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Study Notes 3rd Year > FRSC 3330 > Flashcards

FRSC 3330 Flashcards

1
Q

Steven Truscott Case

A

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
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2
Q

Easiest method for collecting sylphid beetles

A

easiest method is to look under dead animals larvae and adults

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3
Q

Preservation of sylphid beetles

A

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

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4
Q

What are larvae preserved in

A

Larvae: preserved in ethanol

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5
Q

Instrinsic factors

A
  • timing of colonizing
  • distance
  • number of colonizers
  • competition
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6
Q

Extrinsic Factors

A

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?

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7
Q

where are eggs generally deposited

A

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

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8
Q

How many instars do maggots have

A

3

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9
Q

how many instars do beetles have

A

3

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10
Q

What type of insects are gnerally associated with mummified remains

A

Carpet beetles
Centipedes
Spiders

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11
Q

Describe necrophagous insects

A

Insects that feed on decaying carrion

Siliphadae -> carrion beetles, maggots –> phormia

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12
Q

Describe predators

A

Prey on carrion and insect species

Siliphadae -> carrion beetles, cockroaches->blataria

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13
Q

Describe omnivorous insects

A

Prey on foliage and carrion

Mites and pill bugs

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14
Q

Describe accidental species

A

There by chance

Arachnidae -> spiders
Bedbugs
Earwigs

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15
Q

Purposes for collecting insects

A

taxonomic, ecological purposes, regionally and/or taxonomically specific

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16
Q

What is included in a colletor label

A

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

17
Q

What do ecological labels contain

A

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

18
Q

Where are large insects pinned

A

Through thorax

19
Q

Where are small insects pinned

A

glued to pin

20
Q

What are maggots identified by

A

identified by mouthparts and spiracle
patterns (breathing tubes)

21
Q

What is the correlation between temperature and develpment

A

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

22
Q

Sampling maggots at corpses

A

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

23
Q

Maggot rearing cups

A

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

24
Q

DR merritts evidence in the truscott case

A

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
25
Q

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

A

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

26
Q

insect searching behaviour

A

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

27
Q

trap heights: choice vs no-choice tests

A

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?

28
Q

Corpses in water

A
  • 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
29
Q

Fate of ecoparasites

A

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)
30
Q

mummification

A

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
31
Q

Mites

A

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).

32
Q

Two nymph stages

A

protonymph and
deutonymph

33
Q

Cuticular hydrocarbons

A

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.:

34
Q

Drift

A

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

35
Q

Ecology of poisons in plants

A

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.

36
Q

General model of populations of blowflies

A

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=aH +bU

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

Study Notes 3rd Year (11 decks)

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