tence your required reading to answer the questions Questions do you rear half o
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tence your required reading to answer the questions Questions do you rear half of your collected specimens to adulthood implications for your killed larval maggots if your reared adu species? How would this impact your work? lts returned a mix of 2. F or larval identification, which morphological features seem to be the most important, and why do you think this is so? 3. In your weather table, there was a column about the weather condition for each day, how might these conditions affect your PMI determination, if at all (cloudy, thunderstorms, fog and rain)? Appendix I Table 1: Weather information for region fies were collected in for the two weeks prior to body discovery Date 8/22/15 8/21/15 8/20/15 max (C") min (C") Condition 12 10 12 clear 27clear 27 24 cloudy 8/19/15 27 18-storms 28 31 8/16/15 31 19 18 19 16 17 t-storms t-storms t-storms t-storms 8/18/15 8/15/15 8/14/15 8/13/15 8/12/15 2813 cloudy 29 30 29 clear clear 29 8/10/1529 25 16 18 20 rain rain 8/9/15Explanation / Answer
Ans 1
To estimate the time of death insects play major role. There are various types of species of insect feed on the decomposing remain, to prey on other insects present, or to find a suitable place to lay their eggs. Forensic entomologists study the insects, eggs and larvae present at a death scene, utilizing the type of bugs found and their stage of development and time at which they arrived, which can predict when the victim died.
When the adult fly arrives at the scene of a death, it lay eggs, around the nostrils, mouth and ears, as well as any open wounds. These eggs hatch within 24 hours to release a larva or maggot. Larvae undergo three stages of development which are known as instar, As the larvae feed on the cadaver they grow rapidly, and reaches the third and final instar, when the larvae migrates away from the remains to find a safe location to pupate. At this stage the maggot’s skin contracts and form a hardened capsule known as the puparium, which is designed to protect the insect through metamorphosis until it becomes an adult. Pupal cases are not of the great use to the forensic entomologist, the presence of empty cases to complete cycle of development. So, the adult fly is beneficial in determining the species present.
Ans 2.
Chrysomya species are mainly present in the dead body and morphology and stages of the larvae is helpful in the collection for evidence and to estimate the postmortem index (PMI).Identification of correct species is the first step of investigation because different species differs in their growth rates and maturation. To estimate the PMI, age of larvae has to be determined.
When the eggs hatch they produce a larva called maggot. They are peg shaped small organisms with a pair of hook on the anterior end of mouth. Maggots grow into the three stages of instars .In the first instar larvae of Ch. Species following morphological features are studied pseudo cephalon, antennal complex, maxillary palpus, facial mask, thoracic and abdominal spinulation, spiracular field, posterior spiracles and cephaloskeleton.
Ans 3.
Development rate of the larvae is dependent on the surrounding ambient temperatures. Each stage of larvae development has its own temperature requirement which defines by the number of accumulated days or accumulated hours to complete its development. With the help of thermal history of the larvae temperature can be compared at the death scene and PMI can be estimated.
Models of the relationship between PAI and temperature are dependent on the habitats, seasons, and biogeographic areas. With the help of this it can be suggested that PAI can be estimated using case-specific temperature data and a species and stage-specific model. Temperature and air humidity is a determining factor, for models of PMI to be worked.
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