The Nocturnal Ovipositing Behavior of Carrion Flies in Cincinnati, Ohio

Abstract:  The behavioral patterns of nocturnal oviposition represent a window of time that potentially has a large impact on postmortem interval estimations. We investigated the behavioral patterns of carrion flies at night by exposing euthanized rats between sunset and sunrise to see if carrion flies oviposited upon the carrion over two consecutive summers. We investigated urban and rural locations, in both lit and unlit conditions with n  = 125. We found that nocturnal ovipositing did not occur in the Cincinnati metropolitan area. We conclude that nocturnal oviposition is an unlikely event in the Cincinnati metropolitan area.     

Necrophagous Caterpillars Provide Human mtDNA Evidence*

Abstract: Decomposition of large mammalian carcasses is greatly accelerated through the action of insects. Specialized feeders capable of digesting keratin and collagen found in skin, hair, and tendons and ligaments are attracted to corpses in late stages of dry decomposition and include Tinea pellionella, the casemaking clothes moth, and Tineola bisselliella, the webbing clothes moth (Lepidoptera; Tineidae). Until now, details of the caterpillar behavior as necrophagous insects were vague. Here, we detail the behavior of each species and document the incorporation of human hair into the portable larval shelters constructed by the caterpillars of T. pellionella. Hair of the decedent used as building material for caterpillar shelters provided enough starting template to amplify and sequence the HVI and HVII sections of the control region (mtDNA) of the decedent.     

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。     

利用嗜尸性蝇类生活史推测死亡时间

目的积累一些嗜尸性蝇类生活史的资料及群落组成的季节性变动规律。方法采用动物尸体作诱饵,分别对自然飞到诱饵上繁殖生长的8种嗜尸性蝇类的生活史及群落组成的季节性变动规律进行观察研究。结果夏季高温时段蝇类群落组成物种较为丰富,冬季低温时段蝇类种群较为单一。常见8种嗜尸性蝇类虫态经历时间在气温高时较短,气温低时较长。结论嗜尸性蝇类生活史及群落组成的季节性变动规律可为推测死亡时间提供依据。     

Internal Morphological Analysis for Age Estimation of Blow Fly Pupae (Diptera: Calliphoridae) in Postmortem Interval Estimation*

Abstract: Larvae and pupae of blow fly species are frequently used in postmortem interval estimation, their age indicating minimum time since death. Most studies have considered age estimation of larvae, neglecting study of pupae. Relative development of external pupal features is useful, but there are also internal changes during metamorphosis that may be indicators of age, utilizing histological techniques. This study aimed to optimize preservation and histological analysis of blow fly pupae, specifically Calliphora vicina Robineau‐Desvoidy and Lucilia sericata (Meigen), and to examine internal features with potential for age estimation. Effect of hot‐water‐killing and different preservatives were examined. It was determined that blow fly pupae should be pierced through the three tagma, hot‐water‐killed, and preserved in 80% ethanol as the optimal preservation for subsequent analyses. Hematoxylin and eosin stained pupal sections revealed differences in brain and thoracic muscle development throughout the pupal stage with potential for age estimation.     

Investigation of nocturnal oviposition by necrophilous flies in central Texas

The need to accurately estimate the postmortem interval (PMI) has prompted research into factors affecting fly oviposition (i.e., oviposition and/or larviposition) on a corpse. Research efforts have focused on whether or not diurnally active flies oviposit during nighttime hours. This study reports that nocturnal oviposition (defined as occurring between 2100-0600 h CDST (Central Daylight Savings Time)) did not occur on freshly killed white rats or mice, on beef (fresh or aged up to 48 h), on freshly thawed pigs, nor, usually, on thawed pigs that were aged for up to 48 h. Limited oviposition did occur between 2100 and 2120 h on one bloated pig at a lighted rural site. Necrophilous flies were present and active at lighted and dark sites (urban and rural) before and immediately after sunset, but fly activity on the bait ceased within 50 min postsunset and did not resume until after 0600 h. These observations support other studies reporting that diurnally active flies do not oviposit during the nighttime.     

Growth of Chrysomya megacephala (Fabricius) Maggots in a Morgue Cooler*

Abstract: In estimating the postmortem interval (PMI) using maggots obtained during autopsy, the forensic entomologist makes decisions regarding the effects of low‐temperature storage of the body on the insects. In this case report, a corpse was found in an abandoned house in the residential area of Bukit Mertajam, Penang, Malaysia. The maggots were found to be alive inside the mouth of the deceased although the corpse had been in the morgue cooler for 12 days. The maggots were reared and identified as Chrysomya megacephala (Fabricius). The emerged adult flies were kept as a stock colony, and the duration of development under the indoor fluctuating temperature regime was studied. The total duration of developmental process of this species was 9.5 ± 0.5 days, and the PMI estimated was 3.2 ± 0.6 days. This case report demonstrates the survival of Ch. megacephala maggots for 12 days and their growth inside the morgue cooler.     

Variation in Developmental Time for Geographically Distinct Populations of the Common Green Bottle Fly,Lucilia sericata (Meigen)*

Abstract: Time between death and discovery of remains, or postmortem interval (PMI), can be assessed using blow fly maggot age. Forensic entomologists rely on published, often nonlocal, species‐specific developmental tables to determine maggot age. In a series of common garden experiments, we investigated the developmental rate variation between populations of Lucilia sericata collected from Sacramento, CA, San Diego, CA, and Easton, MA at 16°C, 26°C, and 36°C. For the 16°C trial the time measurement started at egg hatch, while for the higher temperatures the experiment began at oviposition; the wandering stage signified the endpoint for all experiments. The distribution of developmental times differed significantly (ANOVA, p < 0.001) between the three populations within each temperature treatment. We discovered that regional variation of developmental times within a blow fly species exists. This study demonstrates the importance of assembling local population‐specific developmental tables when estimating larval age to determine PMI.     

DNA‐Based Identification of Forensically Important Lucilia (Diptera: Calliphoridae) in the Continental United States*

Abstract: Correct species identification is critical when dipteran larvae are used for inference of the postmortem interval. To facilitate DNA‐based identification of forensically important flies of the genus Lucilia in the continental United States, we develop a vouchered reference collection and DNA sequence database. A total of 122 specimens were collected for nine of the 10 species of Lucilia reported to occur in the continental United States. Using the polymerase chain reaction and DNA sequencing, data were obtained for an 1100‐bp region of the mitochondrial gene encoding cytochrome oxidase I (COI). We consider a species suitable for DNA‐based identification if it is exclusively monophyletic in >95% of bootstrap pseudoreplicate phylogenetic analyses. Seven of the nine species meet that criterion. Two species (Lucilia coeruleiviridis and Lucilia mexicana) share COI sequence and cannot be distinguished using our reference database. We conclude that DNA‐based identification is likely to be successful for the other seven species.     

近十年来我国现代法医昆虫学研究进展

法医昆虫学(Forensic entomology)指的是应用昆虫学知识解决法律上问题的法医学分支学科,在死后间隔时间判断,特别是腐败尸体的死后间隔时间判断等方面有著无可比拟的优越性。本文讨论了法医昆虫学的研究领域,从理论研究与实践应用两方面概述了近十年来法医昆虫学在我国的进展。     

A Checklist of Calliphoridae Blowflies (Insecta,Diptera) Associated with a Pig Carrion in Central Brazil*

Abstract: Although the Cerrado is the second major Brazilian biome, few studies have been undertaken about its entomofauna. Blowflies have an important role in forensic entomology, helping in the determination of postmortem intervals. The main goal of this exploratory study was to identify and to catalog the blowfly species associated with a pig carcass. The study was conducted in a pasture in Brasília, Distrito Federal. A pig (Sus scrofa) was killed with a .22 caliber shot in the frontal region of the head. Adult blowflies were surveyed daily from June 1 through 30, 2004. A total of 14,910 adult calliphorids were collected, representing eight species: Chrysomya albiceps, C. megacephala, Cochliomyia macellaria, Chloroprocta idioidea, Hemilucilia semidiaphana, H. segmentaria, Lucilia cuprina, and L. eximia. C. albiceps was the most frequent species, amounting to 94.76% of the catch. Five decomposition stages were observed, and for calliphorids, the most attractive stage was the bloated one.     

Generalized additive models and Lucilia sericata growth: assessing confidence intervals and error rates in forensic entomology

Forensic entomologists use blow fly development to estimate a postmortem interval. Although accurate, fly age estimates can be imprecise for older developmental stages and no standard means of assigning confidence intervals exists. Presented here is a method for modeling growth of the forensically important blow fly Lucilia sericata, using generalized additive models (GAMs). Eighteen GAMs were created to predict the extent of juvenile fly development, encompassing developmental stage, length, weight, strain, and temperature data, collected from 2559 individuals. All measures were informative, explaining up to 92.6% of the deviance in the data, though strain and temperature exerted negligible influences. Predictions made with an independent data set allowed for a subsequent examination of error. Estimates using length and developmental stage were within 5% of true development percent during the feeding portion of the larval life cycle, while predictions for postfeeding third instars were less precise, but within expected error.     

Determination of Calliphoridae (Diptera) Fauna and Seasonal Distribution on Carrion in Ankara Province*

Abstract: This study was conducted from March 2006 to 2007. The aim of the study was to determine the forensically significant Calliphoridae (Diptera) species and their seasonal distribution in Ankara province at Beytepe Campus. Pig carcasses were killed by a veterinary using pentobarbital sodium with intervals from 2 to 3 weeks to a month. Samples were collected from the carcass everyday in the morning, in the afternoon, and at sunset. Temperature and parameters of weather, such as cloudy, sunny, rainy, and snowy, were recorded at each visit. Phaenicia sericata (Meigen), Chrysomya albiceps (Wiedemann), Calliphora vomitoria (Linnaeus), and Calliphora vicina (Robineau‐Desvoidy) species, which belong to Calliphoridae family, were collected. It was shown that the seasonal distribution of the collected species was different from each other. The species were determined on carcass between the following times; P. sericata, from April to November; C. albiceps, from May to November; Ca. vomitoria, from February to June and from September to December; and Ca. vicina, from February to May and in June and September. Calliphoridae fauna and its annual seasonal distribution in Turkey on 12 pig carcasses were reported for the first time in this study.     

Estimating the preappearance interval from temperature in Creophilus maxillosus L. (Coleoptera: Staphylinidae)

Abstract: Some carrion insects appear on carcasses late in decomposition. While using these late‐arriving taxa to estimate postmortem interval, it is vital to accurately estimate an interval preceding their appearance on a cadaver called the preappearance interval (PAI). This paper tests the possibilities of a PAI estimation from temperature in case of late‐arriving, predatory carrion beetle Creophilus maxillosus. The relationship between temperature and PAI of adult and larval C. maxillosus was modeled using the results of a large‐scale experiment on succession in forests of Central Europe. In both stages, PAI was found to be strongly, inversely related to temperature averaged for the duration of PAI. The PAI estimation from mean degree‐day accumulations (mDDA), estimated DDA, and “PAI*T” functions were tested using external successional data. The greatest accuracy of PAI estimates was achieved using an exponential “PAI*T” function.     

Insect Successional Pattern of a Corpse in Cooler Months of Subtropical Southeastern Texas

Abstract:  Here, we characterize the cool weather insect fauna found associated with partially skeletonized and desiccated human remains recovered from an abandoned house in an urban area of subtropical, coastal Galveston County, Texas, and use the information to conclude an approximate postmortem interval of 7–10 months. The predominant factors that allow for a confident assessment of the postmortem interval include climatological data, entomological data, and anthropological data. The documented insect fauna represents a unique assemblage present in a particular environment (an urban abandoned house in coastal Texas) at a particular time of year (winter) and includes expected forensically significant insects such as calliphorid flies, muscid flies, and dermestid beetles but also includes less commonly encountered insects such as an unusually dense population of live case-making clothes moths.     

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.     

广东省室内、室外及中毒死亡案件中法医昆虫学的应用报道

基于昆虫的死亡时间推断是目前最为有效和最准确的方法,本文介绍了广东省4例应用昆虫准确判断死亡时间的案例,这些案例分别发生于3月、5月和6月,现场包括室外现场和室内现场,尸体类型包括死亡不久的尸体和高度腐败的尸体,死亡原因包括钝器窒息、锐器致死、勒颈致死及过量药物中毒致死,其中过量药物中毒致死的案例由于体内含有49倍致死剂量的氯氮平从而使昆虫的发育受到严重影响进一步使得死亡时间推断时间结果比真实时间短。     

The black soldier-fly, Hermetia illucens (Diptera, Stratiomyidae), used to estimate the postmortem interval in a case in Amapá State, Brazil

The black soldier-fly (Hermetia illucens) is a generalist detritivore which is commonly present in corpses in later stages of decomposition and may be useful in forensic entomology. This paper describes the estimation of the postmortem interval (PMI) based on the life cycle of the black soldier-fly in a case in northern Brazil. A male child was abducted from his home and 42 days later his corpse was found in an advanced stage of decay. Two black soldier-fly larvae were found associated with the body. The larvae emerged as adults after 25-26 days. Considering the development cycle of H. illucens, the date of oviposition was estimated as 24-25 days after abduction. Since H. illucens usually (but not always) colonizes corpses in more advanced stages of decay, this estimate is consistent with the hypothesis that the child was killed immediately after abduction.