paraquat was at retention time 12.8 min. Blowfly larvae tissue has proven useful as a secondary detector in paraquat-related deaths.

The Importance of Habitat in the Ecology of Decomposition on Rabbit Carcasses in Malaysia: Implications in Forensic Entomology

The stages of decomposition and the faunal succession on rabbit carcasses in three different habitats, namely jungle, rural, and highland areas, were studied. Three New Zealand White rabbit (Oryctolagus cuniculus) carcasses weighing ∼2 kg were sampled daily until the decomposition process was completed. Representative specimens of adult flies, larvae, pupa, and mites were collected from the carcasses and processed in the laboratory. There were differences in decomposition rate and faunal succession between the carcasses. The fastest rate of decomposition was recorded in rural area, and the slowest rate of decomposition was recorded in highland area. The carcasses exhibited the same pattern of colonization by adult flies, but the dominant species of larvae and adult flies on each carcass in specific habitats were different. The primary species of flies recorded in jungle were Chrysomya megacephala F., Chrysomya rufifacies (Macquart), Chrysomya chani Kurahashi, Chrysomya villenuevi Patton, Chrysomya nigripes Aubertin, Chrysomya pinguis (Walker), Hemipyrellia ligurriens (Wiedemann), Hemipyrellia tagaliana (Bigot), Hypopyiopsis fumipennis (Walker), Hypopygiopsis violacea (Macquart), and Hydrotaea spinigera Stein represented by both adults and larvae. Musca domestica L., Atherigona sp., Lioproctia pattoni (Senior-White), Lioproctia saprianovae Pape & Bänziger, and Seniorwhitea princeps (Wiedemann) were represented by adults only. The biodiversity of flies in the rural area were C. megacephala, C. rufifacies, H. ligurriens, Fannia canicularis L., Hydrotaea chalcogaster (Wiedemann), and Hyd. spinigera represented by both adults and larvae, meanwhile M. domestica, Atherigona sp., Boettcherisca peregrina (Robineau-Desvoidy), Parasarcophaga taenionota Wiedemann, Parasarcophaga scopariiformis Senior-White, and S. princeps were represented by adults only. The species of flies collected in the highland area were Lucilia porphyrina (Walker), C. megacephala, C. rufifacies, C. villenuevi, C. pinguis, H. ligurriens, Hyd. spinigera, Hyd. chalcogaster, F. canicularis, and Boettcherisca highlandica Kurahashi & Tan represented by both adults and larvae, whereas C. nigripes, Chrysomya thanomthini Kurahashi & Tumrasvin, M. domestica, Atherigona sp., Parasarcophaga albiceps Meigen, P. taenionota, Sepsidae, Phoridae, and Millichidae were represented by adults only. Faunal succession followed the sequence of dominant flies, i.e., Calliphoridae, Sarcophagidae, Muscidae, Sepsidae, and lastly Stratiomyidae for jungle, or Sepsidae for rural and highland studies. Mites, from suborders Mesostigmata, Prostigmata, Astigmatina, and Oribatida, were also recovered throughout decomposition, which could be used for future implementation in forensic investigations. The data obtained from this study could provide more accurate indicators for local forensic scientists in solving criminal cases especially on the determination of time and primary location of death.

Preliminary observations of arthropods associated with buried carrion on Oahu

Several studies in Hawaii have focused on arthropod succession and decomposition patterns of surface remains, but the current research presents the first study to focus on shallow burials in this context. Three domestic pig carcasses (Sus scrofa L.) were buried at the depths of 20-40 cm in silty clay loam soil on an exposed ridge on the leeward side of the volcanically formed Koolau Mountain Range. One carcass was exhumed after 3 weeks, another after 6 weeks, and the last carcass was exhumed after 9 weeks. An inventory of arthropod taxa present on the carrion and in the surrounding soil and observations pertaining to decomposition were recorded at each exhumation. The longer the carrion was buried, the greater the diversity of arthropod species that were recovered from the remains. Biomass loss was calculated to be 49% at the 3-week interval, 56% at the 6-week interval, and 59% at the 9-week interval.

Coleoptera associated with buried carrion: potential forensic importance and seasonal composition

Burial has a unique effect on carrion fauna and this may affect the decomposition rate, consequently interfering with postmortem estimates. We surveyed the Coleoptera on buried rabbit carcasses between April 2008 and March 2009. The insects of forensic importance totaled 1,502 individuals, constituting 87.12% of the Coleoptera collected. The composition of the beetle community varied seasonally. Exposed carcasses lost weight much faster than buried ones. The weight lost by exposed cadavers in a week was greater than those carcasses buried for 10 wk. The temperature variations of the buried carcasses and the soil were around three times less variable than the environmental temperature. The proximity between the temperature variations of the soil and buried carcasses was because of the absence of larval masses. The results show differences in decomposition and faunal composition, demonstrating their relevance in the interpretation of cases with bodies in a similar situation.

Beetles (Insecta, Coleoptera) associated with pig carcasses exposed in a Caatinga area, Northeastern Brazil

The species richness, abundance and seasonality of Coleoptera fauna associated with pig carcasses exposed in a Caatinga area were examined. Tray, pitfall and modified Shannon traps were settled together to collect these insects during two seasons (dry and rainy). 4,851 beetles were collected, belonging to 19 families and 88 species. Staphylinidae (2,184) and Histeridae (1,264) were the most abundant families and accounted for 71.1% of the specimens collected. Scarabaeidae (15) showed the highest species richness. The most abundant species were Atheta iheringi Bernhauer, 1908 (Staphylinidae) (1,685), Euspilotus sp. (Histeridae) (461), Stelidota geminata (Say, 1825) (Nitidulidae) (394), Xerosaprinus diptychus(Marseul, 1855) (Histeridae) (331) and Dermestes maculatus De Geer, 1774 (Dermestidae). Amongst these species, X. diptychus showed to be strongly influenced by seasonality, since 96.1% of the specimens were collected during the dry season.

Blowflies (Diptera, Calliphoridae) Associated with Pig Carcasses in a Caatinga Area, Northeastern Brazil

Studies that focused on Calliphoridae associated with pig carcasses are abundant in southern and southeastern Brazil; however, there are few in northeast. Here, we present an inventory of the blowfly species associated with the stages of decomposition of pig carcasses in a caatinga area during dry and rainy seasons. The study took place at the Private Reserve for the Environmental Inheritance "Fazenda Almas," state of Paraíba, Brazil. Using a modified version of the Shannon trap, 32,909 adult specimens belonging to eight species were captured. During the dry season, Cochliomyia macellaria (Fabricius) (52.2%) and Chrysomya albiceps (Wiedemann) (39.9%) were the most abundant species. In the rainy season, when the majority of individuals were captured (93.7%), Chloroprocta idioidea (Robineau-Desvoidy) (71.1%) was the most abundant. Five decomposition stages were recognized, being the active decay the most attractive to colonization by blowflies, except for Lucilia eximia (Wiedemann), which was more abundant in the bloated stage.

An illustrated key to and diagnoses of the species of Histeridae (Coleoptera) associated with decaying carcasses in Argentina

A key to 16 histerid species associated with decaying carcasses in Argentina is presented, including diagnoses and habitus photographs for these species. This article provides a table of all species associated with carcasses, detailing the substrate from which they were collected and geographical distribution by province. All 16 Histeridae species registered are grouped into three subfamilies: Saprininae (twelve species of Euspilotus Lewis and one species of Xerosaprinus Wenzel), Histerinae (one species of Hololepta Paykull and one species of Phelister Marseul) and Dendrophilinae (one species of Carcinops Marseul). Two species are new records for Argentina: Phelister rufinotus Marseuland Carcinops troglodytes (Paykull). A discussion is presented on the potential forensic importance of some species collected on human and pig carcasses.

Insects breeding in pig carrion in two environments of a rural area of the state of minas gerais, Brazil

The main objective of this study was to identify potential forensic indicators in the insect fauna associated with pig carrion and the pattern of insect succession during the decomposition process in two environments of a rural area in Uberlândia, State of Minas Gerais, Brazil. The study was conducted at two locations: in a pasture and in a fragment of a semi-deciduous forest (vegetation profile of the Cerrado biome) in two different seasons (rainy and dry) of 2010. The decomposition process was more rapid in the rainy season. More than 32,000 insects belonging to 17 species of 6 families of Diptera and 2 species of Coleoptera bred in the carcasses. The majority of Diptera bred in the first three stages of decomposition. However, Phoridae and Coleoptera bred mainly in the last two stages. The insects bred more abundantly in the pasture and in the humid season. The exceptions were the Fanniidae (Diptera), which bred more abundantly in the forest and the Dermestidae and Cleridae (Coleoptera), which did not demonstrate any preference in terms of environments and were more abundant in the dry season, respectively. Species such as Chrysomya albiceps (Wiedemann), Peckia (Patonella) intermutans (Walker), Necrobia rufipes (De Geer), and Dermestes maculatus (De Geer) may be potential indicators of post-mortem interval. Hemilucilia segmentaria (Fabricius) and Ophyra aenescens (Wiedemann) may be indicators of localization of the natural environment, while Musca domestica Linnaeus may be an indicator of the anthropic environment. The study thus presented many species of potential forensic indicators in rural areas of this region.

The composition of carcass volatile profiles in relation to storage time and climate conditions

After death organisms are decomposed by a variety of enzymes and microorganisms. The decay is typically accompanied by the emission of a plethora of volatile organic compounds responsible for the unpleasant odour of a carcass and thus, for the attraction of necrophagous insects. The composition of carcass-related odour profiles strongly depends on the composition of macro-nutrients like fat, carbohydrates, and particularly protein, as well as on the presence of oxygen which influences the community of microorganisms colonising the corpse. The impact of abiotic factors like temperature and humidity on carcass-related volatile emission is less well understood although these parameters are known to have a strong impact on the growth of microorganisms. In the present study we investigated the volatile succession released from dead mice stored for one, ten and 30 days under warm/hot (wh, 22°C/80-90% RH) or cold/dry (cd, 12°C/40-60% RH) climate conditions. We identified 51 typical carcass volatiles by coupled gas chromatography-mass spectrometry and analysed the volatile profiles by multivariate statistical methods to find compounds characterising the different stages. Dead mice stored under wh conditions released volatiles much faster, in higher amounts, and in a greater diversity than those stored under cd conditions. The relatively low amount of sulphur chemicals released under cd conditions were most striking. The results are discussed with respect to their possible applicability in forensic science and insect ecology studies.

Adult Fanniidae associated to pig carcasses during the winter season in a semiarid environment: initial examination of their potential as complementary PMI indicators

Besides the dominant necrophagous dipteran of the families Sarcophagidae and Calliphoridae usually used for post mortem interval (PMI) estimations, species of other families such as Fanniidae have frequently been reported in forensic studies. Though less abundant, these species are prevalent in decomposing carcasses with most reports being anecdotal. In this study we identified adults of the fly family Fanniidae associated to pig carcasses located under different local environmental conditions (sun and shade) in a semiarid area at Mendoza, Argentina during the winter season. We examined the potential of species of this family as indicators of PMI by measuring abundance, time of occurrence and residency time at the carcasses. We identified six species of Fanniidae: Euryomma peregrinum Meigen, Fannia albitarsis Stein, Fannia femoralis Stein, Fannia fusconotata Rondani, Fannia heydenii Wiedemann and Fannia sanihue Domínguez and Aballay. Overall, fly abundance was higher at the sunlit than at the shaded carcass. The most abundant species at the sun was F. fusconotata while at the shaded carcass F. femoralis was the most abundant species. Based on their residency time, however, species with higher potential as PMI indicators seem to be F. heydenii and F. sanihue as their residency time at the carcass was restricted to a short period of the decomposition process. Other species were present throughout most of the decomposition process or in such a low abundance (E. peregrinum) that they were not useful as indicators. These preliminary results indicate that adults of some species of Fanniidae could act as a good complementary indicator species during the winter season. In particular, F. heydenii and F. sanihue should be the focus of further studies which should also expand to other seasons.

Preliminary study of the succession pattern of necrobiont insects, colonising species and larvae on pig carcasses in Temuco (Chile) for forensic applications

Knowledge regarding the succession patterns of insects that visit carcasses as well as the other arthropod that colonise them and analysis of the parameters that are associated with larvae allow calculation of the minimum postmortem interval (PMI). This information is obtained from experiments carried out under specific geoclimatic conditions, which determine their application in forensic environments under similar conditions. The field study presented here is the first in Chile to analyse the decomposition process of pig carcasses and the associated succession of insects, colonising species and parameters related to larval masses. All of the larvae obtained from daily samples were measured (in mm), and their mean, range, standard deviation and stage of development (instars) were determined. The carcasses reached the dry remains stage in only 11 days. Seven species of Diptera visited the carcass during the process, but only two species colonised it by means of egg deposition followed by development of larvae: Cochliomyia macellaria (Fabricius) and Lucilia sericata (Meigen) (Diptera: Calliphoridae), which exhibited a duration of the development cycle from egg to adult of 21 days. The collected Coleoptera correspond to five predator species (Staphilinidae and Histeridae). From the results of this study, it can be concluded that only some of the insect species present in this region can provide information that can be used in forensic entomology and that analysis of larval masses of colonising species can be a valuable tool for determining the PMI(min) in this region of Chile.

Skipping clues: forensic importance of the family Piophilidae (Diptera)

Among the insects which are typically considered of forensic interest, the family Piophilidae (Diptera) is frequently cited because of its common occurrence on carcasses in different stages of decay. Piophilids are mainly known from the cosmopolitan species Piophila casei, which can be also a major pest for the food industry and an agent of myiasis. However, many other species of Piophilidae occur frequently on carrion, including human corpses; hence, it is essential to ensure a careful identification of specimens. Reviews of relevant published information about the Piophilidae species of potential forensic use, including recent interesting records, are presented.