THE US military is drafting wasps and training them to give an early warning of chemical weapon attacks.
In the wild, the small predatory wasp Microplitis croceipes uses its ultra-sensitive sense of smell to locate its caterpillar prey, in which it lays eggs. But it can easily turn its talents to detecting other chemicals.
Glen Rains at the University of Georgia, Tifton, says the wasp can pick up scents at a concentration of one part in a thousand billion 鈥� a hundred thousand times weaker than the lowest concentrations detectable by commercial 鈥渆lectronic noses鈥�.
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It takes just a few minutes to train the wasps to detect a chemical threat. They are exposed to a very weak, non-toxic puff of the target chemical and, for the first three times, are given access to a bowl of sugary water as a reward. After that, the wasps will head for the source of the scent, says Torsten Meiners at the Free University of Berlin, who鈥檚 been working with the team in Georgia.
The team has now trained the wasps to detect a range of neurotoxins and explosives and is working on a prototype handheld detector that would use the wasps as its 鈥渘ose鈥�. The device works by sucking air samples through a short pipe into a cartridge containing a few wasps. If the wasps smell the target chemical, they dive down the pipe looking for its source. In the process, they break a beam of light inside the pipe, triggering an alarm.
Such a device could be carried into battle by soldiers to use as an early-warning system for chemical weapons attacks.