Bees put sting into crime fight
AN AMERICAN researcher explaining the intricacies of teaching honey bees to detect land mines was a topic bound to test the imagination of Southern Downs beekeepers.
A talk by Montana University's Jerry Bromenshenkat the Queensland Beekeepers Association state conference in Warwick held recently the audience captive.
And while the topic sounded disconcertingly like science fiction, it was firmly steeped in fact and backed by more than 30 years of research.
So how did this innovative work begin?
Back in the 1970s, Professor Bromenshenk and a team of university researchers started sending out bees to explore and collect samples from environments within a two to four kilometre radius of their hives.
"A honey bee's body has branched hairs that develop a static electricity charge, making them an extremely effective collector of samples from their environment," Prof. Bromenshenk explained.
"Bees are like flying dust mops - while they forage for nectar or pollen, they attract particles of dust, soil and pollen, bringing samples back to their hive.
"In doing so, they provide a chemical and biological survey of an area around their hive.
"So, if pollutants, biological warfare agents and explosives are out there, they will bring traces back."
Bees cannot find a mine that is not leaking but they can be trained to recognise other odours, like casing materials, which may improve performance.
Bees were then used to test air and soil quality in heavily industrialised sites throughout the United States.
And in what to the average apiarist might seem like a quantum leap - and circumvents years of work - in the early 2000s, Prof. Bromenshenk and his team began training bees to search for "odours of interest".
"For years, we were refining our ability to condition or train bees to go to odours of interest," he explained.
"Bees have an acute sense of smell and with training can be taught to find explosives, as well as other chemicals, including drugs or even decomposing bodies."
Prof Bromenshenk said bees were trained in much the same way as dogs, using traditional operant conditioning methods.
"The reward is food, which during training we associate with the odour of interest," he said.
"Like dogs, bees can detect a suite of chemicals over a wide range of concentrations.
"Bees indicate the presence of an odour by the numbers of bees following vapour plumes toward and over the source or target.
"We have observed that bees detect the vapour plume several metres from the source and then navigate towards the source."
The researchers "mapped" the density of the bees over an area using laser-assisted counting, relayed to a computer.
This innovative work ignited the interest of American miltary and before
long, they were working with the Montana University team to see if honey bees could detect actual landmines.
"We were pretty confident bees could detect vapours from leaking landmines and most of these anti-personnel or anti-tank mines were plastic, so you couldn't use metal detectors to locate them," Prof. Bromenshenk said.
"In order to demonstrate the bee concept was useful, we had to show we had a means of detecting or tracking bees at a distance from the hive and over the landmine site."
He said with bees being able to fly 3-5km it was vital they had a detection system, which could cover the same range.
"Our earlier trials demonstrated bees could be trained to efficiently and accurately locate explosive signatures in the environment," Prof Bromenshenk said.
"But it was challenging to track bees and determine precisely where the targets were located: video equipment wasn't practical because it had limited resolution and range and it wasn't always safe to set up cameras in a minefield."
Initially researchers tried attaching tiny microchips to the backs of the insects but these proved too heavy.
It was also incredibly time-consuming work and often near-impossible.
Then researchers stumbled across a laser light system being used to track schools of fish.
The LIDAR system sends laser light pulses over an area and the light is bounced back off the bees, allowing researchers to chart and map their activity with pinpoint accuracy. With this advanced technology, the researchers were able to follow the movements of bees specifically trained to sniff out explosives.
When comprehensive tests came back showing bees had a 98% accuracy rate identifying and pinpointing landmines during testing, even Prof. Bromenshenk was impressed.
"We were impressed and the miltary was totally flabbergasted," he said. "Bees were incredibly accurate - no other instrument in the world had the same sort of detection ability over the same time."
But as with other detection animals, like dogs, there has proven a downside to relying on these honey-producing insects.
"Bees cannot find a mine that is not leaking but they can be trained to recognise other odours, like casing materials, which may improve performance," Prof. Bromenshenk said. "Bees do not fly at night, during heavy rain or wind or when temperatures drop to near or below freezing.
"So the use of bees in some regions is seasonal but these sorts of limitations are not unique to bees.
"Dogs also don't perform well in wind, rain or when the ground is frozen and dogs and their handlers are usually reluctant to work in the dark."
But Prof. Bromenshenk said there were also significant advantages to using bees.
"They weigh 1/10 of a gram, so they are not going to set off any trip wires or trigger any mines," he said.
"Bee colonies can be established along the perimeter of the minefield, allowing beekeepers to stay well clear of dangerous zones."
In short, the the advantages of using bees to detect explosives are:
- bees can be conditioned and put to use in one or two days;
- local bees and beekeepers are used;
- overall costs are significantly less than dog teams; and
- bees are essential for revitalising agriculture in war-torn countries.