LECTURE 7: ENTEMOLOGY // CHAPTER 3

Question 1

What is Forensic Science?

Answer 1

• Forensic Science is the application of science to criminal/civil cases in order to provide information suitable to courts of justice.
• Any science can become a forensic science if its applied to legal or public concern

Question 2

`Crime scene

Answer 2

• Place where an offence has been committed and forensic evidence may be gathered

Question 3

entomology divided into 3

Answer 3

1) Urban entomology – insects that affect houses, buildings, and similar human environments
2) Stored product entomology – insects infesting stored goods such as food or clothing
3) Medicolegal entomology – insects and their utility in solving criminal cases

Question 4

use of entomology

Answer 4

• PMI
• presence of drugs/toxins
• if corpse has been moved
• lesions/ injuries
• presence of foreign DNA
• cause of death

Question 5

Define wildlife crime

Answer 5

• any non-human biological evidence

Question 6

Taphonomy

Answer 6

– study of an organism from the time it dies until the time it reaches a laboratory

Question 7

Forensic entomology

Answer 7

• is the application of the study of arthropods, including insects, arachnids (spiders and their kin), centipedes, millipedes, and crustaceans, to criminal or legal cases

Question 8

insect biology

Answer 8

• Exoskeleton – an external skeleton composed of chitin and protein
  o Protects animals’ internal organs, conserves fluids, acts as a structure for muscle attachment
• 3 segments – joined together by flexible joints
  1) Head
  2) Thorax – further divided into prothorax, mesothorax, metathorax
  3) Abdomen
• Meso and metathorax are sites for wing attachment
• Abdomen carries internal organs and is segmented – each bears a pair of holes called spiracles, used for breathing

Question 9

Life cycle of insects

Answer 9

1) Ametabolous metamorphosis
2) paurometabolous metamorphosis
3) holometabolous metamorphosis

Question 10

• Four ecological categories exist in the cadaver community:

Answer 10

1) Necrophagous species – feed on the carrion itself, contributing directly to estimation of PMI
e. g. diptera, coleoptera, silphidae, dermestidae
2) Predatotory and parasitic species – prey on other insects, including necrophagous ones
e. g. certain coleoptera, siliphidae, some diptera
3) Omnivorous species – only eat on material from body, other insects or whatever source presents itself
e. g. wasps, ants, some coleopetra
4) Incidental species – uses cadaver as an extension of their habitat
e. g. butterflies, spiders, collembola

Question 11

1) Ametabolous (without change) Metamorphosis –

Answer 11

where eggs yield immature forms that look like smaller forms of the adults

Question 12

2) Paurometabolous (gradual) metamorphosis –

Answer 12

hatchlings emerge in a form called nymph (resembles wingless version of adult) nymphs grow by moulting with each shed producing a new instar – each phase gets closer to resemble parent and then grows wings

Question 13

3) Holometabolous (complete) metamorphosis –

Answer 13

adult lays an egg (oviposits) or deposits larva (larvaposits) onto food source, larvae eat it and start molting through instars, larval form and adult form different in both habitat and appearance – at end of instars larvae transition into pupal stage (inactive phase) – pupa is a harded outer shell or skin… such as butterfly cocoon, puparium of flies is most common in forensic sense

Question 14

o RIGOR MORTIS “death stiffness”

Answer 14

 Stiffness of muscles due to lactic acid
 Starts around 2-4 hours after death
 Reaches maximum stiffness 8-12 hours after death
 Begins to fade 18-24 hours after death
 Disappears 24-30 hours after death

Question 15

o LIVOR MORTIS “death color”

Answer 15

 Settling of blood in body due to gravity
 Develops 2-4 hours after death occurs
 Non-fixed (blanchable) 8-12 hours after death
 Fixed (non-blanchable) >8-12 hours after death

Question 16

o ALGOR MORTIS “death heat”

Answer 16

 Post Mortem cooling of the body((about 1°C/h)
 Multiple variable on algor mortis are:
 Body dimensions
 Posture
 Clothing
 Ambient Temperature
 Air movement
 Tends to level off the environmental temperature