Forensic Entomology Part-1

Entomology means the study of various types of arthropods (insects).

In simple terms, Forensic entomology is the scientific study of insects with respect to criminal investigation.

We can also define it as the invasion of the arthropods with their developmental stages, of different species found on the cadavers.

It is basically, involves the study of

i.  Insects

ii. Arachnids

iii. Centipedes

iv. Millipedes

v. Crustaceans

In 13th century, 1st crime was recorded in China, where insects were used to solve the case.

There are 4 categories of insects can be found on carrion(decaying flesh). These are:

1. Necrophagous species; feeding on the tissue of the corpse

2. Predators and the parasites; Feeding on the necrophagous species and other insects. 

3. Omnivorous species; feeding on the dead body and some arthropods.

4. Other species like spiders, centipedes millipedes, and other that use the dead body as normal part of their habitat.

The insects which are mostly found during the forensic investigation are true flies or Diptera, blowflies, houseflies , flesh flies, etc.

Most often the flesh flies scientifically known as sacrophagidae may arrive within minutes following the death. 

The house flies delay the colonization until the body reaches to the bloating stage of decomposition.

The blowflies in the adult form appears as shiny with metallic coloring often with blue green or black thorax and abdomen. 

The flesh flies a medium sized flies with black and Gray longitudinal stripes on the thorax and checkering on the abdomen. 

The adult houseflies are 8-12 millimeter long with their thoraxes Gray with four longitudinal dark lines in the back, the entire body is covered with hair like projection.

There are certain stages which covers the forensic in entomology. These are;

1. Fresh stage (one to two days)

2. Bloated stage (two to six days) 

3. Decay stage (5 to 11 days)

4. Post decay stage (10 to 24 days)

5. Dry stage (24 + days)

Forensic entomology, also helps in detecting or finding the presence of drugs, poisons, determine the location of an incident and find the presence and time of the infliction of wound.

The larva stages of the flies which feed on the carrion, can accumulate drugs ingested by the deceased person. The analysis of the above, is done by the technique like TLC, GC or MS.

Cocaine and heroin in the carcass(dead body of animal) can accelerate the  larval development . Poisons like malathion and carrion poison can delay the insect colonization.

Samples of insects of all stages should be collected from different areas of the body, from the clothing and from the soil or carpet etc.

Insects will often congregate in wounds and in around natural orifice.

As we know the two main insert groups in the bodies are flies and beetles both types of insect look very different in different stages of their life cycle. Flies can be found as eggs (in egg masses usually), larva or maggots (in a range of sizes from 1-2 mm millimeters to 17 mm ), or empty pupal cases, adults.

Usage of entomology in forensics:-

1. It helps to detect whether the body have been moved after death or not. 

2.  To analyze whether the body have been disturbed after death or not.

3. Insects health and detection about the presence and position of the wounds.

4. It helps to detect the presence of  drugs.

5. The insects can be used to place a suspect at the scene of the crime. 

6. In civil cases and child or senior abuse or neglect forensic in terminology plays avital role in forensic investigation.

7.     Most important is to identify the time of death.