February 26, 2009

Desert ants use odor trails for navigation

Germany scientists have used gas chromatography to determine desert ants use their olfactory sense to find their way without landmarks for guidance.

Researchers from the Max Planck Institute for Chemical Ecology discovered desert microhabitats have unique odor signatures that can be used to guide the ants back to their nest.

Until now scientists thought the desert ant Cataglyphis fortis, which makes its home in the Tunisian desert, was a vision-guided insect.

But the researchers -- Kathrin Steck, Bill Hansson and Markus Knaden -- trained ants in field experiments to recognize the odors pointing to a hidden nest entrance. The ants not only learned to associate their nest entrance with a single odor but even picked out the training odor from a four-odor blend.

Although most ants rely on self-generated pheromone trails, Cataglyphis roams for more than 100 meters in search for food in a habitat where high temperatures and changeable food locations make pheromone trails ineffective.

We are amazed to discover that while keeping track of the path integrator and learning visual landmarks, these ants can also collect information about the olfactory world, said Knaden, who hopes to investigate the interaction between visual and olfactory information in future research.

The study appears in the journal Frontiers in Zoology.