youtube/watch?v=4YTUcmIKM1A youtube/watch?v=z7JtKGqJxU0

1. http://www.youtube.com/watch?v=4YTUcmIKM1A http://www.youtube.com/watch?v=z7JtKGqJxU0 http://www.youtube.com/watch?v=xIXweDteiSo

2. The Process Of Decay

3. Forensic Entomology

4. What is Forensic Entomology ? • It is the interpretation of entomological evidence to help resolve a criminal or civil investigation • The investigation of insects and other arthropods recovered from crime scenes and corpses. • The use of insects that inhabit decomposing human remains to aid legal investigations. 

5. Entomology is the Study of Insects

6. Insect Biology • Insects are the most diverse and abundant forms of life on earth. • There are over a million described species- more than 2/3 of all known organisms • There is more total biomass of insects than of humans. • Larva have a soft tubular body and look like worms. Fly species larvae are “maggots”

7. http://www.youtube.com/watch?v=xyXezzemVvs

8. Succesion • Colinisers • Anaerobic bacteria thrive in lactic conditions • Found in the gut and breed freely

9. Blow flies • Sensitive to smell of dead organisms • Can arrive within minutes of dead • Attracted by moisture and smell of body ofifices and open wounds • Lay eggs • Maggots hatch and start feeding on tissues • Burrow deeper down • Maggots pupate, turn into flies and the cycle starts over • The soft tissues liquify

10. Blowflies

11. Carcass Beetles Lay eggs on body as their larvae feed on the maggots

12. Parasitic Wasps Lay their eggs in the fly and beetle larvae

13. Coffin Flies As the body dries out cheeses flies and coffin flies arrive

14. The body becomes too dry for maggots • Beetles with strong chewing mouthparts are more common, feeding on connective tissue and muscle

15. Mites And moth larvae feed on the hair until only dry bone are found

16. Image: http://www.nlm.nih.gov/visibleproofs

17. http://www.youtube.com/watch?v=G3_658mAMsw

18. Decay Rates Are Variable • Studies of decay rates of 150 human corpses at in the Anthropological Facility in Tennessee (The Body Farm) • Most important environment factors in corpse decay: • Temperature – warmer = faster decay • Access by insects • Depth of burial – buried deeper takes longer to decay • Other Factors • Chemical-- embalming agent, insecticides, lime, etc. • Animals disrupting the corpse

19. http://video.nationalgeographic.com/video/player/science/health-human-body-sci/human-body/body-farm-sci.htmlhttp://video.nationalgeographic.com/video/player/science/health-human-body-sci/human-body/body-farm-sci.html

20. Five Stages of Decomposition Fueled by Insect Activity. • Fresh • Bloat • Decay • Post-decay • Dry (skeletal)

21. Begins at death Flies begin to arrive Temperature falls to that of the ambient temperature. Autolysis, the degradation of complex protein and carbohydrate molecules, occurs. Fresh

22. Swells due to gases produced by bacteria Temperature rise of the corpse Flies still present Bloat

23. Gases subside, decomposition fluids seep from body. Bacteria and maggots break through the skin. Large maggot masses and extreme amounts of fluid. Unpleasant odor Larvae beginning to pupate. Corpse reduced to about 20% of it’s original mass. Decay

24. Carcass reduced to hair, skin, and bones. Fly population reduced and replaced by other arthropods. Hide beetles are dominant in dry environments. Mite and predatory beetle populations increase. Post-Decay

25. Dry (Skeletal) • Does not always occur especially if corpse is in a wet region. Maggots will stay longer and hide beetles will not appear. • In wet environments the hide beetles are replaced with nabid and reduviid insects. • The corpse is reduced to at least ten percent of the original mass. • In the last stage (Skeletal Stage), only bone and hair remain.

27. ACTIVE TEACH BOOK VIDEO

28. Putrefaction • GIT micro-organisms multiply, invade and colonise the body • Skin becomes greenish and marbled by haemolysis

29. The cadaver swells as gas producing bacteria multiply producing bloating which may rupture the body cavities. Odour of decay begins. The change in body odour attracts insects, especially Diptera to the cadaver.

31. Putrefaction • Exposed skin blackens (“black putrefaction”) • Body collapses as gas escapes • The internal organs loose integrity and become liquefied • The integrity of the GI tract is lost and “purge fluid” oozes out of the body orifices

33. Putrefaction • Skin and hair can begin to be lost (Decay odour at this point is very strong) • Cadaver starts to dry out; exposed skin becomes leathery • Butyric fermentation produces a cheesy odour • Remaining body parts are subject to extensive mould growth • Dry decay then sets in • Skeletonisation.