Explain Forensic entomology is the study of insects in criminal investigations. Such investigations can include using the presence of insect species and their life stages to gain insight into cases of abuse, ingestion of illicit substances, and the movement of corpses, but most often post mortem interval (PMI). There are many important variables, however, that need to be accounted for when using insect evidence such as: corpse temperature, ambient temperature, rain or snowfall, placement of the corpse (e.g., indoors, outdoors, sun, shade, fully or partially buried), geographical location, among others.