Left: A sapphire blowflyon a bush near a
carcass. The stains on the leaves are from
flies that have been feeding fluids from the
carcass. If the animal dies of anthrax, these
stains can spread anthrax spores to other
browsing animals that eat the leaves. The
stains are a good indication that a body was
in the area, even if it has been removed
by poachers or scavengers. The scientific
name for blowflies ((Calliphoridae
Calliphoridae)) means
Calliphoridae
'beautiful flies', but probably applies to their
colours rather than their habits!
How do bugs and
insects help forensic
entomologists
to settle disputes
and solve crimes?
Martin Villet and
Nikite Muller explain.
The six-legged flying squad
T
here’s a new flying squad
helping the South African
police. That familiar nuisance,
the blowfly or ‘brommer’, is rapidly
becoming the mascot, like the fruitfly
to genetics, of an international scientific
discipline: forensic entomology.
The public’s fascination with
forensic entomology has grown over
the last couple of decades in step with
Above: Studying the effects of different levels of dissolved
magnesium sulphate on stream-dwelling insects. Results
from such experiments, conducted under standardized
laboratory conditions, help forensic entomologists to decide
if a river has been polluted illegally by using the behavioural
responses of the insects in the river as a guide.
24 Quest 2(4) 2006
its increasing prominence in popular
culture. From cameo appearances in
the movie Silence of the Lambs, the
discipline moved to more central roles
in The Body Farm and Blowfly, and
now has regular ‘guest’ appearances in
television crime dramas like Clancey
and CSI. Scientists are not distant
from these trends, and the attention
directed towards forensic entomology
is increasing worldwide.
South Africa’s high rate of murders,
including serial killings, has brought
urgency to this research. The country
has its own forensic entomologists
and, in two recent Supreme Court
murder cases, entomological evidence
was taken into account to assist in
the judgements. School-leavers are
beginning to ask about careers in
forensic entomology: what would they
be letting themselves in for? Parents
may be relieved to know there’s
more to it than crime novelist Patricia
Cornwell has let on.
What is forensic entomology?
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, storedproduct, 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.
Do the swarms of flies around your
house really come from the new horse
stud down the road? If the fumigators
were right about treating your house
for fleas, why are you still getting bites?
How reliable is the Borer Certificate for
the house you’re thinking of buying?
Entomological evidence for the most
part allows these concerns to be settled
out of court.
An unusual case in this field comes
from Norway and is known as “The
Case of the Cleaning Woman”. One
morning, a government official found
some large maggots on his office carpet.
He summoned the cleaning woman
who cleaned his office each night and
accused her of neglecting her job, which
she denied. Reasoning that such large
maggots could not have developed since
the previous evening, he concluded that
she was lying and had her dismissed. A
veterinary inspector working in the same
building heard of the events and asked
to see the maggots. He concluded that
they were mature larvae of a greenbottle
fly, and that they had migrated to the
office from a dead animal, perhaps a
rat, that had died in some other part of
the building. Without such food, they
certainly could not have developed
where they were found – and its
presence would have been obvious
from the smell if it had been in the
office. The evidence corroborated the
cleaning woman’s claims, and she was
reinstated without the need for a court
hearing.
Stored-product forensic entomology
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.
▲
▲
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.
A less run-of-the-mill case concerns
the criminal investigation of an illegal
stored product in New Zealand.
Two consignments of cannabis were
intercepted and yielded a rich sample
of insects. By compiling details of the
ecology and geographical distribution
of the wasps, ants, and beetles in the
cannabis, investigators deduced that
the crop was grown in a specific part
of South-East Asia, in fields near a
water body in a hilly area, and then
hidden for a while in termite mounds.
The details were sufficiently accurate
to persuade one of the suspects to
grass on the others in the hope of
a lighter sentence. This is a good
example of the sort of puzzle-solving
skills that forensic entomologists need.
Top: Martin Villet examines a rhinoceros that had died after
being attacked by an elephant. An autopsy was performed on
the carcass, which was soon covered in maggots. Their growth
was studied so that the information could be used in future
cases of poaching to determine an animal’s time of death.
Middle: A technician monitors insect cultures for indications of
poor water quality in the responses of insects in the laboratory.
Below: Environmental toxicologists collect samples of insects
from a stream to assess the health of the water.
Quest 2(4) 2006 25
Investigating death
Death and the process
of corpse decay
Forensic
examination
Conclusions
Fresh
Analysis of
Estimates of
Bloating
Maggots
Active decaying
Maggots, beetles
Advanced decaying
Beetles, communities
• time
• manner
&
Dry remains
Above: Maggots feeding on a dead warthog. Two species
are present, differentiated by their colours. They have
different habitat preferences on the carcass, which is why
they are separated. This type of information can be useful in
forensic investigations.
▲
For instance, the development of
maggots allows the detection of cocaine
in overdose cases, and toxicologists
can detect heroin, barbiturates,
organophosphates, and heavy metals
in samples of maggots long after these
chemicals can no longer be traced in
the corpse itself. In South Africa, robbers
used alcohol and sleeping pills to drug
mineworkers on trains so that their
pay packets could be stolen. Several
mineworkers died from overdosing
and their bodies were thrown from the
trains to hide the crime, but the drugs
were traced in samples of maggots,
successfully linking the deaths to the
investigation.
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
For more about forensic entomology, visit the Science Careers.org web site
http://sciencecareers.sciencemag.org/career_development/
previous_issues/articles/0000/forensic_science_resources_
for_making_the_transition;; the Southern African Forensic Entomology
Research Laboratory at www.ru.ac.za/zoology/SAFER%20Lab/
www.ru.ac.za/zoology/SAFER%20Lab/;
and the Unilever Centre for Environmental Water Quality at www.ru.ac.
za/institutes/iwr/ucewq/.. You can find more details about the history
of research in this field in southern Africa in K.A. Williams and M.H. Villet,
“A history of southern African research relevant to forensic entomology”,
South African Journal of Science,, vol. 102 (2006), pp.59–63.
26 Quest 2(4) 2006
• other insects
• environmental
details &
conditions
of death
The processes of forensic entomology help police with evidence when they investigate
deaths that have occurred. Based on an understanding of the decaying processes of a
corpse, and knowledge of the living organisms that invade a corpse, experts are able to
estimate the conditions in which the person or animal died.
has won growing acceptance since the
publication of Rachel Carson's landmark
book Silent Spring in 1962.
An example of an application
in criminal law involves the South
African National Water Act, which
governs the management and use of
freshwater resources. This act makes
it illegal to dump waste into rivers at
concentrations that affect organisms
living in the water. Insects are used in
laboratory experiments to set guidelines
and environmentally safe thresholds
for these concentrations, and their
populations are monitored in rivers and
streams to provide evidence of whether
the water is being chemically insulted.
Occasionally, industries release
their toxic waste into a nearby river
late at night, so that the flow of river
water takes the waste downstream
by sunrise and the industry can avoid
spending enormous sums of money to
convert their waste to an acceptable,
environmentally safe level. But the
abnormal community of insects and
other invertebrates left living in the
river can quickly reveal whether there
has been an incident of ‘leaky valve’,
although chemical analysis of the
water might not indicate any problem.
Insects can also accumulate
pollutants in their bodies to detectable
levels, even when the substances
are too diluted to detect in the
environment. Blowflies were used
in this way to provide evidence of
mercury pollution in Sweden.
Although it has yet to become a
legal issue, insects have also provided
Above: Collecting samples for analysis.
evidence of global climatic warming
in Europe and North America. As
average temperatures rise, butterflies
that prefer warmer conditions have
been found at higher altitudes and
latitudes than before, and other insects
that prefer cooler climates are also
migrating to new localities.
The field of forensic entomology
is a fastgrowing one, with further
applications being introduced and
developed all the time. The six-legged
flying squad is coming into its own. ■
Professor Villet heads the Southern African
Forensic Entomology Research Laboratory
at Rhodes University. Dr W.J. Muller
is the Director of the Unilever Centre
for Environmental Water Quality and
specializes in environmental toxicology.
Q Careers in S&T
Work in forensic entomology
F
orensic 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. As the
investigation of the overdosed mineworkers in
the article on page 24 illustrates, 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 puzzlesolving.
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 a 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 selfemployment 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.
Obviously, as your career develops, you
can move from one path to another. Each
has its strengths: choosing the best one
depends on an individual’s personal skills,
interests, and personality.
Where to study
In southern Africa, forensic entomology
is offered as a module of the Entomology
major at Rhodes University, while
postgraduate specializations (at master’s and
doctoral levels) are offered at the University
of the Free State and Rhodes University.
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. ■
Top: A research officer at the Unilever Centre for Environmental
Water Quality tests water quality by examining insect cultures.
Above: Insects on this lion’s skull give clues as to when the
animal died. The beetles living on it indicate that the lion had
been dead for more than six weeks. If this is a case of poaching,
the information gives investigators a timeframe.
For details consult J. Ashcroft, D.J. Daniels, and S.V. Hart, Education and Training in Forensic Science: a guide for forensic science laboratories,
educational institutions, and students. National Institute of Justice Special Report, US Department of Justice, Washington, DC, 2004.
Available from www.ncjrs.gov/pdffiles1/nij/203099.pdf For a list of institutions abroad that offer training in forensic sciences,
visit www.forensiccrimelab.com/training.htm For general information consult Careers in Science, Engineering & Technology
(Beyond 2000 and Department of Science and Technology, 2006) and visit www.careersbeyond2000.co.za
The sexes are different
Thousands of genes express differently in the sexes, reports Xia Yang, head of
the research team at the University of California, Los Angeles, after his team
had conducted comparisons in male and female mice. Over half the genes were
different, he said, “an order of magnitude more than previously thought.”
A total of 23 574 genes were profiled from 34 mice. Up to 70% of the
genes in fat, liver, and muscle produced different amounts of protein in the two
genders, as did 14% of the genes in brain tissue.
The implications are that the mechanisms underlying many common diseases
may differ between males and females, says Yang. Aspirin gives better protection
against heart disease to men than to women, for instance, while the heart drug
digitalis causes more deaths in women than in men.
The reason could go deeper than just different drug metabolism in
male and female livers, as was previously thought, and sex hormones are
Q News
probably the key factor so all tissues are likely to be affected. Drug trials
need to be gender-specific, Yang concludes.
Reported from Genome Research in New Scientist (15 July 2006).
Scorpions help fight cancer
Biotech company TransMolecular, in Cambridge, Massachusetts, says that
venom from scorpions with a dose of radioactive iodine could help to
treat brain cancer. A protein in the venom bonds to malignant cells, not to
healthy ones, and this concentrates the radiation dosage in the tumour.
Reported in New Scientist (1 July 2006).
Quest 2(4) 2006 27