A Honey of a Skill: Dogs That Detect Diseased Bee Colonies
Dogs can detect diseased beehives, while bees can scent explosives.
Posted June 28, 2010
Most people know that dogs can be trained to sniff out just about anything. We are familiar with some of these, such as their ability to find drugs, lost people, bombs, and agricultural products. Less familiar, perhaps is their ability to detect termites, bed bugs, deceased bodies, cancer, low blood sugar, and more recently, citrus and other plant diseases. The dogs nose is many hundreds of times more sensitive than a human's and are often more sensitive than a room full of scientific equipment in identifying faint odors. Many specialized dog trainers claim that they can teach a dog to pick out even the smallest traces of a target odor as long as they can isolate the scent and show it to the dog. This skill has now been aimed at an unusual buy extremely important problem.
In agriculture the activities of bees which pollinate plants is responsible for $15 billion in added crop value, particularly for specialty crops such as almonds and other nuts, berries, fruits, and vegetables. About one mouthful in every three in your diet directly or indirectly benefits from honey bee pollination and if it were not for the bees, there would not be enough food on the planet to support life as we know it.
While there are native pollinators (honey bees came from the Old World with European colonists), honey bees are more prolific and the easiest to manage for the large scale pollination that U.S. agriculture requires. In California, the almond crop alone uses 1.3 million colonies of bees. Unfortunately, the number of managed honey bee colonies has dropped from 5 million in the 1940s to only 2.5 million today. At the same time, the need for hives to supply pollination service has continued to climb, which means that honey bee colonies are trucked from one are to another to service various crops.
One reason for the diminishing number of bees is because of disease--very specifically a problem called foulbrood. It is caused by bacteria that form microscopic spores that can survive for decades and can spread quickly from hive to hive, killing all of the bee larvae. If the infection is caught early, the hive can be treated with antibiotics. If not, the hive usually must be destroyed, along with any equipment that came into contact with it, which is a massive financial blow for the beekeeper. Inspecting bee colonies is time consuming, and the best inspectors can perhaps go over around 50 in a day, and even then, the process is not 100 percent accurate.
Faced with this threat to bee keepers, in the 1970's the state of Maryland had a dog trained to detect foulbrood disease in bees, and they have continued to keep a full-time "bee dog" on its staff since then.
For such a dog, the normal workday consists of walking along rows of hives. When the dog smells evidence of the bacterial infection, it sits in order to alert its handler. Early detection of the disease can save beekeepers substantial monetary loss from eradication of diseased bees and destruction of infected equipment. Compared to a human the dog is remarkably efficient, and can inspect the same 50 colonies that would take a person a full day, in just over 20 minutes with virtually perfect accuracy.
The bees often take offence at the intrusion of a dog into their territory, and bee stings to a dog's sensitive nose can be painful and off-putting. Therefore most inspections are conducted in the fall and winter, when the cold temperatures reduce the activity levels of the bees significantly.
Recently there has been an interesting reversal of function. Scientists have been thinking that since bees have a very sensitive sense of smell, they might be able to perform the same tasks as a sniffer dog in finding drugs or explosives. The problem involves how to train them. A consortium of UK companies including Insectinel, ML Electronics and Realise Product Design, thinks it has the answer. They have designed a sort of bee ‘hotel' that turns residents insects into reliable sniffers. Groups of bees in the device are exposed to a variety of odours and rewarded with sugar syrup only when a particular odour (say the scent of an explosive) is present. After a few hours they learn to associate the reward with that odor. There is a reflex that bees have which causes them to stick their tongues out when they expect food. Like most reflexes this one can be trained in much the same way that Pavlov taught dogs to salivate when they heard a bell or a clicking sound. Thus the tongue coming out becomes classically conditioned to the target odor and in effect we have taught the bees to indicate that they have detected it. The trained bees are then placed in individual compartments in a portable carrying case called a VASOR (Volatile Analysis by Specific Olfactory Recognition). Near each bee's head is a beam of infrared light which is partially blocked by the insect's tongue. The apparatus picks up the reduction in light intensity and this is an indication that the bee has sensed the target odor.
There are some limitations on the use of bees in this way. First each bee can only be trained to respond to one specific odor, and second the amount of time that each bee can be used is rather short. Dogs take more time to train, but can be trained to respond to multiple target scents and can do their work for years.
Still it does seem a bit of an irony to me to be training dogs to save a species of animal that might be putting many of their canine colleagues out of work.
Stanley Coren is the author of many books including: The Modern Dog, Why Do Dogs Have Wet Noses? The Pawprints of History, How Dogs Think, How To Speak Dog, Why We Love the Dogs We Do, What Do Dogs Know? The Intelligence of Dogs, Why Does My Dog Act That Way? Understanding Dogs for Dummies, Sleep Thieves, The Left-hander Syndrome
Copyright SC Psychological Enterprises Ltd. May not be reprinted or reposted without permission.