Move over, sniffer dogs: now you will find explosive-sensing grasshoppers. Barani Raman and his colleagues at Washington University in Missouri have tapped into the olfactory senses of the American grasshopper, Schistocerca americana, to make Biology bomb sniffers. In turn, these neurons send electric signals to a part of the insect brain known as the antennal lobe. Every grasshopper antenna has approximately 50,000 of these neurons. As controls, they utilized non-explosives like hot air and benzaldehyde, the primary component in the oil of bitter almonds.
By implanting electrodes to the antennal lobes of grasshoppers, the researchers found that distinct kinds of neurons were activated upon exposure to the explosives. They analysed the electrical signals and could tell the volatile vapours apart from non-explosives, in addition to from every other.
The team fitted grasshoppers with tiny, lightweight detector backpacks which were able to record and transmit the electrical activity of the antennal lobes almost immediately into a computer.
The grasshoppers continued to successfully detect explosives up to seven hours after the researchers implanted the electrodes, before they became fatigued and finally died.
The process immobilised the grasshoppers, hence the researchers place them on a wheeled, remote-controlled platform to test their ability to sense explosives at different locations. The grasshoppers were able to detect where the maximum concentration of explosives was when the team moved the platform to distinct locations.
The team also tested the effect of combining sensory data from several grasshoppers, provided that in the real world substances may be dispersed by environmental variables, including end.
Taking neural action from seven grasshoppers yielded an average accuracy of detection of 80 per cent, compared with 60 per cent for one grasshopper.
The project was financed by the US Office of Naval Research and the researchers believe the grasshoppers could be used for homeland security purposes.
A limitation of this study was that it didn’t examine the grasshoppers’ explosives-detecting capability when multiple odours were present in precisely the exact same moment.