Locusts to 'sniff out explosives'

Scientists are researching technology they hope will allow locusts to detect explosives using their sense of smell.

They say heat-generating "tattoos" will enable them to be guided into dangerous or remote areas via remote control

Neural signals from the locust's brain will then be processed by an on-board low-power processing chip that will decode the information and send a wireless alert back to the authorities.

And the result will appear on a simple LED: red for present, green for absent.

Baranidharan Raman, associate professor of biomedical engineering in the School of Engineering and Applied Science Washington University, has studied the way locusts smell for several years.

And the Office of Naval Research in the US has now given him a $750,000 (£565,000) grant to continue his research.

Olfaction, better known as the ability to smell, is considered a primary sensory quality in insects whereas it is more of an aesthetic sense for humans, according to Prof Raman.

But locusts have a similar sense of smell to humans in that they can identify a particular smell even when it is mixed in with other odours.

Prof Raman said they had "robotic noses" that could be trained to pinpoint and recall a smell such as dangerous chemicals.

He told the BBC: "It took only a few hundred milliseconds for the locust's brain to begin tracking a novel odour introduced in its surroundings. The locusts are processing chemical cues in an extremely rapid fashion.

"Even the state-of-the-art miniaturised chemical-sensing devices have a handful of sensors. On the other hand, if you look at the insect antennae, where their chemical sensors are located, there are several hundreds of thousands of sensors and of a variety of types," he said.

Meanwhile, Srikanth Singamaneni, associate professor of materials science, who specialises in nanomaterials, will be creating a plasmonic "tattoo" made of a biocompatible silk that will be applied to the locusts' wings to generate mild heat and help steer them towards particular locations by remote control.

The tattoos will also be able to collect samples of volatile organic compounds in their proximity for other testing methods.

Prof Raman estimates the prototype will be ready for rigorous testing in a year and if successful the locusts could be ready in less than two years.

He also believes this new sensor technology could help to detect medical conditions in humans that are currently diagnosed by smell.