Forensic Entomological Determinant - PowerPoint Presentation

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Forensic Entomological Determinant

Presented by

Dr. Ayesha QamarDepartment of ZoologySECTION-ENTOMOLOGYAligarh Muslim University

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Introduction

Forensic entomology is the scientific study of the invasion and succession pattern of insects and other arthropods with their developmental stages of different species found on the decomposed cadavers during legal investigations.

The first documented case involving the use of an insect in a death investigation can be dated to 13th century China.Sung Tz’u was a practicing lawyer and death investigator who became a leading criminologist with the publication of his manuscript in 1247 AD entitled "Washing Away of Wrongs".

Child Neglect

Elderly Neglect

Animal NeglectDeath investigationsPoor quality of foodAnimal myiasis

DOCTRINE OF RES IPSA LOQUITOR

Evidence (here presence of maggots/things) speaks for itself regarding negligence. For example:

https://says.com/my/news/pj-man-was-halfway-through-his-meal-when-he-noticed-maggots-crawling-inside-his-chicken

northconwayrotary.org

Maggots in Pet animals (animal neglect)

Maggots in food served at a restaurant (negligence of hygienic conditions)

Res Ipsa

Loquitor: Elderly neglect

Larvae on cotton swab removed

from the lesions.

Larval

infesttion

in wounded elderly

Medical negligence cases where doctors left scissors and

foreceps

inside the patient

Other cases

Larvae

Pupa

Adult

Grub

Pupa

Adult

Life cycle of blow fly

Eggs(200-250)

1

st

Instar

2

nd

Instar

3

rd

Instar(12 mm)

Pupa (10 mm)

Adult

Insects associated with dead carcasses

Above ground

Below ground

Dry stage reached in about 10 days

Dry stage reached in about 1.5 months

Synthesiomya

nudiseta Ophyra capensis Megaselia scalaris

Saprinus

quadriguttatus

Saprinus

splendens

Onthophagous quadridentatus

Saprinus

splendens

S. quadriguttatus

Sarcophaga

dux

C.megacephala

Chrysomya

.

rufifacies

Calliphora

vicina

Larvae on human carcasses

A dead body was recovered from roadside dig

at Chherat, district Aligarh, UP.A dead body was recovered from the shore of water canal at Jawa, district Aligarh, UP.

Collected maggots reared on to the

buffalo

meat

Cephaloskeleton

Spiracles enclosed

in circular pit

Spiracles not enclosed in pit

Chrysomya

megacephala

Sarcophaga

dux

Estimation of minimum Post Mortem Interval (PMI)

Case StudyAn unclaimed body was recovered on 17

th January 2019 by police and brought to the Post Mortem House, Aligarh.The body was partially clothed and was in advanced decomposition stage, found stuck to an obstruction in a waterbody at Atrauli.The larvae were found crawling on the arms, buttock region which was scavenged by some animal.Cause of death: Accidental Drowning.

Arrows showing the site of collection of maggots

Estimation of minimum Post Mortem Interval (PMI)

LIFE STAGE

DEVELOPMENT DURATION(DAYS)EGG2-3

LARVAE(L1-L3)

5-6 (144hours)

PUPATION

3-5

Sarcophaga

sps

.

Larviparous

50-100 larvae

Arrives within minutes after death

Development of

Sarcophaga

sps

at 28

0

C*

*

Shiravi

, Ah et al. “Temperature Requirements of Some Common Forensically Important Blow and Flesh Flies (

Diptera

) under Laboratory Conditions” 

Iranian journal of arthropod-borne diseases

 vol. 5,1 (2011): 54-62.

Determination of Accumulated Degree Hours (ADH) for

Sarcophaga sps

life cycle from 30th December 2018 to 17th January 2019.

Date

Temperature

0 CAverage t emp.Temperature0 CThreshold temperature

Temperature

0 C

GDD

Avg

temp-Threshold temp

ADH

(GDDX24)

MAX

MIN

30/12/2018

23

3

13

5.9

7.1

170.4

31/12/2018

22

4

13

5.9

7.1

170.4

1/01/2019

23

4

13.5

5.9

7.6

182.4

2/01/2019

23

7

15

5.9

9.4

225.6

3/01/2019

21

7

14

5.9

8.1

194.4

4/01/2019

18

7

12.5

5.9

6.6

158.4

5/01/2019

21

5

13

5.9

7.1

170.4

6/01/2019

20

9

14.5

5.9

8.6

206.4

7/01/2019

20

7

13.5

5.9

7.6

182.4

8/01/2019

20

7

13.5

5.9

7.6

182.4

9/01/2019

20

8

14

5.9

8.1

194.4

10/01/2019

21

5

13

5.9

7.1

170.4

11/01/2019

22

5

13.5

5.9

7.6

182.4

12/01/2019

23

7

15

5.9

9.4

225.6

13/01/2019

24

9

16.5

5.9

10.6

254.4

14/01/2019

20

8

14

5.9

8.1

194.4

15/01/2019

19

6

12.5

5.9

6.6

158.4

16/01/2019

21

5

13

5.9

7.1

170.4

17/01/2019

22

7

14.5

5.9

8.6

206.4

Table1 showing the calculated value of ADH.

Weather data of

Atrauli

is obtained by

accuweather

application.

Calculation of ADH

ADH taken by

Sarcophaga

sps

to reach the 3

rd

instar 28

0

C (Table 1)

= (144X24)

=

3456 ADH

Total ADH from 30

th

December 2018 to 17

th

January 2019 = 3417.6

Difference between ADH taken by

Sarcophaga

sps

to reach the 3

rd

instar at 28

0

C – Total ADH

= 3456-3417.6

= 38.4

30

th

dec

17

th

jan

Total ADH

3417

L

arviposition

Date of corpse recovery.

3

rd

instar stage of maggot

Since, ADH = Development time X GDD

Value Therefore,

38.2= Development time x 8.6 Development time = 38.4/8.6 = 4.46 hoursDetermination of mPMI= period that the body took to lift up at the surface (24 to 30 hours) + Period of insect activityThe female Sarcophaga

sps

might have deposited its larvae on the dead body : 4.40 to 5.00 hours on 30

th December 2018

Thus,

mPMI = 19 to 20 days.

Helps

associate the victim and suspect to each other and to the scene.

 Additionally, entomological evidences can be utilized as alternate toxicological samples, and their gut contents can be sources of human DNA viable for forensic testing.Help the pathologist identify sites of trauma on the corpse.

The major area of research and case application of entomology in forensic

sciences

is the use of species identification, known growth rates, and insect succession data to determine both the location and approximate time of the victim's death

.

Within the forensic sciences, forensic entomologists can help to establish a portion of the postmortem

interval.

Assist in establishing the geographic location of death in cases of body transport.