Use of Blowflies in Forensic Entomology - Essay Example

? The use of blowflies in forensic entomology  The use of blowflies in forensic entomology  As the study of insects, entomology isalso applicable in determining various aspects related to forensic science. Different kinds of insects flock decomposing bodies, however, the primary kinds of bugs of insects found on corpses are beetles and flies. Specifically, blowflies flock to dead flesh within minutes. Fly larvae, which are referred to as maggots, do most of the eating and are largely responsible for most of the decay in a corpse. Determining the time of death of a corpse only considers the life cycle of an insect. The life cycle of insects encompasses four discrete stages (Amendt, Campobasso, Gaudry, Reiter, LeBlanc & Hall, 2007). Despite the effectiveness of forensic entomology in determining the time of death, only less than one percent of homicide cases are resolves using forensic entomology. However, forensic entomology can be utilized in a broad area of forensic science, for instance to ascertain whether the corpse was moved posthumously and the accurate time of death. This paper will assess the determination of time of death through the use of blowflies in forensic entomology. In blowflies, the initial life cycle stage encompasses eggs, which hatch into maggots or larvae in the second stage. At the larvae stage, the anterior end of blowflies has a pair of sharp digging hooks, which are used for both feeding and movement. The posterior end of larvae consists of the insect’s respiratory system that ensures that maggots receive sufficient oxygen as they rummage through the corpse (Goff, 2000). Typically, as soon as blowflies’ maggots attain their full size, they stop feeding and start moving into drier regions of the surrounding, often into the soil. During the third stage of development, blowfly maggots develop into pupae; during this stage, the outer skin of the insect hardens, forming a tough protective casing around the insect. In a week’s time, the pupa goes through metamorphosis, emerging from the shell in the form of an adult blowfly to mark the concluding stage of the insect’s life cycle (Amendt, Campobasso, Gaudry, Reiter, LeBlanc & Hall, 2007). Insects such as blowflies can serve as an easy tool of ascertaining the unknown, especially with regards to the time of death. For instance, when a coroner seeks to find out the time of death of a corpse, the entomologist only has to examine the blowflies around the corpse and report details. However, it is hardly this easy since investigators take into account a number of variables, including the temperature of the immediate region in order to ascertain the speed of larvae growth in a corpse. For instance, when someone is killed during summer and left outside for a number of days, the ambient temperature neighbouring the corpse changes dramatically. Different types of blowflies develop speedily in warm weather; however, the development rate diminishes when temperatures drop (Greenberg & Kunich, 2002). Blowflies discovered on a corpse that has been outside for several weeks or months are indicative of drastic variations in the growth cycles of the insects. Therefore, entomologists must carefully assess the available specimens in order to determine a probable range of times of death. The use of insects to solve crimes in forensic entomology dates back to the 13th century when investigators found the murderer of a rice field worker by examining the trend of blowflies, which flocked to the murderer’s sickle after being attracted by the smell of blood. Ultimately, the murderer confessed to the crime (Goff, 2000). Today, forensic entomologists use post-mortem interval or PMI in order to ascertain the total quantity of time that has lapsed since death. The development and age of the maggot, as well as the utilization of successive insect waves, provides a succinct determination of the duration of the interval between the time of death and the time the corpse was discovered. As soon as a person dies, the first creatures to visit the corpse are flesh flies and blowflies (Amendt, Campobasso, Gaudry, Reiter, LeBlanc & Hall, 2007). The odour of bodily gases and blood attracts these flies approximately 10 minutes after death, depositing their eggs in cavities such as the eyes, ears, nose, and mouth or in wounds around the body. As soon as the eggs hatch, they consume all soft bodily tissues before moving to the corpse’s body and nearby soil. Therefore, an examination of the life cycle of blowflies found in and around the body is bound to determine the precise duration the individual has been dead. After collecting maggots and pupae on and around the corpse, forensic entomologists immediately determine the species under examination in order to find the distinguishing features of different life cycle stages before calculating the PMI (Erzinclioglu, 2000). Alternatively, an examination of other insects that inhabit the body also helps determine the amount of time elapsed between time of death and discovery. Subsequent to the invasion of blowflies, other species of flies also move in to devour the decomposing tissue of the corpse. When a body is discovered, there are different insect species crawling on the body; however, blowflies are perhaps the most effective in terms of helping entomologists determine the time. On the other hand, when the cause of death is drug-related, mass spectrometry and gas chromatography can be done on the blowfly larvae so as to test for the existence of cocaine, methamphetamine, heroin, phencyclidine and amitriptyline (Greenberg & Kunich, 2002). The presence of these drugs helps determine the time of death since certain drugs are undetectable after certain duration of time. This means that if, for instance, cocaine is discovered in the larvae of blowflies found in and around a corpse, the entomologists can calculate the amount of time cocaine stays in the body of the fly, thus determining the time of death. Similar to all scientific fields, forensic entomology encompasses diverse advantages and demerits. Perhaps the greatest advantage of using blowflies to ascertain the time of death is that this approach is often more accurate than conventional methods such as assessing the stages of decomposition since the blowfly approach primarily centres on body heat. However, one of the primary disadvantages of utilizing blowflies to ascertain the time of death is that the rate of maggot growth is mostly impacted by shifts in humidity, temperature and geographic location. Temperature plays a critical role in ensuring the effectiveness of this method since it is impossible for blowflies to lay eggs in temperature below 40 degrees (Balme, Denning, Cammack & Watson, 2011). Therefore, blowflies can indicate the weather conditions under which the body has been exposed while outside. Therefore, forensic entomologists have to take all these factors into consideration so as to supply an accurate calculation of PMI (Erzinclioglu, 2000). The accuracy of such estimation can also be impacted by the existence of foreign elements on or in the decomposing copse, for instance, toxins and drugs, which can impact the rate at which feeing maggots grow and develop from one stage to another. Such information is critical in the estimation of the PMI. From various studies performed to date, it is evident that blowflies typically lay eggs in corpses between 20 and 30 days post-mortem, thereby dominating the corpse during the post decay stage of body decomposition. As a consequence of such domination, these flies are effective in determining the PMI, especially in the course of advanced stages of body decomposition. Corpses typically go through diverse biological and physical changes, which constitute decomposition stages that attract different insects. The determination of time of death centres on appreciating the duration it takes for a blowfly to move from one developmental stage to the other (Balme, Denning, Cammack & Watson, 2011). This helps identify the flies’ developmental stage when the body is discovered, thus ascertaining the time elapsed between the time of death and when the body was found. The development stage of the blowflies found on a corpse help with the determination of accumulated degree days that determine the physiological time elapsed. References Amendt, J., Campobasso, C., Gaudry, E., Reiter, C., LeBlanc, H., & Hall, M. (2007). Best practice in forensic entomology - standards and guidelines. International Journal of Legal Medicine, 121, 90-104. Balme, G. R., Denning, S. S., Cammack, J. A., & Watson, D. W. (2011). Blow flies (Diptera: Calliphoridae) survive burial: Evidence of ascending vertical dispersal. Forensic Science International, DOI:10.1016/j.forsciint.2011.07.017. Erzinclioglu, Z. (2000). Maggots, murder and men: memories and reflections of a forensic entomologist. Boston: Harley Books. Goff, M. L. (2000). A fly for the prosecution - how insect evidence helps solve crimes. New York: Harvard University Press. Greenberg, B., & Kunich, J. C. (2002). Entomology and the law - flies as forensic indicators. New York: Cambridge University Press. Read More