Honeybees as Mine Detection “Soldiers”
Every month, hundreds of victims worldwide suffer injuries or fatalities due to landmines. As a result, mine clearance has become a top priority. To accomplish this mission, the military typically uses handheld metal detectors. However, their reliability has not been as high as desired. This is why Pentagon experts have proposed using…honeybees.
Since 1998, the U.S. military has conducted two projects under the direction of Jerry Bromenshenk, an entomologist at the University of Montana. One project aims to detect and locate explosive mines, while the other focuses on identifying potential terrorist attacks. The remarkable aspect of honeybees is their acute sense of smell, which is significantly better than that of trained dogs, as well as their unique ability to memorize a vast array of different scents. Honeybees are also easily trained to fly towards a fragrant location, even if it is unrelated to food. This training can occur in a laboratory setting, based on the reflex conditioning model established by Russian physiologist Pavlov (1849 – 1936).
The experiment involves familiarizing the bees with a specific scent (for example, sugar water). Next, they are taught to recognize this scent, and researchers observe that the bees extend their tongues as if they are about to be fed when the food is presented. This entire process takes less than 10 seconds. Another interesting trait of bees is their remarkable memory; not only do they remember the scents they have encountered, but they also pass on this recognition to their fellow bees. In other words, by training just one honeybee, other bees that come into contact with it will also learn to recognize the scent. American scientists have successfully trained bees to identify the smell of TNT, the primary component in explosive mines. At a training facility in the state of New Mexico, a comprehensive test has been developed with increasing levels of difficulty aimed at studying the behavior of trained honeybees.
The first test involves placing a beehive in a greenhouse filled with flowers that have been treated with TNT. Sensitive to the scent of this explosive, the honeybees move towards the nectar of the TNT-infused flowers. The next test is conducted outdoors, where mines are buried underground, and nearby flower clusters absorb TNT vapors. Surprisingly, even when TNT particles emanate from locations several kilometers away from the hive, the honeybees still head straight for the flowers contaminated with TNT.
Researchers have also discovered that honeybees can be used to detect pathogens released into the air during a terrorist attack. This method is based on a phenomenon familiar to physicists. The surface of an object in motion can carry a static charge due to friction with air molecules. This static charge can attract lightweight particles that have an opposite charge along the bee’s flight path. For instance, pollen can be attracted to honeybees. So why not any airborne pathogens that could also be drawn to the bees? This is the hypothesis being explored by scientists in the aerosol microbiology laboratory. To demonstrate this, they released a bee into an airflow containing spores of anthrax bacteria and observed that these microorganisms “stuck” to the honeybee’s body. Using this data, scientists developed a mathematical model based on the accumulation of spores on the honeybee. They have recently reported similar results with bacteria released as aerosolized agents. However, honeybees are not the only insects capturing the attention of the U.S. military.
In the near future, honeybees may join the military’s “arsenal,” alongside dogs, elephants, and pigeons… This is likely, as the U.S. has invested $25 million in research on honeybees with excellent olfactory capabilities.
Hornets as “Drug Reconnaissance Agents”
Future drug traffickers and terrorists may soon face a formidable adversary: hornets, known as “scout wasps,” are exceptionally skilled at detecting chemical substances related to drugs, explosives, and plant diseases. Approximately five hornets will be housed in a special box called a handheld chemical detector. They are trained to respond to the aforementioned scents, resulting in body movements that trigger an alarm system back at the monitoring station.
Glen Rains, a biologist at the University of Georgia, one of the inventors of this device, explains: Known for their precise sense of smell, the parasitic hornets do not sting humans and are small, resembling winged ants. Researchers believe this species of hornet is ideal for detecting bomb scents. Parasitic hornets require only 30 minutes of training, and they can lay thousands of eggs at once, providing an unlimited supply of “scouts.”
The “scout wasp” project is a continuation of research on a parasitic hornet species in Georgia, scientifically named Microplitis croceipes, which has a sense of smell 100,000 times more sensitive than the strongest detectors created by humans. In nature, this hornet uses its antennae to locate a moth species that bores into corn stalks. The hornet lives parasitically on the moth’s body, which serves as both a breeding ground and a food source. Eventually, the hornet larvae consume the host, weakening and killing the moth over time.
In the 1970s, W. Joe Lewis, co-inventor of the “scout wasp” and an expert on parasitic hornets, and his colleagues discovered that these hornets could find corn moths through a specific chemical in the moth’s feces. Subsequent studies revealed that the olfactory system of hornets is directly related to various odor entities, and they can learn to recognize specific scents from foods like corn. Lewis quickly realized that he could train them to identify certain odors. While recognizing specific scents is not unusual in mammals, it is quite novel for invertebrates!
The principle of odor recognition in hornets is as follows: Typically, when in the box they crawl around slowly, but upon detecting a scent they have been trained to recognize, the hornets behave like predators sensing blood; they move closer to the source of the scent, waiting to be rewarded. A tiny camera monitors all the hornets’ movements, transmitting images to a computer for analysis and triggering an alarm system within 30 seconds. This project, if all goes well, could be widely implemented within the next 5 to 10 years.
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