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1.
Forensic Sci Res ; 3(1): 52-59, 2018.
Article in English | MEDLINE | ID: mdl-30483651

ABSTRACT

Knowledge of necrophagous insects' developmental data is necessary for the forensic entomologist to estimate a reliable minimum postmortem interval (PMImin). Among the most represented necrophagous species, Lucilia sericata (Diptera, Calliphoridae) is particularly interesting. It is regularly identified in samples, with a predominance in summer, and is commonly used by analysts of our entomology department (Institut de Recherche Criminelle de la Gendarmerie Nationale) to estimate the PMImin with the accumulated degree days (ADD) method. This method requires the mathematical lower thermal threshold to be known. This value dictates the quality of the applied ADD method but cannot be considered as fixed, especially when insect development occurs at temperatures close to the biological threshold. In such conditions, it is necessary to study the influence of such temperatures on development rate, as well as the consequences of estimating the period of first oviposition on cadavers, when using the ADD method. Seven replicate rearings were conducted at six different temperatures: 30 °C, 24 °C, 18 °C, 15 °C, 12 °C and 10 °C. Time of development and time of emergence were recorded. The effect of low temperature on the development cycle and the reliability of the ADD method under this entire temperature spectrum were studied using different linear regression models. Calculated durations of total insect time development and experimental rearing duration were then compared. A global linear model cannot be used on the whole temperature spectrum experienced by L. sericata without resulting in an overestimation at some temperatures. We found a combination of two linear regression models to be suitable for the estimation of the total development time, depending on the temperature experienced by L. sericata. This approach allowed us to obtain a variation lower than 2% at 12 °C and 10 °C between the calculated duration and experimental duration of development. In comparison, the results obtained with a global model show a variation higher than 3% at 12 °C and 10% at 10 °C.

2.
Int J Legal Med ; 127(5): 1031-7, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23842668

ABSTRACT

The Department of Forensic Entomology (Institut de Recherche Criminelle de la Gendarmerie Nationale, France) was accredited by the French Committee of Accreditation (Cofrac's Healthcare section) in October 2007 on the basis of NF EN ISO/CEI 17025 standard. It was the first accreditation in this specific field of forensic sciences in France and in Europe. The present paper introduces the accreditation process in forensic entomology (FE) through the experience of the Department of Forensic Entomology. Based upon the identification of necrophagous insects and the study of their biology, FE must, as any other expertise work in forensic sciences, demonstrate integrity and good working practice to satisfy both the courts and the scientific community. FE does not, strictly speaking, follow an analytical method. This could explain why, to make up for a lack of appropriate quality reference, a specific documentation was drafted and written by the staff of the Department of Forensic Entomology in order to define working methods complying with quality standards (testing methods). A quality assurance system is laborious to set up and maintain and can be perceived as complex, time-consuming and never-ending. However, a survey performed in 2011 revealed that the accreditation process in the frame of expertise work has led to new well-defined working habits, based on an effort at transparency. It also requires constant questioning and a proactive approach, both profitable for customers (magistrates, investigators) and analysts (forensic entomologists).


Subject(s)
Entomology/standards , Forensic Anthropology/standards , Forensic Pathology/standards , Laboratories/standards , Quality Control , Accreditation/standards , Animals , Certification , Entomology/education , Feedback , Feeding Behavior , Forensic Anthropology/education , Forensic Pathology/education , France , Humans , Management Audit , Postmortem Changes , Professional Competence/standards , Temperature
3.
Int J Legal Med ; 121(2): 90-104, 2007 Mar.
Article in English | MEDLINE | ID: mdl-16633812

ABSTRACT

Forensic entomology, the use of insects and other arthropods in forensic investigations, is becoming increasingly more important in such investigations. To ensure its optimal use by a diverse group of professionals including pathologists, entomologists and police officers, a common frame of guidelines and standards is essential. Therefore, the European Association for Forensic Entomology has developed a protocol document for best practice in forensic entomology, which includes an overview of equipment used for collection of entomological evidence and a detailed description of the methods applied. Together with the definitions of key terms and a short introduction to the most important methods for the estimation of the minimum postmortem interval, the present paper aims to encourage a high level of competency in the field of forensic entomology.


Subject(s)
Benchmarking , Entomology/standards , Forensic Sciences/standards , Animals , Autopsy/methods , Documentation , Entomology/instrumentation , Entomology/methods , Europe , Forensic Sciences/instrumentation , Forensic Sciences/methods , Humans , Life Cycle Stages , Postmortem Changes , Specimen Handling
4.
Forensic Sci Int ; 160(1): 27-34, 2006 Jun 27.
Article in English | MEDLINE | ID: mdl-16183227

ABSTRACT

Protophormia terraenovae is a forensically important fly whose development time is studied by forensic entomologists to establish the time elapsed since death (post-mortem interval, PMI). Quantity and nature of ecdysteroid hormones present in P. terraenovae pupae were analysed in order to determine if they could be correlated to the age of pupae found on corpses and thereby could give information on the PMI. Ecdysteroid levels were quantified during the pupal-adult development of synchronised animals using enzyme immunoassay (EIA), a sensitive method allowing acurate quantification in one pupa. Two types of pupae were compared: "fresh" pupae, kept frozen until analysis and "experimentally dried" pupae, which were left for several weeks at ambient temperature. A peak of ecdysteroids was detected between 36 and 96 h after pupariation in fresh animals. It was not observed in "experimentally dried" pupae. High-pressure liquid chromatography (HPLC) analyses combined with EIA showed that 20-hydroxyecdysone (20E) was the major free ecdysteroid at various pupal ages. Enzymatic hydrolysis experiments revealed the presence of apolar conjugates at all ages tested. However, neither qualitative nor quantitative difference was detected between early and late pupae. This study gives precise information on the nature and quantity of ecdysteroids in the course of pupal development of a calliphorid fly. The limits of using ecdysteroid measurement as a tool in forensic entomology are discussed.


Subject(s)
Diptera/metabolism , Ecdysteroids/metabolism , Animals , Chromatography, High Pressure Liquid , Diptera/growth & development , Entomology , Forensic Anthropology/methods , Humans , Immunoenzyme Techniques , Pupa , Time Factors
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