Cocaine-Seeking Cockroaches

Last year, Idaho State University researchers, led by biological sciences master’s student Kayla Pavlick, experimented with cockroaches to see how well they can be trained to detect narcotics. “We are training them to detect cocaine and Adderall XR (an amphetamine),” Pavlick said. “It is a really simple design, but it takes a long time. We are just rewarding them sugar water when we give them drugs.”

She said it’s possible that in the future, cockroaches could be used to complement canine units that search for drugs or in environments where canines can’t be used, although this is out of the scope of her research.

Pavlick, working with biological sciences undergraduate student Walker Mink and biological sciences professor Dave Delehanty, had encouraging results working with American cockroaches (Periplaneta americana) to find the drugs.

“I am soaking little bits of filter paper in those solutions and presenting it to the cockroaches and pairing that olfactory stimulus, that smell that they are getting, with a sucrose solution because they really love sugar,” said Pavlick, who is originally from Jackson, Miss.

During the first stage of her experiment, the ISU researchers rewarded cockroaches with sugar water after the insects investigated a beaker containing filter paper with narcotics in it.

Then, the cockroaches were put in a two-sided testing chamber that Pavlick designed. On one side of the chamber a cockroach would be released and on the other side there were four compartments, each with a Petri dish. Only one of the Petri dishes had a narcotic and the others were loaded with vanilla. After researchers lifted a barrier between the two sides, they tracked which Petri dish the cockroaches would visit. They consistently chose the Petri dish with drugs. “They were very consistent,” Pavlick said.

The second phase of the experiment was larger scale. The researchers used a 5-foot by 9-foot gridded square enclosure and randomly planted the target substance drugs in different grids. They then released cockroaches into the larger grid and tracked how well the cockroaches went to the target substances.

They tagged the cockroaches with metallic or infrared paint, mounted an infrared camera from the ceiling of the laboratory and tracked where the cockroaches went. Eight of the 10 cockroaches released successfully located the drug Adderall and seven of 10 cockroaches found the cocaine.

“I think the experiment went really well,” Pavlick said. “This is likely the first time anything like this has been done with insects as far as a location task is concerned and on non-food borne odors, the narcotics. Even though they didn’t have a 100 percent success rate the results are still promising.”

The hardest part about pulling off the experiment was getting the drugs used with the cockroaches.

© Idaho State University

“The reason we couldn’t get anything done for so long is because obtaining narcotic drugs legally is quite the process,” she said. “It took some time getting the licensing from everybody we need and clearing it with the Office of Research so no one would get in trouble.”

Working with cockroaches has helped the ISU students gain some unusual skills.

“There are certain skills you acquire that you think you will never acquire,” Pavlick said. “And one of those things is your reaction time, because these guys are so fast. They are incredibly fast.”

The cockroaches have a life span of up to 18 months and the researchers have worked with between 50 and 150 of them since the project began.

“Way down the line in the future, the way I see it playing out is that insects and cockroaches, specifically, could be used to complement current detection methods,” she said. “Canines are fantastic and they’ve been very useful for narcotic and explosive detection, but they do have limitations. One of them is their size — they can’t fit everywhere a roach can.”

Hypothetically, a canine detection unit could be employed to narrow down an area search and then insects could be used to pinpoint the exact source. With current technology, it would even be possible to outfit cockroaches with tiny electronic GPS tracking devices.

“Somebody has already done that so now we just have to train the roaches successfully, so you could track them from afar using GPS technology,” she said.

She emphasized that cockroaches would never replace canines, but could potentially augment the use of them. Source: Idaho State University

Pavlick, who graduated in 2019, successfully defended her master’s thesis, which was devoted to this project. She will pursue a Ph.D. program in biological sciences and plans to complete a scientific paper about the project and submit it to a scientific journal.