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This study highlights the importance of insect evidence by evaluating 949 insect-associated cases, including 139 entomological reports, from 2001 to 2019 at the Institute of Legal Medicine Frankfurt/Germany. With a high number of cases in the summer months and a low number in the colder season, 78.5% of the bodies were found indoors, regardless of year or month. In more than 80% of the cases, where PMI information was available (n = 704), the presumed PMI ranged from 1 to 21 days, a period during which entomological evidence can provide a day-specific estimate of PMI min . In cases where insects have been identified to species level (n = 279), most bodies were infested by one or two species with a maximum of 10 different species. Overall, a total of 55 insect species were found. Information on biology, activity and distribution of the most abundant taxa is given and applied for 5 case histories estimating different PMI min s of up to over 6 months. Despite proved importance and scientific development of forensic entomology, insects are still rarely considered as a tool in forensic case work. The main reasons are a lack of awareness and (too) late involvement of a forensic entomologist. Our work shows that forensic entomology is an independent discipline that requires specialist expertise., (© 2021. The Author(s).)

Forensic entomology is the science of collecting and analysing insect evidence to aid in forensic investigations. Its main application is in the determination of the minimum time since death in cases of suspicious death, either by estimating the age of the oldest necrophagous insects that developed on the corpse, or by analysing the insect species composition on the corpse. In addition, toxicological and molecular examinations of these insects may help reveal the cause of death or even the identity of a victim, by associating a larva with its last meal, for example, in cases where insect evidence is left at a scene after human remains have been deliberately removed. Some fly species can develop not only on corpses but on living bodies too, causing myiasis. Analysis of larvae in such cases can demonstrate the period of neglect of humans or animals. Without the appropriate professional collection of insect evidence, an accurate and convincing presentation of such evidence in court will be hampered or even impossible. The present paper describes the principles and methods of forensic entomology and the optimal techniques for collecting insect evidence.

Forensic entomology analyzes and evaluates the presence of necrophagous or necrophilic insects on human corpses to estimate the post-mortem interval. The three cases presented are good examples illustrating that not only the various stages of development of the necrophagous insects from egg via larva to pupa are useful for forensic assessment. Depending on the situation in the individual case, even inconspicuous remains of past insect activity such as empty pupal cases or larval skins may supply important entomological information. For this purpose it is indispensable to preserve such evidence, which may appear only as fragments or pieces at first sight, for proper entomological assessment.

Necrophagous insects are important in the decomposition of cadavers. The close association between insects and corpses and the use of insects in medicocriminal investigations is the subject of forensic entomology. The present paper reviews the historical background of this discipline, important postmortem processes, and discusses the scientific basis underlying attempts to determine the time interval since death. Using medical techniques, such as the measurement of body temperature or analysing livor and rigor mortis, time since death can only be accurately measured for the first two or three days after death. In contrast, by calculating the age of immature insect stages feeding on a corpse and analysing the necrophagous species present, postmortem intervals from the first day to several weeks can be estimated. These entomological methods may be hampered by difficulties associated with species identification, but modern DNA techniques are contributing to the rapid and authoritative identification of necrophagous insects. Other uses of entomological data include the toxicological examination of necrophagous larvae from a corpse to identify and estimate drugs and toxicants ingested by the person when alive and the proof of possible postmortem manipulations. Forensic entomology may even help in investigations dealing with people who are alive but in need of care, by revealing information about cases of neglect.