While waiting in line at TSA a few weeks ago, I was sniffed by a drug dog and his handler (well, the handler didn’t sniff me, but you know what I mean). Resisting the urge to get on the floor and roll around with the absolutely adorable black lab, I stood patiently in line as the puppy sniffed my bags and walked away. Fortunately, I left my drugs at home…
This got me thinking about a conversation I had with some of my friends from my hometown. About a year ago, Miami-Dade county reduced the penalty for possession of marijuana to a civil citation– a $100 fine and no threat of criminal record. This was a big deal in the state of Florida where pot is still illegal, but compared to other states like Colorado and Oregon where recreational marijuana is legalized, Miami-Dade county is just following a national pot trend.
This poses an interesting dilemma for drug sniffing K-9 units: dogs must now be retrained to distinguish between different kinds of drugs, or more specifically to not react to the presence of cannabis, in order to justify probable cause for police searches. Alternatively, forensic scientists and entomologists have proposed using trained insects as biosensors for illegal drugs.
We all know that dogs have super sensitive sniffers, which is why they have been efficiently used for detection of illicit substances. However, insect antennae are the most sensitive “sniffers” discovered in the natural world. Depending on the chemical, some insects can detect odors 10-90 times better than a dog can!
In light of all of all of this, a group of biologists and forensic chemists from Germany have set out to determine if insects could be trained to reliably detect illegal drugs.
This group of researchers first determined that insects could detect specific odors by connecting insect antennae to an electroantennogram (EAG). This piece of technology consists of electrodes that amplify and record the signals produced when odorant receptors in the insect antennae are stimulated. They did this with three insects– the European grapevine moth, the Madagascar hissing cockroach, and the western honeybee; and four drug types– heroin, cocaine, amphetamine and cannabis.
The western honeybee (Apis mellifera) antennae produce the strongest electrical signals, indicating that honeybees can respond reliably and discriminately to pure and diluted samples of cocaine and heroin. Cockroach antennae produced the second strongest signals and were the only antennae that responded to amphetamines. Placing their bets on the more reliable (and more endearing) of the two insects, the investigators decided to put the honeybees through drug bug training.
But how does one go about training a honeybee to do… anything? The answer is simple, classical conditioning.
Classical conditioning occurs when two stimuli are paired to elicit a specific response so that eventually the presence of one of the stimuli can elicit the same response as both. Perhaps “Pavlov’s dog” rings a bell (see what I did there?).
Anyway, the honeybees in this study were individually placed in small glass vials and treated with a small electrical shock in the presence of the conditioned stimuli (cocaine or heroin). When shocked, the bees responded with intense buzzing and spinning. After a few rounds of conditioning, the honeybees were responding distinctly to the drug stimuli in the absence of the electric shock, thereby creating a behavioral “alert” in the presence of narcotics.
Ultimately, this study showed that a population of 67 trained honeybees could reliably detect pure and diluted samples heroin and cocaine, with an error rate of less than 5%. The authors of this study envision a future where a multi-chambered fleet of drug bugs (consisting of trained honeybees and cockroaches) could effectively detect heroin, cocaine and amphetamines.
Though further research and development is needed before science and policy can collide to bring buzzing chambers of insects to airports and drug investigations, this study is one of many advocating for the utility of insects as biosensors. Not only are insect antennae better at detecting odors than dog sniffers, but this study also suggests that these particular insects are cheaper, faster to train, and easier to transport than police dogs.
But can these fancy drug bugs fetch? No, I didn’t think so.
|Michelle Ziadie is a Ph.D. student in the Department of Genetics at UGA working on the evolution of maternal effects and undergraduate evolution education. A native of Miami, Florida with caribbean roots, Michelle never turns down an opportunity to engage with spicy food or spicy music. When she’s not dancing the night away with friends or getting lost in the Georgia wilderness, Michelle can be found sipping a café Cubano and watching Teenage Mutant Ninja Turtles with her kitten, Thomas. More from Michelle Ziadie.|