The first insects arrive at the corpse attracted by the smell of gases that are released in the process of degradation of the immediate principles, gases such as ammonia, sulfuric acid, free nitrogen and carbon dioxide.
Long before humans can detect it, insects detect these gases and are attracted to the corpse, depositing eggs in the natural orifices of the body, thus beginning the cycle.
There are two methods to determine the time since death using entomological evidence: the first uses the age of the larvae and the rate of development; the second method uses the succession of insects in the decomposition of the body
