Buried land mines kill more than 15,000 people each year worldwide. At the current removal rate, it will take about 450 years to clear the world of undetected anti-personnel land mines. Many detection methods have been tried, including the use of high-tech ones, such as ground-penetrating radar, infrared imaging, acoustic and seismic methods. But right now, the most common technique is the use of dogs who locate buried land mines through smell. Still, the dogs need to be accompanied by men. And their combined weights can inadvertently cause the explosion of a mine, putting them in constant danger. Now, researchers from several U. S. universities are training honey bees to locate buried land mines through odor detection. Read more.
And this is a very clever idea, which could save many lives. For example, here are some short excerpts from an article from Optics.org, "Honey bees sniff-out landmines."
Bees do not explode the mines, do not require a handler and can be trained in a couple of days to pick up the scent of the explosive in the landmine.
Jerry Bromenshenk and his colleagues from the University of Montana at Missoula are responsible for training the bees. "By injecting trace amounts of target chemical into feeders, the foraging bees seek sources of food with the same smell. Bees can be trained in one or two days to seek out buried explosives because of their high odor sensitivity in the low parts per trillion range."
Now, let's look at another article, "Finding Land Mines by Following a Bee," from BusinessWeek Online, to discover what bees do after being trained to smell traces of explosives.
After one or two days, the insects naturally become attracted to the smell. When released into a minefield, the bees find their way toward the mines. Of course, they find no actual food, and after lingering disappointedly for a few seconds, they fly off. With thousands of bees flying around, however, scientists have to be able to track these swarms.
But is this method really working?
this frenzy,
like bees stinging the heart all morning,
will keep the angels
with their windows open,
wide as an English bathtub.
—Anne Sexton (1928–1974)
Bees are too small to detect either with the naked eye or high-resolution video at long ranges. So instead, the team employs a laser emitter that sweeps an area like radar or sonar. When the light hits a bee, it reflects, and sensors are able to tell by the reflection just where the bee is. After sweeping several times, the scientists are able to crunch the data and see statistically where the higher occurrences of bees are located.
In controlled situations, the method is extremely effective: Bees can detect very small traces of explosive vapors with 97% accuracy and are "wrong" -- that is, passing over a mine without noticing it -- less than 1% of the time.
For more information, the latest research work about bees sniffing for land mines has been published by Optics Express on July 25, 2005 under the name "Polarization lidar measurements of honey bees in flight for locating land mines" (Vol. 13, No. 15, Pages 5853 - 5863).
[Note: LIDAR is an acronym for LIght Detection And Ranging. In fact, Lidar, laser radar, optical radar, and ladar are all names used for "radar" systems utilizing electromagnetic radiation at optical frequencies. FOr more information about lidar systems,please check thes two pages from the NASA web site, here or there.]
Here are the links to the abstract and to the full paper (PDF format, 11 pages, 284 KB).
After reading how bees can help us, I will never look at them as I did before.
Sources: Jacqueline Hewett, Optics.org, August 11, 2005; Burt Helm, BusinessWeek Online, August 16, 2005; and various web sites
In a valley late bees with whining gold
Thread summer to the loose ends of sleep....
—Allen Tate (1899–1979)
Related stories can be found in the following categories.
Military Applications
Nature
Optics
Technology
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