Sensorimotor sequence learning in the ant Gigantiops destructor

In several ant species, foragers venture outside the nest individually to collect food at a remote location, relying on memorized views of the surroundings to find their way. Although sensorimotor learning has been described previously in bees and a few ant species, its potential importance for navigation has often been underestimated. Motor memories independent of landmark identification could nevertheless prove useful for ants such as the tropical species Gigantiops destructor that forages in visually complex environments. We tested the sensorimotor learning ability of these ants using unmarked Y-mazes of increasing difficulty: constant-turn mazes, simple and double alternation mazes and irregular mazes. In the absence of visual cues, the ants were able to learn not only motor displacement rules but also route-specific patterns of movement. The ants' preference for simple navigation strategies was also demonstrated by their tendency to use a simple repetitive motor rule different from the rule they were expected to learn. These findings suggest that relying on different sensorimotor memories eliminates the need to form, store and retrieve numerous landmark views along foraging routes, which are potentially cognitively demanding and time consuming in naturally cluttered environments.