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.     

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.     

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.     

Genetic relationships between blowflies (Calliphoridae) of forensic importance.

Phylogenetic relationships among blowfly (Calliphoridae) species of forensic importance are explored using DNA sequence data from the large sub-unit (lsu, 28S) ribosomal RNA (rRNA) gene, the study includes representatives of a range of calliphorid species commonly encountered in forensic analysis in Britain and Europe. The data presented provide a basis to define molecular markers, including the identification of highly informative intra-sequence regions, which may be of use in the identification of larvae for forensic entomology. Phylogenetic analysis of the sequences also provides new insights into the different evolutionary patterns apparent within the family Calliphoridae which, additionally, can provide a measure of the degree of genetic variation likely to be encountered within taxonomic groups of differing forensic utility.     

Morphology of second and third instars of Chrysomya villeneuvi Patton (Diptera: Calliphoridae), a fly species of forensic importance

The morphology of the second and third instars of Chrysomya villeneuvi Patton, a fly species of forensic importance, was presented by use of light microscopy. Both instars were of hairy appearance, bearing elongated tubercles along the abdominal and caudal segments. The anterior spiracle had 13-15 papillae. Minute dark spots were observed to thoroughly cover the tubercle's surface, with 4-6 strong dark tips. Regarding the third instar, the intersegmental spines between the prothorax and mesothorax were heavily pigmented. The posterior spiracle had a thick and heavily pigmented incomplete peritreme. The surface and tip of the tubercles was covered with heavily pigmented sharp spines. The integument of the body was covered with numerous distinct net-like patches. A comparison with another well-known hairy maggot, Chrysomya rufifacies (Macquart), was discussed.     

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.     

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.     

The forensic application of allozyme electrophoresis to the identification of blowfly larvae (Diptera: Calliphoridae) in southern Australia

Most known carrion-breeding species of blowflies in southern Australia are of the genus Calliphora. The morphological similarity of the immatures of these species means that correctly identifying them poses a challenge for forensic entomologists. This study investigates the potential of allozyme analysis to assist with this task. Molecular profiles of third-instar larvae and adults representing four of these carrion-breeding species, Calliphora stygia, C. dubia, C. hilli hilli, and C. vicina, were compared at 42 allozyme loci. The two life stages were found to display almost identical allozyme profiles in each species (93% of loci were expressed in both life history stages), enabling the reliable identification of larvae in these four species. Integration of these results with data from a previous study indicates that allozyme analysis would also be suitable for rapid, species-level identification of the larvae of six other carrion-breeding Calliphora species occurring in southern Australia. This is the first report of the application of allozyme data to the identification of forensically important blowflies.     

Blood-spatter patterns: hands hold clues for the forensic reconstruction of the sequence of events

Biologic and nonbiologic traces on the hands are of particular importance for the forensic reconstruction of shooting incidents; gunpowder residue analysis in particular helps determine whether the gunshot is close range or distant. In crime scene investigation, knowledge about the morphology of bloodstain patterns-including gunshot-related back spatter-has increased since various experimental examinations have been performed in the last years; nowadays, these traces are frequently used for forensic crime scene reconstruction. The goal of this study was to deduce the position and orientation of the hands, and therefore the firearm, according to the bloodstain patterns on the hands of the deceased. For this purpose blood-spatter stains on the hands were examined on site in 5 suicides caused by gunshot. In all cases, forensically relevant conclusions regarding forensic reconstruction were enabled through close examination of the spatter marks. Therefore, in shooting incidents, analysis and documentation of blood-spatter findings on the hands is recommended before hands are tested for gunpowder residue or wrapped for the transport of the body.     

The nocturnal oviposition behaviour of blowflies (Diptera: Calliphoridae) in Central Europe and its forensic implications

Numerous factors may cause delayed colonisation of a corpse by blowflies, leading to a discrepancy between the entomologically determined post-mortem interval (PMI) and the time of death. Blowflies, for example, are considered to be inactive at night, however, published observations are contradictory. In the present study, several field experiments and one type of indoor experiment were conducted in summer of 2004 and 2005 in order to investigate the nocturnal ovipositional behaviour of blowflies. In the field, two types of bait, dead hedgehogs and fresh beef liver, were placed at night in different urban and rural locations in Frankfurt and in Munich, Germany. For the indoor-experiments beef liver was placed in small plastic boxes containing caged Lucilia sericata females in the evening and left overnight. At night, no ovipositon was observed in the field (n=51, T=10-24 degrees C). Nocturnal oviposition in complete darkness occurred in the plastic boxes in two of six cases (T=25 degrees C). Considering the behavioural and physiological characteristics of flies we suggest that nocturnal oviposition of blowflies appears to be unlikely under natural conditions in Central Europe but may occur under certain circumstances, such as unusual high nightly temperatures and the presence of gravid flies with an appropriate arousal threshold.     

Lucilia silvarum Meigen, 1826 (Diptera: Calliphoridae)-A new species of interest for forensic entomology in Europe

In Europe, the blowfly genus Lucilia is represented in Forensic Entomology mainly by the species L. ampullacea, L. caesar, L. illustris and L. sericata. In the US, Lucilia silvarum is rarely recorded as a carrion breeding species but usually as a more or less exclusive parasite of frogs and toads. We present three forensic cases from different European countries reporting, for the first time, L. silvarum on human bodies that were found close to lakes, wetlands, or riversides. To use this species for post-mortem interval estimations, thermal development data is needed. The first step is accurate identification by morphological and molecular means. Therefore, we analysed a 611bp part of the mitochondrial COI region for 23 specimens of L. silvarum from 9 different geographical regions, all of which give the same haplotype. Differences within the haplotype varied by up to 0.2%. Comparison between the haplotype found and those published on GenBank showed up to 1.2% variance. Moreover, we present an updated key for the morphological identification of the third larval instars of European Lucilia spp. of forensic importance, adding not only L. silvarum, but also L. cuprina which was recorded in Europe for the first time about 20 years ago.     

Effects of refrigeration on the biometry and development of Protophormia terraenovae (Robineau-Desvoidy) (Diptera: Calliphoridae) and its consequences in estimating post-mortem interval in forensic investigations

The aim of this study was to simulate the low temperatures that insects could experience between the time being sampled from cadavers and their arrival in the laboratory. This was in order to investigate the effect of low temperature on development of maggots. At different stages of development, individuals of Protophormia terraenovae (Robineau-Desvoidy) reared at 24 degrees C were submitted to a temperature of 4.0+/-0.5 degrees C for a period varying from 1 to 10 days. Independent of the stage of development at which the insects were refrigerated, the treatment induced significant changes on the duration of development. The effect of low temperature on the developmental time between the return to 24 degrees C to adult emergence depended on the larval stage that was refrigerated. When first instar larvae and prepupae were refrigerated, the time to emergence at 24 degrees C decreased with an increase of duration of the refrigeration period. Time to emergence increased under the same conditions when second instar larvae and pupae were refrigerated. These results indicate that keeping larvae of P. terraenovae at 4 degrees C does not just simply lead to a cessation of metabolism but disturbs the regular development. Ten days of cooling induced an error in estimating post-mortem interval (PMI) of more than 6h.     

必须重视法医的命案现场勘验

命案现场勘验是法医的一项重要工作任务。但近几年没有得到足够的重视，甚至有的认为法医就是检验尸体，现场勘验可有可无，从而导致临案法医的作用被弱化和检案水平得不到提高。笔者就此结合案例进行相关探讨。     

必须重视法医的命案现场勘验

命案现场勘验是法医的一项重要工作任务。但近几年没有得到足够的重视 ,甚至有的认为法医就是检验尸体 ,现场勘验可有可无 ,从而导致临案法医的作用被弱化和检案水平得不到提高。笔者就此结合案例进行相关探讨。案例介绍【案例 1】　某日下午 ,本县一招待所客房内一 80岁老妪死于床上 ,刑技人员处理现场后即将尸体交由法医检验 ,发现 :( 1)死者颈部有 4道勒索 (第 1条为长条毛巾 ,其他 3条为长短不一的布条 ) ,都在颈前部打有死结 ,其索道间绞夹着头发和衣领等 ,勒索相应处软组织出血 ;( 2 )颜面部青紫肿胀 ,左耳道出血 ,心血呈暗红色流动性…     

The importance of forensic evidence for decisions on criminal guilt

Recent studies have found that the general public perceives forensic evidence to be relatively inaccurate and to involve high levels of human judgement. This study examines how important the general public finds forensic evidence by comparing decisions on guilt and punishment in criminal cases that involve forensic versus eyewitness testimony evidence and examining whether a CSI effect exists. Specifically, this experimental survey study utilized a 2 (crime type: murder or rape) × 4 (evidence type: DNA, fingerprint, victim eyewitness testimony, or bystander eyewitness testimony) ? 1 (no victim testimony for murder scenario) design, yielding seven vignettes scenarios to which participants were randomly assigned. Results indicate that forensic evidence was associated with more guilty verdicts and higher confidence in a guilty verdict. Forensic evidence did not change the expected sentence length and did not generally affect the ideal sentence length. However, for rape, respondents believed that the defendant should receive a longer sentence when forensic evidence was presented but forensic evidence did not alter likely sentence that respondents expected the defendant to receive. The results of this study did not support a CSI effect. Overall, this study suggests that forensic evidence – particularly DNA – has a stronger influence during the verdict stage than the sentencing stage.     

Shrunken head (tsantsa): A complete forensic analysis procedure

Based on the analysis of shrunken heads referred to our forensic laboratory for anthropological expertise, and data from both anthropological and medical literature, we propose a complete forensic procedure for the analysis of such pieces. A list of 14 original morphological criteria has been developed, based on the global aspect, color, physical deformation, anatomical details, and eventual associated material (wood, vegetal fibers, sand, charcoals, etc.). Such criteria have been tested on a control sample of 20 tsantsa (i.e. shrunken heads from the Jivaro or Shuar tribes of South America). Further complementary analyses are described such as CT-scan and microscopic examination. Such expertise is more and more asked to forensic anthropologists and practitioners in a context of global repatriation of human artifacts to native communities.     

Seasonal structure and dynamics of sarcosaprophagous fauna on pig carrion in a rural area of Cordoba (Argentina): their importance in forensic science

Four experiments, one in each season, were carried out during 2004 in a rural area of Córdoba, central Argentina. Two pigs (Sus scrofa L.), weighing approximately 8 kg each, were used in each of the four experiments. The animals were killed by a sharp blow to the head and immediately placed in an appropriate arthropod trap. One pig was placed in the shade and the other under direct sunlight. This research was conducted to determine the seasonal structure and dynamics of arthropods that constitute the sarcosaprophagous community in a given area of the central region of Argentina. The decomposition process was divided into five stages: fresh, bloated, decay, advanced decay and dry. The duration of each stage varied in different seasons, showing that the temperature and humidity are the most important variables that influence this process. A total of 51,500 adults and 36,909 immature were collected. More than 80% of the specimens collected belong to Insecta, and within this, Diptera were the most abundant order. The flies were mainly represented by adults and immature of the following species: Chrysomya albiceps (Wiedemann) (Calliphoridae), Musca domestica Linnaeus (Muscidae) and Fannia femoralis (Stein) (Fanniidae). Coleoptera were mainly represented by adults and immature of the species Creophilus maxillosus (Linnaeus) (Staphylinidae) and Dermestes maculatus (Geer) (Dermestidae). More than 50% of hymenopteran fauna collected belong to Formicidae. The trophic levels associated with the decomposition of the remains included five categories: necrophagous, parasites and predators of the necrophagous species, omnivores, opportunists and adventives. During faunal succession a strong dominance of the necrophagous species of the family Calliphoridae and Muscidae was observed, mainly during the early stages of decay process in all seasons.