Deepika Bhandari et al. / Journal of Science / Vol 5 / Issue 1 / 2015 / 9-12.
e ISSN 2277 - 3290
Print ISSN 2277 - 3282
Journal of Science
Forensic Science
www.journalofscience.net
FORENSIC SIGNIFICANCE OF THE EFFECT OF SEDATIVES ON
THE LIFE CYCLE OF CALLIPHORIDAE AND SACROPHAGIDAE
Deepika Bhandari1*, Deepak Kaldhone1, Swati Wavhal2
1
Assistant Professor (Forensic Science), Institute of Forensic Science, Mumbai-400032, India.
2
Director, Institute of Forensic Science, Mumbai-400032, India.
ABSTRACT
Forensic entomology is a term applied to the use of entomological (insect) evidence in the court of law. The insects
provide an accurate information regarding the time since death or Post Mortem Interval (PMI). Various insect groups
populate a cadaver in succession. Crime scene cadavers are often found with toxic substances either ingested to commit
suicide or administered to the person causing death. These toxic substances in or on the cadavers can be found and the
feeding larvae will have an altered rate of development. This study involves the effect of the toxins present in the cadaver
affecting the developmental stages of two necrophagus species of flies viz. (Calliphoridae, Sacrophagidae). The sedatives
chosen for the study were Clonazepam and Diazepam as they are commonly used in the act of committing suicide. Larvae
were fed on liver spiked with various concentrations of the drugs and a comparison was made with the control samples
(having no drugs). Changes were observed in duration of metamorphosis and emergence. This time variation indicates a need
to factor in a correction in establishing PMI.
Keywords: Forensic Entomology, PMI, Sedatives, Metamorphosis.
INTRODUCTION
Forensic Entomology is the branch of forensic
science in which information obtained using insects is
used to draw conclusions while investigating legal cases
relating to both humans and wildlife. Although on
occasions the term may also be expanded to include other
arthropods.The fact that insects and other arthropods
contribute to the decomposition of corpses and even may
help to solve killings was known for years. Many
researchers have written about the history of forensic
entomology. The Chinese used the presence of flies and
other insects as part of their investigative armoury for
crime scene investigation and instances of their use were
recorded as early as the mid-10th century.
The time that has elapsed since death is a major
objective in Forensic Entomology. Some scientists
estimate that there are over 200 million insects for each
human on the planet. These ubiquitous insects can act as
friend and foe. For a forensic investigator both these roles
are well known. Just as insects consume the evidence they
Corresponding Author:- Deepika Bhandari
also help us, by leaving subtle clues which aid in solving
a case.
The establishment of Time Since Death or PMI
has been of paramount importance for Crime
Investigating Agencies and Judicial Agencies throughout
the world. PMI has its legal and investigative significance
as it helps in reducing suspect lists and establishing the
facts. Medico legal Experts use the visible and
measureable changes in body to estimate PMI, namely:
Algor Mortis (cooling of body); Rigor Mortis (hardening
of body tissue due to protein degradation); Livor Mortis
(pooling of blood under the effect of gravity)
Decomposition (degradation of body parts due to bacterial
infestation).
A large number of suicides committed across the
world involve using sleeping pills (sedatives). This
research was taken up in order to study the effect on the
life cycle of Calliphoridae and Sacrophagidae in
presence of drugs (sedatives) in the corpse. Diazepam and
Email:- [email protected]
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Deepika Bhandari et al. / Journal of Science / Vol 5 / Issue 1 / 2015 / 9-12.
Clonazepam are the widely prescribed drugs used for
relaxation in anxiety disorders or insomnia and are easily
available Over the Counter drugs.
Background
During the decomposition of body, its smell acts
as a powerful entomological magnet. Blowflies
(Calliphoridae) are generally the first to arrive, they
colonise the body most rapidly after death and in greater
numbers than most other insect groups. The female
blowflies lay their eggs, and after a short period of time
(exact time depends on the species), the larvae emerge
and begin gorging on the remains. In due course the
larvae pupate and again after a specific period appear as
newborn flies. If the body remains undiscovered, the
cycle repeats itself with other insects joining the feast.
The behaviour and the life cycle of each insect species is
well documented, therefore they can provide a reasonably
accurate estimate of the time that has elapsed since death
or PMI.
Limitations
When a large swarm of maggots infests a
decomposing body they raise the temperature of the body
to the point where it becomes warm. This heat accelerates
the rapid formation of the fatty substance known as
adipocere. Adipocere generally takes several months to
develop helped by moist surroundings, so it’s premature
presence can point to a wrong PMI.
Strengths
Sometimes increased insect activity can strip the
carcass down to the bone depriving the forensic
investigator of any soft tissue. In most cases poisons are
traced by analysis of blood, urine and stomach contents,
but after a while all of these degrade to the point of
uselessness as specimens. So if there are maggots, empty
pupa present, these may be used to test for the presence of
poisons or drugs (sedatives) to establish cause of death.
Figure 1. Weight changes in Sarcophagidae across the
specimens at different development landmark.
These chemical substances, however accelerate (in case of
high doses of cocaine) or decelerate (in cases of
antidepressants consumed) insect developmental time of
the same species by up to several hours. In these cases the
work done and results obtained can be put to good use.
Modern DNA techniques are contributing to the rapid and
authoritative identification of necrophagous insects.
MATERIALS AND METHODS
Chicken liver was used as a substrate for
attracting blowflies and flesh flies. It was placed in
various petri dishes in an open area. The blowflies laid
eggs on the chicken liver and the flesh flies vivi-posited
larvae on it.
The entire egg/larval cluster were separated into
4 batches of 50 larvae each. These 50 larvae were then
separated into 5 containers marked A, B, C, D and E
containing 10 larvae in each of them. Container A was
filled with 10 gm of minced chicken liver only and
containers B, C, D and E were filled with minced chicken
liver and sedative. A 0.0512gm/ml solution of sedative
was prepared.10gm of minced chicken liver was spiked
with 2 ml, 4ml, 6ml, 8ml, of the sedative solution and
kept in containers marked B, C, D and E respectively.
These were used as a feed for the larvae. These larvae
were introduced in their respective containers and were
monitored for their development.
After every development land mark the larvae
were removed from the feed, cleaned and every single
larva from each container was weighed using electronic
balance, also sized using graph paper and scale. The
spiked chicken liver was also changed after every
washing session. Monitoring of the larvae continued up to
pupation and final fly emergence. Spiracles were used as
keys for the purpose of identification. Spiracles are body
structures present on the posterior and anterior sides of
the larval body. Diazepam was used for Calliphoridae
and Clonazepam was used for Sarcophagidae larvae in
their feed.
Figure 2. Weight changes in Calliphoridae across the
specimens at different development landmark.
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Deepika Bhandari et al. / Journal of Science / Vol 5 / Issue 1 / 2015 / 9-12.
Figure 3. Fly emergence data measured in hours
Findings
A significant drop in average weight of the
pupae was recorded in containers with higher
concentrations of drugs used in the feed as evident from
graphs (Figure 1, Figure 2). The graph (Figure 3)
represents the time taken for first emergence (the first fly
in the container to complete its metamorphosis) and final
emergence (the last fly emerges from the puparium). It
clearly indicated that flies provided with higher
concentration of drugs showed first emergence at the
same time and faster than flies without doped feed.
Similarly the flies with doped feed achieved final
emergence faster than the neutrally fed flies. Also it was
noted that the container E with highest concentration of
sedative showed the last final emergence leading to a
faster rate of development or metamorphosis.
CONCLUSION
The findings suggested that the drugs used in the
feed had an altering effect on the larvae of both the
species. Two main effects observed were 1) change in
weight with increased concentration of drugs, and 2)
accelerated growth and metamorphosis in the larvae to
attain adulthood earlier.
Future Trends
We have used weight of larvae and their
developmental landmark as forensic marker to estimate
PMI, hence, it is important to include these findings as
corrections. However in order to come up with a formula
for this correction a lot of research work has to be done. A
study throughout the year across various geographical
locations needs to be done so that it can act as a repository
and ready references for forensic entomologists who wish
to use entomological evidence to give an opinion in a
case.
ACKNOWLEDGMENT
We would like to thank Mr. Shashank Singh and
Mr. Allan Fernandes for their assistance in carrying out
the project. We would also like to thank Dr. Rinki Saxena
for critically reading and reviewing the manuscript.
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