The desert ant’s use of its own built-in GPS – consisting of a sun-compass-based path integration system and visual landmarks – in locating its nest is a known phenomenon. Researchers recently ascertained, however, that this system also includes a sense of smell. Even more surprising is the discovery that these animals learn to distinguish between different odors in the nest environment, and use these like a map. Markus Knaden and his team at the Max Planck Institute for Chemical Ecology in Jena set out to search for clues in ant country.
Text: Marcus Anhäuser
Kathrin Steck looks a bit tired. That’s not surprising – she has been up all night. The biologist has been traveling since 2:00 a.m. Her trip started with a two-hour taxi ride through the darkness from the Tunisian town of Maharès to Monastir. From there, she flew back to Germany, took a train from Leipzig airport to Jena and, instead of going home, went straight to the laboratory at the Max Planck Institute for Chemical Ecology.
The reason for the urgency is the small glass of clear liquid in her backpack. It contains invisible odors extracted from the nest entrance of a desert ant. “These must be cooled as much as possible and then quickly processed,” says the 34-year-old post doc, who works with Bill Hansson, an olfaction expert.
Kathrin Steck and her colleagues Cornelia Bühlmann and Markus Knaden want to discover the substances that are contained in the nest odor of desert ants. Does every nest have its own odor? Or do all nests smell the same? What odor emanates from the entrance, a roughly two-centimeter hole in the encrusted ground of a desiccated salt lake? This is the typical habitat of the subject of their research – the feisty, shiny black ant Cataglyphis fortis.