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Forensic entomology is the application of the study of insects and other arthropods to legal issues. It can be divided in three subfields: urban, stored-product and medicolegal.

Medicolegal forensic entomology includes arthropod involvement in events such as murder, suicide and rape, but also includes physical abuse and contraband trafficking. In murder investigations it deals with what insects lay eggs when and where, and in what order they appear in dead bodies. This can be helpful in determining the time or post mortem interval (PMI) and location of the death in question.

There are many types of insects that can be involved in forensic entomology, but the ones listed here are mostly necrophagous (corpse-eating) and related to medicolegal entomology (directly related to the crime and found on the corpse). This is not a full list; there are many variations due to climate, and many other insects that are necrophagous. This is outlined by Mostovski and Mansell *. The order in which the insects feed on the corpse is called the faunal succession *.

Flies (Order Diptera)

Flies are often first on the scene. They prefer a moist corpse for the maggots to feed on, as such a corpse is easier for them to chew. The most important families are:

Beetles (Order Coleoptera)

Beetles are generally found on the corpse when it is more decomposed. In drier conditions, the beetles can be replaced by moth flies (Psychodidae).

  • Rove Beetles - Family Staphylinidae - are elongate beetles with small elytra (wing covers) and large jaws. Like other beetles inhabiting carrion, they have fast larval development with only three larval stages. Creophilus species are common predators of carrion, and since they are large, are a very visible component of the fauna of corpses. Some adult Staphylinidae are early visitors to a corpse, feeding on larvae of all species of fly, including the later predatory fly larvae. They lay their eggs in the corpse, and the emerging larvae are also predators. Some species have a long development time in the egg, and are common only during the later stages of decomposition. Staphylinids can also tear open the pupal cases of flies, to sustain themselves at a corpse for long periods.

  • Hister Beetles - Family Histeridae. Adult histerids are usually shiny beetles (black or metallic-green) which have an introverted head. The carrion-feeding species only become active at night when they enter the maggot-infested part of the corpse to capture and devour their maggot prey. During daylight they hide under the corpse unless it is sufficiently decayed to enable them to hide inside it. They have fast larval development with only two larval stages. Among the first beetles to arrive at a corpse are Histeridae of the genus Saprinus. Saprinus adults feed on both the larvae and pupae of blowflies, although some have a preference for fresh pupae. The adults lay their eggs in the corpse, inhabiting it in the later stages of decay.

  • Skin/Hide Beetles - Family Dermestidae. Hide beetles are important in the final stages of decomposition of a carcass. The adults and larvae, which are hairy, feed on the dried skin, tendons and bone left by fly larvae. Hide beetles are the only beetle with the enzymes necessary for breaking down keratin, a protein component of hair.

Mites (Class Acari)

Many mites feed on a corpse. Macrocheles mites are common in the early stages of decomposition, while Tyroglyphidae and Oribatidae mites such as Rostrozetes feed on dry skin in the later stages of decomposition.

Nicrophorus beetles often carry on their bodies the mite Poecilochirus which feeds on fly eggs. If they arrive at the corpse before any fly eggs hatch into maggots, the first eggs are eaten and maggot development is delayed. This may lead to incorrect PMI estimate. Nicrophorus beetles find the ammonia excretions of blowfly maggots toxic, and the Poecilochirusmites, by keeping the maggot population low, allow Nicrophorus to occupy the corpse.

Moths (Order Lepidoptera)

Clothes-moths - Family Tineidae - feed on mammalian hair during their larval stages and may forage on any hair that remains. They are amongst the final animals contributing to the decomposition of a corpse.

Wasps, ants, and bees (Order Hymenoptera)

The insects in this group, order Hymenoptera, are not necessarily necrophagous. While some feed on the body, some are also predatory, and eat the insects feeding on the body. Bees and wasps have been seen feeding on the body during the early stages. This may cause problems for murder cases in which larval flies are used to estimate the post mortem interval since eggs and larvae on the body may have been consumed prior to the arrival on scene of investigators.

Books on forensic entomology

  • Smith, K. G. V. 1986. A Manual of Forensic Entomology. Comstock Publishing Associates, Cornell Univ. Press, Ithaca, NY, 205 pp. (ISBN 0-8014-1927-1). A technical hardback designed for professional entomologists.
  • Catts, E. P. and N. H. Haskell, eds. 1990. Entomology & Death: A Procedural Guide. Joyce's Print Shop, Inc., Clemson, SC, xii + 182 pp. (ISBN 0-9628696-0-0) Spiralbound also aimed at professional entomologists, but shorter and with a popular style.
  • Greenberg, B. and Kunich, J.C., , 2002 Entomology and the Law: Flies as Forensic Indicators Cambridge University Press, Cambridge, United Kingdom 356 pp (ISBN 0-521-80915-0).
  • Leclerque , M. 1978 Entomologie médicale et Médecine légale Datation de la Mort, Masson ed. Paris, 112p
  • Nuorteva P 1977. Sarcosaprophagous insects as forensic indicators. In CG Tedeschi, WG Eckert & LG Tedeschi (eds), Forensic Medicine: a Study in Trauma and Environmental Hazards, Vol. II, WB Saunders, New York, p.1072-1095.

Other Literature

  • Liu, D.; Greenberg, B. 1989 Immature stages of some flies of forensic importance Annals of the Entomological Society of America 82(1):80-93.

History

A brief history of forensic entomology is presented by Mark Benecke*

See also

External links

Please note - these sites may contain strong graphic images and descriptions.

Forensics | Entomology | Criminology topics

Forensische Entomologie | Forensische entomologie

 

This article is licensed under the GNU Free Documentation License. It uses material from the "Forensic entomology".

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