Lecture 1 Flashcards
What is the major problem for bugs?
there is a little food in the wild and there is either a famine or feast
For forensic use we can use insects to identify:
where and when events occur
what is the theoretical timeline of a carcass?
death -> stages of putrefaction -> stages of mummification
what is the theoretical timeline of a fly?
flies colonize -> growth of larvae -> pupae -> adults emerge
why is the timelines of both carcasses and flies very variable?
because some lay eggs early and some arrive a bit later, variability increases as the carcass ages
Why is growth of flies slow in low temps and fast in high temps?
because they are ectotherms
what are intrinsic factors?
- early
- optimal
- late colonizers
- distance to other nearest corpse
- number of colonizers available
- intraspecific competition from other colonizers
what are extrinsic factors?
- moisture
- sun vs. shade
- species that arrive
- distance to nearest corpse
- commonness or rarity of other corpses, predators, parasites and diseases
Where does variability mainly occur?
- size of corpse
- presence of drugs
- food
- health of individual
- amount of fat vs lean meat
- order of organs colonized
- order of utilization
- exposure of interior organs and body cavities
- access to carcass
What is the most common colonizer?
blow flies that deposit eggs
What happens if a burying beetle finds a fresh corpse?
they will ingest it before the flies arrive
what is the real name for burying beetles? what is the family?
sextant beetle, Silphidae
what happens if burying beetles carry mites?
the mites will eat the fly eggs and first instar larvae, also mites will eat the beetle eggs
what is the latin name for mites?
Machrocheles muscaedomesticae
What is a good example of variability, sunlight and shade?
WW1 trenches
In trenches what was on the sunny portions?
blue bottle flies (Calliphora vicina)
In the trenches what was on the shaded portion?
Green bottle flies (Lucillia)
What makes up an insect cuticle?
polysaccharide called chitin
how is chitin structured?
layers are stacked creating a strong structural membrane
T/F: chitin is flexible
True
what makes the exocuticle hard?
sclerotin
how can you count the age of a insect?
Like a tree count the layers of the cuticular bands
what is the entire external surface of an insect coated in?
wax (cuticular hydrocarbon)
where do insects breath through?
spiracles
where are the most muscles concentrated in insects?
wings
insects have a better ___ system than mammals
leveraging; they are attached to the outside structures that allow leveraging to be applied
what can insect muscle be dissolved in?
KOH at ~10% concentration
what does holometabolous mean?
eggs to larva to pupa to adult
where are eggs generally deposited?
in folds near cavities and openings
T/F: flesh flies lay eggs
False
how can you determine the three different instars?
they have three spiracles for third, two for second, and one for first
Are maggots always smooth?
no some can be hairy and covered in setae
how can you tell the age of a pupa?
darker it is the older it is
