Detouring while foraging up a tree: What bull ants (Myrmecia midas) learn and their reactions to novel sensory cues

Many animals navigate in a structurally complex environment, which requires them to detour around the physical barriers that they encounter. Although many studies in animal cognition suggest that they are able to adeptly avoid obstacles, it is unclear whether a new route is learned to navigate around these barriers and, if so, what sensory information may be used to do so. We investigated detour learning in traveling up a tree in the Australian bull ant, Myrmecia midas, which primarily uses visual landmarks. We first placed a barrier on the ants' upward path. Initially, 46% of foragers were unsuccessful in detouring the obstacle. On subsequent trips, the ants became more successful and established a new route. We observed up to eight successful foraging trips detouring around the barrier. We then tested the same foragers in a series of manipulations, including changing the position of the barrier, making a new gap in the middle of the obstacle, or removing the barrier altogether. The ants mostly showed the same learned motor routine, detouring with a similar path as in the initial trials, suggesting that foragers were not relying on barrier cues and therefore learned a new route around the obstacle. When foragers encountered new olfactory or tactile cues, or the visual environment was blocked; however, their navigation was profoundly disrupted. These results suggest that changing sensory information drastically affects the foragers' navigational performance. (PsycInfo Database Record (c) 2023 APA, all rights reserved).