Bellringer: What are three types of material that can be found in soil? Why is soil analysis important in forensic science?

FORENSIC ENTOMOLOGY

Forensic Entomology: The use of insect knowledge in crime investigations.

Forensic Entomology: A useful tool to decide how long human remains have been undetected.

Forensic Entomology Can Help Determine: The cause of death If a corpse has been moved after death Post mortem interval (PMI) Neglect or abuse while alive

Determining PMI: More accurate measurement than looking at body temperature, body stiffness, chemical tests, or electrical tests Based on the developmental stages of arthropods Calculate the bugs’ developmental stages of when they inhabited the corpse

Determining PMI: Hundreds of arthropod species are attracted to corpses Insects are attracted to specific states of decomposition

Determining PMI: Most species colonize a corpse for a limited time period and then a change of insects occur- faunal succession Suspects can be linked to the scene of crime if bitten by arthropods specific to the crime scene area

Determining PMI: If insects live in a particular area but are found on a corpse in a different area, this may prove the body was moved after death

Determining PMI: Drugs can be identified from the insects that feed on the corpse Location of a stabbing wound can be determined by unusual feeding sites of beetles and maggots.

LIFE CYCLES:

Blow Fly Eggs: Flies lay 30-40 eggs a minute and hatch within hours Larvae (maggots) are commonly recovered from decomposing remains.

Blow Fly Larvae: White or cream-colored, soft bodies Lack functional legs (shaped like sausage) Laid in clumps called maggots Eat until they reach full size, then move to find area to form puparium

Maggot Mass:

Common Blow Fly Larvae Found on Human Remains

Blow Fly Pupae: Pupae are often overlooked. Appear as rat droppings or the egg case of cockroaches

Blow Fly Pupae: Important for evidence- If adult fly has NOT emerged yet, pupa looks featureless and rounded on both ends If adult fly HAS emerged, one end appears as if it has been cut off and the inside is hollow

Unemerged Blow Fly Pupa:

Adult Emerging from the Puparium:

Appear metallic green or blue Blow Fly Adult: Appear metallic green or blue MALE FEMALE

Beetle Life Cycle:

Beetle Eggs: Eggs hatch

Beetle Larvae: Each species look very different from one another Have 3 pairs of legs Body can be white, robust, and hairless Can be dark brown, slender, and hairy Can be black and have armored plates

Common Beetle Larvae:

Beetle Pupae: Incubation until adulthood

Very diverse in appearance Beetle Adult: Very diverse in appearance

Beetle Adults: Sexton Beetle: Nocturnal and typically found under a body or in the soil immediately surrounding the remains during the daylight hours.

Adult Beetles: American Carrion Beetle: Commonly observed on the upper surfaces of a body during the daylight hours

Flesh Flies: