You’ve heard of sniffer dogs, but what about sniffer bees?
It might sound a bit far-fetched, but Croatian scientists have been trying to put the amazing senses of honeybees to a new use: finding potentially fatal landmines.
It’s estimated that about 750 square kilometers (466 square miles) of Croatian land may still harbor active landmines, remnants of the Balklan wars in the 1990s.
As of the start of April 2013, an estimated 509 people have been killed and 1,466 more have been injured by landmines in 1,352 separate incidents in Croatia. This includes the deaths of 66 people who had been tasked with finding and disarming the landmines.
This gives some indication of how dangerous de-mining is and the need to improve current detection and disarmament methods.
Fortunately, this is where the bees might have an edge.
Bees have an almost unparalleled set of olfactory senses, among them an acute sense of smell.
A team of researchers headed by Nikola Kezic, a bee behavioral expert, wondered if bees could be trained to identify the scent of TNT and, when let loose on a suspect area, find landmines.
This isn’t a new form of research, though. In the 1990s, American researchers at Defense Advanced Research Laboratory (DARPA) trained bees to swarm around where they detected what is known as 2,4-dinitrotoluene, a chemical residue left by several different types of bombs.
The difference here is that TNT is much harder to detect because it evaporates quicker than other chemical traces and, as such, wasn’t part of the research.
However, Kezic believed honeybees, used for their general good temperament, might be capable and, in 2007, set about testing his theory as part of his involvement in the multimillion-euro program called Tiramisu.
The bees were exposed to scents of chemicals found in explosives and then immediately after were given a whiff of a sugar water solution that closely mirrors their natural food. Bees extend their proboscis whenever excited by the smell of food, something that would be used as an indicator of success.
After just a few exposures, the bees would learn to predict the more appealing food that was to come whenever they detected the hint of explosives and would extend their proboscis in anticipation.
This behavior was further confirmed in controlled field tests that saw Kezic and his team at the Department of Agriculture at Zagreb University set up large tents in the university grounds.
The tents contained several feeding points, only a few of which contained TNT particles as well as sugar water solution incentives.
When the bees were let loose in these controlled environments the sense training appeared to work, and the bees gathered mainly at the posts laced with TNT molecules.
“Our basic conclusion is that the bees can clearly detect this target, and we are very satisfied,” Kezic is quoted as saying. “It is not a problem for a bee to learn the smell of an explosive, which it can then search.”
However, Kezic has sounded a note of caution that there’s still a lot of work to be done. “You can train a bee, but training their colony of thousands becomes a problem.”
As such, it may take a while before Kezic is ready to take his swarms out to hunt for landmines in the field. Still, he is ready to advance the research to testing the bees with real, albeit marked, landmines.
One problem with the swarms beyond the labor intensive process of training them will be effectively tracking them once they are in the field, but it looks as though there may be several possible solutions to this problem.
Research teams in previous studies fitted the bees with tiny radio transmitters for easier tracking. Keizic has also floated the idea of tracking the swarms using thermal imaging.
While it is unlikely that the bees would ever be used to completely replace human de-miners, they may be especially suited for checking areas that have already been cleared to ensure de-mining teams haven’t missed any landmines.
In this way, local governments could be much more confident when declaring areas “mine free.”
Image credit: Thinkstock.