Forensic is a term from the Latin forensis, used to denote argument in the public forum. In modern use it refers to the use of argument and evidence in a legal context such as a court.

Forensic entomology deals with the use of our knowledge about insects and other arthropods to provide legal evidence. Consider the following situation:

A woman is found drowned in a bathtub. The woman's husband testifies that she must have slipped or fallen asleep. But investigators notice two insects in her hair and show them to a forensic entomologist, who identifies them as larval Baetis intercalaris, an insect species in the family Baetidae, order Ephemeroptera. The entomologist testifies as an expert witness in court that these insects are early colonizers of bodies found in freshwater ponds, but are virtually never found in bathtubs because their biology requires a pond ecosystem. Confronted with this evidence, the husband breaks down and confesses to the murder.

While this story is fictional, insects have played an important role in many criminal investigations. Let's find out how.