Forensic science is a discipline that deals with expert scientific evidence relevant to legal cases. It ranges from the more familiar topics of ballistics and blood-stain analysis to esoteric specialities like pigment analysis and forensic botany.

Forensic entomology concerns legal evidence provided by insects.

Just as law is concerned not only with murders, forensic entomology is broad in scope. In fact, it can be subdivided into four arenas: medico-legal forensic entomology is the one most familiar to the public, while urban, stored product, and environmental forensic entomology form the other specialities.

This classification is based on the communities of insects that are typically involved, but also tends to reflect the branches of law and the types of client that a forensic entomologist encounters.

Although the distinctions are somewhat artificial, they help to outline the diverse scope of this kind of work.

Urban forensic entomology

This branch of the discipline is broadly concerned with insects around people’s homes, and usually relates to issues governed by common law or civil law, so the clients are generally private individuals and small businesses. The overwhelming majority of insects in these cases are fly-by-night pests like borer beetles, termites, cockroaches, and mosquitoes, and the subject of the associated litigation might be the competence of fumigation companies and the sanitary practices of livestock owners.

Stored-product forensic entomology

This kind of forensic entomology relates to cases involving insects in stored products, such as food, woven materials, and timber. As in urban forensic entomology, the cases tend to fall under common or civil law and mostly concern pests, but the species are different, and the commercial interests are generally large companies rather than small businesses. The usual suspects are various grain-feeding beetles, clothes moths, and booklice.

Questions regularly asked by the public are along the lines of “Was the worm I found in my chocolate there when I bought it?” and “Was my woollen Persian carpet infested with clothes moths in the factory?” These cases rarely go to court, but insurance claims regarding infested or damaged consignments of valuable goods may warrant the involvement of lawyers and even magistrates.

Medico-legal forensic entomology

This field can be subdivided on the basis of whether civil or criminal law is relevant. Civil cases may include medical and veterinary malpractice as well as neglect by care-givers of children and the aged, who may acquire infestations through negligence. The civil clients are usually private persons, and the insects are generally blowflies and fleshflies.

Some cases may not even involve insects, however. Psychological cases of delusory parasitosis are sometimes brought to entomologists to deal with. These are cases where people are convinced they are infested with parasitic insects that no one else can detect. It takes careful entomological analysis to distinguish between illusory parasitosis (that is, imaginary parasitic infestations), entomophobia (fear of insects), and genuine infestations by various mites living in hair follicles and the epidermis.

The legal issue here is whether the person has a psychosis that requires commitment to an institution, or whether the medical profession has been incompetent in seeking the parasite. An entomologist can help to make this decision.

Where criminal law is pertinent, the discipline is distinguished as medico-criminal forensic entomology, which is the high-profile subject of public awareness. The client group encompasses accused criminals and the State. The routine CSI (Crime Scene Insects) are blowflies, fleshflies, and certain beetles and moths because a death is most often involved. The deaths are usually of humans, but poaching and stock theft can be investigated by similar entomological methods.

A less well-known component of this work is called forensic entomotoxicology, which relates to the detection of chemicals in corpses where insects as used as an investigative tool. Drugs and poisons affect the development and behaviours of insects and accumulate in their tissues, which can provide a rich source of evidence.

Environmental forensic entomology

Here, insects are used to monitor the natural environment for evidence of pollution and undesirable change, and can provide evidence for both civil and criminal cases. This type of forensic entomology is still in the process of gaining recognition as a distinct discipline, and has gained increasing popularity in detecting effects of humans on the environment, either accidental or deliberate. In particular, the science of environmental toxicology has won growing acceptance since the publication of Rachel Carson’s landmark book Silent Spring in 1962.

Work in forensic entomology

Forensic entomologists have two tasks: they develop sources of evidence through academic research, and they apply evidence in particular cases as expert witnesses.

Being an expert witness does not necessarily mean appearing in court. In many civil cases where expert evidence is involved, the matter is settled out of court. In these instances, the evidence can have a direct bearing on whether the case needs to go to court.

The same is true of criminal cases, but here an expert witness can have another role as well. The forensic entomologist may, in some instances, not contribute direct evidence but rather uncover clues that lead the police to crucial discoveries.

In either of these situations, it helps to be good at puzzle solving.

Jobs for forensic entomologists have been scarce throughout the world, but the situation is changing as the science grows.

In South Africa, work as an expert witness in forensic entomology formed a component of a broader job in forensic science within the laboratories of the South African Police Service. Most other expert witnesses who provided entomological evidence to the South African legal system were employed in universities and other research institutions.

But changes in the modern employment market are emphasizing self-employment and entrepreneurship, and the range of clients interested in forensic entomology is widening so much that a career as a forensic consultant is becoming feasible.

Career paths

There are three ways to become a forensic entomologist in South Africa:

• Obtain a university degree in science subjects including biology or chemistry, then join the South African Police Service and complete a broader training in forensic science in their laboratories. Afterwards, you could work for the State and you could specialize in entomological work that would be primarily medico-criminal.
• Become a self-employed consultant in forensic entomology. The first step in this direction would be university training in applied entomology, preferably with a specialization in forensic entomology at the level of Master of Science or even a doctorate. The next step is to find work in a mixture of urban, stored-product, medico-legal, and environmental cases for State, private, and commercial clients. A business-orientated way of thinking is a vital asset in taking the consultant route.
• A third path lies between self-employment and becoming a police scientist. It, too, entails university training in entomology or zoology, normally to the doctoral level, then joining a university or research institute and doing other things (such as teaching or research) in addition to forensic work. One can even specialize in research on forensic entomology, rather than undertaking case work.

Where to study

• Rhodes University: Zoology and Entomology – http://www.ru.ac.za/zoologyandentomology/
• University of the Free State: Zoology and Entomology – http://natagri.ufs.ac.za/content.aspx?DCode=119

Forensic entomology is a fascinating subject and, far from being limited to solving murders, it can bring science to bear on a surprising array of commercial, social, and environmental problems. The growth of the subject throughout the world makes it international, while its expansion into new areas of law offers new scientific challenges to provide precise and legally reliable evidence.

The above information was extracted from an article originally published in QUEST (2006) by Martin Villet and Nikite Muller. To read the full article please click here.

Additional website

• The Southern African Forensic Entomology Research Laboratory – http://www.ru.ac.za/zoologyandentomology/research/safer/

SciShow – CSI Special Insects Unit: Forensic Entomology

SciShow’s Michael Aranda walks you through the crime-fighting science of forensic entomology, the study of insects used in criminal investigations.

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