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Forensic Entomology outside the Police service: advantages and disadvantages
No full textForensic Entomology represents a fascinating field by applying entomology and ecology under medico-legal aspects. However, medico-entomological expertise requires not only scientific training (= education), but also knowledge about what happens in infested corpses and at scenes of crime (= experience). The achievement of experience differs in respect to the position of the expert; he can be employed within the police service or work in an academic institution such as an institute of legal medicine, entomology, biology, etc. or maybe work as a private consultant. In fact, during a homicide investigation, entomology police services often have a good and immediate access to the scene of death as well as to the corpse during autopsy.
The entomologist at an institute of legal medicine or even the freelancing colleague often face the disadvantage that both are joining the investigation not earlier than during autopsy of the body or even later. This may be even a problem for the expert of an entomological police service, dealing with samples collected by a colleague and not by himself. Therefore there is a need for standardised guidelines and protocols describing how to collect entomological evidence, which should include the training and teaching of crime scene technicians.
The death scene is the most important site of any entomological investigation, and taking notes and samples as early as possible on the scene of death as well as on the corpse is essential for expertise in forensic entomology. On the other hand, entomological case work by the police service is usually restricted on homicides or unexplained death investigations, ordered by prosecution. At an institute of legal medicine corpses not interesting for police investigations may be infested by maggots. Those will be examined, providing the entomologist with the chance of a better understanding of the local necrophagous fauna composition and infestation patterns representative for different sciences (e.g. indoor versus outdoor) and stages of decomposition. Supported by additional information regarding findings at the scene of death and the possible time of death, the expert can perform his entomological examinations and calculations. Accumulating experience is extremely important in real case work.
The disadvantages (prevented or delayed access to the scene of death) and advantages (working with many infested corpses, time for performing research and collecting case relevant data) of a service not associated within a police department illustrates the need of a multidisciplinary approach with a close interaction of investigators, forensic entomologists and pathologists as early as possible. It is actually difficult for an expert, whereever he belongs, to work in every case at the scene of death and on the corpse. We strongly suggest that a single, trained person should collect the data and samples of a case from the beginning at the death scene until the end at the autopsy
Effects of different storage and measuring methods on larval length values for the blow flies (Diptera: calliphoridae) Lucilia sericata and Calliphora vicina
No full textIn forensic entomology, the methods of sampling, killing, and storing entomological samples can affect larval age estimation, and, hence, the estimation of the minimum post-mortem interval. In the existing manuals, there is a certain amount of heterogeneity regarding methods and the recommendations for best practice in forensic ento- mology are insufficiently validated. This study evaluated three different length-measurement methods for larval stages and examined the influence of different killing and storing methods on the larval length of two forensically important blow flies, Lucilia sericata and Calliphora vicina.
The three different measuring methods were a) a ruler with a 0.1 mm scale, b) a geometrical micrometer, and c) a computer-aided stereomicroscope. They were used to measure the length of L1–L3 C. vicina larvae and detect no significant differences. This supports the view that a simple tool like a geometrical micrometer can produce reli- able results in forensic entomology.
Newly hatched larvae of L. sericata and C. vicina were killed with hot water (HW) and divided into two equal sub- samples. Lengths of all larvae were measured immediately after killing, then every 24 h until day 4, and once more after 7 days of storage in ≥70%-ethanol.
L. sericata larvae only showed significant changes in length in the HW group stored at room temperature. After 4 and 7 days of storage, these 24-h- and 72-h-old larvae showed a significant decrease in length compared with those in a fridge at 6 °C. This decrease can, however, be considered a negligible natural variation without foren- sically relevant consequences for larval age estimation of L. sericata samples.
For C. vicina, an increase in length was observed over time. This was significant only for younger larvae (24-48 h old) stored in 70%-ethanol. This variance in length can lead to a wrong estimation of age; however, only for larvae stored in 70%-ethanol, not for those stored in 96%-ethanol.
Novelty statement: We examined the influence of different killing and storing methods on two forensically impor- tant blow flies, Lucilia sericata and Calliphora vicina. For the latter species we additionally were evaluating three different length measurement methods. The results of both experiments suggest that it is possible to kill and store fly larvae directly in (not hot) ≥70%-ethanol. This simplifies the sampling and storing of fly evidence at the crime scene. We also compared the influence of three different measuring methods for estimating the length of L1–L3 C. vicina larvae by using a) a ruler with a 0,1 mm scaling, b) a geometrical micrometer and c) a comput- er-aided stereomicroscope. No significant differences were detected, supporting the view, that a simple tool like a geometrical micrometer can produce reliable results. This study helps to simplify the sampling and evaluation of entomological evidence and to backup or questioning existing guidelines and best practice recommendations
Current Concepts in Forensic Entomology
No full textForensic Entomology deals with the use of insects and other arthropods in medico legal investigations. We are sure that many people know this or a similar definition, maybe even already read a scientific or popular book dealing with this topic. So, do we really need another book on Forensic Entomology? The answer is 13, 29, 31, 38, and 61. These are not some golden bingo numbers, but an excerpt of the increasing amount of annual publications in the current decade dealing with Forensic Entomology. Comparing them with 89 articles which were published during the 1990s it illustrates the growing interest in this very special intersection of Forensic Science and Entomology and clearly underlines the statement: Yes, we need this book because Forensic Entomology is on the move with so many new
things happening every year. One of the most attractive features of Forensic Entomology is that it is multidisciplinary.
There is almost no branch in natural science which cannot find its field of activity here. The chapters included in this book highlight this variety of researches and would like to give the impetus for future work, improving the development of Forensic Entomology, which is clearly needed by the scientific community. On its way to the courtrooms of the world this discipline needs a sound and serious scientific background to receive the acceptance it deserves. This book does not ignore the forensic and entomological basics of the discipline, and gives an update in entomotoxicology, offering a survey about the decomposition of a cadaver (including a protocol for decomposing studies) and keys for identifying the difficult stages of immature insects. Especially the latter topic is an important one,
as we believe that, despite the enormous progress made in bar-coding and identification of many taxa via DNA-analysis in recent years, one should not neglect the very basic skills - particularly because using these “easy lab-tools” could give you a speciously feeling of certainty. Forensic Entomology and Blowflies are very often named in the same breath. We would like to attract the readers to some groups of animals which are neglected or even ignored such as, beetles and mites. Blowflies are much easier to handle in the lab than beetles, which could be the major reason why the majority of developmental studies are dealing with Diptera. If you have ever seen a cadaver infested by thousands of Silphidae or Dermestidae you soon realise that you must know more about them. Mites are not insects, nevertheless they belong traditionally to medical entomology since its early beginnings. So we should recognize them as a part of
forensic entomology as well, keeping in mind that the great Mégnin includes them in his famous Faune des Cadavres in the late nineteenth century. These arthropods are especially abundant in buildings, which leads to another gap in our knowledge: Indoor scenarios. Interestingly the majority of experiments analysing the insect succession on cadavers take place outside in the field. However we should not ignore that vast amount of corpses found every year indoors. No doubt, it’s much easier to conduct experiments out in nature, but we need indoor data sets as well for a better understanding of crime scenes which are located in a building. Working as a forensic entomologist means mainly working with terrestrial ecosystems, but people die in the sea as well, or their dead bodies are dropped there after a homicide. What happens to those corpses? How do the bodies decompose? And are any arthropods or insects involved in this process? You will know this soon. From deep in the sea to down in the ground: It is surprising that our knowledge of forensic entomology of the soil is so incomplete. Dealing with cases where the bodies were buried always creates a lot of difficulties. Is there a succession in the soil as well as on the surface? Are the species found on the body able to colonize the buried cadaver or did they colonize him before? Despite all of the scientific possibilities to improve the quality of entomological reports for the court, there are always pitfalls which cannot always be avoided. This book highlights certain caveats, bearing in mind that we are dealing with biological systems which do not always work in the same predictable manner. Due to the variability, we need statistics and probabilities in our expertises, which information is also covered in this book. A topic such as climate change would not be expected in a book about Forensic Entomology, but the truth is simple: Climate change is everywhere and it will also influence a topic like the use of insects in forensic investigations. Last but not least we dedicate an own chapter to the field of myiasis, which is a well known subject for a veterinary. Insects also infest living humans and feed on them. A forensic entomologist should understand this process because it could bias his work, and at the same time he might be asked to estimate the time of negligence. Curious? Then join us on our journey through the world of Forensic Entomology, but take care: after reading this book you may find you like this subject so much that perhaps you can find your own field of activity there: It is an exciting field of research
Effects of different storage and measuring methods on larval length values for the blow flies (Diptera: Calliphoridae) Lucilia sericata and Calliphora vicina
No full textIn forensic entomology, the methods of sampling, killing, and storing entomological samples can affect larval age estimation, and, hence, the estimation of the minimum post-mortem interval. In the existing manuals, there is a certain amount of heterogeneity regarding methods and the recommendations for best practice in forensic entomology are insufficiently validated. This study evaluated three different length-measurement methods for larval stages and examined the influence of different killing and storing methods on the larval length of two forensically important blow flies, Lucilia sericata and Calliphora vicina.
The three different measuring methods were a) a ruler with a 0.1 mm scale, b) a geometrical micrometer, and c) a computer-aided stereomicroscope. They were used to measure the length of L1 –L 3 C. vicina larvae and detect no significant differences. This supports the view that a simple tool like a geometrical micrometer can produce reliable results in forensic entomology.
Newly hatched larvae of L. sericata and C. vicina were killed with hot water (HW) and divided into two equal subsamples. Lengths of all larvae were measured immediately after killing, then every 24 h until day 4, and once more after 7 days of storage in ≥70%-ethanol.
L. sericata larvae only showed significant changes in length in the HW group stored at room temperature. After 4 and 7 days of storage, these 24-h- and 72-h-old larvae showed a significant decrease in length compared with those in a fridge at 6 °C. This decrease can, however, be considered a negligible natural variation without forensically relevant consequences for larval age estimation of L. sericata samples.
For C. vicina, an increase in length was observed over time. This was significant only for younger larvae (24-48 h old) stored in 70%-ethanol. This variance in length can lead to a wrong estimation of age; however, only for larvae stored in 70%-ethanol, not for those stored in 96%-ethanol.
Novelty statement: We examined the influence of different killing and storing methods on two forensically important blow flies, Lucilia sericata and Calliphora vicina. For the latter species we additionally were evaluating three different length measurement methods. The results of both experiments suggest that it is possible to kill and store fly larvae directly in (not hot) ≥70%-ethanol. This simplifies the sampling and storing of fly evidence at the crime scene. We also compared the influence of three different measuring methods for estimating the length of L1–L3 C. vicina larvae by using a) a ruler with a 0,1 mm scaling, b) a geometrical micrometer and c) a computer-aided stereomicroscope. No significant differences were detected, supporting the view, that a simple tool like a geometrical micrometer can produce reliable results. This study helps to simplify the sampling and evaluation of entomological evidence and to backup or questioning existing guidelines and best practice recommendations
HOW SHOULD LIVING ENTOMOLOGICAL SAMPLES BE STORED?
No full textSampling and storing insect evidence alive is an important task in forensic entomology as it can impact survival and growth rates. To investigate the effect of cooling and storing of insect evidence before its arrival in the laboratory, samples of all three larval stages of the blow fly species Lucilia sericata and Calliphora vicina were analysed. A first group was stored at room temperature and a second one in a refrigerator (~5°C) for 16h, all without air, supply of food and sawdust. Afterwards they were kept at 6-8°C in a Styrofoam box for 8h, simulating a transport situation. Mortality rate (MR) was calculated and 25% of the surviving larvae were killed and measured to check for interim growth. The remaining alive specimens were reared at 25 °C until adult’s eclosion for estimating a possible storage impact on survival during later development. The results were then compared with a control which was not temporary stored and chilled but left feeding in boxes with air-permeable lid on food substrate at 25°C. A 24h temporary storage stopped the larval growth in comparison with the control especially in early larval stages in both species. A high MR of up to100% for third instar (L3) larvae stored both at room temperature and in a cold environment without air supply was found. Oxygen supply can reduce significantly the MR at least for L3 larvae of L. sericata. Findings provide scientific evidence for the recommendation to store larval samples at cold temperatures with both oxygen and food supply. The high MR for samples of the last larval stage clearly shows the need for a fast delivery after sampling and a more sophisticated storage procedure like e.g. air supply. Storing live samples at room temperature without air access should be avoided
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Indoor arthropods of forensic importance: insects associated with indoor decomposition and mites as indoor markers
No full textTime Flies—Age Grading of Adult Flies for the Estimation of the Post-Mortem Interval
No full textThe estimation of the minimum time since death is one of the main applications of forensic entomology. This can be done by calculating the age of the immature stage of necrophagous flies developing on the corpse, which is confined to approximately 2–4 weeks, depending on temperature and species of the first colonizing wave of flies. Adding the age of the adult flies developed on the dead body could extend this time frame up to several weeks when the body is in a building or closed premise. However, the techniques for accurately estimating the age of adult flies are still in their beginning stages or not sufficiently validated. Here we review the current state of the art of analysing the aging of flies by evaluating the ovarian development, the amount of pteridine in the eyes, the degree of wing damage, the modification of their cuticular hydrocarbon patterns, and the increasing number of growth layers in the cuticula. New approaches, including the use of age specific molecular profiles based on the levels of gene and protein expression and the application of near infrared spectroscopy, are introduced, and the forensic relevance of these methods is discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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