Lesson 1 Flashcards
Forensic Entomology
The study of insects and other arthropods that feed on decaying remains to aid legal investigations
X’tics of insects
Have a segmented body
Pair of antennae
Chitinous exoskeleton
Invertebrates
Most have wings
Some undergo homometabolous ( complete metamorphosis)
Jointed legs
Evidence may be in the form as
Nymphs
Adults
Pupae
Larvae
Eggs
Insect body parts
Fxn of exoskeleton
Defense mechanism
Outer layer called cuticle
Attachment of muscles
Protection against predators & dessication
Insect skin
Sclerites ( hardened plates put together through seams and sutures)
Why don’t insects go extinct ??
Camouflage
Ability to thrive in harsh conditions
Lay more eggs
Ability to lay in small crevices
Short life cycle
Application of insects
Inhabit in human remains
Damage to structures
Infestation of foodstuffs
Families in Order Diptera
Calliphoridae
Muscidae
Piophilidae
Sarcophagidae
Family Calliphoridae
- Large population of medium sized flies
- Attracted to carrion and excrement
- Some are attracted to open wounds
- Provide info for the accurate estimation of PMI
Egs. green and blue bottle fly, calliphora, chrysoma, clusterfly
Family Sarcophagidae
- Flesh eating insects
- Feed on exposed meat & carrion
- Parasitic on other insects e.g. bees, wasps
- Cause myiasis and may be involved in the transmission of diseases
- Can be found in both the early & late stages on decomposition in carcasses
Egs. sarcophaga, s. carnaria
Family Muscidae
- First attracted to excrement and carrion after blowflies
- Present only in the presence of excrement and gut contents exposed
Egs. houseflies, Musca,muscina, stablefly
Family Piophilidae
- Scavengers
- Feed on dry high protein foods
- Found in carrion, waste, fur
Families in order Coleoptera
Silphidae: carrion beetle
Dermestidae: skin, leather, hide, carpet, larder beetles
Staphylinidae: rove beetles
Histeridae: clown beetles
Cleridae: checkered beetles
What attracts insects to decomposing bodies
Apeneumones
Autolysis
The digestion of cells by enzymes
Apeneumones produced to attract insects
Methane, ammonia, sulphur dioxide, hydrogen, copper, carbon dioxide, H2S
Medio legal forensic entomology
Focuses on violent crimes
Traffic accidents with no immediately obvious cause
Determination of PMI
Case involving sudden death
Possible criminal misuse of insects eg. bees used to kill
PMI
Time between time of death and body discovery
Uses of PMI
Movement of the corpse
Manner and cause of death
Association of suspects with the death scene (sickle story)
Detection of toxin, drugs/ even the DNA of the victim through analysis of insect larvae
Homometabolous
Undergo all stages of insects
Hemimetabolous
Doesn’t involve a pupal stage
But involves nymphs
Fxns of F.E
Identifies immature insects
Calculates the growth & passage through stages of life cycle
Determine the size and development of insects
Compares the growth against weather conditions to estimate the time of oviposition
Collects & preserve insects as evidence
Testifies in court to explain insect-related evidence found at crime scenes
Determine an estimation for PMI using factors like insect evidence, weather conditions , location & conditions of the body
Uses of insects in forensic science
