1. Decomposition Begins at the moment of death, caused by two factors
Autolysis
The breaking down of tissues by the body's own internal chemicals and enzymes
Putrefaction
The breakdown of tissues by bacteria
These processes release gases that are the chief source of the characteristic odor of dead bodies
These gases swell the body

2. Decomposition Scavengers play an important role in decomposition
Insects and other animals are typically the next agent of decomposition, if the body is accessible to them
The most important insects that are typically involved in the process include the fleshflies (Sarcophagidae) and blowflies (Calliphoridae)
The green-bottle fly seen in the summer is a blowfly
Larger scavengers, including coyotes, dogs, wolves, foxes, rats, and mice may eat a body if it is accessible to them
Some of these animals also remove and scatter bones.

3. Factors Involved in Decomposition
In a roughly descending degree of importance, those factors include:
Temperature
The availability of oxygen
Prior embalming
Cause of death
Access by insects
Burial, and depth of burial
Access by scavengers
Trauma, including wounds and crushing blows
Humidity, or dryness
Rainfall
Body size and weight
Clothing
The surface on which the body rests

4. Differentiate between PMI and Time of Death
These may not always equate.
Post mortem interval is restricted to the time that the corpse or body has been exposed to an environment which would allow insect activity to begin.
Closed windows
Body in box or bag
Cold temperatures
Deeper burial

5. Major Groups of Insects Associated with Cadavers
Flies
Blowflies
Flesh Flies
House Flies
Cheese Skippers
Beetles
Carrion Beetles
Dermestids
Scarab Beetles

6. Blow Fly Metamorphosis
Adult
Pupa
Eggs
3rd Instar Larva
1st Instar Larva
2nd Instar Larva
It takes approximately days from egg to adult depending on the temperatures and humidity levels at the location of the body.
Image:
Information: and

9. Decay Rates Are Variable
Studies of decay rates of 150 human corpses at in the Anthropological Facility in Tennessee (The Body Farm)
Most important environment factors in corpse decay:
Temperature
Access by insects
Depth of burial
Other Factors
Chemical-- embalming agent, insecticides, lime, etc.
Animals disrupting the corpse

10. Determining Whether the Body has been Moved
Insects present on the deceased body that are not prevalent to the crime scene can indicate that the victim was murdered elsewhere and was dumped at another location

11. Drugs
Insects that feed on the body of individuals that have been poisoned can be examined to determine what type of drug or toxin the person was poisoned with
It is important to note that specific drugs either speed up or slow down larval development
Can influence entomologist’s final report

12. Challenges to Forensic Entomology
3 challenges exist
Temperature
Temperature of crime scene and the temperature that the insects have been exposed to us unknown
Season
Entomology is valuable only in spring, summer, and fall
Exclusion of insects
Insects are excluded based on condition of body