Piophila megastigmata (Diptera: Piophilidae): first records on human corpses

Piophila megastigmata McAlpine, 1978, for many years only known from South Africa, was recently recorded in Spain. The present work reports for the first time the occurrence of P. megastigmata in human corpses in Portugal. The species was also collected in succession studies conducted with piglet carcasses, where it coexisted with Stearibia nigriceps (Meigen, 1826), showing similar periods of presence in the carcass. However, P. megastigmata was more abundant than S. nigriceps in autumn, with the opposite in summer. During winter neither species was able to colonize carrion and in spring, only S. nigriceps. This first record of P. megastigmata in human corpses confirms it as a potentially useful forensic species in Europe. The species, well established in the Iberian Peninsula, probably has a wider distribution but has been previously overlooked and possibly confused with Piophila casei (Linnaeus, 1758) in many studies.     

Use of PCR-RFLP for differentiation of calliphorid larvae (Diptera,Calliphoridae) on human corpses

Blowfly larvae found on human corpses are important for the estimation of the postmortem interval (PMI) and other questions of forensic relevance. Some of these species are difficult to differentiate morphologically, therefore a molecular method was elaborated for species identification. Specific fragments of the COI and COII region of the mitochondrial DNA (mtDNA) were amplified followed by digestion with different restriction enzymes. Using a 1.3 kb fragment, identification of Lucilia sericata, Calliphora vicina and Calliphora vomitoria was possible by digestion with only one restriction enzyme using either DraI or HinfI. Furthermore, we sequenced 349 bp (a part of the COI and COII regions) from the same three species and found 34 nucleotide distinctions between C. vicina and L. sericata, 30 between C. vomitoria and L. sericata and 15 between the two Calliphora species. These results aid in quick identification of species used for estimation of PMI.     

Black soldier fly (Diptera: Stratiomyidae) colonization of pig carrion in south Georgia

The black soldier fly, Hermetia illucens (L.), is thought to colonize corpses 20-30 days postmortem. However, recent observations indicate this might not be true for all cases. Therefore, we conducted a study examining colonization by the black soldier fly and other Diptera on pig carrion in a plowed field in southern Georgia from 20 September through 21 February. Our data indicate black soldier flies could colonize a corpse within the first week after death. Knowing this information could prevent a serious mistake in estimating the time at which a corpse is colonized by this species. This study also represents the first record of Chrysomya rufifacies in Georgia.     

Data for nine autosomal STRs markers from Valencia (East Mediterranean coast of the Iberian Peninsula)

Nine STRs loci have been typed in a sample from Valencia, a population from the East Mediterranean coast of the Iberian Peninsula.     

The transfer of human DNA by Lucilia cuprina (Meigen) (Diptera: Calliphoridae)

Blowflies leave deposits, termed artefacts, through the processes of excretion and regurgitation. To date, little consideration has been given to the possibility of adult blowflies consuming biological material and subsequently acting as vectors of human DNA through these artefacts. In this study, Lucilia cuprina (Meigen) (Diptera: Calliphoridae) were fed either human blood or human semen ad libitum and their artefacts were analysed for human DNA content. Samples containing 1, 10, 30 and 50 artefacts were tested. Quantifiable and typeable levels of human DNA were found in samples derived from both food sources, and even in samples containing a single artefact. Semen-derived artefacts contained significantly more human DNA than artefacts produced after a blood meal. Consequently a smaller number of artefacts was required to collect sufficient DNA for genotyping. These findings are forensically important as it provides investigators with another potential source of DNA at a crime scene where a body has been moved, or an attempt has been made to clean up biological material. They also highlight how fly artefacts could potentially contaminate and compromise evidence.     

Morphological observation of puparia of Chrysomya nigripes (Diptera: Calliphoridae) from human corpse

This article presents Chrysomya nigripes Aubertin as a blow fly species of forensic importance in Thailand, and morphological observation of fly puparia using scanning electron microscopy (SEM). Morphologically, we focused on the characteristics of puparia used to accurately identify fly species. Numerous puparia of C. nigripes were found aggregated, adhering side by side, on the tibia of a skeletonized corpse, which was recovered from a forested area of Chiang Mai, northern Thailand. In the triangular shape of the anterior end of the puparia, three thoracic segments and broad hairy patches beginning dorsolaterally at the sixth segments were distinguishing characteristics. This study, showing pupariation of the flies along the bone of a corpse as well as morphological features, provides important guidance in identifying C. nigripes puparia. A key to differentiate puparia of C. nigripes from the other flies of forensic importance in Thailand is given.     

Calliphora vicina (Diptera: Calliphoridae) collected from a human corpse above 3400 m in elevation

In the summer of 2005 an adult hiker was killed in a fall in Rocky Mountain National Park, Colorado (U.S.A.). His body was subsequently colonized by the blowfly Calliphora vicina (Diptera: Calliphoridae). The body was discovered 9 days later at an elevation of 3475 m (11,400 feet). This is the first report of C. vicina on a human corpse at this elevation in Colorado. This paper provides additional confirmation of this fly colonizing a human corpse at high elevations in Colorado.     

Occurrences of flesh flies (Diptera: Sarcophagidae) on human cadavers in Switzerland, and their importance as forensic indicators

From 1993 to 2008, criminal investigations were conducted in the western part of Switzerland with special attention to blowfly and flesh fly species in order to estimate the post-mortem interval when requested by the police authorities. Flesh flies were found in only 33 cases out of 160. Five species of the genus Sarcophaga were identified (S. africa, S. argyrostoma, S. caerulescens, S. similis and S. sp.). The main species found on corpses (larval stage) was S. argyrostoma. The thermal constant (K) calculated for this species in Switzerland is 380.6 ± 16.3 (mean ± S.D.) degree-days. With the exception of S. caerulescens, found three times in the larval stage on corpses, the three other species are of minor forensic importance. S. argyrostoma is found during summer and indoors. This species colonises dead bodies, usually the same day as blowfly species, and it could be used to estimate the post-mortem interval. Other species are discussed in the light of current knowledge on their biology and ecology. It is recommended that voucher material be deposited in a museum, allowing further studies by relevant specialists, thereby helping investigators and avoiding misidentifications.     

北京地区尸生性蝇类研究及其在法医鉴定中的应用

为提供法医学尸体死亡时间鉴定的准确性，对北京地区人尸上蝇类区系进行了系统调查（1994～1996）。发现本地区共有双翅目尸生性蝇类3科、12属、14种。其中常见种有红头丽蝇、丝光绿蝇、大头金蝇、肥须亚麻蝇、急钓亚麻蝇、棕尾别麻蝇和家蝇7种。对其常见种的幼虫进行不同温度和湿度下培养，观察常见环境因素，如日历期、风雨天气等因素对其生长发育速率的影响。结果表明，蝇类幼虫在其适宜生长发育的温度范围内，随着温度的升高发育速率加快，历期缩短；在同一温度和同一饲养条件下，发育速率因种而异；平均温度在28℃左右时，蝇类幼虫发育最快，尤其是1～2龄幼虫，时间为1天左右，且较稳定。这些数据对法医学推断死亡时间具有参考价值。     

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.     

Experimental studies on the mechanism of ethanol formation in corpses

Various in vitro experiments were performed for the purpose of clarifying the mechanism of ethanol production in corpses. Whereas a negligible quantity of ethanol was produced in the blood alone, which was left at room temperature, the quantity of ethanol was slightly increased by addition of glucose to the blood. When saprogens were further added, the quantity was markedly increased. Various materials were added to blood-liver homogenates as specimens, and the mixtures were stored in an incubator at 37 degrees C. As a result of the addition of an antibiotic to the mixture every day, there was hardly any production of ethanol. When alcohol dehydrogenase (ADH) and reduced nicotinamide adenine dinucleotide (NADH) were added, ethanol production was slightly increased. When acetaldehyde was added first, ethanol production was inhibited the next day, but on and after day 2, the quantity of ethanol was more than that in the control material. When pyruvic acid was added first, the results were similar to the above. Pyrazole, cyanamide, and disulfiram completely inhibited the production of ethanol. Ethanol production in corpses is believed to take place through a pathway opposite to that of ethanol metabolism in the living body, under the influence of ADH, ALDH, etc., in saprogens using carbohydrates as substrates.     

Implications of dimorphism, population variation, and secular change in estimating population affinity in the Iberian Peninsula

Morphometric cranial variation among Spanish samples was compared to a 19th century Portuguese sample using both traditional and three-dimensional approaches. The Spanish samples included the regional 19th century Oloriz collection and the local 16-17th century Villanubla and Vallolid sample from northwestern Spain. Results suggest moderate variation among the samples and suggest that varying patterns of regional variation, sexual dimorphism and secular change represent important factors to be considered in the evaluation of population affinity using craniometric approaches.     

Effects of morphine in decomposing bodies on the development of Lucilia sericata (Diptera: Calliphoridae)

This study concerns the effects of morphine in tissues on the rate of development of Lucilia sericata (Diptera: Calliphoridae) using those tissues as a food source. Lucilia sericata is a species of fly commonly found on human corpses in Europe during the early stages of decomposition and thus of forensic interest. Three rabbits were administered 12.5, 25.0 and 50.0 mg/h of morphine chlorhydrate via ear perfusion over a period of 3 h. These dosages and duration of perfusion were calculated to give tissue concentrations of morphine similar to those encountered in fatal human overdoses. A fourth rabbit was used as a control. Following administration of the drug, rabbits were sacrificed and 400 eggs of Lucilia sericata, all of the same age, were placed in the eyes, nostrils and mouth of each rabbit. Developing larvae were sampled daily to determine growth rate and weight. Puparia and emerging adult flies were also sampled. Data were analyzed using analysis of variance (ANOVA) and Student's T-test. Results of this study show that an underestimation of the postmortem interval of 24 h is possible if the presence of morphine in tissues is not considered. This study demonstrates again the necessity of considering the possible effects of drugs in tissues on insect growth rates when estimating the postmortem interval using entomological techniques.     

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.     

Effect of temperature on development of Liopygia (= Sarcophaga) argyrostoma (Robineau-Desvoidy) (Diptera: Sarcophagidae) and its forensic implications

The temperature-dependent development of the forensically important flesh fly Liopygia (Thomsonea) argyrostoma (Robineau-Desvoidy) (=Sarcophaga argyrostoma) was studied at six constant temperature regimes in the laboratory. Total developmental time of L. argyrostoma from larviposition to adult emergence was 54.9+/-1.45, 31.3+/-1.1, 22.2+/-0.67, 16.3+/-0.54, and 14.9+/-0.4 days (+/-S.D.) when reared at 15, 20, 25, 30, and 35 degrees C, respectively. At 8 degrees C, larval development was not completed. From linear regression of development rates of five of the six studied constant temperature regimes, it was determined that the minimum development threshold (tL) for total immature development is 7.4 degrees C, and the overall thermal constant (K) for L. argyrostoma is 396.4+/-19.18 (mean +/- S.D.) day-degrees (DD) above the threshold.     

Origin assignment of unidentified corpses by use of stable isotope ratios of light (bio-) and heavy (geo-) elements--a case report

An unknown male body was found near an expressway in Germany. As different criminalistic and forensic methods (e.g. tooth status, fingerprint or DNA-analysis) could not help to identify the person, multielement stable isotope investigations were applied. The combined analysis of stable isotope ratios of light (H, C, N) and heavy elements (Pb, Sr) on the man's body tissues supported to assign him to Romania. The case report demonstrates an application of multielement-isotope analysis in the forensic fields and its potential.     

Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae) established in the vicinity of Knoxville, Tennessee, USA

The hairy maggot blow fly, Chrsomya rufifacies (Macquart) (Diptera: Calliphoridae) was collected in large numbers as both adults and immatures in the Knoxville, Tennessee, area during 1998 and is likely established there. The distribution of this species in the Old World, isothermal data, and its collection from mid-Michigan during 1998 suggest that it will eventually occupy most of the U.S. The forensic importance of C. rufifacies makes it probable that it will factor into an increasing number of medicolegal cases, but the expanding distribution of this species decreases its utility as a geographic indicator when postmortem movement of decedents is suspected.     

Spread and habitat selection of Chrysomya albiceps (Wiedemann) (Diptera Calliphoridae) in Northern Italy: forensic implications

Abstract: Habitat selection exploited by Chrysomya albiceps during its initial spread in Northern Italy was analyzed in relation to landscape structure. The results of two short studies and a case report are here discussed. C. albiceps was not found on experimental pig carcasses in the urban area of Pavia. It was missing in the woody mountains surrounding Lecco, but it was found in the same area, at a lower altitude, within the typical “urban sprawl” landscape. It was then recorded in a natural reserve, among a rich carrion‐fly population. Indications coming from habitat selection suggest that C. albiceps has not yet saturated its potential ecological niche in newly colonized areas of Northern Italy. Factors like temperature, altitude, and interspecific competition can act as limiting factors, affecting habitat selection and distribution in newly colonized areas; the influence of those factors has to be taken into account for forensic purposes.     

Some notes on the nocturnal larviposition by two species of Sarcophaga (Diptera: Sarcophagidae)

Experiments in the month of September 2005 were performed to study nocturnal larviposition by the flesh flies (Diptera: Sarcophagidae). Two species namely Sarcophaga albiceps Meigen and Sarcophaga hirtipes Wiedemann were observed to deposit their larvae during night time as well. Therefore, possibility of night larviposition by flesh flies should always be taken into consideration while determining age of maggots.