Forensic entomology

insect evidence should be collected

at the scene by a forensic entomologist or trained investigator

this stage occurs because of the activity bacteria which produces gases inside the body

bloated stage

according to forensic entomologists, which "witness" is the first to arrive at the crime scene

blow fly

prior to 72 hours after death, livor mortis, rigor mortis, and algor mortis are used instead of ________ evidence.

entomological

how should insect evidence be collected?

insect evidence should be collected by an entomologist. insect preservation at the crime scene stops the clock on the insects. different stage of larval growth should be collected and bagged separately. sample of soil should also be collected from just outside the area marked by body fluids.

are insects cold-blooded or warm blooded? how does this impact their rate of development?

insects are cold- blooded. as temperature increase, they develop more rapidly, as temperature decrease , they develop more slowly.

how can insects be used to determine if a body has been moved to another location since death?

insects present on the deceased body that are not prevalent to the crime scene can indicate that the victim was murdered elsewhere and was dumped at another location

an important clue to the condition of a body at death is the location of the

larval mass

the major variable in the fly's life cycle is ____

temeperature

list five factors involved in decompostion

temperature, the availability of oxygen, prior embalming, cause of death, and access by insects.

how are insects used at a crime scene (5 ways)

-to determine whether the body has been moved after death -to determine whether it has been disturbed - to determine the presence or position of wound sites -to determine whether the victim used drugs or was poisoned. - to determine the length of time of neglect or abuse in living victims

prior to _____ hours after death, algor mortis, livor mortis, and rigor mortis are used instead of entomology evidence

72

are entomologist a basic service of a crime lab? if not, explain.

No, because most are primarily employed as a researcher or a teacher. They have little or no experience with crime scenes, legal report writing, or court testimonies, so one isn't needed full time.

_____ blowflies are of little forensic value, as it is unclear whether they have just arrived at the scene or have developed on the body

adult

estimations of the postmortem interval (pmi) using entomological evidence must take into account

all of these

during this stage house flies begin to appear and deposit eggs

decay stage

this stage begins with the splitting of the skin to allow the gases to escape

decay stage

during which stage does the body take on a compressed appearance and give off a powerful odor

decay stage.

degree days or degree hours are the number of days/hours multiplied by the number of ____ above a threshold temperature

degrees

during the ______ stage, blow fly larvae are delicate and prone to desiccation

first instar

describe each stage of the blow fly life cycle

first instar- larvae that rely on protein for their meals second instar- first instar larvae shed larval cuticle and mouth parts when entering second instar stage. third instar- second instar sheds its cuticle, now are called maggots. fter a period of intense feeding, the third instar enters a non-feeding or wander stage, looking for a suitable pupation site.

how are blow flies used to determine time elapsed since death (first method)

first method based on the predictable development of larval diptera. Used from the first time the first egg is laid on the remains until the first adult flied emerge from pupal cases and leave the body.

blow flies will be the mine insects used to determine time since death in the ______ after death

first weeks

______ is a broad term meaning the application of the study of insects to legal cases

forensic entomology

describe forensic entomology

forensic entomology is the study of insects associated with a dead body

decomposition of a mammal begins at this stage

fresh stage

Describe each stage of the decomposition process

fresh- begins at death, flies begin to arrive, temperature falls, autolysis occurrs bloat- swells due to gases produced by bacteria, temperature rise of the corpse, decay- gases subside, decomposition fluids seep from body, bacteria and maggots break through the skin., post-decay- carcass reduced to hair, skin, and bones dry- does not always occur especially if corpse is in a wet region. maggots will stay longer and hide, beetles will not appear

during this stage/ phase, the larvae stops feeding and travels several feet away from the corpse

migration phase

in most cases, forensic entomology will only determine a ______ time since death

minimum

what are the four factors that must be taken into account when determine time since death?

oldest stage of blow fly associated with the body, species of insects, temperature data, and developmental data.

the life cycle of a blow fly begins with

ovipositon

during this stage, beetles begin to colonize the body and consume the dry, less nutrient- rich components.

post-decay stage

the fact that insect development is ____ allows insects to be used to determine time since death.

predictable

insect _____at the crime scene stops the clock on the insects

preservation

the three levels of certainty are ______, _______, and __________

probability, consistency, and certainty

the living insect in the stage prior to metamorphosis in the blow fly life-cycle is called the

pupae

the nonliving part of the insect in the stage prior to metamorphosis in the blow fly life- cycle is called the

puparium

what is the second method of determining time elapsed since death?

second method is based on predictable, successional colonization of the body by a sequence of carrion insects.

the entomologist must be able to identify the ____ of blow fly because each ___ develops at a different rate

species

the four types of information one needs to known when using maggot evidence are

species of insect, oldest stage of blowfly, temperature data and development data

define putrefaction

the breakdown of tissues by bacteria

define autolysis

the breaking down of tissues by the body's own internal chemicals and enzymes

the stage of the fly cycle during which larvae are voracious feeders is called the _______ stage

third instar

pupae will be found in the same areas as ________ third-instar larvae

wandering

describe successional colonization

when the decomposing body attracts insects and they colonize and feed until there's no nutritional value left.