L5 Entomology

Forensic Entomology



  1. What is entomology? 



Study of insects, branch of zoology and used to reveal body parts and remains by presence of flies, larvae or eggs, or other insects

  • Can determine if body was moved

  • Helps estimate time of death

  • Figure out geographic range/location of crime



  1. What are factors to consider in entomology? 



  • Insect life cycle

  • Successional colonization



  1. What is ADH?



Accumulated degree hours

  • Hours for specific insect species to reach a certain stage of their life 



  1. Fill in the chart about stages of a blowfly life cycle.



Stage

Size

Color

First Appearance

Duration in Phase

Characteristics

egg

2

white

Soon after death

8 hours

Found in warm moist areas of the body like the eyes and mouth

Larva 1

5

white

1.8 days

20 hours

Black mouth hooks visible; thin body; 1 spiracle slit near the anus

Larva 2

10

white

2.5 days

15-20 hours

Black mouth hooks; actively feeding; 2 spiracle slits

Larva 3

17

white

4.5 days

36-56 hours

Black mouth hooks; fat body; 3 spiracle slits

pre -pupa

9

Light brown

8-12 days

86-180 hours

Larva migrates away from the body and to a dry area

Early and late pupa

9

Light brown; changes to dark brown

18-24 days

6-12 days

immobile ; does not feed; changes to dark brown with age; pupa case splits open prior to adult emerging

adult

varies

Black or green

21-24 days

Several weeks 

Incapable of flight for the first few hours 



  1. Fill out the chart about bug location.



Blow Fly

  • Body likely inside

  • Typically first insect to reach decomposing bodies and lay eggs

  • Most important in estimating time of death using stage of larvae

Bot Fly

  • Body likely was outside

Beetle

  • Body has likely been decomposing for a while



  1. What is oviposition?



It is the egg laying process

  • Will not occur at night, in rain, or in other unsuitable temperatures/conditions



  1. Fill out the chart on decomposition rate.



Fresh

1-3 days postmortem, can attract insects

Bloat

3-5 postmortem, body bloats (doubles in size) due to internal gasses

Active Decay

7-10 days postmortem, organs/tissues release fluids greatly attract insects

Advanced Decay

Weeks postmortem, organs/tissue are done breaking down, leathery skin and teeth/nails fall out, lot of insects like flies and beetles

Skeleton

Months postmortem, only bones, residual of decomposed fluid goes into soil little to no insects



  1. What is MDT?



Medical method that uses sterile maggots (larvae) or specific fly species and their antibiotics to remove necrotic (dead) tissue from wounds to healing