Forensic Entomology Applications - Assignment Example

Running Header: Forensic Entomology Student’s Name: Instructor’s Name Course Name & Code: Date of Submission: Table of Contents Table of Contents 2 Introduction 3 Definition 3 Forensic Entomology Applications 3 Tools used in Forensic Entomology 4 Decomposition by Insects 5 Post-Mortem Interval 9 Conclusion 9 References 10 Forensic Entomology Introduction Definition Forensic entomology is the use and study of the insects and other arthropods that live in the corpse or remains that are decomposing to assist in the legal and crime investigations. Forensic entomology can also be defined as the science of using evidence from insects to help solving the crimes. It can as well be described as the use of entomology knowledge in investigating criminal activities. Forensic entomology is associated with death investigations. It is used to determine the number of days that have passed after somebody died or the minimum time since death. This is through identification of age of the insects found on the human corpse. The significant assumption is that the body has not been dead for a longer time than insects took to arrive and even develop (Answers.com, 2010). Forensic Entomology Applications Forensic entomology is also used to detect poisons and drugs. It is used in determining the exact location where incident took place. Forensic entomology is also used to detect or determine the duration of a period of neglect in the children or elderly as well as time and presence of wounds infliction. It is widely used in detecting abuse in children and in elderly. There have been cases that that some parents intentionally use wasps and bees to punish their children using insects to sting them (Greenberg, 2002). Entomological evidence has for a long time been used as a way to prove abandon or neglect as well as lack of proper care of wounds in elderly who are under institutional and private care. Forensic entomology is also used to examine insect remains lodged and impacted in windshield and radiators of automobiles. Such remains give evidence on the possible path and particular areas through which the automobile passed. Forensic entomology examines the insects that feed on living, dried or decomposing vegetable matters submitted to forensic entomologists in trying to establish the country of origin. This applies mostly on the plants like cannabis and other drug plants (Byrd, 2000). Tools used in Forensic Entomology There are various tools used in forensic entomology in collecting proper evidence. Good entomological evidence collection requires proper types of equipment. They are several forensic preconfigured kits that are available. Some of the essential tools used in entomology evidence collection include nets, vials, forceps, preservation chemicals, latex gloves, sticky traps, and collection containers among others. Nets are used to trap the insects to be used in forensic investigation. They can be aerial or sweep nets. The most used nets have 18” handle that is wooden and a sturdy 15-18” diameter steel ring that is galvanized. The net is constructed from polyester with muslin ring band. Collection vials are also referred as kill jars. Screw-cap types are the best and is used in most crime scene collections and is usually preferred and used by law enforcement officials. It is used to store or preserve specimens or insects collected for the investigation. Vials have preservation fluid used to preserve specimens collected. Vials are used together with preservation chemicals like Acetone and Ethyl Alcohol. Other important tools include forceps. Forceps are used to collect specimens mainly larvae for entomological purposes without damaging them. The most preferred types are Feather-touch and soft touch forceps; this is because they are made of thin and flexible metal which prevent the crushing of larvae bodies when too much force is applied. Collection container is equipment used to collect living larvae to be taken to forensic entomologist to be investigated. This container ensures they survive when being transported. Collection containers should have a lid that is tight fitting. Aluminum foil is used to construct a pouch for holding the live larvae as well as their sources of food during the time of shipment. Paper labels are other tools used in labeling container for both the preserved and live specimen. They may include heavy bond paper and non-adhesive paper. Paper labels that are adhesive are used to label exterior part of the containers for both live and preserved specimen. Number 2 graphite pencils are used for making labels. Ink should not be used because preservative fluids makes it smear hence not adhere to the paper. Small hand trowel or garden spade is used for sampling soil, and digging for migrating pupae or larvae in outdoor scenes of death. 35mm SLR camera, flash, and lens are used for scene macro-photography of insects. Paper towels are used for cleaning utensils and in kill jars. Disposable gloves are other essential materials used in forensic entomological investigation. They are put in hands to avoid contact of the specimen which may interfere with investigation. Sifting screens are used to process samples of soil for insects and insect artifacts. Another vital tool used is thermos of boiling water used for boiling larvae (Byrd, 2010). Decomposition by Insects Decomposition is the chemical breakdown of organic matter into its component due to the action by bacteria and other organisms. It is a biodegradation natural process of plant and animal materials. It involves separation of compound bodies into their component parts. Decomposition can also be defined as the process by which body tissues of a dead organism break down into matters that are in simpler forms. Decomposition process undergoes through various stages that includes starting immediately after death. It is a process that undergoes through various stages. Decomposition can be viewed in five stages that include fresh (autolysis), bloat (putrefaction), decay, dry and skeletal stages. In all decomposition stages, there are insect activities that take place on the body. The first stage is fresh, this stage occurs on the first few days after death. It occurs at approximately four minutes after death and goes up to at least three days where putrefaction starts. At this phase, there are no symptoms of decomposition that are physical or notable. Autolysis starts the decay as digestive enzymes start breaking down cell membranes in the body and digesting the internal organs. Body at this moment has extremely low or no odor with skins turning pale. There is loss of heat by the body which reaches up to ambient temperature. Muscles fibers in the body begin to stiffen and bind together a process known as rigor mortis. Insects will feed during rigor mortis between the muscles due to produced lactic acid released during muscle breakdown. The first observed necrophages on the body after death include Calliphorid flies. The first fly to colonize the body is female green bottle fly. Hairy Maggot Blowfly (Chrysomya rufifacies) is the second fly to colonize after green bottle fly. Piophilidae, Sarcophagidae, and Muscidae are other families of fly present at this stage. Predators of both adult and immature flies are common at the start of decomposition stages. Hairy Maggot Blowfly being second to colonize, predates on fly larvae in its both second and third larval stage. Early fly larvae are feed on by a predaceous beetle referred to as Saprinus pennsylvanicus. Parasitic fire ants, wasps, and other insects predate on fly larvae. Chalcidae (parasitic wasps) uses the pupae form flies to nest their eggs. The larvae of wasps feed on pupae or host maggots after hatching. After the wasp larvae kill the host, it uses the remains of the fly to pupate to mature wasps. Putrefaction or bloat is the second stage that takes place between 4 to 10 days following death. During this stage, microorganism and bacteria continue to anaerobically metabolize the tissues that are soft in the body. Tissue breakdown causes the release of gases into the body resulting to increased internal pressure and eventually a bloated corpse. Gases like hydrogen sulfide, methane, hydrogen and sulfur dioxide among others accumulate, and as the body continues to decay, and decay progressing, the corpse begins emitting smell. The smell attracts several species of beetles, flies and other arthropods. During this stage, habitation of maggot begins as more flies starts arriving and even oviposit in the orifices and other openings of the corpse. Furthermore, the blowflies that got into the corpse first at the initial decay stage have already produced larva which are in their first and second instars. Clown beetles of Histeridae family like Hister quadrinotatus are also attracted at bloat stage and are usually found under the decomposing body (Katherine, 2009). The other stage is black putrefaction which is also referred as active decay. It occurs 10-25 days after death and it is always characterized by black coloration of the corpse and strong odor from the corpse. The bloating starts to collapse as the skin starts to peel and even breaking from large fluids and gas amounts produced. This allows insects and other consumers get access to body cavity increasing the rate of soft tissue decay. The number of maggot starts to decrease at this stage. This is because most of them have already reached the third molt, and they start leaving the body so as to pupate in the soil. These maggots may live with larvae and also carrion beetles adults as well as skin beetles. The major part of the insect population at this black putrefaction stage is beetles. Parasitic wasps go on feeding on the maggots while mites fed on fluid let out in the body (Martin & Amoret, 2006). Fourth decomposition of decomposition is butyric fermentation. This fermentation process starts 20-25 days after death. At this stage, the fluids and flesh are drying up slowly. Insects and maggots that usually fed on soft flesh are now not capable to feed due to the drying up of the body. Insects and beetles with chewing mouth appendages are not capable of crushing or even crushing dead body tough segments. Most of the beetles at this time are at larval stage. Parasitic wasps and cheese skippers are also present. Other common insects at this stage are hide beetles from Trogidae family and Carcass Beetles from Derestidae family and they are the last beetles in this stage. Hide and carcass beetles are found in tough portions of the body and they are not predacious. They are the only beetles with enzymes capable of breaking proteins like keratin. Cheese fly from Piophilidae family is usually attracted by butyric acid at this stage. The skeletal or dry decay stage is the last stage, and starts between 25 to 50 days after death and can last for even one year. Bones, dry skin and hair are some of the remains at this stage. Tineid moths are found at this stage feeding on the remaining hair. Silphidae from carrion beetles family are present at this stage. They arrive early in the decomposition stage and stay up to dry decay stage feeding on other insect’s larvae. Nitidulidae family beetles are also seen inhabiting the body. Other insects associated with this stage are Acarina, Cleridae, Sphaeroceridae, Trogidae and Tyroglyphid mites among others. The soil-inhabiting arthropods include Coleoptera, Dermaptera, Heteroptera and their larvae among others. It is vital to take samples of soil under the body and the surrounding area. Most of the insects at this time are insects that dwell on the soil (Catts & Neal, 2005). Post-Mortem Interval Post-Mortem Interval Calculations is important to determine the time of death. It is vital to know the time insect takes to arrive at the corpse. Post time interval is the time that elapsed since the death occurred. The postmortem interval is based on the age of the insect found in the area of incident. The types of insects and larval weight as well as larval length are extremely crucial in determining the postmortem interval. The postmortem interval is determined by identifying the insect age present on human corpse. It uses the assumption that since the body died, it did not take any time for insects to arrive and develop in the corpse. The age of the oldest insect found in the body determines the minimum postmortem interval. This is because every stage of decomposition is associated with different type of insects and larvae. These are taken to the laboratory and hence used in estimating the exact time of the corpse. In most cases, the age of the oldest blow fly gives the accurate postmortem interval or time. Flies are first to get into the body when it is still fresh. Beetles are found when the body has decomposed. Mites like Marcrocheles are found during the early decomposition stages. Moths are usually the final animals that contribute to the corpse decomposition (Aggarwal, 2005; Anderson, 2001). Conclusion Forensic entomology has been of great importance in evaluating and curbing crimes for a very long time. Forensic entomology has gained a strong legality in current years as it introduces crucial evidence in the investigation field for a long time. Proper collection and preservation of insects associated with scenes of death have provided accurate time of death and vital information regarding the death. Study of different insect’s behavior has contributed greatly in this field (Stevens & Wells, 2008). Forensic entomology has been used for along time in detecting death scenes and other criminal activities. Scientists have has become a fascinating field in biological studies. The entomological research has contributed greatly to legal investigations for almost 700 years. Insect’s development and habitual habits have been of great importance towards determining the time at which the death occurred. There are several applications of forensic development towards investigation of various criminal activities. References Aggarwal, D. (2005). Estimating the postmortem interval with entomological evidence. Journal of Forensic Medicine and Toxicology, 6(2), 12-45. Anderson, G. (2001). Insect Succession on Carrion and its Relationship to determining Time of Death. Florida: CRC Press. Answers.com. (2010, January). Forensic Entomology. Retrieved April 29, 2010, from http://www.answers.com/topic/forensic-entomology Byrd, H. (2000). Forensic Entomology: the utility of Arthropods in legal Investigations. Boca Raton, FL.: Forensic Entomology Associates. Byrd, J. (2010, January). Entomological Collection Equipment. Retrieved February 29, 2010, from http://www.forensicentomology.com/equipment.htm Catts, E. and Neal, H. (2005). Entomology and Death. South Carolina: Joyce’s Print Shop. Greenberg, B. (2002). Entomology and the law: Flies as Forensic indicators. Cambridge, UK: Cambridge University Press. Katherine, S. (2009, September). The Role of Entomology in Forensic Investigations. Retrieved April 29, 2010, from http://www.crimeandclues.com/index.php/death- investigation/67-entomology/95-the- role-of-entomology-in-forensic-investigations Martin, H. and Amoret, B. (2006). Forensic entomology. Journal on Entomology Forensic science. 12(2), 49-53. Stevens, J. and Wells, D. (2008). Forensic Entomology. Annual Review of Entomology, 53(3), 103-120. Read More