The relative landmark shift during free movement on a treadmill may enhance visual learning for ant foragers.

Ants are known for their sophisticated navigational abilities and rely on various cues to locate food sources efficiently. Visual landmarks play a crucial role in guiding foraging behavior. However, the significance of walking ants perceiving the relative motion of a landmark to themselves during learning is still not fully understood. Here, Japanese carpenter ants were observed on a treadmill device where they could walk in place on the treadmill. Two types of conditions were set for the training process: the fixed condition involved a stationary landmark, and the moving condition featured a landmark oscillating at a constant speed from side to side after feeding, which was independent of the movements of the ants. In the Y-maze test, a significantly greater number of ants in the moving training condition associated the landmark with food (82% of the ants) than in the fixed training condition (56% of the ants). Our results thus suggest that perceiving the relative movement of landmarks during the learning process on a treadmill is important for ant foragers.