What a Bee Smells

Evocative tastes and smells play crucial roles in animals' abilities to find food. A new study of smell perception in honeybees explains how bees react to a suite of scents, and unfolds an olfactory map that shows remarkable correspondence to brain activity.

A team of researchers, led by Martin Giurfa of the Université Paul-Sabatier in France, trained thousands of bees to associate a specific chemical scent with a sugary reward. Next, the researchers tested the bees' response to a set of different smells, varying in chemical composition. By watching how often the bees responded positively to a particular scent when they'd been trained on another, the researchers could assign perceptual "distances" between pairs of chemicals.

By connecting-the-dots between all these distances, they created a preliminary map of the bees' "perceptual space," similar to how surveyors measure distances between landmarks to map a landscape. From this map they found that the bees generalized more by specific molecular markers on a chemical rather than its size.

After comparing their map data to previous bee research, which recorded brain responses and used the same chemical scents, Giufra's team found that the perceptual and neural distances correlated well, which suggests there's a species-specific code that ties together the insects' brain and behavior.

Future studies should only improve our ability to investigate the correlations between brain and behavior.  Such studies would go even further toward cracking the codes underlying animals' perception and memory.

This study can be found in the current online edition of the Public Library of Science Biology journal.