Honeybees and Landmines
(This column was first published in the February 9, 2004 issue of The Buffalo News.)
Honeybees are widely recognized as our most beneficial insects. Not only do they provide us honey and wax but they also serve as pollinators for many important crops. Now these industrious bees are being trained to serve us in still another quite remarkable way.
One of the saddest leftovers from warfare is the wide distribution of landmines. Worldwide, thousands of innocent civilians are killed each year by these mines; still more are crippled. In Cambodia alone today there are an estimated 35,000 amputees who were injured by mines, many of them innocent children.
The mines are also a continuing daily threat in Afghanistan, Angola, Bosnia, Chechnya, Croatia, Iraq, Mozambique, Nicaragua, Somalia, and dozens of other countries. More than 50 countries, unfortunately including the United States, have manufactured and distributed 200 million antipersonnel landmines in the last 25 years.
Identifying and clearing minefields is itself a life-threatening activity and a wide range of techniques is being implemented. Although humans with metal detectors remain a common method, huge machines, chain mats dragged by helicopters and trained dogs have also been employed.
And here is where the bees come in.
A group of entomologists at the University of Montana led by Jerry Bromenshenk have spent several years developing techniques to employ honeybees in landmine and biological weapon detection. Their work is sponsored by a section of that often criticized Defense Advanced Research Project Agency (DARPA) called the Controlled Biological and Biomimetic Systems Program. (Biomimetics are chemicals that mimic biological substances.)
According to Bromenshenk, "A honeybee's body has branched hairs that develop a static electricity charge, making it an extremely effective collector of chemical and biological particles, including pollutants, biological warfare agents and explosives. They also inhale large quantities of air and bring back water for evaporative cooling of the hive." Thus an individual hive has tens of thousands of foragers out sampling local air, soil, water and vegetation.
Examination by the scientific team of a number of returning bees provides initial information about areas where materials of concern are to be found and appropriate relocation of hives can further zero in to areas of a few hundred meters. But even this detection is now being refined.
The scientists have devised methods to train the bees by the same kind of reward techniques (formally called operant conditioning) that are employed by dog trainers. The reward provided the bees is food which is associated with the particular target being sought -- the smell of the chemicals in land mine explosives in this instance.
Again from the Bromenshank report: Bees follow "vapor plumes toward and over the source or target. We have observed that bees detect the vapor plume several meters from the source, then navigate up the plume to the source. We then map the density of bees over an area, using visual, camera or laser-assisted counts."
In the summer of 2003 field trials were conducted at Fort Leonard Wood in Missouri. Ten full-size bee colonies were conditioned to search for explosive vapors and the hives were placed in the test area.
The trial results were spectacular:
* The detection equipment worked over hundreds of meters with location to within a few centimeters.
* Bees found both individual mines and clusters of mines.
* The bees even made a surprise detection of a site contaminated with left-over TNT where none was expected.
The researchers are now exploring ways to make their procedures simple enough to be used by local beekeepers anywhere in the world.
Here is still another reason to appreciate these wonderful insects.-- Gerry Rising