Cyborg grasshoppers have been engineered to sniff out explosives

Move over, sniffer dogs: now there are 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 create biological bomb sniffers.

In insects, olfactory receptor neurons in their antennae detect chemical odours in the air. In turn, these neurons send electrical signals to a part of the insect brain known as the antennal lobe. Each grasshopper antenna has approximately 50,000 of these neurons.

To test bomb-sniffing ability, the team puffed vapours of different explosive materials onto grasshopper antennae, including vapours of trinitrotoluene (TNT) and its precursor 2,4-dinitrotoluene (DNT). As controls, they used non-explosives such as hot air and benzaldehyde, the primary component in the oil of bitter almonds.