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Forensic Entomology

Forensic Entomology. Forensic Entomology:. the use of arthropods that inhabit decomposing remains to aid in legal investigations. all about forensic entomology. Do you ever fear as a hearse goes by,

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Forensic Entomology

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  1. Forensic Entomology

  2. Forensic Entomology: the use of arthropods that inhabit decomposing remains to aid in legal investigations

  3. all about forensic entomology

  4. Do you ever fear as a hearse goes by, That you may be the next to die.They wrap you up in a big white sheet,From your head down to your tired feet. The worms crawl in, the worms crawl out,The worms play pinochle on your snout. They eat your eyes, they eat your nose,They eat the jelly between your toes They put you in a big black box,cover it up with dirt and rocks.All goes well for about a week,then your coffin begins to leak. The worms crawl in, the worms crawl out,The worms play pinochle on your snout. They eat your eyes, they eat your nose,They eat the jelly between your toes. A big green worm with rolling eyes,Crawls in your stomach and out your eyes. Your stomach turns a slimy green,And pus pours out like whipping cream. You spread it on a slice of bread… -” The Hearse Song” http://www.youtube.com/watch?v=5NNJ6bjLdeo https://www.youtube.com/watch?v=xclh_676KwE https://www.youtube.com/watch?v=j3qIBHStUc0

  5. Why is forensic insectevidence not used more often? • Lack of training of investigators • “Worms” were considered just another disgusting part of decay and the investigation process • Reliability • Factual proof • Lack of interest • Disappearing evidence • Lack of forensic entomologists

  6. Insects Stand Ready to Help A dead body is carrion - dead animal matter Insects are macro-decomposers - they arrive in a predictable manner Insects are among the first decomposers - others may disturb the corpse

  7. bugs in crime • Krug's Bugs The broad field of forensic entomology is commonly broken down into three general areas: • Medico legal • Urban • Stored product pests. 

  8. Medico legal/criminal The use of arthropod evidence in solving crimes –most often crimes of violence

  9. Medico urban Insects that affect the human environment Insect marks and Wounds. Pests - cockroaches, flies, maggots, etc.

  10. Stored product pests Insects found in foods – medical and economic Frozen foods Candies Restaurants Processed foods Scientists must find the country of origin When bugs entered the product

  11. The diversity of forensicentomology • Wasp and bee stings as punishment • Neglect of young, elderly, ill • Single occupant vehicle accidents • Insect remains to detail probable path • Insects in drugs • Insects and blood spatter patterns • Fly “specks” - blood

  12. Successional Faunal Waves

  13. Post Mortem Interval (PMI) the time that has elapsed since a person has died. If the time in question is not known, a number of medical/scientific techniques are used to determine it.

  14. Eggs in Nostrils Adult blow flies may begin ovipositing within minutes of death, depending on environmental circumstances. First egg-laying on fresh bodies focuses on orifices around the head where delicate mucous membranes facilitate easy access by freshly hatched larvae, and sites of trauma. Eggs look like sawdust, as do hatched eggs. Collect egg masses. Also collect adult flies and other insects with a net, forceps, or fingers, etc.

  15. Insects invade an unprotected body in successive waves Bluebottle flies prefer relatively fresh bodies and will lay eggs on moist areas -eyelids, eyes, nostrils, lips, genitals, anus, open wounds. House flies prefer decomposed bodies

  16. At the Crime Scene: Take temperature of maggot mass and environmental temperature Local meteorological records Note vegetation, trees, undergrowth… Collect live and fixed specimens Take soil sample

  17. Blow fly pupae can be confused with rodent droppings. Lighter colored pupae are the most recently formed. Keep all recovered pupae alive, but indicate on the label that they were pupae when collected. Find pupae in soil up to 12’or more from the body, under the body, in clothing, the body bag, on bones, etc. Indoors, look under carpets, mattresses…

  18. A thermometer is used to collect maggot mass temperature. • Liquefied areas are teaming with maggots. Maggot mass temperatures may be as much as 20 C° or more than the surrounding temperature. • Take the most conservative estimate of time of insects first colonizing remains is based on the warmest temperatures that can be recovered. This time is somewhat consistent with time of death, depending on environmental conditions. • Temperatures are used quantitatively in arriving at this estimate.

  19. Maggot Development Understanding life cycles and developmental times under varying conditions is essential

  20. Pupal Development

  21. Beetles are the best way to clean a corpse. The beetle in particular is called the Dermestid officially, but goes by many other names like the hide beetle, the carpet beetle, the larder beetle, and the flesh-eating beetle, because of what they eat - everything except glass, steel, and bone

  22. Carrion Beetle

  23. Larder beetle larvae feeding on a country ham

  24. The red-tailed flesh fly, Sarcophaga haemorrhoidalis (adult female).  Flies in the family Sarcophagi deposit living first instars larvae.  They "skip" the egg stage required by the blow flies.  Therefore, large egg masses will not be visible on remains colonized by these flies. 

  25. An adult female Sarcophagi fly deposits a fewer number of living first instar larvae than female blowflies do when depositing their eggs.  In most cases, their overall abundance on decomposing remains is less than egg laying flies but their larger size makes them highly visible. 

  26. The pupa of Piophila casei, the cheese skipper.  The intermediate stage between the active larva (maggot) and the adult fly.  Often present on body several months after death.

  27. Investigators often overlook the pupa stage mistaking it as roach eggs or rat droppings.  This is actually the dried, hardened, outer skin of the third instar larva.  After the developing adult fly emerges from within, the empty shell will remain in the environment for extended periods of time.  These cases have been recovered in Egyptian mummies, Mexican tomb shafts, and in the skulls of ancient Bison.   The presence of pupa at a death scene is valuable evidence that should not be overlooked.   

  28. ommon larvae or "maggots" found on human remains: Chrysomya rufifacies (left), one of the hairy maggot blow flies, was introduced into the United States in the late 1980's and has now established itself over the southern US from Florida to California.  During the warm summer months, this species can be found as far North as Michigan.  Hydrotaea aenescens (center), the bronze dump fly, is common on decomposing remains when fecal material or exposed gut contents are present. 

  29. sarcophaga haemorrhoidalis (right), one of the red-tailed flesh flies, is a common occurrence on carcasses in early and advanced stages of decomposition.  This species typically arrives along with the early arriving greenbottle blow flies, which they quickly outgrow.   This species can be recovered throughout the year in the southern United States, and the larvae can live in moist semi-aquatic habitats that would be unsuitable to many other fly species. 

  30. Faunal evidence may help show • Movement of corpse • Changes in species composition • Antemortum conditions • Lice, mites,wounds • Evidence can be durable

  31. Delayed recovery of the corpse

  32. Supplemental Evidence • Weather History important to development • Topography, exposure, site description • Personal information • When last seen • When body was discovered

  33. Analysis of Faunal Evidence • Age determination • Influences of Site • Influences of insects themselves • Influence of scavengers • Regional and seasonal occurrence of fauna

  34. Complications • When was corpse accessible to fauna • Weather and site conditions • Disturbance of corpse • Treatment of corpse after discovery • Collection of insects

  35. collection

  36. Write these on the back of your paper: • Oviposit-To lay eggs, especially by means of an ovipositor. • Instar-A stage of an insect or other arthropod between molts. • Pupa- life stage of some insects undergoing transformation - complete metamorphosis. • Maggot - common name of the larval phase of development in insects of the order Diptera (flies)

  37. Estimating time of death (TOD) The major use of forensic entomology is estimating the time of death or the post mortem interval (PMI) of a corpse. The post mortem interval is the amount of time that has elapsed since the person died. Two main factors need to be considered when estimating a PMI; 1. the time it has taken each species of fly to reach 2. the rate of development for each species.

  38. Body Farm http://video.nationalgeographic

  39. http://www.bing.com/search?q=body+farm&qs=n&sk=&sc=8-9&form=QBRE&adlt=stricthttp://www.bing.com/search?q=body+farm&qs=n&sk=&sc=8-9&form=QBRE&adlt=strict

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