Role of blowflies calliphoridae in forensic investigation
Forensic entomology is the emerging field in forensic sciences, in which insects feed on corpses and used as a tool in criminal investigation.
Post mortem is the most vital part of the investigation process especially when someone died in sceptical conditions and from this point they are trying to find out the possible cause of death.
Similarly, a scientist and an investigator find out the criminal easily with the help of forensic entomologist or through blow flies. After analysis the life cycle of different insects especially the “Calliphoridae” on a dead body,
Then on the other hand forensic entomologists accurately measure the death time by assessing the breeding hours of “Calliphoridae” on a dead body because they are the most attracted toward a carcass.
Its life cycle completes within a 3-4 weeks. Eggs are immediately laid as they find a corpse. Then these eggs hatches into larvae and then move toward the next phase that is pupal stage and after a week later they become adult. Larval stage feed on the corpse only. Its growth rate totally depends on the temperature and humidity.
The range of the temperature is from 35 degree to 50 degree. Optimum temperature is 35 degree and highest temperature is in between 50-55 degree. Optimum Humidity is 55%. Forensic entomologist estimate the victim died that is based on the different life stages of the life cycle of blowfly.
- Eggs: Adult flies lay eggs on corpse within 1 day.
- Larvae: Larvae comes out from the eggs in 2 day.
- Larval Period: It remains for 3-7 days because they grow and feed on the corpse.
- Pupa: Then larvae move towards pupal stage which remains for 8-9 days and they form a hard cocoon around themselves as a shelter.
- Adult: From these hard cocoon pupae, adult emerge after 2 weeks.
“Calliphoridae” can lay 250 -350 eggs in a cluster form, and an adult can survive up to 35 days after maturation.
MAGGOTS PROVIDE PHYSICAL EVIDENCE FOR FORENSIC CASES:
Estimation of the post mortem interval (PMI) is one of the most critical matters in necropsy and insects have been widely used to determine PMI even after 72 hours of death. However, it is done by using the oldest blowflies larvae found and from the succession pattern of insects that colonize the dead remains.
We use the pattern of “Calliphoridae” insects that colonize the dead remains are decisive. For the forensic investigation of these cases, the collection of physical evidences are really important part from the sight of crime.
It help us in extreme condition, when the bullet case is not found and the body is actively decomposing. The maggots of the “Calliphoridae” which are obtained from the dead body or corpse remains hold potential clues in aiding the forensic investigation.
CALLIPHORIDAE ESTIMATE DEATH TIME:
These flies arrive at the corpse within short period of time after the death, and developmental stages of these flies’ helps to determine when the person died and some other insects also move toward that but the most important difference is the life cycle through which we take help.
Researchers has two options for the identification of the species,
1. They collect the larvae from the corpse and raise them in lab, that will take two weeks and after that choose the DNA profiling, which is quite expensive.
2. Mass spectrometry which gives a picture of the mass based chemical composition of a sample, chemical and engineering news reports. This method is easy and ready to use for an active investigation by the forensic scientists and provide a data base profile of the blowfly.
INVESTIGATION SIGNS OF CALLIPHORIDAE:
They can smell meat from a distant and arrive there for feeding purpose on decaying matter. Blowflies require a significant amount of protein for egg laying.
Female feed on the flesh and lay eggs there. Adults resting on the surfaces and buzzing around the odor sources. Larvae just crawling on the dead body, feed there and move away from the food source for pupation.
Female do not bite human only produce the loud buzzing sound. They contaminate our food and dangerous for humans as well as for animals. They are responsible for carrying the bacteria that causes dysentery, typhus and cholera.
After mentioning the above information, as blowflies facilitate in post mortem, forensic entomology is an emerging field in the forensic sciences, where insects feed on carrion are studied. It has become an important tool in criminal investigation.