Forensic Entomology Notes – Flashcards

Apply their knowledge of entomology (insects) to provide information for criminal investigations

1. Identification... 2. Collection... 3. Determining... 4. Testifying...

of insects at various stages of their cycles; such as eggs, larva, and adults

and preservation of insects as evidence

an estimate for the postmortem interval (PMI) using different factors

The time between death and the discovery of the body

- Insect evidence - Weather conditions - Location and condition of the body

in court to explain insect-related evidence found at a crime scene

1. Flies (Diptera) 2. Beetles (Coleoptera)

Different species arrive after different amounts of time has elapsed after death

- Some arrive right away, while others prefer to feed on an older corpse - Certain species will also arrive that prey on the insects already feeding on the corpse

-air -ground surface next to body -interface area (between the body and the ground) -soil under the body -inside any maggot masses

-Daily temperature (highs/lows) -Precipitation -Data needed from before the body was discovered to the time the insect evidence was collected

-Was the body enclosed in an area or wrapped in a material that would have prevented flies from finding the corpse and laying eggs on it? -Were other insect species present that may have affected the development of the collected species? -Were there other drugs or poisons in/on the body that might have affected the larvae's development? -Microbes might make a difference

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.

Eggs hatch into larvae (maggots) in 12-24 hours

Larvae continue to grow and molt (shed their exoskeleton) as they pass through the various instar stages

5mm long after 1.8 days

10mm long after 2.5 days

14-16mm long after 4-5 days

The larvae (17mm) develop into pupae after burrowing in surrounding soil

Adult flies emerge from pupa cases after 6-8 days

-Eggs -1st Instar Larva -2nd Instar Larva -3rd Instar Larva -Pupa -Adult

14-16 days, depending on the temperatures and humidity levels at the location of the body

1. Blow and Greenbottle flies (metallic thorax and abdomen) 2. Flesh Fly (striped thorax)

1. House Fly 2. Cheese Skipper (long body, segmented)

1. Carrion Beetles (adults and larvae feed on fly larvae)

1. Rove Beetles (predator of fly eggs) 2. Clown Beetles (predator of fly eggs)

1. Ham and Checkered Beetles (predator of flies and beetles; also feed on dead tissue) 2. Skin Beetles (feed on dried skin and tissues) 3. Hide Beetles (usually the last to arrive)

A number that entomologists calculate

Accumulated Degree Hour

The amount of heat that it takes for an insect to change from one larval stage to another

Time between stages x (multiplied by) Temperature

If a stage takes 12 hours at 70 degrees, the the ADH (12x70) = 840 degree-hour

It is constant (does not change) for each species and life cycle stage

You can use ADH to figure out how long it has been since the eggs were laid on the body by dividing the ADH by the average temperature

Time of Death