Entomology• the study of the life cycles and distribution of insects.Forensic Entomology• study of the life cycles of insects found on a decomposing body
Entomology• The time of death can be estimated fairly accurately by an entomologist by analyzing what type of insects are on the body and which stage of their life cycle they are in.
Entomology• A human corpse becomes an ecosystem of natural decay. For insects, it provides food, a home, and a place to lay eggs.
Carrion Insects(feed on dead organisms) – Necrophagous species – feed directly on the human corpse. • Blow flies • Flesh flies – Predators and Parasites (are attracted to the dead body because of the carrion insects) – Omnivorous insects (feed on both the dead body and the other insects) • Wasps, beetles, ants – Normal insects (those that are already in the area) • Hunting spiders • Soil-dwelling organisms
Stages of Insect-aided Decomposition(Goff, 2001)1. The “fresh” stage – – body temperature falls to match environment, – insects land on body, feed on body fluids, lay eggs in body cavities. – eggs take 12-18 hours to hatch, – maggots feed on body. – predators and parasites arrive next.
Stages of Insect-aided Decomposition(Goff, 2001)2. The “Bloated” Stage – – bacteria inside body release gases during putrefaction, – abdomen and then the whole body blows up like a balloon, – body becomes very hot, – houseflies arrive and lay eggs, – eggs hatch and maggots feed on body tissue, – more predatory insects are attracted to the scene, – body fluids begin to seep from the body.
Stages of Insect-aided Decomposition(Goff, 2001)3. The “Decay” Stage – – skin cracks open as maggots feed – gases escape body – strong foul odor is released – number and types of insects increase – beetles arrive and remove flesh
Stages of Insect-aided Decomposition(Goff, 2001)4. The “Post-Decay” Stage – – mostly bones, cartilage, skin, and hair are left – different types of beetles arrive – mites begin to inhabit soil under body as they feed on by-products of the body’s decomposition
Stages of Insect-aided Decomposition(Goff, 2001)5. The “Skeletal” Stage – – only bones and hair remain – no more insects