FRSC 3330

Question 1

Steven Truscott Case

Answer 1

Steven Murray Truscott (born Jan. 18, 1945 in Vancouver, British Columbia, Canada)

1959, at age 14 found guilty of murder of 12 year old Lynne Harper

sentenced to death by hanging

2007, conviction declared a miscarriage of justice, and he was acquitted

Entomological evidence
samples sent to the Attorney General’s laboratory, came into the hands of Mr. Elgin

Brown, reared maggots identified to family, and specimens from the other sample to genus

• 50 years later, this information was used by entomology experts to determine time of
  death

Question 2

Easiest method for collecting sylphid beetles

Answer 2

easiest method is to look under dead animals larvae and adults

Question 3

Preservation of sylphid beetles

Answer 3

standard entomological techniques used
kill adults with ethyl acetate in killing jar (this is just cheap nail polish remover)
DO NOT PUT ETHYLE ACETATE IN PLASTIC BOTTLES IT DISSOLVES SOME PLASTICS!
leave insects in killing jar for 2 hours, then pin within 24 hours before they become brittle

Question 4

What are larvae preserved in

Answer 4

Larvae: preserved in ethanol

Question 5

Instrinsic factors

Answer 5

• timing of colonizing
• distance
• number of colonizers
• competition

Question 6

Extrinsic Factors

Answer 6

moisture, sun vs shade, species that arrive, distance to nearest corpse,
commonness or rarity of other corpses, predators, parasites, disease
- the carcass: size of corpse, presence of drugs, food, health of individual,
amount of fat vs lean meat (and location of that fat), order of organs colonized,
order of utilization, exposure of interior organs and body cavity, access to
carcass eg partially submerged?

Question 7

where are eggs generally deposited

Answer 7

deposited at various locations, generally in folds, near cavities and openings

Question 8

How many instars do maggots have

Answer 8

3

Question 9

how many instars do beetles have

Answer 9

3

Question 10

What type of insects are gnerally associated with mummified remains

Answer 10

Carpet beetles
Centipedes
Spiders

Question 11

Describe necrophagous insects

Answer 11

Insects that feed on decaying carrion

Siliphadae -> carrion beetles, maggots –> phormia

Question 12

Describe predators

Answer 12

Prey on carrion and insect species

Siliphadae -> carrion beetles, cockroaches->blataria

Question 13

Describe omnivorous insects

Answer 13

Prey on foliage and carrion

Mites and pill bugs

Question 14

Describe accidental species

Answer 14

There by chance

Arachnidae -> spiders
Bedbugs
Earwigs

Question 15

Purposes for collecting insects

Answer 15

taxonomic, ecological purposes, regionally and/or taxonomically specific

Question 16

What is included in a colletor label

Answer 16

include place of capture
able to be found on a small scale map
clear to anyone unfamiliar with region
latitude and longitude co-ordinates if in an isolated area

Question 17

What do ecological labels contain

Answer 17

includes habitat and life history information that the collector identifies as important:

Question 18

Where are large insects pinned

Answer 18

Through thorax

Question 19

Where are small insects pinned

Answer 19

glued to pin

Question 20

What are maggots identified by

Answer 20

identified by mouthparts and spiracle
patterns (breathing tubes)

Question 21

What is the correlation between temperature and develpment

Answer 21

development assumed to be linear with respect to temperature across a range of
temperatures typical of the habitat

Question 22

Sampling maggots at corpses

Answer 22

maggots must be killed on site: boiled to kill rapidly and prevent shrinkage
transfer maggots to 70% or 80% ethanol (160 proof rum), or Pampel’s fluid

Question 23

Maggot rearing cups

Answer 23

aluminum foil and liver, with 1 inch (2-3- cm) vermiculite or sterile
sand for pupae to migrate into

Question 24

DR merritts evidence in the truscott case

Answer 24

one of Truscott’s experts:
- testified he did not see any maggots on the face that were larger than the eggs

• blow fly eggs are typically 1.4 to 1.5 mm. (i.e., about 1/16th inch)
• Drs. VanLaerhoven and Merritt testified (and Dr. Anderson agreed)
  if a blow fly colonized genital area,
• a mass of maggots in vaginal region, as was found on hair, face and abdomen
• conclude that the larger maggots of the genital area were flesh flies
• Dr. Haskell testified the maggots observed by Dr. Penistan in vaginal area were blow flies
• based on Drs. Penistan and Brooks comment that there was a “tremendous population”
  of maggots.
• which type of maggots were they?
• if flesh flies, then early morning colonization and Truscott innocent
• if blow flies, then late afternoon colonization and Truscott guilty

Question 25

experiments of sun vs shade total AHD during 10 day experimental period

Answer 25

shaded = 4891 or 489.1/day or 20.4 DD0 sunlit = 5155 or 515.5/day or 21.5 DD0 - no difference in maggot mass temps between sites! - yet more rapid decay in sunlit than shaded site, almost twice as fast - P regina arrived after 84 hours at both sites - 3rd instars at 48 hrs[sun], 60 hrs [shade] - Phaenecia coeruleiviridis arrived 84 hours both sites, 3rd instars 48 hrs[sun], 60 hrs [shade] - sun: P c. 3rd instars most common up to 132 hrs, - P. r. after 132 hours shaded, similar pattern but less obvious -P. regina is considered a cool weather and cool climate species, but is prevalent in mean daily temps of 24 C

Question 26

insect searching behaviour

Answer 26

odour hits fly - response fly upwind fly tracks across wind until gets new odour packet - then goes upwind continues upwind until it sees corpse flies in by sight

Question 27

trap heights: choice vs no-choice tests

Answer 27

choice, random height traps 2 metres apart - flies choose optimal height no choice, random height traps > 100 metres apart - are flies willing to go outside of their optimum height?

Question 28

Corpses in water

Answer 28

- body heat is lost 2 times as fast as on land and decay is delayed - the head sinks below the surface of the water, and decomposition begins at the head - greenish colour on flanks can occur at 5 - 6 days, peels off after 10-12 days - skin on hands and feet become wrinkled after 10 to 12 hours - gases cause the body to float after 6-10 days - hair loose at 3-4 weeks, finger and toe nails are detachable - flesh becomes slime and skeleton collapses - under summer temperatures the process is quicker

Question 29

Fate of ecoparasites

Answer 29

fleas drowned after 24 hours - after 12 hours, fleas can revive in 1 hour, after 18 –20 hours require 4 - 5 hours to revive - body lice die after 12 hours in water - **blow fly larvae on corpses drown in water, if still alive, indicate recent submersion, perhaps moved from another site - chemicals, sewage etc, affect rate of corpse decay - blowflies can survive on partially submerged corpses, colonize less than ideal areas (ie exposed limbs)

Question 30

mummification

Answer 30

high temperatures and dry conditions can produce mummification, putrefaction prevented: - can occur in hidden bodies, in chimneys, cupboards, under floorboards, etc - newborn infants are born sterile and more easily mummified - liable to invasion by stored product insects ie dermestid beetles (carpet beetles), clothes moths, mites

Question 31

Mites

Answer 31

house mites, chiggers, dust mites, Types of mites by body shape no antennae, 1-4 pair legs 55,000 described species, >1,000,000 spp. two body parts: front called capitulum (little head) or gnathosoma (jaw body) rest of body called idiosoma, has no primary segmentation capitulum has chelicerae and palps larval mites have 6 legs; nymphs and adults 8 legs(usually).

Question 32

Two nymph stages

Answer 32

protonymph and deutonymph

Question 33

Cuticular hydrocarbons

Answer 33

still in early stage of investigation - free lipids on outside of insect - protective coating, includes hydrocarbons (most abundant), alcohols, fatty acids, waxes - stops drying out, and prevents bacterial infection - in all life stages - biologically stable, although they do change with time, (weathering), possibly reproductive status, age, nutrition level - potential use for aging pupae, larvae, or inexpensive method for identifying to species different chain lengths, saturated (paraffin's) vs. unsaturated (olefins, double bonds between carbons) analyzed using mass spectrometry e.g.:

Question 34

Drift

Answer 34

different species drift and colonize downstream at different rates, so proportional abundance of species on a carcass may provide useful information on PMI scrapers arrive early on submerged pigs, mayflies arrived later by drift

Question 35

Ecology of poisons in plants

Answer 35

The various ingredients made by plants that make them useful as therapeutic drugs, or desirable as relaxants or stimulants, are produced by the plants to act as insecticides.

Question 36

General model of populations of blowflies

Answer 36

Blow fly species in an urban area is some combination of rural (H) and urban (U) blow flies - e.g. species endemic to the surrounding plus urban species Dubran=a*H +b*U Hypothesis 1: blow flies in urban areas are rural flies that came to urban areas Durban=a*H b=0 Hypothesis 2: blow flies in urban areas are urban flies Durban = b*U a=0