Forensic Entomology

Forensic Entomology

Bud and Patti Bertino

Forensic Entomology is based on:

• Insect life cycles• Knowledge of length of stage of

development• Predatory food chain on corpse• Gases produced by decomposing bodies

draw insects, not blood• These gases are carbon dioxide,

methane, ammonia and nitrogen

A first ‘wave’ of insects• Usually blow arrive first laying

150-300 eggs on soft tissue lining body openings on corpse• In 1-2 days, eggs hatch and

maggots feed on corpse (1st instar stage)

•Maggots mature through 3 instar stages before forming a cocoon (pupa stage)•About a week later, adult flies emerge

What might effect the accuracy of the time sequence of the life cycle of the blow fly?

Blow fly arrives in less than one minute

Various Types of Maggots

Life Cycle of the Flesh Fly

Second wavecould include:

• Beetles or other insects who feed on blow flies and have a life cycle of their own

• The corpse may really be the origin of a food chain.

How does a food chain work?

How would each of these factors affect time of death estimations?

• Burial• Immersion in water• Mummification• Geographic location

• Temperature & Humidity• Light & Shade• Season• Length of day• Manner of death (Poisons may slow down

decomposition)

Time to get to work!

Forensic examination kit

Project ideas:1. Study the life cycle of a blow fly and

determine the timeline used by forensic scientists.

2. Obtain some liver and grow your own ‘time line’.

3. Search the internet for crimes that were solved through the use of forensic entomology.