FORENSIC ENTOMOLOGY MUSA. A. ALI. A. GINDEEL. (BSC.MSC STUDENT) AL-NEELAIN UNIVERSITY FACULTY Of Medical Laboratory Sciences PARASITOLOGY AND MEDICAL ENTOMOLOGY FORENSIC ENTOMOLOGY PRESENTED BY` MUSA. A. ALI. A. GINDEEL. (BSC.MSC STUDENT) Symposium on: Advances in Parasitology “Education and Research in Parasitology in the service of Mankind “ 28 MARCH 2015

Maggots and Time of Death Estimation FORENSIC ENTOMOLOGY Insects as Evidence Maggots and Time of Death Estimation

Entomology is the Study of Insects

What is Forensic Entomology? Forensic Entomology is the use of the insects and other arthropods that feed on decaying remains to aid legal investigations.  (Medicolegal criminal)

History of Forensic Entomology Is one of the oldest forensic sciences used in death investigation First recorded use was in 13th century in China First report in North America was in Quebec in 1897 American Board was established in 1966 European Association was established in 2001

Medicolegal Forensic Entomology Use to ; Determination of the time (postmortem interval or PMI) or site of human death based on identification of arthropods collected from or near corpses. Traffic accidents with no immediately obvious cause Possible criminal misuse of insects

Insects as Evidence Forensic entomologists use their knowledge of insects and their life cycles and behaviors to give them clues about a crime. Most insects used in investigations are in two major orders: 1 – Flies (Diptera). 2 – Beetles (Coleoptera) Blow Fly Carrion Beetle

What do they do? A forensic entomologist’s job may include: Identification of insects at various stages of their life cycle, such as eggs, larva, and adults. Collection and preservation of insects as evidence. Determining an estimate for the postmortem interval or PMI using factors such as insect evidence, weather conditions, location and condition of the body, etc. Testifying in court to explain insect-related evidence found at a crime scene.

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. Insects undergo either incomplete or complete metamorphosis. Larva have a soft tubular body and look like worms. Fly species larvae are “maggots”

Postmortem interval (PMI) Forensic Entomology is used to determine time since death (the time between death and corpse discovery) This is called postmortem interval or PMI). Other uses include movement of the corpse manner and cause of death association of suspects with the death scene detection of toxins, drugs, or even the DNA of the victim through analysis of insect larvae.

factors that might affect their PMI estimates: Was the body enclosed in an area or wrapped in a material that would have prevented flies from finding the corpse and laying eggs (body in box or bag) Were other insect species present that may have affected the development of the collected species Were there drugs or other poisons in or on the body that might have affected the larvae’s development Deeper burial

Differentiate between PMI and Time of Death These may not always equate. Post mortem interval is restricted to the time that the corpse or body has been exposed to an environment which would allow insect activity to begin.

Succession of Insects on the Corpse Ecological succession occurs as an unexploited habitat (like a corpse) is invaded by a series of different organisms. The first invasion is by insect species which will alter the habitat in some form by their activities. These changes make the habitat attractive to a second wave of organisms which, in turn, alter the habitat for use by yet another organisms.

Examples of Diptera (Flies) Early Stage Decomposition Blow & Greenbottle Flies (Calliphoridae) Metallic thorax and abdomen Flesh Fly (Sarcophagidae) Striped thorax Life Cycle of a Calliphoridae Fly Late Stage Decomposition House Fly (Muscidae) Cheese Skipper (Piophilidae)

Blow Fly Metamorphosis Blow flies are attracted to dead bodies and often arrive within minutes of the death of an animal. They have a complete life cycle that consists of egg, larva, pupa, and adult stages. 1st – Adult flies lay eggs on the carcass especially at wound areas or around the openings in the body such as the nose, eyes, ears, anus, etc. 2nd – Eggs hatch into larva (maggots) in 12-24 hours. 3rd– Larvae continue to grow and molt (shed their exoskeletons) as they pass through the various instar stages. 1st Instar - 5 mm long after 1.8 days 2nd Instar - 10 mm long after 2.5 days 3rd Instar – 14-16 mm long after 4-5 days 4th – The larvae (17 mm) develop into pupa after burrowing in surrounding soil. 5th – Adult flies emerge from pupa cases after 6-8 days. Adult Pupa Eggs 3rd Instar Larva 1st Instar Larva 2nd Instar Larva It takes approximately 14-16 days from egg to adult depending on the temperatures and humidity levels at the location of the body.

Examples of Coleoptera (Beetles) Early Stage Decomposition Early to Late Stage Decomposition Rove Beetles (Staphylinidae) Predator of fly eggs Clown Beetles (Histeridae) Predator of fly eggs Carrion Beetles (Silphidae) Adults & larvae feed on fly larvae Late Stage Decomposition Ham & Checkered Beetles (Cleridae) Predator of flies & beetles; also feed on dead tissue Hide Beetles (Scarabidae) Usually the last to arrive Skin Beetles (Dermestidae) Feed on dried skin & tissues

Forensic Entomology is Applied Biology If it weren’t for decomposition of all living things, our world would fill up with dead bodies. Did you know… The “Body Farm” in Knoxville, Tennessee is a university research facility to investigate human decomposition under various conditions in order to understand the factors which affect its rate.

Ecology of Decomposition Necrophages - the first species feeding on corpse tissue. Includes true flies (Diptera) and beetles (Coleoptera). Omnivores - species such as ants, wasps, and some beetles that feed on both the corpse and associated maggots. Large populations of ominvores may slow the rate of corpse’s decomposition by reducing populations of necrophagous species. Incidentals – pill bugs, spiders, mites, centipedes that use the corpse as an extension of their normal habitat

Decay Rates Are Variable Most important environment factors in corpse decay: Temperature Access by insects Depth of burial Other Factors Chemical-- embalming agent, insecticides, lime, etc. Animals disrupting the corpse

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

Fresh 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. Gasses produced by the metabolic activities of the anaerobic bacteria first cause a slight inflation of the abdomen. The carcass may later assume a fully inflated, balloon-like appearance. Adult and larval blowflies in large numbers attracted to fluids seeping from body, normal soil dwelling fauna depart soil because of seepage of fluids; some muscid flies and ants which can feed on larvae and retard maggot activity.

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

Decay 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 Stage - Black Putrefaction (Days 5-11) -- Decay stage begins when the abdominal wall is broken, allowing gasses to escape and carcass deflates. This process is facilitated by feeding activities of larval flies present on the exposed remains. Adult flies start to leave body, mainly larval mass. Carcass begins to assume a blackened, wet appearance, and most of the flesh will be removed by the maggots. Toward end of this period, carcass will begin to dry and beetles feed on drier tissue. Flies start to pupate. Predatory beetles such as rove beetles and histerids come to feed on other insects.

Post-Decay 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. Postdecay Stage - Butyric fermentation (Days 10-25) -- In dry habitats, remains consisted of dry skin, cartilage and bones. Site for dermestid beetles, histerids, fly pupae, immature and adult rove beetles. In wet habitats, a large quantity of wet, viscous material, termed byproducts of decomposition, was found in the soil under the remains. Site for immature and adult moth flies, sphaerocerid and muscid flies, rove beetles.

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 other insects. In the last stage (Skeletal Stage), only bone and hair remain. Dry Stage (Days 25 +) -- This stage is reached when mainly bones and hair remain. Odor is primarily that of normal soil and litter. Some dermestid beetles, histerids, fly pupae, immature and adult rove beetles, normal soil fauna (mites) start to return. Can last several months to even years.

Two Different Maggot Generations These are distinguishable by the length and obvious size difference.

Challenge to Forensic Entomology Temperature of crime scene and temperature that the insect have been exposed to us unknown Exclusion of insects by; -animal -first attendance to crime scene -refrigerate the corpse before collection the sample

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