Forensic Entomology is the use of the insects, and their arthropod relatives that inhabit decomposing remains, to aid legal investigations.Forensic entomology is commonly used to estimate the time of death when the circumstances surrounding the crime are unknown.Insects arrive at a decomposing body in a particular order and then complete their life cycle based on the surrounding temperature. By collecting and studying the types of insects found on a body, a forensic entomologist can predict the time of death

1. FORENSIC
ENTOMOLOGY
1

2. Introduction
– Entomology is the study of insects and their relationship to humans, the
environment, and other organisms. Entomologists make great contributions to
such diverse fields as agriculture, chemistry, biology, human/animal health,
molecular science, criminology, and forensics.
– FORENSIC ENTMOLOGY
– Forensic Entomology is the use of the insects, and their arthropod relatives that
inhabit decomposing remains, to aid legal investigations.
2

3. What is Forensic Entomology?
– Application of insects to legal issues.
– Medicocriminal forensic entomology.
– Arthropods associated with crimes Usually violent crimes such as murder, suicide,
and rape, Physical abuse and contraband trafficking.
– Death investigations
– Establishing timelines (time since death to time of discovery
– (postmortem interval or PMI)
– Movement of the corpse, manner and cause of death.
– Association of suspects with the death scene
– Detection of toxins or drugs ® insect larvae
3

4. What is Forensic Entomology?
– Forensic Entomology is the use of the insects and other arthropods that feed on decaying remains
to aid legal investigations.
Forensic Entomology is Applied Biology
– If it weren’t for decomposition of all living things, our world would fill up with dead bodies.
– When an animal dies, female insects will be attracted to the body. They enter exposed orifices or
wounds and lay eggs or larvae.
– A forensic entomologist:
– identifies the immature insects
– determines the size and development of the insects
– calculates the growth of the insects and passage through stages of the life cycle in laboratory
– compares the growth against weather conditions to estimate time of oviposition
4

5. 5

6. The Process of Death
A pathologist estimates time of death from these factors.
6
Livor mortis
Rigor
mortis
Algor mortis
Greenish
discoloration
Marbling
Skin slippage mummification

7. Types of Insect Development
– A. Ametabolous metamorphosis - without change- spring tails
– B. Gradual metamorphosis - gradual change from immature to adult. Cockroaches,
predatory bugs
– C. Complete metamorphosis - egg-larvae-pupa-adult-larvae different from adult,
example maggot and fly. Probably the most common stage encountered in crime
investigations -- important to collect both adults and immatures.
7

8. Parts of an Insect
Insects
Head Thorax
Prothorax
Mesothorax
Metathorax
Abdomen
8
Dimension
Dorsum Sternum Pleuron
Lineage Chelicerata
MyriapodaHexapoda
Crustacea

9. – Arthropoda :- open circulatory system known as coelom
– Exoskeleton :- polysaccharide called chitin and protein
– Arthropod body supports jointed appendages .
– Two pair of membranous wings :- mesothorax , metathorax .
– Out of two one may be modified
– The membranous wings are supported by veins.
– The first of the wing veins, vein 1, is called the costa. This is a thick, hardened vein and gives the
wing some rigidity for flying.
– The second vein, vein 2, is called the stem vein or subcosta.
– The third vein at the proximal (body) pointof attachment, vein 3, is called the radius.
– The fourth long vein, vein 4, is the media (or medial vein). This can be split into four veins as it passes
to the wing edge.
– The fifth vein, vein 5, is called the cubitus vein and in some insect species also splits.
9

10. – Segmented structure on head called antennae also called feelers (chemical and
mechanical information).
– Adult blow fly have two large compounds eyes
– Female have widely spaced as those of male fly.
10

11. Pooja Sharma
11

12. FORENSIC ENTMOLOGY
The broad field of forensic entomology is commonly broken down into four general
areas:
– Medico-legal forensic entomology
– Urban forensic entomology
– Stored food-stuff forensic entomology
12

13. Forensic entomology can be
divided into three sub-fields:
– Urban forensic entomology. It typically focuses on pests infestations that are related to
litigation such as legal disputes between exterminators and landlords. Besides studying insects
and other arthropods, urban forensic entomology typically also involves toxicological studies,
for example the appropriateness of pesticide application.
– Stored-product forensic entomology. It investigates cases of insect infestation or
contamination of commercial foods with an aim to find evidence relevant for litigation.
– Medico-legal forensic entomology. This sub-field of forensic entomology gathers evidence
through the study of insects and other arthropods at a crime scene such as murder and
suicide. It most often involves the study of insect eggs and maggots, in what order their
appear and where on the body they are found. Because insects occur only in particular places
and are active only at a particular season, their presence can reveal a lot about location and
time of the crime.
13

14. PRINCIPLES OF FORENSIC
ENTOMOLOGY
– Reliable information about;
– •Insects Behavior
– •Growth
– •Development
– •Habit & Habitat All of these gathered over 2 and half centuries.
– Megnin’s Work on progressive stages of decomposition (Insect Succession Method)
– • Physical Changes of Decomposing Body
– • Biochemical Changes and Insect Succession
14

15. – What has been learned from the many studies on insect succession is that the
timing of the insect groups can be variable given the following;
– Geographic location (which is a factor of temperature)
– Season of the year
– Habitat PRINCIPLES OF FORENSIC ENTOMOLOGY
– This insect succession method is used when remains have been exposed for
long periods of time, such as for weeks or more
15

16. – This method can be very accurate, but not as precise as the second method
used for estimation of the PMI.
– Use of an Insect’s Known Growth and Development Time
– Applied to the fly group (Diptera), but not exclusively (Coleopterans can be
used too)
– The underlying principle in using this method to estimate PMI is that the
blowflies (the gold standard mostly used) will colonize immediately upon death
16

17. Categories of insects on
decomposed carrion
Categories
Nacrophages Predators
and parasites
omnivores
Incidentals
17

18. Ecological Role of Insects in
Decomposition
– 1. Necrophages - the species feeding on corpse tissue. Include most rue flies
(Diptera) and beetles (Coleoptera). Age determination of these insects usually
basis for making PMI estimations.
– 2. Omnivores - species such as ants, wasps, and some beetles that feed on
both the corpse and associated fauna. Large populations of these may retard
the rate of corpse decomposition by depleting populations of necrophagous
species.
– 3. Parasites and Predators - many beetles, true flies and wasps that parasiize
immature flies.
18

19. – 4. Incidentals - arthropods that use the corpse as a concentrated resource
extension of their normal habitat, eg. Eprintails, spiders, centipides, pill bugs,
and some mites.
19

20. 20

21. 21

22. 22

23. 23
Blue Bottle Flies (Blow flies)
Family name: Calliphoridae
Green Bottle Flies (Blow flies)
Family name: Calliphoridae
Common House Flies Family
name: Muscidae

24. 24
Flesh Flies Family name:
Sarcophagidae
Cheese Skipper Family name:
Piophilidae

25. 25

26. Beetles
– Order :- coleoptera
– they have biting mouthparts or mandibles, their antennae characteristically
have 11 segments (although in some species there may be fewer than this)
– Beetle adults are composed of a head, a thorax in three parts all fused together
(although the second and third parts are less visible dorsally) and an abdomen.
They have two pairs of wings; the two forewings are hardened and form a
protective covering over the second, membranous pair of wings. These
chitinous, and on occasion ‘leathery’, protective cases are called the elytra.
26

27. – Beetles are insects which also show complete metamorphosis.
– To become adults, they too pass through an egg stage, three to five larval
stages depending on species, and a pupal stage.
– Coleopteran eggs tend to be oval, spherical or spheroid in shape and are usually
considered very similar, irrespective of family.
– Beetles usually bury themselves in the ground, or in a specially constructed
chamber, when they pupate.
– Less detailed information is available about beetle life cycles than is known
about the Diptera.
27

28. – The length of the life cycle will vary, depending upon the family and species of
beetle.
– Development through the complete life cycle, from egg to adult (imago) can take 7–
10 days in rove beetles (Staphylindae), whereas in the ground beetles (Carabidae)
completion of the life cycle to the adult stage may take a year andthe adults may
live for 2–3 years.
– In some species the number of instars in the larval stage is not fixed, but is
dependent on environmental conditions.
– In Dermestidae, for example, there may be as many as nine instars .Usually,
however, there is only one generation of beetles per year.
.
28

29. – Carrion Beetles Family name:
Silphildae
– Hister beetles Family name:
Histeridae
29

30. – Rove Beetles Family name:
Staphylinidae
– Hide Beetles Family name:
Dermistidae
30

31. 31

32. The role of aquatic insects in forensic
investigations
32
SUBMEREGED FRESH :- Time between the submersion and beginning of bloating.
 Depends upon the geographic location of a running or standing water habitat,
microhabitat within this water body and the time of the year.
 In the spring in mid latitudes- no bloating till about 2-6 days
 In the northern latitudes- no bloating till about 11-13 day
 Immatures of caddisflies (Trichoptera: Hydropsychidae), chironomid midges
(Diptera:Chironimidae) and heptageniid mayflies (Ephemeroptera: Heptageniidae)
observed during this stage.

33. EARLY FLOATING :- As the gases in the abdomen increase, the carcass floats to the
surface and attracts terrestrial insect species (Calliphorids, sarcophagids and
muscids) which lay eggs or larvae on exposed areas. Carrion and rove beetles
may feed on larvae of flies or animal flesh. Yellowjacket and bald-faced hornets
prey on adult and larval blowflies.
• For totally submerged carcasses the previously mentioned invertebrate species
are found.
• Decay odors are quite evident at this stage, fluids and gases ooze from the
anus, tissue shades change.
• Algal growth increased significantly on the carcass
33

34. FLOATING DECAY :- Intense feeding activity by Calliphorid maggots creates many
openings in the exposed skin. Silphid, staphylinid and histerid beetles present in
high abundance.
• Aquatic macro-invertebrate colonization varies between different waterbodies
for totally submerged carcasses. Perlodid stonefly (Plecoptera:Perlodidae)
larvae seen feeding on both black fly larvae and chironomid midge larvae.
Crayfish feeding activity increased.
• Gases released from the carcass but carcass still floats.
34

35. Bloated Deterioration
• Most of the exposed tissues of pig carcasses floating or projecting above the
water surface disappears due to blowfly maggots.
• Totally submerged carcasses were colonized mainly by chironomid and black fly
larvae.
• Blood and other fluids leaked from carcass orifices, large sections of flesh
sloughed off .
• The duration of this stage too varied between different water bodies.
35

36. Floating remains
• Carcass with limbs or parts of tissue projecting above the water surface show
little maggot activity, probably due to migration from the carcass, death by
drowning, or predation from aquatic or other terrestrial insects.
• Aquatic invertebrates same as the last stage. Some vertebrate predators (e.g.
sunfish, dace etc. observed feeding on carcass flesh or on aquatic
macroinvertebrates found on carcass.
• Duration of submergence may also be estimated from the pupae of terrestrial
sarcophagic insects that colonize, develop and are later found adhering to or
entangled in decaying flesh, hair, or clothes of a corpse even after complete
submergence.
36

37. Sunken remains
• Duration of this stage ,quite variable but characterized by only bones, and bits of
skin remaining on the substrate.
• Decomposition completed by bacteria and fungi
• The remaining flesh resembles a soupy texture, and the decay odour is
negligible
• In addition to the fish scavengers,benthic aquatic fauna such as crayfish may be
found within the carcass remains as well as chironomid and mayfly
larvae,annelids,snails etc.
37

38. – Despite their name, mayflies are not
actually flies. They are aquatic
insects and are an important food
source for fish and reptiles. Their
most distinguishing features are their
two or three tails that are often
longer than their bodies. Read on to
learn how to get rid of mayflies.
– larvae can be grouped in 4
forms swimming ,creeping and
climing ,flattened and stramlined
,burrowing
– Associated with clean ,cool running
water can be divided into two
functional group :-shredders or
predators.
38

39. Forensic Entomology
– Forensic entomology is commonly used to estimate the time of death when the
circumstances surrounding the crime are unknown.
– Insects arrive at a decomposing body in a particular order and then complete
their life cycle based on the surrounding temperature.
– By collecting and studying the types of insects found on a body, a forensic
entomologist can predict the time of death

40. • site of human death based on identification of arthropods collected from or near
corpses.
• Cases involving possible sudden death.

41. Succession of Insects on the
Corpse
– Estimates of postmortem intervals based on insects
present on the remains are based on:
• The time required for a given species to reach a particular stage of development.
• Comparisons of all insect species present on the remains at the time of examination.
– Ecological succession occurs as an unexploited habitat
(like a corpse) is invaded by a series of different
organisms.
– The first invasion is by insect species which will alter the
habitat in some form by their activities.

42. – The time it takes for a fly to move through each stage depends on the species of
fly and the temperature conditions.
– The time required for stage development is affected by environmental
influences such as geographical location, climate, and weather conditions.
– Volatile molecules release at different stages of decomposition and attracts the
different types of insects is called Apeneumones.
“When one biological clock stops, others begin.”

43. Insect Succession on Carrion
Carrion – comes from Latin word Caro
which means The decaying dead flesh of an animal.

44. Process of body Decomposition
Death
Autolysis
Gases
accumulate in
the body (bloat)
Pressure
increase (body
deflate )
Insect attract Due
to the smell of the
gases released
from body and
body fluids

45. Stages of carrion decomposition
Fresh stage
Bloated
stage
Active
Decay stage
Advanced
/post decay
Dry remains

46. FRESH STAGE
(1-2)
– Begins at the moment of death and ends when carcass
starts bloating.
– Autolysis, the degradation of complex protein and
carbohydrate molecules. No gross morphological
changes occur at this stage.
– Temperature falls to that of the ambient temperature
– Blow flies and flesh Flies begin to arrive within 24 hours
of death but within a minutes if blood or other body
fluids are present.
– At this stage blow flies are prominent and provides the
more accurate estimation of time since death.
– Egg laying will be takes place on the natural orifices and
on any wound any injury.
– Adult flies of Sacrophagidae and Muscidae attracts to
the carcass to feed upon the soft tissue and on the other
insects.

47. Decay stage
– Dipterian larvae pierce into the body to feed and gases released .
– Abdominal wall penetrated leads to deflation of carcass and the end of the bloat
stage.
– Odour is very high.
– Temperature rise 14 degree from ambient temperature.
– Carcass biomass convert into the dipterian larval biomass.
– Carcass wet appearance
– Steady decrease in the wt. of the carcass by the 10th day.
– Early stages of decay-larva – conc. In natural orifices
– Later stages- flesh remove –larva – thoracic and abdominal cavity
– Feeding larva of calliforidae larva dominant and starts to move
– Non-calliforidae dipterian
– Sepsidae -1st member
– Coleoptera dominant (staphilinidae & Histeridae)

48. Advanced /post
decay stage
(10-23days)
– Butyric acid formation.
– Dipterian larva leaves the carcass.
– Strong odour fades away.
– Larva leaves behind bones, cartilage, hair and
small portion of tissues and large amount of wet,
viscous material( by product of decay)
– 1st migration of 3rd instar larva calliphoridae
family
– Piophilidae larva
– Few adults of calliphoridae family
– Adult dermestidae (skin bettle )

49. Dry remains
stage(18-90+)
– Bones , cartilage
– BOD dries up
– Very few adult calliphoridae & adult
piophilidae emerge
– Dermestids leaves the carcass
– Centipedes,millipedes,Isop-
odes,snails&cockroaches are common

50. Human decomposition and insect
succession
Autolysis
•Green bottle
flies,calliphoridae
, adult muscidae
& sacrophagidae
family flies at
later stages
Putrefaction
•Coleoptera
(staphilinidae,
silphidae ,
histeridae),
•Flesh flies
prominent
•Calliphoridian
larva hatch out
Black putrefaction
•Dermestidae
•Non calliphordae
diptera
•Sapsidae
•Coleoptera
prominent
Dry decay
•Fungus
•Beetles
•Ants and mites
•Moths
•snails and
cockroaches

51. Post mortem interval
– Postmortem Interval An estimation of the duration of PMI involves setting the
minimal and maximal time between death and corpse discovery and is
important in narrowing the field of suspects.
– Minimum PMI is determined by estimating the age of developing immature
insects collected at the time the corpse is discovered.
– Maximum PMI is determined from the species of insects that are present and
the weather conditions necessary for the specific activity of these species

53. Basic steps in PMI Estimation
– Collect samples of the insects present
– Determine temperature history at crime scene
– Estimate time of egg laying
– What other insect evidence is available?

54. Factors Used to Determine Time
Since Death
– 4 factors must be taken into account
1)Oldest stage of blow fly associated with the body
– Look at old pupal cases
2)Species of insects
– Each species develop at different rates so each species of insects at the scene
need to be collected
3)Temperature data
– Must be able to determine temperature of crime scene for a period of time
4)Developmental data
– Must know how fast or how slow the specific species develop

55. – Two different ways to use collected data in PMI determination
– The isomegalen diagram
– Controlled rearing

56. Isomegalen Diagram for Phaenicia (=
Lucilia) sericata

58. Accumumulative degree days
– forensic investigators can use weather data for an area in which a body was
found to calculate how much thermal energy insects have been exposed to.
They measure the amount of heat or thermal energy insects have been exposed
to in unit called Accumulated Degree Hours.
– Investigators can then use their knowledge of insect life cycles to calculate how
long the insects have been present on the body.

59. ADD/ADH =
(average
temp.-
threshold
temp.)*time

60. – Example : A Chrysomya albiceps was exposed to outer enviornment at a temp. with
maxima 68degree and with minima 54 degree.
 The threshold temp. of Chrysomya albiceps is 58 degree.
– Average temp.=(68-54)=61degree
– ADD/ADH =(61-58)*24h
=72degree hours/3 days
– 2nd days, average temp. was 64 degree
– ADD/ADH=(64-58)*24h
=144 ADH
And total ADH After 2nd day was 216 ADH

61. – Example 2 : situation will be reversed for the forensic entomologist .
– Maggots are collected from the crime scene at 2nd instar stage and the temperature
of crime scene was 72 degree.
– Threshold temp. of Chrysomya albiceps is 64degree. Degree hours for 2nd instar
stage is 320 ADH and for the 3rd instar stage is 480 days
– (Av.temp.- threshold temp.)*time = ADH
– 2nd instar =(72-64)*T=320
– Time=320/8=40h
– 3rd instar =(72-64)*T =480
– Time =480/8=60h

62. species Average
temperature
Threshold
temperature
ADD/ADH Total ADD/ADH
Chrysomya albiceps 61deg 58deg 72 h
64deg 58deg 144h 216 h
61deg 58deg 72 h 288 h

63. Factors Involved in Decomposition
– In a roughly descending degree of importance, those factors include:
– Temperature
– The availability of oxygen
– Prior embalming
– Cause of death
– Access by insects
– Burial, and depth of burial
– Access by scavengers
– Trauma, including wounds and crushing blows
– Humidity, or dryness
– Rainfall
– Body size and weight
– Clothing
– The surface on which the body rests

64. Insect application to Medico-legal
Forensic Entomology
– To determine the time since death
– Body may have been moved after death
– Body may have been disturbed after death
– Presence and position of wounds
– Insects can be used to place a suspect at the scene of a crime
– Length of time of neglect
– Possible criminal misuse of insects
– Cases involving sudden death
– Drugs trafficking

65. Case studies involving forensic
entomology
– The first recorded use of insects in crime investigation dates back to 13th
century from a Chinese village.
– In 18th the entomologist data was submitted in the modern court .when the
remains of a child was found in a building.

66. Case study in Malaysia
– Three forensic cases involving dipterans in high-rise buildings in Kuala Lumpur,
Malaysia.
– Case 1 involved a corpse of adult female found at the top floor of a fifteen-story
apartment.
– Case 2 dealt with a body of a 75-year-old female discovered in a bedroom on the
eleventh floor of an eighteen-story building.
– Case 3 was a 52-year-old male found in his fifth floor shop house.
– Interestingly, entomological analysis revealed that all corpses were infested with
similar Dipterans: Megaselia scalaris (Loew) (Diptera: Phoridae), Synthesiomyia
nudiseta (Wulp) (Diptera: Muscidae) and sarcophagid

67. 1st case study In kuwait
– Entomology has not been used in legal investigations in Kuwait. There are no known studies
on necrophagous species in the region, nor any knowledge of cadaver succession with which
to compare case material.
– In Al-Rowdah district, a man was found dead in his bedroom which was air-conditioned and
the windows were closed. The temperature of the room was 20°C.
– The cause of death was morphine overdose. At autopsy, fly larvae were collected from the
blanket with which the body was wrapped and were identified as postfeeding 3rd instars of
Parasarcophaga (Liopygia) ruficornis using molecular analysis.
– In addition, the face and neck were extensively and exclusively colonized by different stages of
Chrysomya albiceps (secondary fly).
– Based on the age of P. ruficornis full mature 3rd instars and the location of the body,
approximately 7.5-8.5 days postmortem was estimated for the corpse at the time of its
discovery.

68. AMAZON RAIN FOREST
– The corpses of 26 men were found in the rainforest in Rondonia State, Brazil.
– Fly larvae collected on the bodies during autopsy were identified as Paralucilia
fulvinota (Diptera, Calliphoridae).
– At the laboratory, the larvae developed into pupae in 58 h and into adults in
110.5 h.
– The age of the larvae when collected from the bodies was estimated as the
difference between the time required for them to become adults and the total
development time for this species. The estimated age of the maggots and the
minimum postmortem interval was 5.7 days.

69. PMI in indoors
– The bodies of socially isolated people and old people living alone were
discovered in central Italy between June and November.
– PMI ranged from a few days to several weeks
– Sarcophagidae and Calliphoridae species were present in 75% of the cases with
Lucilia sericata and Chrysomya albiceps collected in 50% of the cases.
Chrysomya albiceps was always found in association with Lucilia species. Scuttle
flies (Phoridae) were found in 37.5% of the cases, confirming the ability of these
species in indoor body colonization.

70. Case studies in India
– Corpse Found from Residential Area : On March 30th, 2015, the body of 40
years old male, in the bloated stage of decomposition was recovered from a
residential area of distt. Ludhiana, Punjab (India). The body of the deceased was
discolored, facial features were hardly recognizable and genitals were fully
decomposed as the genitals were chopped off.
– Entomofauna found on the body were maggots and pupae of Chrysomya
megacephala.

71. Case study 2
– Diptera and Coleoptera on Skeletonized Body: A mummified body of a 26 years
old girl was recovered from his residence at Patiala, Punjab (India) on 22nd
April, 2015. Body was in livor mortis stage. In this stage blood appears on the
skin as purplish-red discoloration (like a bruise) and can give indication of
position of the body at the time of death.
– Entomofauna found on the corpse consists of different instars of larvae of
Chrysomya rufifacies and beetles belonging to family Dermestidae and Cleridae
i.e Dermestes maculatus

72. Case study 3
– Drowning Case: A dead body of about 52 years old female was recovered from
Bhakra canal, Patiala, Punjab (India) on 22nd April, 2015. The body was in
bloating stage of decomposition with partially identifiable facial feactures .
– Egg batches and adults of Chrysomya megacephala were present all over the
body. Beetles belonging to family Histeridae were reported on corpse.
– Later egg batches were transferred to rearing jar provided with a piece of goat
meat as rearing medium for the calculation of PMI

73. North India case
– Jayanti, a 14-year-old sex worker, lay in a pool of blood along a highway in a
north Indian state. Her autopsy revealed that her death was due to multiple
head and neck injuries inflicted with a sharp object. Jayanti had last been
spotted alive four days ago with a 30-year old army sergeant, the prime suspect

74. Dr Devinder Singh, India’s lone practising forensic entomologist, “Hundreds of
cases in developed countries are today being solved with insect .
Singh, an entomologist at the Punjabi University in Patiala, is currently working on
a Department of Science and Technology project to create base-line data on
carrion insects (those that thrive on dead and putrefying flesh) which can be used
as evidence in the Punjab region.
“Insects have an acute power of smell and they are the earliest to find a dead
body, long before the police can,” he says

75. Challenges to forensic entomology
– 3 challenges exist
 Temperature
– Temperature of crime scene and the temperature that the insects have been exposed to us
unknown
 Season
– Entomology is valuable only in spring, summer, and fall
 Exclusion of insects
– Insects are excluded based on condition of body