THE ROLE OF INSECTS IN FORENSIC ENTOMOLOGY

Being a Term Paper Presentation (VMPE 800)

Presented to:

Staffs and Students of the Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine

Ahmadu Bello University, Zaria.

By:Akanni Azeez Olamide

(P13SCBS8070)Lecturing Team: Prof. Natala

Dr. Ogo1

WHAT IS FORENSIC ENTOMOLOGY?

INTRODUCTION

2

Forensic Entomology is the use of the insects, and their arthropod relatives that inhabit decomposing remains to aid

legal investigations (Amendt et al, 2007).

INTRODUCTION

3

SCOPE OF FORENSIC ENTOMOLOGY

INTRODUCTION CONT’D

4

Medico-legal

Urban

Stored Product Insects

INTRODUCTION CONT’D

5

Useful Insects in Forensic Entomology

HISTORY OF FORENSIC ENTOMOLOGY

INTRODUCTION CONT’D

6

7

INTRODUCTION CONT’D Early 13th Century

• Sòng Cí (Legal expert and Death Investigator’s Report )

13th – 19th Century• Redi’s (1668) Experiment• Linnaeus’ (1775) Development of Systematics

and Taxonomy • Megnin’s (1894)Observation on Decomposing

Remains Stages of decomposition vs Speed vs

Environmental conditions

PRINCIPLES OF FORENSIC ENTOMOLOGY

8

9

PRINCIPLES OF FORENSIC ENTOMOLOGY

Reliable information about; • Insects Behaviour• 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

10

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

11

PRINCIPLES OF FORENSIC ENTOMOLOGY

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

12

PRINCIPLES OF FORENSIC ENTOMOLOGYTABLE 1: Major family of flies (Dipterans) found on or near a carrion

Family Example Description

Calliphoridiae Blowfly (blue and green bottle flies) Colonizes the carrion during early stages of decomposition

Often the most abundant larvae on carrion

Possess specific preference for light intensity and temperature being a poikilotherm.

Sarcophagidae Flesh Flies Large in size Lays live larvae Larvae parasitizes blowfly

maggot May also be present shortly after

death

Muscidae House Fly Usually found during the last stages of decomposition

Piophilidae Cheese skippers Associated with late stage of decomposition

Source: Self

13

PRINCIPLES OF FORENSIC ENTOMOLOGYTABLE 2: Different family of Coleopterans that colonizes a carrion

Source: Commons.wikimedia.org/wiki

14

PRINCIPLES OF FORENSIC ENTOMOLOGY

Calliphoridiae: Caliphora vomitoria Sarcophagidae: Sarcophaga bercaea

Plate 1: Different groups/ families of insects that colonizes a carrion

Source:commons.wikimedia.org/wiki/Dipterans

15

PRINCIPLES OF FORENSIC ENTOMOLOGY

Muscidae: Housefly Piophilidae: Cheese skipper

Plate 2: Different groups/ families of insects that colonizes a carrion

Source: Commons.wikimedia.org/wiki/Dipterans

16

PRINCIPLES OF FORENSIC ENTOMOLOGY

Plate 3: Typical lifecycle of a blowfly /dipterans

Source:commons.wikimedia.org

17

PRINCIPLES OF FORENSIC ENTOMOLOGY

Staphylinidae: (Rove Beetles) Silphidae: Carrion Beetles/Sexton Beetles

Source (1&2): Serajo and Michael K. Oliver, Ph.D

18

USES OF INSECT IN FORENSIC ENTOMOLOGY

19

USES OF INSECT IN FORENSIC ENTOMOLOGY

Estimation of Time Since Death/Post Mortem Interval (PMI)

• The primary application of insects answering questions in death investigation is to estimate when the victim died (Rodriguez, 1989)

•This possibility exists due to the insects being the very first organisms to colonize dead animals.

20

Days after death House fly Blow fly Flesh fly Skipper fly1 EGG LARVAE2 EGG LARVAE LARVAE3 EGG LARVAE LARVAE4 LARVAE LARVAE LARVAE5 LARVAE LARVAE LARVAE EGG6 LARVAE LARVAE LARVAE EGG7 LARVAE LARVAE LARVAE LARVAE8 LARVAE LARVAE LARVAE LARVAE9 LARVAE LARVAE LARVAE LARVAE

10 LARVAE LARVAE PUPA LARVAE11 LARVAE LARVAE PUPA LARVAE12 PUPA LARVAE PUPA LARVAE13 PUPA LARVAE PUPA PUPA14 PUPA PUPA PUPA PUPA15 PUPA PUPA PUPA PUPA16 PUPA PUPA PUPA PUPA17 PUPA PUPA PUPA PUPA18 PUPA PUPA PUPA19 PUPA ADULT ADULT20 PUPA21 ADULT

TABLE 3:Developmental stages of seral wave of flies that colonizes carrion and their key indication of time of death.

21

Temperature

(oF)

House fly Blow fly Flesh fly Skipper fly

55o Delayed 4 Delayed 4.5 Delayed 4 Delayed 3

65o Delayed 4 Delayed 3 Delayed 2 Delayed 1

80o Accelerated 1 Accelerated 2 Accelerated 1.5 Accelerated 1

85o Accelerated 3 Accelerated 4 Accelerated 3 Accelerated 2

USES OF INSECT IN FORENSIC ENTOMOLOGY

Table 4: Various temperature ranges and their effects on development of flies which may affect estimation of time of death.

22

Estimation of Location or Point of Death.

USES OF INSECT IN FORENSIC ENTOMOLOGY

• Another application of entomology is using the ranges of a specific insect species’ geographic distribution (where it lives) to establish from where a body originated

• Case Study 1: California• Case Study 2: Belgium

23

Identification of Area of Trauma in Extensively Decomposed Body

USES OF INSECT IN FORENSIC ENTOMOLOGY

• Carrion insects (primarily blowflies) can be used to identify areas of trauma on badly decomposed remains when major changes have taken place in the appearance of the soft tissues on the body

24

Entomotoxicology

USES OF INSECT IN FORENSIC ENTOMOLOGY

• The maggots may be used to determine the presence or absence of drugs when human body tissues are too badly decomposed to do toxicology on the tissue remains

•Role of Chitin in trapping residue of controlled drugs

•Case study 3: involving using puparial cases

25

Identification of Suspect/Criminal

USES OF INSECT IN FORENSIC ENTOMOLOGY

• Techniques for analyzing molecular DNA structures of insects for species identification and the human DNA in insects that feed on humans have recently been developed

• Case study 4: Rapist

• Maggots feeding on decomposing humans have been tested for human DNA and found to retain testable levels

26

CONCLUSION

27

From the elucidated uses of insects in forensic entomology above, it is obvious that forensic entomology is an interesting aspect of entomology with useful application to investigation and in aiding justice.

Despite the enormous usefulness, little or no work is done in Nigeria and Western Africa as a whole, therefore, I the justice department will be better enhanced and the people better served if this branch of science can be utilized.

CONCLUSION

28

THANK YOU FOR LISTENING!!!