Module 8: Forensic Entomology Flashcards
Factors affecting decomposition rate
- age (middle age decompose slower) (young quicker than old)
- size (overweight faster; fat hasten decom)
- clothing (less exposed, slower)
- health (sick faster)
- environment ( high temp & humidity, faster)
- location (faster in air, slow in water and soil)
Name the 5 stages of decomposition
- Fresh
- Bloat (Putrefaction)
- Active decay (Black Putrefaction)
- Advanced decay
- Skeletonization
Fresh description
- autolysis
- no physical changes
- begins right after death up to next 2 days
- first flies
- body and environment temp equilibrium
- mortises
Bloat (putrefaction) description
- around day 4
- leaking enzyme ->gases ->expanded abdomen
- sulfur compound -> skin discoloration
- purging
- mabaho
- peak number of flies
Active Decay (black putrefaction) description
- around day 6-10
- lumiit na tiyan
- maggot feeding -> loss in mass
- skin turning black
- maggots leaving -> end of this stage
Advanced decay
- around day 10-20
- begins to dry
- most flesh is gone (skin, cartilage, bone)
- mostly beetles
- possible adipocere formation/grave wax
Skeletonization
- day 50 onwards
- skeleton
- few beetles, some mites
Forensic Entomology
study of insects in relation to criminal investigations
True or False
Ancient times don’t know association of decomposing bodies and insects
False
Who disproved spontaneous generation theory?
Francesco Redi
True or False
Life cycle of species have known time intervals
True
Blow Fly Life Cycle
- Eggs - found in warm and moist area of a corpse in less than 8hrs.
- LS 1 (instar 1) - within 23hrs
- LS 2 (instar 2) - 2 days postdeath
- LS 3 (instar 3) - 3 days postdeath
- Pupa - about a week postdeath
- Adult - about 2 weeks postdeath
True or False
Different species colonize at the same time
False
Succesion of beetles
Blow flies ->Flesh flies-> Clown Beetles - >Carrion Beetles -> Dermestidae Beetles
(Sequence is predictable, but timings will differ.)
True or False
Life stages of insects can help determine/estimate PMI
True
Types of insect evidence
- presence of insects on the body
- developmental stages of insects
- insect artifacts ( feces, pupal cases)
Importance of FE
- evidence
- estimate PMI
- was the body moved?
- locate clandestine graves or crime scenes
- locate wounds concealed by decom
- detect presence of drugs
Techniques in FE
- collect and preserve of insect evidence
- rearing insects to determine life cycle
- molecular techniques for species ID
- statistical models for PMI estimation based oon insect evidence
What do you need to know in when conducting FE?
- species
- stage of development for the specific species
- standards for development timings
- temperature and precipitation history
Why do you need temp and ppt history?
Sometimes insects were washed away.
Challenges in Forensic Entomology
- envi. factors affect insect activity
- lack of standardization in FE techniques
- limited understanding of insect behavior in different environments.
Future Directions in FE
- advances in DNA analysis for ID species
- development of more accurate model for PMI estimation
- integration of entomological data with other forensic disciplines.
