Entomology
- Created by: meganjayne15
- Created on: 30-04-14 11:13
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- Entomolgy
- stages of decomposition
- 1. Fresh
- 2. Bloat
- 3. Putrefaction
- 4. Putrid Dry
- skin and soft tissue gone
- loss of tendons, hair, cartilage and nails
- 19- 30 days
- loss of skin and soft tissue
- body starts to deflate and dry out
- 8 – 18 days (in later summer/early autumn)
- body starts to deflate and dry out
- 4. Putrid Dry
- active decay
- Gradual inflation of corpse occurs 4 – 6 days after death in Spring/Summer. Longer when colder.
- 3. Putrefaction
- cells quickly start to die
- algor mortis
- livor mortis
- rigor mortis
- cells are deprived of oxygen
- 2. Bloat
- 1. Fresh
- Pigs are used when research is taken place on entomology
- same size as human torso
- similar digestion to humans
- relatively hairless and skin tissue similar to humans
- putrefaction occurs around the same time as it does in humans
- The interpretation of entomological evidence to help resolve criminal
or civil investigations
- 3 main aspects
- Medico-legal, urban, and stored product
- 3 main aspects
- insects found on corpses
- Necrophagous insects – those that feed on dead flesh
- Omnivores - Feed on both body and associated insects.
- Predators & Parasites
- Calliphoridae – blowflies
- bluebottles
- greenbottles
- Sarcophagidae (flesh flies)
- Muscidae (houseflies)
- Phoridae – scuttle flies
- Cleridae bone beetles
- Dermestidae hide & skin beetles
- Silphidae carrion beetles
- Estimating Time of Death (TOD)
- The effect
of temperature on the development time of insects.
- possible to determine an estimate EOD - earliest oviposition dates
- from this we can estimate PMI - post mortem interval which is the time since death
- minimum PMI estimated by insect age
- PMI can help us to put the suspect and victim together in same time frame
- from this we can estimate PMI - post mortem interval which is the time since death
- other factors which effect development of insects
- Night-time
- larval crowding
- rainfall
- drugs/toxins
- burning
- access to body
- intrinsic factors
- possible to determine an estimate EOD - earliest oviposition dates
- refer to image to see the cycle of a blow fly
- two main methods
- Calculate the accumulated degree-hours/days required by larvae to reach particular stages of development
- Kill larvae from crime scene and compare length with reference data from species-specific growth curves
- The effect
of temperature on the development time of insects.
- Retrieving insects from a crime scene
- colellct maggots from body
- sub sample taken for estimate of PMI
- kill maggots in boiling water
- pour off water rinse once with 80% ethanol and then refill bottle with fresh 80% ethanol
- kill and preserve puparia by immersion and storage in 80% ethanol
- kill maggots in boiling water
- some frozen and some left alive
- sub sample taken for estimate of PMI
- collect puparia from on and under the body and nearby
- sub sample taken for estimate of PMI
- kill maggots in boiling water
- pour off water rinse once with 80% ethanol and then refill bottle with fresh 80% ethanol
- kill and preserve puparia by immersion and storage in 80% ethanol
- kill maggots in boiling water
- some frozen and some left alive
- sub sample taken for estimate of PMI
- colellct maggots from body
- stages of decomposition
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