VICK, K. A. ; Univ. of Maryland, College Park: Gravity as a Navigational Cue for the Leaf Cutter Ant Atta cephalotes

A vertical T-maze is used to investigate the role that gravity plays in Atta cephalotes navigation. The gravitational cue was put in direct conflict with odor cues and light cues. There was an asymmetry to the ants� response to the gravity cue in that ants returning to a food source had a tendency to go up regardless of the previous position of the food source or the position of the odor trail. Recruited ants consistently followed the odor trail regardless of its direction. Introducing a light cue changed the angle required to make the ants respond to the gravitational cue. This suggests that the fusion of response observed in geotaxis and phototaxis also exists in more sophisticated forms of navigation.