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Transcript of Forensic Entomology
Change in temperature after death
Most useful indicator of the time of death during first 24 h
Livor mortis / Hypostasis
Settling of blood in the body gives off a bluish-purple colour
The area where the blood collects goes reddish-purple
Stiffening of the muscles after death
Tissue breakdown by the body's own internal chemicals and enzymes
The breakdown of tissues by bacteria. These processes release gases that are the chief source of the characteristic odour of dead bodies.
Dehydration or desiccation of tissues
Time of Death Determination
Concerns the use of arthropod evidence in solving crimes –most often crimes of violence
Deliberate homicide or assault using insects
Cases of unexplained death - E.g. anaphylaxis from bee stings
Causation of traffic accidents - E.g. wasp in a vehicle
But more commonly:
Estimation of time of death - “Postmortem interval” PMI
And less often –site where death occurred.
Disputes over arthropods and arthropod parts in food and other products
Insect debris in breakfast cereal
Caterpillars in cans of vegetables
Fly maggots in sandwiches from fast-food restaurants
“planted” with intent to defraud…
Stored Product Entomology
Problems involving cockroaches and other pests
Lawsuits on damage, extermination, real estate value
Also includes Rural Entomology -Insect nuisance related to agricultural endeavors
Flies from livestock and insects in cattle feedlots, poultry houses and pig farms.
Patients in hospitals with
Mortuary neglect –maggot infested corpses
What is it? - Interaction between arthropod science and judicial system
Stored Products Entomology
Forensic Medical Entomology / Medico-criminal entomology
American Board of Forensic Entomology
Quality assurance mechanism
Educational and performance criteria
PhD in medical entomology
Involvement with and contribution to both research and case work in medicocriminal entomology.
Ability to qualify as an expert witness
Peer recommendations, committee screening, approval of Board, Certification Examination
Membership in the ABFE
Observe maggots & take samples
id species via instars and spiracles
Find out temperature & weather
Find out growth rate
Figure out PMI
How it's done
Insects are cold blooded.
Rate of development is more or less dependent on ambient temperature
For each species there is a threshold temperature below which no development occurs
As temperature rises above this threshold, a certain amount of time is required for the insect to pass through each life stage.
Blow flies (usually Calliphora vomitoria)
Help break down corpse
Help us determine location of deceased and the time since death
Accuracy really important!
Access by insects
Burial, and depth of burial
Access by carnivores or rodents
Trauma, including wounds and crushing blows
Humidity, or dryness
Body size and weight
The surface the body rests on
Variables Affecting Decomposition
Triazolam - benzodiazepine
Oxazepam - benzodiazepine
Alimemazine - (sedating) antihistamine
Chloripriamine - antihistamine
Phenobarbitol - anticonvulsant
Malathion - insecticide
Amitriptyline - antidepressant
Nortriptyline - antidepressant
The following list of chemicals has been traced in maggots:
(This can cause problems with inhibition or enhancement of life-stage duration.)
Time of Death Determination
Spiracles & Instars