Forensic Entomology

Trent FRSC-3330

Where are eggs typically deposited

in folds, near cavities, or near openings

What are setae

bristles

what are spiracles

breathing tubes

What is TU

upper development threshold

what is Tmax

daily max temperature

what is Tmin

daily min temperature

what is TL

lower developmental threshold

What is a degree day?

a measure of heat accumulation used to estimate insect development rate

Formula for calculating degree days?

DD=(Tmax+Tmin)/2-Tbase

What are accumulated degree days (ADD)

the sum of daily degree days over time, used to predict insect stage or PMI

Life stages in complete metamorphosis

egg → larva → pupa → adult

life stages in incomplete metamorphosis

egg → nymph → adult

how many larval instars do blowflies have

3

what happens in the first instar

feeds lightly

what happens in the second instar

active feeding

what happens in the third instar

wandering/pre-pupal

what are the five stages of carcass decomp

fresh, bloated, active decay, advanced decay, dry remains

which insects arrive first

blowflies and flesh flies

during which stage are maggots most abundant

active decay

which insects dominate late stages

beetles and mites

example of terrestrial carrion insects

blowflies, flesh flies, beetles

example of aquatic carrion insects

Chironomidae, Notonectidae

what are necrophilous insects

feed on dead tissue

what are omnivorous insects

feed on both tissues and other insects

what are adventive species

accidentally present, not associated w decay

what samples are collected from a body

maggots, pupae, adults

what tools are used for collection

forceps, sweep nets, vials

how are adult flies identified

wing venation, bristle pattern, antennae shape

what structures identify larvae

posterior spiracles and peritreme shape

main body regions of an adult insect

head, thorax, abdomen

function of posterior spiracles

breathing

when do flies usually lay eggs on a body

within minutes-hours

examples of non-insect arthropods relevant to forensics

mites, spiders

when do mites appear in succession

late stages (dry remains)

why might spiders be found near remains

hunting for insects on corpse

Who was Steven Truscott

14 year old wrongfully convicted of murder in 1959

why was entomology evidence important in the Truscott case

TOD estimation based on maggot development key

what was the problems with the entomological analysis in the Truscott case

poor temperature data, lack of expert standards, incomplete methods

what did modern review of insect evidence in the Truscott case show

maggot data showed Truscott’s innocence