1. Forensic Entomology
Study of insects and their relation to legal issues

2. Types of Forensic Entomology
Medicolegal- Criminal acts/legal issues that involve insect infestation of human remains

3. Urban- Legal issues that involve insects that damage manmade items

4. Stored Product- Legal issues that deal with insects infesting stored commodities
Ex) Insects in cereal

5. Necrophilous insects Insects that consume dead flesh
Carrion-Decaying carcasses/remains

6. Roles of the Medicolegal Entomologist
Calculate time elapsed since death
PMI- Postmortem interval
Determine if body was moved after death
Establish presence & position of wounds

7. Place a suspect at the crime scene
Detect abuse and neglect in children or elderly
Toxicology tests - run on maggots, they bioaccumulate toxins

8. PMI: Postmortem Interval
Medicolegal entomologists are called for cases 72 or more hours old
Prior to this, other forensic methods are more accurate
PMI is calculated in 2 ways:
Use maggot age and development
Use insect succession

9. Maggot Age & Development
Used within first few weeks of death
Accurate to a day or less, or a range of days
Blowflies are attracted to corpse very soon after death to lay eggs
Their life cycle is predictable:
Adult Eggs  Larva 1 Larva 2 Larva 3Pre-PupaPupaAdult

10. Succession of insects Used from a few weeks of death to a year or more
During body decomposition rapid changes occur
Stages of decomposition:
Fresh  Bloated  Decay  Post Decay  Skeletal
Different insects are attracted based on decomposition stage

11. Fly Life Cycle
Blowfly: First bug to arrive at corpse within the first hour of death
Lay their eggs in moist areas of corpse. Ex) Nose, armpit, mouth and open wounds
Eggs hatch within 24 hours as maggots
Reach a length of 1cm after 3 days
Next 6-10 days maggots grow, molt and eventually pupate (cocoon)
12 days later adult flies emerge from cocoon.

13. Figure 2-15  Typical blowfly life cycle from egg deposition to adult fly emergence. This cycle is representative of any one of the nearly ninety species of blowflies in North America. Courtesy E. P. Catts, Ph.D., deceased, and Neal H. Haskell, Ph.D., forensic entomology consultant

14. Factors that Affect Insects
Blow flies don’t deposit eggs at night.
Flies are fewer during winter months.
Extreme cold can cause maggots to go dormant.
- Low temps delay maggot development
- High temps accelerate maggot development

15. Entomological Succession
The order in which the bugs show up on and in a corpse
Blowflies of which there are several species.
House flies
Flesh flies
Rove Beetles feed on the maggots
Carrion Beetles also feed on the different stages of fly offspring
Hister Beetles
Parasitic Wasps

16. Blow Fly

17. House Fly

18. Flesh Fly

19. Rove Beetle

20. Carrion Beetle

21. Hister Beetle

22. Parasitic Wasp

23. Insect Collection Procedure
Use a net to collect adult insects first
Eggs can be collected with a wet paintbrush
Use forceps to pick up larvae and pupae
Place eggs, larvae, and adults into separate “kill” jar with 75% ethyl alcohol
Do not do this to pupae, not necessary because they don’t grow
Duplicate samples should be made for live specimens
Use separate jars for each colony found

24. Use pencil for labels, one in the jar and one outside
DO NOT use pen because alcohol dissolves ink
Labels:
Geographic location
Date and hour of collection
Case #
Location of insects on body
Stage of development of insects
Collector’s Name

25. Maggot Mouth Hooks

27. Additional Info

28. Entomological Succession
As the corpse dries, it becomes less suitable for the blowflies, flesh flies and house flies that like a semi-liquid environment
Different fly families, the cheese flies and coffin flies, are abundant as the corpse dries
Cheese flies have been found in coffins buried up to 3 m deep and in corpses up to 10 years old
Coffin flies: It has been calculated that with 98% survival, one pair of coffin flies in a protected place could produce 55 million flies in 60 days

29. The Final Devouring of a Corpse
Eventually, the corpse becomes too dry for the mouth hooks of maggots to operate effectively.
The hide beetles, ham beetles and carcass beetles, with their chewing mouthparts, devour the dry flesh, skin and ligaments.
Finally, moth larvae and mites consume the hair, leaving only the bones to slowly disintegrate.