Environmental effects on forensic entomology: Difference between revisions

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Forensic entomology#Factors

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-Forensic entomology, more specifically its medicocriminal branch, has evolved since the first days of its implementation. Yet, the field is still growing and daily, new information and techniques are being attempted to help entomologists more accurately report vital information such as post mortem intervals. There is a standard accepted theory that outlines eight distinct faunal successions, which will be eluded to later in the article. However, what happens when during decomposition the maggot mass found on the body differs from what should be expected?  It is the forensic entomologist’s job to determine the level of difference from the norm and to scientifically account for the deviation.
-==Climate==
-===Moisture levels===
-Rain and [[humidity]] levels in the area where the body is found can affect the time for insect development. In most species, large amounts of rain will indirectly cause slower development due to drop in temperature. Light rain or a very humid environment, by acting as an insulator, will permit a greater core temperature within the maggot mass, resulting in faster development.<ref>[http://www.clt.uwa.edu.au/__data/page/112507/fse07_forensic_entomology.pdf "Forensic entomology: use of insects to help solve crimes"]. Uwa.edu.au. [[20 March]] [[2008]].</ref>
-===Sun exposure===
-"Because insects are cold-blooded animals, their rate of development is more or less dependent on ambient temperature." <ref>Catts, E. P. and N. H. Haskell, eds. ''Entomology & Death: A Procedural Guide''. Joyce's Print Shop, Inc. 1990. p5.</ref>
-Bodies exposed to large amounts of sunlight will heat up, giving the insects a warmer area to develop, reducing their development time.
-In one experiment conducted by Bernard Greenberg and John Charles Kunich with the use of rabbit carcasses to study accumulation of degree days found that with temperature ranging in the mid 70s to high 80s the amount of deveopmental time for maggots was signifigantly reduced. <ref>Greenberg, Bernard, and John C. Kunich. Entomology and the Law. United Kingdom: Cambridge University Press, 2002.</ref>
-In contrast, bodies found in shaded areas will be cooler, and insects will require longer growth periods. In addition, if temperatures reach extreme levels of cold insects instinctively know to prolong their development time in order to hatch into a more accepting, viable climate in order to increase the chance of survival and reproduction.
-===Climate measurement===
-Important concepts in forensic science are '''threshold temperature''' and '''[[degree day]]s'''.
-*For each type of insect, development will not occur unless the surrounding temperature is above the minimum threshold for that insect.
-*A given amount of thermal energy is needed to develop from one stage of an insect life cycle, such as egg laying or egg hatching, to the next. This is measured as degree days. The degree days in a specific location over a specific period is calculated as the mean of the minimum and maximum temperature, minus the threshold temperature, mulitplied by the number of days.
-Observations of the life stage of the insects present, in combination with the calculated degree days, can be used to estimate the post mortem interval.
-==Geographic distribution==
-According to [[Jean Pierre Mégnin]]'s book ''La Faune des Cadavres'' there are eight distinct faunal successions attracted to a corpse. While most [[beetle]]s and [[fly|flies]] of forensic importance can be found worldwide, a portion of them are limited to a specific range of habitats. It is forensically important to know the geographical distribution of these insects is order to determine information such as post mortem interval or whether a body has been moved from its original place of death.
-[[Calliphoridae]] is arguably the most important family concerning forensic entomology given that they are the first to arrive on the corpse. The family’s habitat ranges into the southern portion of the [[United States]]. However, while ''Chrysonoma rufifaces'', the hairy maggot [[blow fly]], is part of the Calliphoridae family and is widespread, it is not prevalent in the Southern [[California]], [[Arizona]], [[New Mexico]], [[Louisiana]], [[Florida]], or [[Illinois]] regions.<ref>Whitworth, Terry. "Keys to Genera and Species of Blow Flies of America North of Mexico." ''Proceedings of the Entomological Society of Washington'' 108.3 (2006): 710. </ref>
-[[Flesh fly|Flesh flies]] fall under the family Sacrophagidae and generally arrive to a corpse following Calliphoridae. However, as previously mention the are capable of flying in the rain. This key advantage enables them to occasionally reach a body before Calliphoridae overall effecting the maggot mass that will be discovered. Flesh flies are globally distributed including habitats in the United States, Europe, Asia, and the Middle East. <ref>Pape, Thomas. ''Catalog of the Sarcophagidae of the World''. Memoirs on Entomology. Gainesville, FL: Associated, 1996. 288-289.</ref>
-Beetles are representative of the order [[Coleoptera]] which accounts for the largest of the insect orders. Beetles are very adaptive and can be found in almost all environments with the exception of [[Antarctica]] and high mountainous regions. The most diverse beetle fauna can be found in the tropics. In addition, beetles are less submissive to temperatures. Thus, if a carcass has been found in cold temperatures, the beetle will be prevalent over Calliphoridae.
-<!-- This section commented out because it has nothing to do with the title of the article. It belongs elsewhere, possibly in [[pest control]].
-==Utilizing environment factors for pest control==
-[[Pest control]] experts and agencies put environmental information to practical use everyday so as to predict insect behavior and location. Pest control is a multi-million dollar operation enforced worldwide.
-===Weather factors===
-Various weather conditions in a given amount of time cause certain pests to invade human households. This is because the insects are in search of food, water, and shelter.
-Damp weather causes reproduction and growth enhancement in many insect types, especially when coupled with warm temperatures. Most pests concerned at this time are [[ant]]s, [[spider]]s, [[cricket (insect)|]]s, [[cockroach]]es, [[ladybug]]s, [[yellowjacket]]s, [[hornet]]s, [[mouse|mice]], and [[rat]]s.
-When conditions are dry, the deprivation of moisture outside drives many pests inside searching for water. While the rainy weather increases the numbers of insects, this dry weather causes pest invasions to increase. The pests most commonly known during dry conditions are [[scorpion]]s, ants, [[pillbug]]s, [[millipede]]s, crickets, and spiders. Extreme drought does kill many populations of insects, but also drives surviving insects to invade more often.
-Cold temperatures outside will cause invasions beginning in the late summer months and early fall. [[Box elder bug]]s, [[cluster fly|cluster flies]], ladybugs, and [[silverfish]] are noticed some of the most common insects to seek the warm indoors.<ref name="terminix">[http://terminix.com/information/weather/ "Pest Control Tips: Pests and Weather"]. ''Terminix.com''. [[19 March]] [[2008]].</ref>
-===Precautions===
-There are a few measures homeowners can implement in preventing serious pest breakouts. Sealing any cracks/holes outside the home is extremely helpful, especially on the south and west areas of the home because the sun will heat those walls, creating a comfortable habitat for pests.
-Utilizing information about insect behavior due to outside influences enables humans to take the necessary steps for pest control.<<ref name="terminix"/>
-===IPM===
-IPM, short for [[Integrated Pest Management]], is a program designed to undertake pest problems, using a strong background of information about each pest in order to choose the best course of action. The overall goal of IPM is to reduce harmful effects from insects on crops, houses, and livestock while avoiding any unnecessary harm on the surrounding environment. The program utilizes and enhances any natural pest control methods, using pesticides as a last resort if possible. A general technique is outlined with regard to formulating an active plan and evaluating the best policy.
-End of commented out section -->
-==References==
-{{reflist}}
-==External links==
-*[http://www.clt.uwa.edu.au/__data/page/112507/fse07_forensic_entomology.pdf Forensic entomology - use of insects to help solve crime]
-*[http://www.blackwell-synergy.com/doi/abs/10.1111/j.1556-4029.2006.00217.x A Forensic Entomology Case from the Amazon Rain Forest of Brazil]
-*[http://www.ipm.ucdavis.edu/WEATHER/ddretrieve.html Run models and calculate degree-days]
-*[http://www.oardc.ohio-state.edu/gdd/glossary.htm Growing Degree Days]
-*[http://www.grounds-mag.com ''Grounds Maintenance'' magazine]
-[[Category:Entomology]]