U of T is one of the few universities where you will find a body farm, a place where scientists conduct the controlled decomposition of animals. You can find the “Maggot Ranch” off a lonely road in the backwoods behind Erindale campus.
It’s a fenced-off enclosure housing twenty-six wooden boxes aligned in rows. In the boxes lie corpses, stabbed and mutilated. Their flesh was chewed off their skeletons earlier this fall by beetles, flies, and ravenous maggots.
The corpses aren’t humans, they’re rats. And fortunately these rats met their murderous ends posthumously.
“We do not contribute to the death of rats,” said Dr. David Gibo, who runs the place. “We intercept them on their way to being cremated by the psychology department. I think the Maggot Ranch is a better fate than being cremated, in my opinion, at least for a dead rat.”
On the Maggot Ranch, Gibo and his team study the behaviour of fleshflies, blowflies, and beetles-insects that have a taste for dead flesh. These bugs need an animal carcass to grow, and excel at smelling death and seeking it out. This makes them, and Gibo’s research, very valuable to the field of forensic entomology, the application of insect biology to criminal investigation.
Insects that feed on flesh need to grow up fast, before their food supply rots away. So by identifying the growth stage of insects found on a corpse, forensic entomologists can estimate how long that corpse has been dead.
“Of course, using insect developmental rates tells you when the body was exposed to the possibility of insects getting to it, which is different from the time of death,” corrected Gibo. “It would be ideal if the insects were punctual and showed up immediately upon death but they show up when they show up. But a rough estimate is better than none.”
Different insects occupy a body at different times: first come blowflies, then fleshflies, and beetles that eat maggots, cartilage or skin.
Often, forensic entomologists use knowledge of insect development as well as insect type to approximate a corpse’s demise, although Gibo warned that insects don’t follow fixed schedules.
“If you think it’s all very nicely scripted with certain species showing up at certain times and developing at a certain rate, guess again. A lot depends on the environment and your starting assumptions.”
Gibo’s research on the Maggot Ranch has already challenged some of the assumptions of forensic entomology. One is that maggots found on a body hatched and developed on that body. But Gibo and his team have found that not only can maggots smell another body and inch their way towards it, but they can also continue to develop on it.
“Somehow these maggots can converge on dead flesh, but I haven’t seen maggots with tablets and pencils (or arms and hands for that matter) so I don’t know how they calculate where to go,” he quipped.
Gibo’s find has grave consequences for how forensic entomologists use maggots to estimate the time since death.
“The original assumption is if you take the oldest maggots and figure out how long it took ’em to get to that size you would have an idea as to how long the body has been there,” explained Gibo. “But if those maggots spent half their development on the thigh of a mouse that dropped out of the corner of a fox’s mouth and then crawled over to a freshly dumped body in the vicinity, [forensic entomologists] would think the body’s been there longer than it was.” Gibo presented his findings to the American Academy of Forensic Sciences last February in New Orleans.
In addition to research, Gibo teaches an introductory forensic entomology course, where students oversee a grisly term project. Students receive a dead rat, inflict murderous injuries, plunk ’em in the Maggot Ranch, and track the decomposition of the rat as well as the ensuing insect invasion. Gibo even expects students to take maggots home and rear them to adulthood. The remains of this year’s projects still lie in the Maggot Farm’s wooden boxes.
“They can feed the raccoons this winter,” said Gibo, “they’ve got to eat something and it’s better than roadkill, even though there’s a lot of that lying around.”
Students who have taken the class have not forgotten their brush with death. The Varsity spoke with some members of Erindale’s student forensics club, IVNVI (pronounced “4-N-6,” get it?).
“It takes some getting used to once [the rats] start decomposing,” said third-year forensic anthropology student Monica Maika, waving her hand in front of her nose.
“It was gagworthy,” agreed Stephanie Migchelsen, a fourth-year forensic biology student. “But if you want to go into forensics it’s good to take this course. I mean, you can’t smell the smells on CSI.”
