Chapter 11: Forensic Entomology
Student Learning Objective (Emphasis on Blowflies and beetles)
Forensic Science: Fundamentals and Investigations, 2nd ed., Bertino & Bertino, 2015
At the conclusion of this chapter, the student should be able to:
General Information on Insects
____ 1. Define forensic entomology.
____ 2. Discuss the history of using insects to estimate postmortem interval (PMI).
____ 3. Describe the main identifying characteristics of insects including:
a. body support
b. number of body regions
c. number of legs
____ 4. Define the terms:
a. anterior
b. posterior
c. dorsal
d. ventral
____ 5. Compare and contrast the anterior and posterior of blowfly larvae.
____6. Compare and contrast the ventral and dorsal surfaces of blowfly larvae.
____ 7. Prepare a chart describing the structure, function, and location of each of the
following blowfly structures:
a. exoskeleton
b. spiracles
c. setae (on larvae)
d. crop
e. hooks
____ 8. Relate the process of molting to the presence of an exoskeleton.
____ 9. List and describe each stage of complete metamorphosis in blowflies. Include in
your answer:
a. Which stages demonstrate active feeding
b. Which stages demonstrate immobility
____ 10. Explain why the crop of a larva sometimes appears dark.
____ 11. Compare and contrast a blowfly larva to a beetle larva.
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____ 12. Laying, or oviposition, of eggs by blowflies is influenced by environmental
factors. Describe the effect of the following on blowfly oviposition:
Environmental influences:
a. cold temperatures
b. very hot temperatures
c. very sunny locations
d. nighttime
e. wind
f. rain
Condition of the body
a. clothed or naked
b. wrapped in material impermeable to insects
c. encased in something that prevents odors from dispersing
d. exposed to drugs, toxins, or poisons
e. dehydrated body
f. moist body
Location of the body
a. above ground
b. buried
c. submerged
Other organisms
a. number of organisms already on the decomposing body
b. presence of insect predators
c. presence of scavengers
Decomposition and Insects
____ 13. Describe the distinguishing characteristics of each of the 5 stages of
decomposition of a corpse.
a. fresh
b. bloated
c. active decay
d. advanced decay
e. dry decay
____ 14. Put the following characteristics of decomposition in sequence from shortly
after death to advanced decay:
a. discoloration of skin
b. mostly bones
c. body is warm with no odors
d. abdomen swollen and distended
e. most of the flesh is gone
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_____ 15. Describe the relationship between the changing habitat of a decomposing body
and the arrival of different types of insects. Include in your answer insect
succession and the changing stages of a corpse.
Forensic Entomology
_____16. Forensic entomology plays a role in many aspects of solving a crime. Provide
an example of how insects can provide information regarding:
(a) estimating postmortem interval(PMI)
(b) identifying a geographical area where a crime was committed
(c) linking a suspect, car, or object to a crime scene
(d) determining if a body was moved after death
(e) locating areas of trauma on decomposing bodies
(f) providing evidence of drug, poison, or toxin exposure in the deceased
(g) providing evidence of neglect in children and older adults
(h) indicating the time of the year a person died
(i) providing a timeline for PMI based on the presence of different insects or
insect remains.
_____ 17. Discuss the limitations of estimating postmortem interval using forensic
entomology.
_____ 18. Describe different ways that insects are attracted to a decomposing body.
_____ 19. Compare and contrast the types of insects that would be attracted to a moist
body found in the early stages of decomposition to the types of insects that
would arrive as the body starts to dry out.
_____ 20. Discuss the succession of different insects as the
body undergoes decomposition.
_____ 21. Propose an explanation for why eggs or maggot masses found on a
decomposing body provide clues to injury sites. Support your claim citing
evidence from your text or other references.
_____22 .Explain why the following claim is invalid. "Insect evidence is of little forensic
value if you don't find living insects on the body." Support your argument with
evidence from the chapter.
_____23. Summarize how ADH (accumulated degree hours) are calculated at a constant
temperature.
_____24. Describe how ADH are calculated using the daily average temperatures.
_____25. Describe how forensic entomologists use ADH to estimate PMI.
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_____26. Describe the type of research that is being conducted at the Body Farm and its
significance in helping to solve crimes.
_____27.Describe how ADH (accumulated degree hours) are used to calculate the time
required for an insect to reach maturity.
_____28. Estimate a PMI based upon the presence or absence of one or several different
types of insects or insect remains.
Blowflies
_____29. Identify the developmental stages of a blowfly: egg; first, second, and third
instar; pupa; adult
_____30. Distinguish among the first, second and third instar stages of blowfly larva
based on spiracles, size, and presence or absence of a visible crop.
_____31. Compare and contrast an immature adult blowfly that has just emerged from its
pupa with an adult blowfly.
_____32. Describe the forensic significance of finding the following insect evidence at a
crime scene.
a. eggs
b. larvae
c. pupal cases
d. pupal cases (empty)
e. legs, wings
f. empty cuticles (exoskeletons)
_____ 33. Compare and contrast the diet of an adult blowfly and a larva. Include in your
answer any specialized body parts that assist in obtaining food.
_____ 34. Explain why the presence of spiracles on the posterior of a blowfly larva is
advantageous to the blowfly.
_____ 35. Explain why the presence of adult blowflies on a decomposing body are not
second generation blowflies, the offspring of the first generation of blowflies
who landed on the body soon after death.
_____ 36. Explain why blowflies are usually found on decomposing bodies, but
houseflies are more often found in neglect cases.
Beetles
______37. Identify and describe the developmental stages of beetles.
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_____38. Relate the arrival of beetles to the presence of blowflies. Why do beetles tend
to arrive after blowflies?
Other Insects
_____39. Describe other insects that could be found at a crime scene. Indicate if they are
early, middle, or late arrivers. Include in your answer both terrestrial and aquatic
insects.
Evidence Documentation and Collection
_____40. Describe the types of photos that should be taken at the crime scene.
_____41. Explain why the search for entomological evidence should extend several feet
beyond the body.
_____42. Explain why it is important to document environmental factors at the crime
scene including:
a. temperatures taken at chest level, at ground level, under the body and
inside the center of maggot masses
b. sun or shade
c. wind or no wind
d. humidity/rain
d. presence of other insects
f. body clothed, naked, buried, or submerged
_____ 43. What is the significance of recording the following:
a. location of crime scene
b. location on the body or at the crime scene where insects were found
c. number and exact location of any maggot masses
_____44. Explain the significance of searching for insect evidence:
a. on the body
b. under the body
c. several inches below the ground around the body
c. in wound on the body
d. inside pockets or cuffs
e. up to 8 feet away from the body
______45. Explain why some insects found at crime scene need to be immediately
preserved and others are collected as living specimens.
______46. Describe how to kill and preserve insects at the crime scene.
______47. Discuss the proper collection of insects at a crime scene. Include in your
answer:
a. Which should be collected first: adults or larva?
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b. What method is suggested for collecting adult insects that are either flying
above the body or that are on the body?
c. How many insects should be collected?
d. Why should insects be collected from the area after the body is removed?
_____ 48. Describe how to package live insects that will be sent to a forensic
entomologist. Include materials that should be included in addition to the
insects.
_____49. If larvae are collected from a crime scene and sent to a forensic entomologist,
the insects are usually raised to adults.
a. What is the advantage of examining adults rather than larva?
b. Once adult insects have developed, what does the forensic entomologist
do with the adults?
c. Why does the forensic entomologist rear them under conditions similar
the crime scene?
_____50. What is the significance of each item listed below that is included in
insect collection jars? This information is labeled both inside and outside of the
collection jar:
a. geographical region of origin
b. date
c. hour
d. case number
e. location insect was found on the body
f. name of the collector
Postmortem Interval (PMI)
______51. What is the forensic significance of estimating a postmortem interval?
______52. Explain why postmortem interval estimates should be based on multiple types
of evidence.
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