Forensic Entomology is the study of insects found at the crime scene. For complete explanation of videos, click on the link- https://youtu.be/RXs9BKFkUXk.

1. FORENSIC
ENTOMOLOGY
Tanu P. Chandel
Volunteer of Applied Forensic Research Sciences

2. Contents:
■ Introduction
■ Basic Principle of Insect Biology
■ Life Cycle of the Blow Fly
■ Life Cycle of Flesh Fly
■ Stages Of Decomposition Fueled By Insect Activity
■ Estimation Of Time Since Death
■ Collection and Preservation of Entomological Evidences
■ MCQs

3. Introduction:-
Forensic Entomology is the scientific study of
conquering of the progressive patterns of the
arthropods with their developmental stages found
on the decomposed corpse during legal
investigations. It is primarily used to estimate the
time since death of the dead body.

4. Basic principle of insect biology:-
■ Insects are the dominant life-forms on Earth.
■ Insects are main consumers of plants and major source of
food too.
■ Insects are extraordinarily adaptable creatures.
■ Insects have wide diversity in size, form and behaviour.
■ Insects have hard exoskeleton as an armour.
■ Insects produce large numbers of offsprings at a time.
■ Insects provide honey, silk, wax and other useful products.
■ Insects are major pests to humans, animals and plants
sometimes.

5. ■ Eggs Laid: Eggs are laid by a mature female blowfly in carcass holes
or open wounds.
■ Eggs Hatch (Larvae): Eggs are 1-2 mm in length and hatch after 24-
45 hours.
■ 1st Stage Maggots (Larvae): Maggots produce an enzyme that breaks
down protein so they feed on semi-liquid bodily fluids. After several
days, they shed their exoskeleton.
■ 2nd Stage Maggots (Larvae): They grow in size and continue to feed
off the decomposing body. This stage ends when they molt for a
second time.
■ 3rd Stage Maggots (Pupae): They fall to ground and no longer feed or
move. Their exoskeleton hardens and turns from a light brown to a
black color.
■ Adult Blowfly: It emerges from the exoskeleton and can fly after only
a few hours. A male blowfly is able to mate right away while a
female must feed on protein before being able to lay her own eggs.
Life cycle of blow fly:-

6. Life cycle of flesh fly:-
■ The lifecycle of a fly begins as an egg.
■ After some time the egg hatches and larva comes out
of it. Larva feeds on the organic matter and when it
has stored sufficient nutrients it goes into pupal stage.
■ Pupal stage can again be of several days or months.
During the pupal period the development of the
actual fly like features begin.
■ From the pupa, the adult fly comes out and is ready to
start the cycle again

7. StAges of decomposition fueled by insect activity:-
Fresh Stage:--
■ Begins at death;
■ First sign of bloating due to putrefaction by anerobic
respiration;
■ Autolysis, the degradation of complex protein and
carbohydrate molecules, occur.

8. StAges of decomposition fueled by insect activity:-
Bloat Stage:--
■ Swells due the production of gases by bacteria;
■ Temperature of dead body rises;
■ Flies are attracted in large numbers;
■ Soil fauna moves away due to wetness of land.

9. StAges of decomposition fueled by insect activity:-
Decay Stage:--
■ Gases and fluids ooze out from the body;
■ Maggots break through the skin;
■ Predatory bettles are attracted;
■ Unpleasant odour;
■ Larvae pupate;
■ Corpse is reduced to 20%.

10. StAges of decomposition fueled by insect activity:-
Post-Decay Stage:--
■ Corpse get reduced to hair, bones and skin.

11. StAges of decomposition fueled by insect activity:-
Dry Stage:--
■ Doesn’t occur in wet areas;
■ Corpse is reduced to 10% of original mass;
■ Only bones and hair remains;
■ Normal soil fauna starts to return;
■ This stage may last from several months to years.

12. Estimation of time since death:-
When a body is discovered more than 72 hours after
death, details normally examined to establish time of
deatth are body temperature, skin color, and degree
of muscle rigidity, etc. Blowflies, however, lay eggs
within minutes of someone dying and so
investigators can use the growth timeline of blowfly
maggots to find out exactly when a person died.

13. Collection and preservation of entomological evidence:-
■ Camera and video should be fixed to evidence
site.
■ Net or sticky traps are used to catch fly.
■ Collect insects in live specimen containers
using forceps.
■ Preserve evidences in 98% alcohol.
■ Record details about crime scene.
■ Contamination of evidences must be avoided
by using gloves and hand towels.

14. Mcqs
■ In most cases, forensic entomology will
only determine a __________ time since
death.
A) approximate
B) maximum
C) minimum
D) probable

15. Mcqs
■ What method of forensic entomology is used to
determine time since death when the corpse has
been dead from one month to a year or more?
A) Accumulated degree hour technique
B) Maggot age and development
C) Successional waves of insects
D) Questioned epistemological examination

16. References:-
■ https://www.terminix.com/blog/science-nature/how-are-insects-used-in-forensic-entomology/
■ https://www.pctonline.com/article/forensic-entomology/
■ https://sites.google.com/site/magicofforensicscience/lesson-4
■ https://bekkabrodie.com/2014/10/29/the-beginning-of-the-end-how-blow-flies-find-corpses/amp/
■ https://medium.com/@stopwatch740/brief-history-of-stopwatch-227b3071ba82
■ https://entomologytoday.org/2020/04/15/why-forensic-entomologists-say-crime-scene-investigators-
should-carry-cans-tuna/
■ https://en.m.wikipedia.org/wiki/Insect
■ https://sites.google.com/site/magicofforensicscience/lesson-4
■ https://www.nlm.nih.gov/ visibleproofs/galleries/technologies/blowfly.html

17. Thank you!!!