The Ant Odometer: Stepping on Stilts and Stumps

Wittlinger, Matthias
Wehner, Rüdiger
Wolf, Harald

¹Department of Neurobiology, University of Ulm, D-89069 Ulm, Germany. ²Institute of Zoology, University of Zürich, CH-8057 Zürich, Switzerland.

*To whom correspondence should be addressed. E-mail: [email protected]

Supporting Online Material: www.sciencemag.org/cgi/content/full/312/5782/1965/DC1; Materials and Methods; SOM Text; References and Notes; Movie S1

2 March 2006; accepted 26 May 2006

10.1126/science.1126912

Science 312(5782):p 1965-1967, June 30, 2006.

Desert ants, Cataglyphis, navigate in their vast desert habitat by path integration. They continuously integrate directions steered (as determined by their celestial compass) and distances traveled, gauged by as-yet-unknown mechanisms. Here we test the hypothesis that navigating ants measure distances traveled by using some kind of step integrator, or "step counter." We manipulated the lengths of the legs and, hence, the stride lengths, in freely walking ants. Animals with elongated ("stilts") or shortened legs ("stumps") take larger or shorter strides, respectively, and concomitantly misgauge travel distance. Travel distance is overestimated by experimental animals walking on stilts and underestimated by animals walking on stumps.