Forensic entomology

Forensic entomology is a branch of applied entomology that uses insects and other arthropods as a basis for legal evidence. Insects may be found on cadavers or elsewhere around crime scenes in the interest of forensic science. Forensic entomology is also used in cases of neglect and abuse of a property, as well as subjects of a toxicology analysis to detect drugs and incidents of food contamination. Therefore, forensic entomology is divided into three subfields: medico-legal/medico-criminal entomology, urban, and stored-product.

The field revolves around studying the types of insects commonly found in and on the place of interest (such as cadavers), their life cycles, their presence in different environments, and how insect assemblages change with the progression of decomposition (the process of "succession"). Insect assemblages can help approximate a body's primary location, as some insects are unique to specific areas. In medico-criminal cases, the primary goal is often to determine the postmortem interval (PMI; time since death) to aid in death investigations.

Insect succession patterns are identified based on the time a species spends in each developmental stage and the number of generations produced since the insect's introduction to a food source. By analyzing insect development alongside environmental data such as temperature, humidity, and vapor density, forensic entomologists can estimate the time since death, as flying insects are attracted to a body shortly after death. This field also provides clues about antemortem trauma and the displacement of a body after death.

Urban forensic entomology typically concerns pest infestations in buildings, gardens, or other urban environments, and may be the basis of litigation between private parties and service providers such as landlords or exterminators. For instance, urban forensic entomology can be used to evaluate the efficiency of pest control techniques such as pesticide treatments, ascertaining the size of an infestation, and identifying the responsible party in situations involving infestations in rental homes. Urban forensic entomology can also assist in determining liability when stored goods, like grains or packaged foods, are contaminated with insects, helping to identify the infestation's origin. These techniques may be used in stored products cases where they can help to determine the chain of custody, when all points of possible infestation onset are examined to determine who is at fault.^{[additional citation(s) needed]} Moreover, environmental management and public health depend heavily on urban forensic entomology; researchers can track the transmission of disease carried by insects by examining insect populations in urban settings. Forensic techniques can also guide conservation efforts by evaluating the environmental effects of urbanization on insect populations.

Stored-product forensic entomology is often used in litigation over insect infestation or contamination of commercially distributed foods, including grains, flour, and packaged meals. Stored-product forensic entomologists may be asked to identify the species involved, evaluate the extent of an infestation, and pinpoint the infestation's source in a legal proceeding. They might also offer expert testimony about the circumstances that gave rise to the infestation and suggest safeguards to prevent similar risks in the future.

In general, forensic entomology of stored products adds both critical evidence to legal evaluation and contributes to overall food safety and quality assurances; forensic entomologists work to guarantee that food products are safe for consumption by identifying insect species and tracking their presence in stored goods. Additionally, this sector contributes to the general enhancement of food business practices by researching and developing novel techniques for pest management and product preservation.

Medico-legal forensic entomology involves the study of arthropods found at the scene of various incidents such as murder, suicide, rape, physical abuse, and the smuggling of contraband. This discipline provides the techniques to associate the victim(s), suspect(s), and scene together by identifying different arthropod species found in specific geographical locations. Forensic investigators can learn important details from insect activities, including the length of time passed since death (PMI), the presence of substances ― medicative or toxic ― in the body, and the movement or disturbance of the body following death. In murder investigations, forensic entomologists analyze the species of eggs which appear on the cadaver, their location on the body, and their development stage to determine the PMI and the location of death. The presence of specific insect species, which may be endemic (occurring only in certain places) or a well-defined phenology (active only at a certain season, or time of day). In association with other evidence, these can provide crucial links to times and locations where the criminal acts have occurred. Entomology can also aid when determining the time of an injury. One determining factor might be the observed species' preference of alimentation; when blowfly eggs laid on a hatch into the first larval instar (life stage), they require a liquid protein meal. Due to their minute size and fragility blowflies are unable to break through human skin themselves to attain this nutrition.^{[citation needed]} Therefore, the female typically oviposits near a pre-existing wound or natural orifices to provide an accessible meal to her brood, such as blood, mucous, or other body fluids.

Another area covered by medico-legal forensic entomology is the relatively new field of entomotoxicology. This particular branch involves the testing of entomological specimens found at a scene for different drugs that may have possibly played a role in the death of the victim. The analytical perspective behind these methods relies upon the fact that the presence of drugs within the cadaver specifically affects the growth and morphology of the insects ingesting those toxins from the corpse. Due to these alterations, the presence of drugs can potentially lead to an erroneous PMI when basing it on the abnormal physical development of insects who have fed on them.