A drone equipped with an antenna from a male moth can locate the source of a smell more accurately than any electrical sensors. Unfortunately, however, the only smell it can detect is the sex pheromone emitted by female moths.

Electrical sensors for odours are commonly used to detect gas leaks, but these are relatively slow to react to smells and even slower to reset between measurements, says Daigo Terutsuki at Shinshu University, Japan. “It’s very difficult to apply that to…