Forensic entomology can be said to be the application of the study of insects and other arthropods to legal issues. It can be divided in three subfields: urban, stored-product and medicolegal.

     Medicolegal forensic entomology includes arthropod involvement in events such as murders, suicides and rapes, but also includes physical abuse and contraband trafficking.

     Since the earth is a predominantly arthropod world, it is not uncommon that we mere humans come in contact with these creatures everyday of our lives. They pollinate, eat other arthropods, living plants and trees, dead plants and trees, living vertebrates, dead vertebrates and vertebrate dung and urine among a plethora of other substances.

     The feature with arthropods that is most important in medicolegal forensic entomology is that they are important carrion feeders. That is they eat dead vertebrate bodies, including man.

     One of the first groups of insects that arrive on a dead vertebrate is the blowfly (Diptera: Calliphoridae). Usually the female oviposits within two days after death of the vertebrate. The blowfly then goes trough the following stages: egg, 1. instar larvae, 2. instar larvae, 3. instar larvae, prepupae, pupae within puparium, imago. 

     If we know how long it takes to reach the different stages in an insect life, we can calculate the time that has past sine the eggs were laid. This calculation of the age of the insects can be considered in an estimate of the time of death. Unfortunately, even if the estimate of the insect age is correct, the death of the victim usually occurred before the eggs were laid. The length of the period before the eggs were laid depends on temperature, time of day at the time of death, the time of year of the death, and whether the corpse was exposed or immersed in soil or water. As a general rule insects will lay eggs on a corpse two days after the corpse is available for insects.

     By comparing the fauna around the body, and the fauna on the body, you can establish whether the corpse has been moved after death. In some instances movement of suspects, goods, victims or suspect vehicles can be traced with the help of insects. Insect parts, or whole insects can for example, be captured in different car parts, such as in radiators or tire treads. By identifying the insects found, and plotting the distribution of each insect, as well as the biology of each species, one can find the greatest degree of overlap, and thus describe the areas where the suspect has been.