Forensic Entomology Flashcards
What is entomology
Entomology is study of insects.
How would a forensic entomologist estimate time since death
A forensic entomologist would estimate time since death by Length of maggot (estimate age) Time taken to pupate Time taken for eggs to hatch What species are present on corpse
What are stages of life of a blow fly
Stages of life of a blowfly are
Egg , larva, pupa and adult.
What are the 3 larva stages
The 3 larva stages are instars. At the end of each instar maggot sheds its skin to allow more growth in next instar.
Why do fisherman put maggots in the fridge and why
Fisherman put maggots in the fridge to slow down the rate of development (slow down life cycle).
They put maggots in the fridge because temperature (which affects enzyme activity) is lower which means there is less kinetic energy, molecules collide less often, less enzyme substrate complexes, slower metabolic processes, grow slower.
How can you speed up how a fly goes through life cycle
You can speed up how quickly a fly goes through its life cycle by increasing temperature, increase kinetic energy of enzymes, increases number of collisions of molecules, increase number of enzyme substrate complexes, increases growth rate.
What is the red line on the maggot graph and what is on the axes of the graph
All black lines which are to the left of the red dotted line are pre feeding maggots and all black lines to the right of dotted line are post feeding maggots.
On x axis you have maggot age in days
On y axis you have temperature of maggot surroundings
Number at top of black line represents length of maggot (mm)
How are maggots used to determine time of death with graph
Maggots are used to determine time of death when
Maggots will be collected from body, species will be identified and will measure length of the maggots. Then they can use graphs to estimate how long body has been there for.
How do you estimate time of death using egg hatching time
Estimate time of death by using egg hatching time by
Forensic collect eggs from corpse, incubate them at temperature corpse is at. Then record how long it takes for egg to hatch.
Normal time period for egg to hatch- hatching time in lab=hours since eggs were laid.
What factors affect estimating time of death using egg hatching times
Factors affecting estimating time of death using egg hatching time are
Temperature - temperature records of body must be recorded and taken into account
Consider time taken for flies to find corpse and lay eggs on it
What is succession on a corpse and what are conditions changed by
Succession on a corpse is longer a person has been dead, more species of insect live on corpse, gradual and predictable.
Previous Species of insect change conditions of corpse , making it suitable for next species to arrive.
Conditions are changed by organisms contributing to decomposition of body.
What happens when a species arrives on a corpse and why (less important
Species of insect change conditions of corpse, making it suitable for next species to arrive. Conditions are changed by organisms contributing to decomposition of body. Insects consume flesh as food and this provides insects with carbs, proteins and fats.
How can scientists predict time of death from succession of a corpse
Scientist can predict time of death because Scientists knows which species arrive in which order, so they can predict time of death
How do insects get in the body
Insects get in the body via openings (mouth/nose) and wounds
What are the waves of succession and what are the changes of conditions
1st wave is fresh corpse (bluebottles, greenbottles)
2nd wave is corpse bloated by gas (fresh flies)
3rd wave is active decomposition with fatty acids turned into waxy substance (beetle larvae)
4th wave is active decomposition (fermentation) (cheese skipper)
