Bugged in Biology: Insects Help Students Solve Forensic Mysteries

Posted: December 13, 2010 at 1:05 am, Last Updated: December 10, 2010 at 5:05 pm

By Colleen Kearney Rich

J. Thomas McClintock at the "death scene" he staged to teach students about forensic entomology. Photo courtesy of J. Thomas McClintock

Forensics shows like “CSI” and “Bones” have captured the attention and imagination of the American television-viewing public. Each week, fans tune in to see attractive actors walk through crime scenes, often in high heels, with relative fuss or muss.

To an armchair crime scene investigator, it looks exciting, even easy.

However, as biology students enrolled in BIOL 590 this semester are finding out, it isn’t as easy as it appears. In fact, it might even be unsettling for some students because there are bugs, and lots of them.

The class is called Forensic Entomology, and it is taught by Mason adjunct professor and molecular biologist J. Thomas McClintock, founder of DNA Diagnostics Inc., a company that provides DNA testing and analysis. McClintock has taught at Mason since 1999.

Forensic entomology is the study and application of insect biology in relation to criminal cases. Although it is primarily associated with death investigations, this field of entomology can be used to detect drugs and poisons, determine the location of an incident or figure out the time of death based on the insects present on the victim.

To help his students better understand some of the questions associated with the use of insects in a crime scene investigation, McClintock planned something special for his students this fall.

Using pigs he obtained from an Amish farm as proxies for human cadavers, McClintock went to great lengths to stage and document a “death scene” near his home in southern Maryland.

McClintock protected the cadavers from wildlife by putting them in a cage. Then, in late August, several students traveled with McClintock to the site, where he walked them through the insect collection process.

“Different insects show up at different stages of the decomposition process,” says McClintock, who has evaluated and provided expert guidance on more than 200 legal cases.

“For example, blowflies show up instantly on a fresh cadaver.”

The insects, mostly larvae, were “frozen” in time using various techniques when collected. Some were put in ethanol; others were frozen and kept dry.

Back in the classroom, students worked to identify the insects and estimate their age to pinpoint the time of death of the “victims.”

According to McClintock, this study was designed to provide information on how the rates of decomposition for estimating postmortem interval (or time of death) are affected by the local climate and insect activity in southern Maryland. It also serves as a teaching tool.

“Getting to do the practical work was the most fun,” says biology major Anne Hess. She isn’t sure a career in forensic science is for her, but she says she learned a lot from the class.

“I used to hate bugs. I appreciate them more now.”

In addition to collecting and identifying the insects, the class also discusses how environmental conditions such as heat, humidity or the amount of rainfall affect the rate of decomposition and insect activity.

Toward the end of the semester, students also learned how they would prepare a report based on their findings and how they would testify in court on their results.

McClintock is the author of “Forensic DNA Analysis: A Laboratory Manual” and also regularly teaches BIOL 509 DNA Analysis of Biological Evidence.

Because of his expertise, McClintock appeared on CNN’s crime show, “Nancy Grace,” to discuss the 2008 Caylee Anthony case, in which a toddler who disappeared was found dead.

“I try to bring in the experience I’ve learned in the real world,” says McClintock.

“Science doesn’t just have to be ‘textbook’ and ho-hum.”

Write to mediarel at gazette@gmu.edu