Insects as vectors of DNA in a forensic context

Insects have historically been used in criminal investigations to provide information in relation to postmortem intervals (PMIs) but the field of forensic entomology is expanding. It is now recognized that insects can act as vectors of human and mammalian DNA through the consumption of biological material, with extraneous DNA able to be extracted and genotyped from all stages of the life cycle, and insect feces and regurgitant (artifacts). To date, DNA recovered from insects have been used to inform investigations into neglect and homicide, link body parts, and to identify victims of crime. It may also potentially be used to identify assailants, confirm the food source of insects to determine their relevance in PMI calculations, determine if a crime has occurred, identify scenes of crimes, and link people to locations and other individuals. However, insects which have consumed biological material may also transfer DNA by traveling to new areas, or depositing it via their artifacts, either within crime scenes or laboratories, or at locations distant to the food source. This could contaminate forensic evidence, confound investigations, and/or falsely incriminate or exclude an individual. Therefore, it is important that there is increased awareness into both the utility of insects as vectors of forensically relevant DNA, and the potential for contamination.