Insects are used in forensic medico-legal purposes and this study is called forensic entomology. The most commonly insects are used for the estimation of the time since death.
When the person dies, the body starts to decompose by microorganisms fungi and bacteria), followed by the action of insects. There are a few stages of decomposition (determinated by different insects) and the speed of this stages and the whole process generally depends on many factors such as body size and weight, place where the body is buried, clothing..
Limitations of this method are:
• Weather (e.g. in winter, there are only fewer insects present, so decomposition is slow or stopped)
• Time-it is hard to have immediate results
• Drugs in the body
• Different kinds of treatments (like freezing, burial or wrapping).