Entomology

Forensic Entomology

From Wikipedia, the free encyclopedia





Overview

Forensic entomology is the application of the science of insect biology, ecology, and behavior – entomology – to legal cases.

Forensic entomology technically consists of three fields: medico-legal, urban, and stored-products entomology.



Medico-legal entomology involves using insects to solve violent crimes and to investigate sudden, suspicious, and accidental deaths such as vehicle accidents. Of the three fields, medico-legal entomology receives the most attention by far in scientific articles and draws the most fascination among the general public, as well as the most coverage on television crime dramas such as CSI and Law & Order. In fact, many scientists use forensic entomology to refer to medico-legal entomology alone. History

The first historical use of entomology in investigation of crimes was in 13th century China. Song Ci, a Judicial Intendant, wrote a medical handbook entitled the Washing Away of Wrongs. Song first used forensic entomology to investigate a murder in a village. Men of the village were all called together, and ordered to bring their sickles. The murder victim had been slashed to death. Song Ci accurately predicted that the owner of the sickle with flies buzzing over it was the murderer, since flies are attracted to blood.



In the 17th century, Italian scientist Francesco Redi disproved the theory of spontaneous generation, which was the theory that uncovered or rotting meat simply produced maggots. In the late 19th century, forensic entomology was further propagated by Hermann Reinhard, who exhumed many bodies and demonstrated that the development of many different types of insect species could be tied to buried bodies.

Lastly, 19th century French army veterinarian Jean Pierre Mégnin published several volumes including the books Faune des Tombeaux and La Faune des Cadavres, which are considered to be among the most important forensic entomology books in history. These four giants in forensic entomology shaped much of the field’s foundations.

Recent Pioneers

Despite the progresses made by Song, Redi, Reinhard, and Mégnin, continuous and coherent development into forensic entomology had been non-existent until the mid-20th century. Modern day pioneers of forensic entomology were led by Professor **Bernard Greenberg** of the University of Chicago. Greenberg studied insects in graduate school in the late 1940s and in 1976 was asked to provide his expert opinion regarding insects in a murder case. The specifics of the case itself involved rotting corpses covered with maggots and were too decayed for traditional means of scientific confirmation in regards to time of death. Greenberg’s testimony and analysis helped to speedily deliver the two suspects to justice.



In Greenberg’s footsteps followed **Madison Lee Goff**, a former soldier who completed his PhD in entomology at the University of Hawaii in 1977. Goff became a forensic entomologist in 1983, head of the forensic science program at Chaminade University of Honolulu, Hawaii in 2001, and has participated in over 250 criminal investigations worldwide. Goff was a major advisor to the hit television series CSI: Crime Scene Investigation, which further helped propagate and popularize forensic entomology. Other pioneers include **Neal Haskell** who was the first to earn a PhD in //Forensic// Entomology in the United States, Gail Anderson who serves as the head of the Forensic Entomology Laboratory at Simon Fraser University, and Zakaria Erzinclioglu who assisted in solving over 200 crimes in England.

The above 20th century pioneers greatly shaped the public’s understanding and acceptance of the use of entomology as a reliable and sometimes critical path to investigating and solving crimes.

Uses

Insects actually make up around 85% of all animal species that are found in any particular vicinity. In warm weather they can consume 60% of a corpse in less than a week. Of the insects that are attracted to a corpse, all arrive in a predictable order known as faunal succession. This means that starting with flies, one group of insects arrives, settles in, and helps prepare the way for the next group of insects to follow. Forensic entomologists most often use **blowflies** (family Calliphoridae) to estimate a victim’s time of death. Flies have a holometabolous life cycle, meaning that the fly’s appearance in its larval stages is drastically different from its appearance in its adult stage. This is one of the qualities that makes flies excellent tools for forensic investigation. The amount of time a fly takes to grow from one stage to the next depends mainly on temperature. In general, flies develop from egg to adult in 12-27 days at 27 degrees Celsius. Since insects cannot regulate their own body temperatures, any extremities in temperature will heavily stunt fly growth. In the case that further specificities are needed in regards to the age of the maggots, **scanning electron microscopes** are used to distinguish finer aspects of insect growth invisible to the nake eye, and **Potassium Permanganate Staining** is also used to compare various morphological features.



The period between the victim’s death and the discovery of his body is called the **PMI (Post-mortem Interval)**. Forensic entomologists record the age, and or development stage of the insects on the body to find out when insects first arrived at the remains. Because blowflies locate a decomposing body within minutes of the victim’s death, the age of flies on the body is quite close to the PMI in most cases. To find out how old the flies are, forensic entomologists need to know what the temperatures were at the crime scene during the suspected time of death, the species of flies on the body, how old these flies are, and how many generations of flies developed on the body. A **weather station** close to the location of the body can usually give forensic entomologists the critical climate information they need.

Identifying the species of flies on the body is important because different species grow and develop at different rates, depending on the temperature of their environment. The growth information helps forensic scientists determine how old the flies are once they know the flies’ development stages. Comparing the known development stage of flies on the corpse with how long laboratory flies of the same species took to reach that stage at a known temperature helps forensic entomologists estimate the age of the flies. In the case that multiple fly generations lived on the body, forensic entomologists must add together the development times from the different generations. The development time of the oldest flies is approximate to the PMI.

Insects also indicate to forensic entomologist the **location** of the crime scene. In some cases, criminals move the body to a different location to hide the scene and any evidence that might lead to their capture. The geographic range and habitat of certain insect species can reveal whether or not the suspect moved the body. If a suspect transports a victim from a city to a forest, forest-dwelling insects should invade the body. But also, an “urban” insect species that typically lives in buildings might be expected to come crawling out of the victim. These urban insects would have remained within the victim on the way from the city to the forest. Processes

Although forensic entomology is a growing field among the forensic sciences, its specialization and special niche is evidenced by the fact that the only university that offers degrees in //forensic entomology// is located in the Netherlands. Other universities around the globe offer undergraduate, graduate, and PhD degrees in plain entomology, which are usually staple degrees for future forensic entomologists.

The average annual salary for entomologists at all levels is **$47,740**. The average starting salary for entomologists in all fields is $29,260. The society reports that the average higher-level salary of entomologists who are established in the field is $71,270. Forensic entomologists typically find employment with local, state or federal government police forces, and the approximate average salary varies by branch. Forensic scientists working for the federal government reported an average annual income of $95,240. Those working for state and local government reported an average annual income of $54,550 and $54,990, respectively.

Case Study

In 1984, a limbless and headless corpse of a woman was discovered floating in a cardboard box in a Pennsylvania river. After the police investigated the area, the victim’s remains were taken to the county medical examiner. During the autopsy several maggots were extracted from the wound, photographed, and cataloged. But this entomological evidence was neglected in the trial, and a suspect, Donald Ruby, was wrongfully convicted and sentenced to time in prison. 10 years later, Ruby was granted a second trial. This time forensic entomologists Robert Hall and **Neal Haskell** were asked to testify using the maggot evidence. Because the maggot eggs found on the body were unhatched, the two determined that the minimum time interval was 3 days in which the victim’s torso could have been dumped at the riverbank was consistent with Ruby’s alibi. Ruby was exonerated an innocent man.

Bibliography

Editor's Introduction. On Maggots and Murders: Forensic Entomology(n.d.): n. pag. Web. []

"Forensic Entomology." Forensic Entomology. N.p., n.d. Web. 16 Jan. 2015. []

Walker, Maryalice. Entomology and Palynology: Evidence from the Natural World. Philadelphia: Mason Crest, 2006. Print.

Yancey, Diane. The Forensic Entomologist. Detroit: Lucent, 2009. Print.

Goff, M. Lee. A Fly for the Prosecution: How Insect Evidence Helps Solve Crimes. Cambridge, MA: Harvard UP, 2000. Print.

External Links

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Project by: Robert Zhang