Insects and Flies in Forensic Medicine

An important factor in estimating the time of death of the deceased can sometimes be their surroundings, which includes what creatures are present in those surroundings. Many insects and flies are synonymous with the decaying of a corpse and from the point of view of a pathologist – accompanied by a forensic scientist – are blatant indicators in the how, why and when a corpse came to meet it’s end (see our article Estimating The Time of Death in this section).

Categorising Insects and Flies

The individual who is best qualified to help with the categorisation and identification of these insects and flies is referred to as a Forensic Entomologist.

It is worth noting also that a corpse – if left exposed outdoors after death – can become predatory food for animals such as foxes, wild dogs and the like, but the most likely means of aiding in the decomposition of a corpse are these myriad of insects and flies who appear within 24 hours of the individual’s demise.

The locale and temperatures surrounding the corpse are also indicative of the insects and flies to be found feeding and nesting within the human form after death.


Blowflies are a prime example and are often to be found laying their eggs in the moist areas of the human body, usually within the first hour following death. The mouth, nose, groin, armpits, and eyes (if they are open) are all common anatomical locations in which the blowfly’s eggs are laid and will normally hatch within 24 hours.

Blowfly larvae reach half an inch in length and continue to feed on the corpse for up to 12 days. In this time, they grow and continue to moult until they eventually transform into the blowfly and then begin repeating the cycle over again.

If a corpse is found outdoors and is only exhibiting the signs of having had eggs deposited upon it, it is taken as a given by the Entomologist that the body has been left out in the open for less than 24 hours. The appearance of maggots but no pupae means that the body has been outdoors for less than 10 days.

Rigor Mortis

During this time, it is worth noting that, given the ambient temperature around the corpse and the fact that this temperature will rise and fall, Rigor Mortis And Lividity will already have been and gone from the body.

Likewise, during this time it should be noted that if the temperature is colder than usual, the blowfly life cycle slows down. Also worth bearing in mind is the fact that blowflies do not lay eggs at night.

The Entomologist will collect up live insects and flies, as well as those that have expired and also their empty pupae cases. He or she will then use them to estimate the life cycle and also how long they have been able to use the deceased body as a breeding ground for their activities. This is an important part of the forensic process.

The study of how the human body, its surroundings and forces of nature react together is one that can provide many interesting clues as to how the body came to be there and also how humanity and nature intertwine. Read more to find out about how body temperature can be used to estimate time of death.

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