Necrophagous Insects Research Articles

Effect of seasons on the decomposition by necrophagous insects of pig (Sus scrofa domesticus L.) carcasses exposed to the open air in the Sudano-guinean and Sub-sudanese zones of Côte d'Ivoire

Determining the post-mortem interval (PMI) of a corpse discovered 72 hours after death is becoming complex and imprecise in forensic medicine. It is necessary to use other investigative methods to determine the date of death. The aim of this research was to determine the impact of the seasons on the decomposition of pig corpses exposed to the open air by necrophagous insects. The research was carried out in the North (at the Botanical Garden of the Peleforo Gon Coulibaly University in Korhogo) and in the Centre (in the Bouaké region). Insects were collected directly from decomposing carcasses using a mowing net and flexible forceps for larvae and Coleoptera. Pitfall-traps were also used for collection. Diptera and Coleoptera were collected during the dry and rainy seasons in the Sudano-guinean and Sub-Sudanese zones. Chrysomya albiceps, belonging to the Calliphoridae, was the majority species. Because of its plethora of species in the two study areas, C. albiceps could be one of the main species for determining the minimum MPI in Côte d'Ivoire. Five stages of decomposition were observed in the two study zones, although a sixth stage (dry putrefaction) was observed in the Sub-sudanese zone during the harmattan period. Stratiomyidae and Piophilidae contributed to the total decomposition of carcasses during the rainy season. The Histeridae family was the richest in species. Dermestes maculatus was the richest in individuals. Carcasses in the rainy and dry seasons were respectively decomposed by an average of 97.18% in the rainy season and 84.32% in the dry season in the two study areas.

Population dynamics of the main necrophagous Diptera in the sub-Sudanese zone of Côte d’Ivoire

The objective of this work was to identify the population variation of the main necrophagous Diptera in the sub-Sudanese zone of Côte d'Ivoire. Three traps, inspired by Upton's and using pig liver and viscera as bait were placed on the site of the Botanical Garden of Peleforo Gon Coulibaly University and Lataha located 10 km from the Botanical Garden. Weekly captures were taken from October 4, 2018 to October 3, 2019. In total, 194,853 individuals from the Calliphoridae, Sarcophagidae and Muscidae were collected. Calliphoridae represented 48%, Sarcophagidae 24% and Muscidae 28% in the Botanical Garden site and in Lataha, Calliphoridae presented 52%, Sarcophagidae 27% and Muscidae 21%. Chrysomya albiceps, Sarcophaga carnaria and Musca domestica were the majority species. The numbers of these three species were higher at relative humidity levels reaching 70 to 85%. A correlation between relative humidity and the numbers of these three species was observed. Apart from relative humidity, these results show that other climatic parameters have a weak influence on the activity of Chrysomya albiceps, Sarcophaga carnaria and Musca domestica. During this study, temperature and rainfall had little influence on the variation in the numbers of these three main species of necrophagous insects. However, the numbers of the three species were correlated with relative humidity levels.

Forensic and ecological significance of necrophagous insects: Insights from animal carcasses, human cadavers, and myiasis patients

Necrophagous insects, including flies and beetles, play pivotal roles in decomposition, ecology, and forensics. Their diversity and activities vary across environments, necessitating comprehensive studies for understanding and management. The aim of the study is to investigate insect infestation on animal carcasses, human cadavers, and myiasis patients to enhance ecological, forensic, and medical entomological understanding, aiding in ecosystem management, forensic investigations, and disease control.Various species of flies and beetles were found associated with animal carcasses, human cadavers, and myiasis patients, as indicated by the comprehensive study. On animal carcasses, notable fly species included Chrysomya rufifacies (Macquart, 1842), Chrysomya megacephala (Fabricius, 1794), Lucilia cuprina (Wiedemann, 1830), and Sarcophaga sp., while beetles such as Dermestes maculatus (De Geer, 1774), Necrobia rufipes (Fabricius, 1781), Saprinus quadrigatattus (Fabricius, 1798), Saprinus splendens (Paykull, 1811), Saprinus optabilis (Marseul, 1855), Saprinus chalcites (Iliger, 1807), and Omorgus sp. (Erichson, 1847) were also observed. Similarly, human cadavers exhibited a presence of flies like Chrysomya albiceps (Wiedemann, 1819), Chrysomya rufifacies (Macquart, 1842), Chrysomya megacephala (Fabricius, 1794), and Sarcophaga dux (Thomson, 1869). In cases of myiasis patients, flies including Chrysomya megacephala, Cochliomyia hominivorax (Coquerel, 1858), and Chrysomya bezziana (Villeneuve, 1914) were identified.These findings underscore the diverse range of insect species involved in carcass decomposition, forensic investigations, and medical entomology, illustrating their crucial roles in ecological processes, forensic assessments, and disease management.

Seasonal Patterns of Resource Use Within Natural Populations of Burying Beetles.

For organisms in temperate environments, seasonal variation in resource availability and weather conditions exert fluctuating selection pressures on survival and fitness, resulting in diverse adaptive responses. By manipulating resource availability on a local spatial scale, we studied seasonal patterns of resource use within natural populations of burying beetles Nicrophorus vespilloides in a Norfolk woodland. Burying beetles are necrophagous insects that breed on vertebrate carcasses. They are active in Europe between April and October, after which they burrow into the soil and overwinter. Using breeding and chemical analyses, we compared the fecundity and physiological state of beetles that differed in their seasonal resource use. We found seasonal variation in carrion use by wild burying beetles and correlated differences in their reproductive success and cuticular hydrocarbon profiles. Our results provide novel insight into the seasonal correlates of behaviour, physiology and life history in burying beetles.

The Effect of Soil Type and Moisture on the Development of Forensically Important Megaselia scalaris and Dohrniphora cornuta (Diptera: Phoridae).

Necrophagous phorid flies are common insects found on buried corpses, and their developmental data play a crucial role in estimating the post-burial interval (PBI). This study aimed to investigate the effects of soil type and moisture content on some life cycle parameters of two forensically important insects, Megaselia scalaris (Loew, 1866) and Dohrniphora cornuta (Bigot, 1857) (Diptera: Phoridae). Larval and pupal survival, development time, and larval body length of M. scalaris and D. cornuta were observed in three different soil types (loamy sand, sandy loam A, and sandy loam B) with six moisture contents (0%, 20%, 40%, 60%, 80%, and 100%). The results indicated that soil types, soil moisture, and their interaction significantly influenced the growth and development of both species, with moisture being the most influential factor. In each soil, 20% and 40% moisture contents were more suitable for their growth and development. Both the development time and maximum larval body length were significantly different among soil types and moisture contents. The larval period of both species lasted the longest in all soils with 0% moisture content. Additionally, a regression analysis of the relationship between larval body length and development time was performed at different moisture contents in three soils. This study expanded our knowledge of the factors that influence the development of necrophagous insects and provided some reference data for applications of M. scalaris and D. cornuta in PBI estimation.

HOFE: an interactive forensic entomological database.

The significance of entomological evidence in inferring the time, location and cause of death has been demonstrated both theoretically and practically. With the advancement of sequencing technologies, reports have emerged on necrophagous insects' nuclear genomes, transcriptomes, proteomes and mitochondrial genomes. However, within the field of forensic entomology, there is currently no available database that can integrate, store and share the resources of necrophagous insects. The absence of a database poses an inconvenience to the application of entomological evidence in judicial practice and hampers the development of the forensic entomology discipline. Given this, we have developed the Home Of Forensic Entomology database, encompassing 10 core functional modules: Home, Browse, Mitochondria, Proteome, JBrowse, Search, BLAST, Tools, Case base and Maps. Notably, the 'Tools' module enables multiple sequence alignment analysis (Muscle), homologous protein prediction (Genewise), primer design (Primer), large-scale genomic analysis (Lastz), Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, as well as expression profiling (PCA Analysis, Hcluster and Correlation Heatmap). In addition, the present database also works as an interactive platform for researchers by sharing forensic entomological case reports and uploading data and material. This database provides potential visitors with a comprehensive function for multi-omics data analysis, offers substantial references to researchers and criminal scene investigators and facilitates the utilization of entomological evidence in court. Database URL: http://ihofe.com/.

Molecular and Morphological Analysis of Forensically Important <i>Sarcophaga Albiceps</i> Meigen

Forensic entomology uses necrophagous insects to determine post mortem interval (PMI) in criminal investigations. Sarcophaga albiceps Meigen is one among the primary colonisers of dead carcasses and hence its identification is crucial for forensic investigations; S. albiceps is a common species of Sarcophagidae found in India. Genitalia of male S. albiceps were dissected to identify the species using taxonomic keys and female S. albiceps were identified using molecular sequencing. Researchers have adopted a number of strategies like molecular identification, particularly the use of the mtCo1 gene and tools like SEM ultrastructural examinations for identification due to the difficulties in using external morphology. The current study offers baseline information that will allow the researchers and forensic officials to correctly identify S. albiceps by morphological, molecular, and SEM examinations.

The influence of altitude on the abundance and occurrence of species of the family Calliphoridae (Diptera) in corpses in a Mediterranean area.

A carcass is defined as a temporary resource that can support high levels of diversity compared to other resources. The level of diversity often depends on the environmental conditions in which the corpse is found. Calliphoridae (Diptera) are the most important necrophagous insects used in forensic investigations because this family is common, widespread, abundant, and usually the first to colonize a corpse. However, understanding the processes responsible for variation in calliphorid species abundance and richness along gradients in ecology remains a key challenge. In this study, we analyzed the influence of altitude on the abundance and diversity of Calliphoridae species in corpses at three different altitudes (400, 900, and 1500 m a.s.l.) in a mountainous area of southeastern Spain. The results revealed a gradient of decreasing abundance with increasing altitude. An altitudinal substitution of species was observed, with Chrysomya albiceps being found at the lowest altitude and Calliphora vicina at the highest altitude. Seasonal variation was also noted, with Ch. albiceps being the dominant species in the warmer months and C. vicina being the dominant species in winter. Our results confirm the importance of Calliphorids as seasonal, altitudinal, and environmental indicators, given the wide distribution and abundance of this family. This information is of great interest on the interpretation of data in forensic practice.

The insect colonisation, succession, and decomposition of the domestic pig (Artiodactyla: Suidae) in southern Ontario, Canada

Abstract Studies documenting insect succession throughout the decomposition of vertebrate remains have been performed in more than half of the provinces and one territory in Canada. However, some areas are not represented in the current published literature. Ontario is one province that does not have published records of local necrophagous insect succession. Therefore, three studies were performed in Oshawa, Ontario, to document the insect community and primary colonisers observed during the decomposition of domestic pig, Sus scrofa domestica (Artiodactyla: Suidae), remains. Adult and immature specimens located on the remains were collected, reared, and identified. Pitfall traps were installed to monitor insects present outside of visits. Pigs that decomposed in higher temperatures yielded fewer colonising dipteran species than those that decomposed in cooler temperatures. The most common primary colonisers were Phormia regina (Diptera: Calliphoridae), Lucilia illustris (Diptera: Calliphoridae), and Lucilia sericata (Diptera: Calliphoridae). In total, 11 Diptera families, six Coleoptera families, and families from the Hymenoptera and Hemiptera orders were observed. When comparing these results to published results from Québec, Ontario’s neighbour, major differences in primary colonisers can be noted. It is therefore important for researchers to study the succession, development, and colonisation patterns of the local fauna during vertebrate decomposition and to publish their findings.

The Diversity of Forensic Entomofauna Associated With Decaying Chicken Liver in the Tropical Region of Kerala, India.

Forensic entomology To elucidate the time of death based on insect evidence, there are several studies on forensic entomology on life cycles, environmental factors, and feeding habitats of insects. However, there have not been any comprehensive studies on forensic entomology and its usage in forensic inquiry specific to the region, especially Kerala, India. The insect succession on decomposed animal matter plays an important role in estimating minimum postmortem intervals (mPMI). Objective The purpose of the study was tounderstand forensically important insect groups and their role in the decomposition process of dead decayingmatter. The different decomposition stages of a corpse vary in attraction to necrophagous insects and the insect fauna depending on its prevailing conditions of decay. The decomposition is highly dependent on the exposition of animal matter and abiotic and biotic factors acting on it. The main objective of the present investigation was to identify the insect fauna associated with decaying chicken liver. The study also envisages comprising the diversity and abundance of insects between two different treatments of animal matter: in contact with soil and controlled conditions in a clean basin. Method The study was conducted for 45 days (until the total decomposition of the samples in both conditions) during the pre-monsoon months of April to May2022 at Chalikadavu, Muvattupuzha, in the Ernakulam district, Kerala, India. The samples were however kept away from direct sunlight and rain to avoid the direct impact on the orienting fauna. The entomofauna found to be associated with the decaying animal matter was carefully collected from the site and stored in 70% isopropyl alcohol for preservation. The total number of insects was recorded along with the hours of maximum incidence, and samples were stored in plastic vials for further identification. Result In this study, we analyzed the activities of ants, mites, wasps, cockroaches, moths, beetles, and flies during the decomposition of decaying chicken liver. Among these insects, flies and beetles are two important arthropod communities associated with animal matter decomposition. We collected these foraging organisms for morpho-taxonomic identification. The decomposition stages among the two treatments could help to understand the variable factors in the decomposition of decaying corpse with special reference to the insect fauna acting on it. Conclusion We got 100 specimens comprising 28 species in 17 families from Blattidae, Coleoptera, Diptera, Hymenoptera, and Lepidoptera. Besides this, we identified two parasitic wasps with their host (dipteran pupa), which is helpful in postmortem interval (PMI) estimation. Our analysis showed an association between decay and the activity of carrion insects. The decomposition stages among the two treatments could help to understand the variable factors in the decomposition of a decaying corpse with special reference to the insect fauna acting upon it.

Necrophagous insect species succession on decomposed pig carcasses in North Dakota, USA.

Necrophagous insect species are widely used during death investigations primarily for the estimation of the minimum postmortem interval, since these species use decomposing organic matter for feeding, oviposition, and larval development. The development stages and successional colonization patterns provide important information for shorter or longer postmortem time intervals. Diptera species are the predominant taxa recovered from decomposed bodies. The temperature variance/seasonality is the main factor affecting the time presence and activity of these species. Other factors, such as geographical location, antemortem conditions, and cause of death, can influence the presence and succession of necrophagous entomofauna. Consequently, successional studies and information regarding species colonization patterns are needed for each geographical region to be used as reference data during death investigations. This study addressed the need to collect forensic entomological data for the State of North Dakota, within the first necrophagous entomofauna diversity report for the month of July 2022, using pig carcasses as human analogs. During the experimental period, 18 species of Diptera and Coleoptera were identified, with 10 new state records, while Calliphoridae was found to be the predominant family. The resulted data on necrophagous insect species diversity and dynamics from exposed pig carcasses will strengthen the current knowledge on forensic entomology in North Dakota and will serve as reference data to be used during death investigations in the Great Plains region.

Observation of the elusive bone-skipper fly Centrophlebomyia furcata (Fabricius, 1794) at least 128 years after its last record in France, and additional data on Thyreophora cynophila (Panzer, 1794) in France (Diptera: Piophilidae)

Summary Once thought to be extinct species, the necrophagous flies Centrophlebomyia furcata and Thyreophora cynophila are iconic representatives of the western Europe dipterofauna. They are extraordinary insects active during the winter season and associated with the carcasses of large mammals. After the discovery of T. cynophila in Ariège in 2020 and the confirmation of its extended presence in the Pyrenees Mountain range, a search for C. furcata was initiated. During a visit to nine vulture feeding stations in the Pyrenees and Corbières mountain ranges, adults of C. furcata were collected in two of them, in the northern Basque country (Pyrénées-Atlantiques department, France). This is the first precisely documented observation of C. furcata in France. The rediscovery of C. furcata and T. cynophila in the Pyrenees Mountain range raises the question of their presence elsewhere in France and Europe, notably in other mountain ranges. An updated map of the distribution area of both species is provided. We also raise concerns about the maintenance of vulture feeding stations to avoid detrimental impacts on those rare necrophagous insects and consider forensic issues.

Analysis of Methamphetamine Using Necrophagous Insects For Forensic Entomotoxicology Applications

The high use of methamphetamine (MA) has resulted in many cases of overdose leading to death, where bodies are generally found after several days which complicates the investigation so that a forensic entomotoxicological analysis using insects is carried out. The use of necrophagous insects was chosen because necrophagous insects such as maggots were at the crime scene. Maggot was then analyzed using Gas Chromatography-Mass Spectrometry (GCMS) with several stages. The preliminary test was carried out using the marquis reagent which changed the color of the sample to orange if positive for methamphetamine, then continued with TLC (Thin Layer Chromatography) analysis and obtained the Rf value close to the comparative Rf value, which means that maggot positively contains methamphetamine. Maggot was extracted by maceration and sonication methods using methanol:chloroform 1:3 solvent. Finally, a confirmatory test was carried out using a GCMS and it was found that methamphetamine had a retention time of 3.554 minutes and a peak of 58.1. The results are matched with NIST (National Institute of Standards and Technology) library data. It can be concluded that the use of maggot in analyzing methamphetamine using GCMS can be realized properly

Effect of Pesticide Poison on Post-Mortem Interval Determination Based on Entomological Study

Determination of post-mortem intervals (PMI) is a major key in forensic investigation. On the discovery of a decomposed corpse, a post mortem examination is difficult. PMI can be made by observation of insects that appear around the corpse, called forensic entomology. Forensic entomology carried out by analyzing the species of larvae and calculating the age of insects so that the time of death can be estimated. Forensic entomology has been developed in toxicological examinations so that insects found can be used as toxicological samples. The cause of death can be due to poisoning. Poisons often used in case of poisoning or suicide is pesticides. This research is a Systematic Review, a study that takes and collects data from various previous studies related to the chosen theme. The study was conducted according to protocol and registration with reference to PRISMA and JBI. Literature searches are obtained from online databases. The results were obtained by 21 studies after selection and elimination in accordance with protocol. The most accurate determination of the post mortem interval depends on post-death changes and the decomposition process. Some types of pesticides can cause the decomposition process to take place faster but some other types of pesticides can slow down the decomposition process. The content of toxins in the body ingested has an effect on the development and growth of necrophagous insects. The growth of flies will be stunted or even stopped, the presence of toxins in the corpse can be a contributing factor in the determination of the post-mortem interval. Deaths caused by toxins still need to be further researched because different types of toxins can show different side effects on the body.

ENTOMOFAUNA DE INTERES FORENSE ASOCIADA AL PROCESO DE DESCOMPOSICIÓN CADAVÉRICA DE Sus scrofa EN ÉPOCA DE VERANO EN UN DISTRITO DEL NORTE DEL PERÚ

Necrophagous insects, mainly Diptera and Coleoptera, are involved in the cadaveric decomposition process depending on time ofstudy and location, are important to estimate the postmortem interval. Pigs have become the most frequently used animal model in forensic science. The objective of this research was to identify the genera and/or species of necrophagous insects in the five stages of the cadaveric decomposition process, at the time of summer 2018 taking place in an urban area of Nuevo Chimbote (Ancash, Peru), using SusscrofaL. as an animal model. It was used a 12-kg pig carcass, recently euthanized and kept for 70 days, at an average temperature of 24.26°C and an average relative humidity of 66.96% inside a Schoenly-type trap to capture insects. Insects of the Diptera and Coleoptera orders were found in the different phases of decomposition: In the initial phase (two days) only dipterous insects, Sarcophagasp., Chrysomyaalbiceps, Cochliomyiamacellariaand Luciliacuprinawere identified; in the phase of active putrefaction(two days) the same species of diptera and coleoptera, Necrobiarufipesand Dermestesfrischii; in the advanced putrefaction phase (three days) the same species and also Muscadomesticadiptera; in the fermentation phase (11 days) the same species and also beetle Ammophorusperuvianus; and in the skeletonization phase (52 days) only beetles Saprinussp., Necrobiarufipesand Dermestesfrischiiwere identified. The results of this study indicate that in an open environment in an urban area of Nuevo Chimbote(Ancash, Peru), in summer season (January-March), the entomofauna was associated with the decomposition of S. scrofwhich is composed of five species of the order Diptera and four of the order Coleoptera. In addition, it was possible to observe that in the initial phase only diptera were present and in the final phase (skeletation) only coleoptera, which could be used as decomposition markers.

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 60days 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.

Effect of diazinon (organophosphate) on the composition and succession of Calliphoridae assemblages in rabbit carcasses in the Eastern Amazon.

Fatal poisonings with diazinon may occur both accidentally or intentionally in suicide cases. Forensic entomotoxicology can aid in understanding these deaths by detecting and analyzing the interference of toxic substances in the biology of necrophagous insects. Hence, this study sought to evaluate diazinon's effect on the composition and succession of calliphorid species in the tropical savannas of the Amazon. Nine rabbit carcasses were divided into three groups: one control and two diazinon treatments (100mg/kg and 300mg/kg); each group had three replicates. Three fragments of the Amazon tropical savanna were selected for the experiments. Daily collections of adult and immature calliphorids were performed. Five decomposition stages were observed: fresh, bloated, active decay co-occurring, advanced decay, and dry. Eight species of Calliphoridae were identified among the collected adults: Chloroprocta idioidea (0.1%), Chrysomya albiceps (58.3%), Chrysomya megacephala (14.2%), Chrysomya putoria (2.6%), Cochliomyia hominivorax (1.3%), Cochliomyia macellaria (0.5%), Lucilia eximia (19.8%), and Paralucilia paraensis (3.3%). The adult specimens in the control group with the highest abundance were observed only from the advanced decay stage onward. In the dry stage, abundance was higher in control than in treated carcasses. From the sampled 941 Calliphorid immatures, three species were identified: C. albiceps (76,3%), C. putoria (1%), and L. eximia (22,7). The number of immatures was higher in control than in treated carcasses. Therefore, diazinon interferes with the putrefaction timeframe in carcasses, slowing the decomposition stages and affecting their colonization by immature forms of Calliphoridae.

New developmental data of Chrysomya megacephala (Diptera: Calliphoridae) in tropical temperatures and its implications in forensic entomology.

The estimation of the postmortem interval (PMI) is an essential information in death investigations. It is necessary to know the developmental data of the most important necrophagous insect species in every geographical area. Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) is one of the most common species associated with human body decomposition, especially in the tropics, so a precise knowledge of its life cycle is crucial. However, despite its ubiquity, developmental data in a range of tropical temperatures is scarce. For this reason, the aim of this study is to provide the developmental data of the blowfly, C. megacephala, in a range of tropical temperatures and to apply these data in forensic entomology. Four temperatures were examined (i.e., 27.0°C 29.5°C, 32.0°C and 34.5°C) and the time of developments from egg to adult were recorded. To build the growth curves, five larvae per day were measured with a digital caliper. Accumulated degree-days were calculated and the isomorphen diagram for this species was plotted. As we predicted, the results showed that the life cycle of this species was affected by the increasing temperature. The implications of these new data for determining the minimum PMI in forensic entomology were discussed.

Initial laboratory validation of temperature development models for Necrodes littoralis L. (Staphylinidae: Silphinae)

Development models of necrophagous insects are applied in forensic entomology for post-mortem interval estimation. Such estimates may be used as scientific evidence in legal investigations. For this reason, it is important that the models are valid and that the expert witness is aware of their limitations. Necrodes littoralis L. (Staphylinidae: Silphinae) is a necrophagous beetle species that frequently colonizes human cadavers. Temperature models of development for the Central European population of these beetles were recently published. In this article, we present results of the laboratory validation study for these models. Errors of beetle age estimation differed significantly between the models. Thermal summation models yielded the most accurate estimates, and the isomegalen diagram least accurate estimates. Errors of the beetle age estimation varied across beetle developmental stages and rearing temperatures. In general, most development models of N. littoralis were satisfactorily accurate in estimating beetle age under laboratory conditions; therefore, the study provides initial evidence to support their validity in forensic cases.

Case closed – Wrappings and encasement delays and reduces fly presence on body parts

Homicide, particularly where a body has been concealed, is uniquely challenging for investigators to estimate the time of occurrence due to the methods employed by perpetrators to hide the body or its constituent parts from detection. The regularity of necrophagous insect lifecycles to determine minimum post-mortem interval (minPMI) is widely employed but remains an unreliable technique if used without a clear understanding of the factors that affect insect access and oviposition behaviour to concealed remains.The purpose of this study was to investigate the effect of wrapping body parts on fly colonisation and implications for minPMI calculations. Field studies were carried out using four treatments of pork (as surrogate body parts), in five replicates, one unwrapped, the other three wrapped in either a black plastic sack, a small-zipped wash bag (to simulate a suitcase), or a plastic sack further placed in a wash bag. Over a 48-h period all the methods of wrapping significantly disrupted the host-finding process of blowflies to dismembered carcasses, with a delay of initial contact and oviposition of 30+h (dependant on wrapping) and even more in wet conditions (48+ h). Egg numbers were also reduced by as much as 99.1% on wrapped samples compared to unwrapped. These new findings highlight the importance of applying adjustments to minPMI calculations when encountering wrapped remains. Advances in the accuracy of minPMI calculations will prevent the waste of valuable police time and resources and better focus the search for witnesses and suspects in homicide investigations.