Intact, well preserved specimen used as reference
voucher specimen
How terminology affects interpretation?
it can be affected due to how people might use PMI, TOC, PCI
Important sections that should always be included in case reports
ferences-Title
- analyst contact info
- Contact of investigator
-Instructions received
- Case information
- Summary of insect evidence (sorting treatment, labels, chain of custody, preservative, storage conditions, rearing conditions)
-Weather station/environmental conditions (supplemental file, distance between remains and weather station)
-identification of species
-TOC
-case summary
- Declaration
-signature, accreditation
Steps to find ADD
-Find average temp (max+min/2)
-Find DD (mean temp-min threshhold)
-Add up all the DD values
Steps to calculate TOC
-Find ADD for climate
-look at temperature aver. and compare to developmental chart
- Find DH( hourly avg.temp-threshold temp x hours spent)
-Calculate DD ( DH/24)
-Add up all DD hours
and compare Climate data to development data
-Communication with non-scientists
-should be scientific but no contradictions
-fact based
-only speak on entomological evidence
Writing to the correct audience
- A written, voluntary declaration of fact or opinion
- statement entered into evidence
Affidavit
- a testimony out of the court but under oath in response to questions posed by attorneys for the opposing side
- done during the discovery process
- case report
Depositions
-convey facts to jury
- offer opinion (expert)
-represent science being discussed
-avoid bias
Courtroom testimony
-USA system allows for confrontation
-Opposing experts offer opinion
-rely on jury to draw conclusions
Opposing experts
who makes up the jury?
-peers
-12 individuals
- selected by attorneys
-Education and background
-people in similar life as person being convicted
Social stereotype about certain groups of people the individuals form outside their own conscious awareness
unconscious bias (explicit bias)
the tendency to search for, interpret, favor, and recall information in a way that confirms or strengthens one's prior personal beliefs or hypotheses
Confirmation bias
Think about the message extensively (details)
Central processing
Overview of message (short-cut) partially driven by emotion/attractiveness
peripheral processing
-testimony of experts
-if scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise
Rule 702
-general acceptance principle
-has to be accepted by the general scientific community
-broader, 1st standard to deal with legal admissibility in court
Frye standard
Trial judge is the "gatekeeper," but additional standards
-question validity of scientific evidence
Daubert standards
What 4 criteria for Daubert standard?
-Evaluation of known error rates, testable, published in peer peer-reviewed journal, and accepted by a specific scientific community
What is the solution to cases without evidence of maggot mass/maggot mass temperature not being recorded?
-Acknowledge it and present estimate as range, not discrete number
What is the solution when other temperatures affect insect development?
Morgue, air conditioning, etc. (if duration/temp. is known, account for it) if not, acknowledge it an present estimate as range
To avoid cherry-picking development data to fit a narrative, what should you do?
Use ADD, present estimate as range, and have a line of reasoning as to why you selected one data set over another
An organism suitable for studying a specific trit, disease, or phenomenon, due to its short generation time, characterized genome, or similarity to humans
Model organisms
What is the purpose of model organisms?
-Ease to rear/maintain
- Fast generation time
- Reproducibility
- Inexpensive (yeast)
- Ethical considerations lessened
What makes pigs good substitutes for humans in decomposition studies?
-similarity to human structure
- muscles
-internal organs
- genitourinary structures
-blood vessels
-Physcial characteristics
- Anatomy, eyes, skin with hair, chest cavity, body mass range, gut microbiota
What are the advantages of using pigs instead of humans?
-easy to replicate
- less sensationlized research and relatively straightforward ethical considerations
-difficult to replicate
-dissimilar to each other in mass, age, sex, ethnicity, body conditions
-limitations of taphonomy facilities like small area, uniform abiotic conditions, and non-natural conditions
-ethical concerns
-expensive, security, donations, replication difficult
-limited locations
Limitations of body farms
CO1 gene is a barcode that is from
mitochondrial DNA
What are the drawbacks to DNA analysis?
-DNA can be easily destroyed
-expensive
-barcode might not be in data
-can you afford to destroy the sample
-Temperature
-Humidity
-Ecoregions
-abiotic factors
Nurture
-genetic variation within a species
-genetic x environment
Nature
(DNA makes RNA which makes proteins)
- DNA transcription to RNA
- RNA translated to proteins
- DNA gets replicated
Central dogma
-Decomposition slowed overall
-head and legs sink, so torso can be open to colonization
- algor mortis twice as fast
- Cools 3-4 F per hour
- water conducts heat better than air
Effects of submersion on corpses (decomposition)
Submerged stages of decomposition
1. Submerged fresh
2. Early floating
3. Floating decay
4. Bloated deterioration
5. Floating remains
6. Sunken remains
How does the body's skin react when submerged in water?
- color loss
-hands, feet wrinkle after 10-12 hrs
- skin and hair fall off after several days
How does the body react when submerged in water?
- finger and toenails easily detachable
-livor mortis may not appear
- bloating usually takes 2x's as long
How does the body's skeleton react when submerged in water?
- flesh broken down by microbes into a slime
-skeletal collapse
PMSI (Postmortem Submersion Interval)
Makes use of organisms which attach themselves to substrate
-understand diff. between moving and still water organisms
-Algae
What insect families are associated with submerged remains?
- Coleoptera: Hydrophilidae (water scavenger beetles)
-Trichoptera (hairy wings) (Caddisflies)
- Diptera: Chironomidae (resemble mosquitos)
- Diptera: Simuliidae (Black flies) blood feeders
-Ephemeroptera: Heptageniidae (Naiads)
The burial effects of decomposition
-hinders the decay process due to oxygen reduction, soil compaction, and weather
- 1 wk above=8 wks below
-limited faunal succession (nature and depth dependent)
What insects are associated with buried remains?
-Muscina stabulans
- Synthesiomyia nudiseta
- Phoridae
- Rhizophagidae
- Staphylinidae
- beetles and ants
How does wrapping a body impact colonization?
-delay or exculde taxa depending on how tight wrapping is
- can affect decomposition rate
Crow-Glassman scale
CGS level 1:
CGS level 2:
CGS level 3:
CGS level 4:
CGS level 5:
-characteristics typical of smoke death
- recognizable, but varying degrees of charring
- major portions of arm and legs missing
-skull fragmented and absent from body
-cremated; little or no tissue present
What insect activity occurs in CGS Level 1 and 2?
-fauna generally the same
-level 2 of charred = earlier colonization
What insect activity occurs in CGS Level 3 and 4?
-changes in faunal attraction (more attracted)
What insect activity occurs in CGS Level 5?
-not much left to colonize
-dermestes ater
-no insect activity but has dermestids
Insect survival on burned victims
-bugs around body where it was dead and insects within 10 cm of body were dead but able to be identified
The study of measuring and analyzing potential toxins, intoxicating or banned substances, and prescription medications present in a person's body
Toxicology
A big quantity of something ca become fatal
"the dose makes the poison"
Why would we use insects in toxicology?
-serve as a reservoir of corpse material
- may be present after corpse tissue is removed
- leave lasting biological evidence
When storing insect evidence for toxicology analysis,
-must be stored dry and tested as soon as possible
How immunoassays work
What are impacts of toxins on insects?
-malformations
-development rates
- survival
-fertility
How does morphine affect insects?
delays pupation and development of insect development?
how does cocaine affect insect developement?
it accelerates development
how does acetominophen affect insect development?
increases maggot mass and cause them to seem up to 12 H older
1. Act/structure produced by a signaler
2. Has to evolve to convey information to the receiver
3. signal elicits response in receiver
4. Response results in fitness consequences for signaler and receiver
4 requirements of a signal
Anything used by one individual to be sent to another individual and is received
Signal
Convey information, but aren't evolved for that purpose
Cues
Signals that an emitter already does that the receiver then detects and evolves
- receiver evolves to be better to detect cue
Signaler precursor
Sensory bias from receiver that an emitter evolves to select
- a sender exploits a sensory bias that the receiver already has
- corpse flower attracts flies to polinate
Receiver precursor
Chemicals that encode information or mediate interactions. can be a signal or cue
Semiochemicals
-Communication between individuals of the same species
Intraspecific
-Communication between different species
interspecific
Only occur in intraspecific relationships
Pheromones
Occurs only in interspecific relationships
Allelochemicals
When temperatures are high, VOC is affected by
dispersing the smell
When temperatures are freezing/cold, VOC is affected by
smell is compressed
less colonization
When windy, VOC is affected by
preventing colonization
When raining, VOC is affected by
Having less flies colonizing
Role of microbes in VOC production
-movement from dying resource to live resource
- and limits competition by moving locations