The development and main achievements of forensic entomology

The history and main achievements of forensic entomology are introduced. The future of forensic entomology is discussed.     

Child neglect and forensic entomology.

Close co-operation between forensic scientists, medico-legal doctors, and police forces made it possible to estimate not only the post-mortem interval but also the time since a child was neglected. On the skin surface under the diaper (anal-genital area), third instar larvae of the false stable fly Muscina stabulans FALLEN, and the lesser house fly Fannia canicularis L. were found. F. canicularis adults are attracted to both feces and urine. From the face, larvae of the bluebottle fly Calliphora vomitoria L. were collected. C. vomitoria maggots are typical early inhabitants of corpses. From the developmental times of the flies, it was estimated that the anal-genital area of the child had not been cleaned for about 14 days (7-21 day range), and that death occurred only 6-8 days prior to discovery of the body. This is the first report where an examination of the maggot fauna on a person illustrated neglect that had occurred prior to death.     

法医昆虫学的发展与主要成就

本文介绍了国内外法医昆虫学的发展历史和取得的主要成就，并对其今后的发展趋势进行了探讨。     

我国法医昆虫学的研究进展

法医昆虫学是应用昆虫学知识解决有关法律问题的法医学分支学科。在推断死亡时间等方面具有明显优势。本文在阐述法医昆虫学定义和研究内容基础上,综述尸体上的昆虫生态群落演替现象、昆虫发育形态学、DNA分析技术的应用、法医昆虫毒理学等法医昆虫学问题在我国的研究进展。     

A brief history of forensic entomology.

Apart from an early case report from China (13th century) and later artistic contributions, the first observations on insects and other arthropods as forensic indicators were documented in Germany and France during mass exhumations in the late 1880s by Reinhard and Hofmann, whom we propose recognizing as co-founders of the discipline. After the French publication of Mégnin's popular book on the applied aspects of forensic entomology, the concept quickly spread to Canada and the US. At the time, researchers recognized that the lack of systematic observations of forensically important insects stood in the way of their use as indicators of postmortem interval. General advances in insect taxonomy, and ecology helped close this gap over the following decades.Many early case reports dealt with alleged child homicides, including the suspected use of sulphuric acid. In this context, it was shown that ants, cockroaches, and freshwater arthropods could produce postmortem artifacts suggestive of child abuse.After the World Wars, few forensic entomology cases entered the scientific literature. From the 1960s to the 1980s, Leclecq and Nuorteva were primarily responsible for maintaining the method in Central Europe, with a focus on case work. Since then, basic research in the US, Russia and Canada has opened the way to the routine use of entomology in forensic investigations. The following article gives a brief overview of historic developments in the field. A major focus is on the work done between 1850 and 1950. Since sources from that time remain difficult to track down, the article also includes a historic bibliographical overview on forensic entomology of that era.     

Use of beetles in forensic entomology.

Beetles (Coleoptera) have been recognised as providing significant entomological evidence in the medico-legal field, particularly with reference to dry human skeletal remains in the later stages of decomposition.The Dermestidae (skin beetles) and Cleridae (bone beetles) have been found as the most common types infesting exposed human remains and providing evidence in estimating the minimum postmortem interval (PMI).     

A model for the aging of fly larvae in forensic entomology

A method is described for determining the time of hatching of blowfly larvae on a corpse with respect to temperature. Temperature is known to have a profound effect on the rate of growth of fly larvae, and it is suggested that past assumptions that the growth of larvae found in a corpse has taken place at one approximated ambient temperature may have led to large overestimates of the development time of the larvae, and thus overestimates of time of death. Larvae of Lucilia cuprina, Calliphora vicina (= erythrocephala), Calliphora stygia and Calliphora hilli were cultured under constant temperatures, and their growth rates modeled with a logistic growth curve. Two programmes have been developed, one to compute the parameters for the logistic equations, the other is used to estimate the time elapsed from the time at which a sample is removed from a body to the estimated hatching time of the larvae comprising the sample, with temperatures and species as variables.     

Gene expression during blow fly development: improving the precision of age estimates in forensic entomology

Forensic entomologists use size and developmental stage to estimate blow fly age, and from those, a postmortem interval. Since such estimates are generally accurate but often lack precision, particularly in the older developmental stages, alternative aging methods would be advantageous. Presented here is a means of incorporating developmentally regulated gene expression levels into traditional stage and size data, with a goal of more precisely estimating developmental age of immature Lucilia sericata. Generalized additive models of development showed improved statistical support compared to models that did not include gene expression data, resulting in an increase in estimate precision, especially for postfeeding third instars and pupae. The models were then used to make blind estimates of development for 86 immature L. sericata raised on rat carcasses. Overall, inclusion of gene expression data resulted in increased precision in aging blow flies.     

An alternative for the extraction and storage of DNA from insects in forensic entomology

An important area of recent research in forensic entomology has been the use of insect DNA to provide identification of insects for fast and accurate estimation of time since death. This requires DNA to be extracted efficiently and in a state suitable for use in molecular procedures, and then stored on a long-term basis. In this study, Whatman FTA cards were tested for use with the Calliphoridae (Diptera). In particular, testing examined their ability to effectively extract DNA from specimens, and store and provide DNA template in a suitable condition for amplification using the polymerase chain reaction (PCR). The cards provided DNA that was able to be amplified from a variety of life stages, and thus appears to be of sufficient quality and quantity for use in subsequent procedures. FTA cards therefore appear suitable for use with calliphorids, and provide a new method of extraction that is simple and efficient and allows for storage and transportation without refrigeration, consequently simplifying the handling of DNA in forensic entomological cases.     

Current status and prospects for developing chemical-toxicological (forensic chemical) studies in the Russian Federation

The authors discuss modern state and prospects of planning and carrying out research in forensic (toxicological) chemistry within the framework of practical forensic medical expert evaluation, state of forensic medical expert evaluation of alcohol and narcotic intoxication, and other pressing problems of forensic medical expert practice.     

microRNAs及其法医学应用前景

microRNAs(miRNAs)是一类内源性的非编码小分子RNA,平均长度约22nt,广泛存在于各种真核细胞中,并参与调节细胞生长发育、分化、凋亡、衰老、疾病及肿瘤的发生等众多重要生命活动。基于其生物学功能,miRNAs可能在法医学体液来源鉴定、个体年龄推断、同卵双生子甄别等方面具有广阔的应用前景。     

Using DNA-barcoding to make the necrobiont beetle family Cholevidae accessible for forensic entomology

Although many cases of fatal hydrogen sulfide poisoning have been reported, in most of these cases, it resulted from the accidental inhalation of hydrogen sulfide gas. In recent years, we experienced 17 autopsy cases of fatal hydrogen sulfide poisoning due to the inhalation of intentionally generated hydrogen sulfide gas. In this study, the concentrations of sulfide and thiosulfate in blood, urine, cerebrospinal fluid and pleural effusion were examined using GC/MS. The sulfide concentrations were blood: 0.11-31.84, urine: 0.01-1.28, cerebrospinal fluid: 0.02-1.59 and pleural effusion: 2.00-8.59 (μg/ml), while the thiosulfate concentrations were blood: 0-0.648, urine: 0-2.669, cerebrospinal fluid: 0.004-0.314 and pleural effusion: 0.019-0.140 (μmol/ml). In previous reports, the blood concentration of thiosulfate was said to be higher than that of sulfide in hydrogen sulfide poisoning cases, although the latter was higher than the former in 8 of the 14 cases examined in this study. These results are believed to be strongly influenced by the atmospheric concentration of hydrogen sulfide the victims were exposed to and the time interval between exposure and death.     

A forensic entomology case from the Amazon rain forest of Brazil

The first case of application of forensic entomology in the Brazilian Amazonia is described. The corpses of 26 men were found in the rainforest in Rondonia State, Brazil. Fly larvae collected on the bodies during autopsy were identified as Paralucilia fulvinota (Diptera, Calliphoridae). No data or specimens were collected at the crime scene. At the laboratory, the larvae developed into pupae in 58 h and into adults in 110.5 h. The total development time for P. fulvinota was measured in field experiments inside the forest. The age of the larvae when collected from the bodies was estimated as the difference between the time required for them to become adults and the total development time for this species. The estimated age of the maggots and the minimum postmortem interval was 5.7 days.     

The use of Megaselia abdita (Diptera: Phoridae) in forensic entomology

This case study demonstrates the importance of the Phorid, Megaselia abdita (Schmitz), as an indicator for post-mortem interval estimation in criminal investigations involving forensic entomology where it is usually the more frequently occurring Calliphorids that are most useful. A case example is discussed where the temperatures were low for the period of time the deceased was missing.