Forensic Entomology

Forensic Entomology

The use of insects and their arthropod relatives that inhabit decomposing remains to aid legal investigations

Forensic entomology is commonly broken down into three general areas:

1. medicolegal

2. urban

3. stored product pests

Medicolegal entomology focuses on

the criminal component of the legal system

is concerned with necrophagous feeding insects that typically infest human remains

The forensic entomologist

1. Identifies the immature insects on or near a dead body

2. determines the size and development of the insects

3. calculates the growth of the insects and passage through stages of the life cycle in laboratory

4. compares the growth against the weather conditions to estimate time of oviposition

Applications of Forensic Entomology in Death Investigations

1. estimate how long the person has been dead (or how long the body has been in the environment)

2. determine where the death occurred

3. identify areas of trauma on the body

4. identify chemicals or drugs in the body antemortem

The most common group of insects to determine PMI

Blowfly

The blowfly is a member of the ....

Calliphoridae family

How many species of blowfly available for PMI estimation in North America?

40

What is the blowfly life cycle known as?

Complete metamorphosis

Instar

an insect in any one of its periods of postembryonic growth between molts

Blowfly Life Stages

Egg stage

1st instar

2nd instar

3rd instar

puparial stage

adult

For PMI estimation, three things are needed

1. the species of blowfly

2. temp

3. life stage

Succession of Species in PMI estimation

insects colonize dead animals in a predictable sequence

The five stages of Decomposition

1. Fresh

2. Bloat

3. Decay

4. Post-Decay

5. Dry

Autolysis

breakdown of tissue by enzymes; self digestion

occurs during the fresh stage

Collecting Entomological data at the Death Scene

1. visual observation and notation, including any observations of insect activity on the remains prior to moving the body

2. begin collecting climate information at the scene

3. Collect specimens from the around the body before the body is moved

4. collect specimens from nearby the body

5. collect specimens beneath the body once it has been removed

Visual observations of insect activity at the scene

1. record the areas of major insect infestation on the body

2. approximate the number and types of insects on or near the body, including the flying

3. record immature stages of insects

4. record any insect predation

5. record position and orientation of the body

6. record insect activity within 10-20 feet of the body

7. record any natural occurring, manmade or scavenger-caused phenomenon