Even fruit flies can help spot bombs and drugs

The "nose" of fruit flies can identify odours emanating from illicit drugs and explosive substances almost as accurately as wine odour, says a study.

A fly's sense of smell could, in fact, be used in a new technology to detect drugs and bombs.

The study brought scientists closer to developing electronic noses (e-noses) that closely replicate the sensitive olfactory sense of animals.

"In looking at fruit flies, we found that contrary to our expectation, unfamiliar odours such as from explosives were not only recognised but broadly recognised with the same accuracy as odours more relevant to a fly's behaviour," said lead researcher Thomas Nowotny, professor at the University of Sussex in Britain.

The researchers recorded how 20 different receptor neurons in fruit flies responded to an ecologically relevant set of 36 chemicals related to wine and an ecologically irrelevant set of 35 chemicals related to hazardous materials.

By monitoring the "firing rate" of each neuron, they were able to assess which smells elicited the strongest reactions from the flies.

They then used a computer programme to simulate the part of the fly's brain used for recognition to show that the receptor responses contained enough information to recognise odours.

Of the wine set, 29 out of the 36 compounds elicited clear excitatory responses in at least one receptor neuron.

The flies also responded to 21 out of the 35 substances related to drugs and explosives.

"The long-term goal of this research direction is to 'recreate' animals' noses for technical applications," Nowotny added.

The study appeared in the journal Bioinspiration and Biomimetics.