Dynamic multimodal interactions in navigating wood ants: What do path details tell us about cue integration?

Ants are expert navigators using multiple cues from multiple sensory modalities to navigate successfully. Here, we present the results of systematic studies of multimodal cue use in navigating wood ants, Formica rufa. Ants learnt to navigate to a feeder that was defined by an olfactory cue, visual cue and airflow presented together. When ants learnt to find a feeder that was placed in the centre of the visual cue, well-trained ants were not anymore able to accurately approach the feeder when either the olfactory or visual cue were removed in tests. This confirms that some form of cue binding has taken place. However, in a visually simpler task with the feeder located at the edge of the visual cue, ants still approached the feeder accurately when individual cue components were removed. Hence, cue binding is flexible and depends on the navigational context. In general, cues act additively in determining the ants paths accuracy, i.e. the use of multiple cues increased navigation performance. Moreover, across different training conditions, we saw different motor patterns in response to different sensory cues. For instance, ants had more sinuous paths with more turns when they followed an odour plume but did not have any visual cues. Having visual information with the odour enhanced performance and therefore positively impacted on plume following. Interestingly, paths characteristics of ants from the two multimodal groups with a different visual task were different, suggesting that the observed flexibility in cue binding may be a result of the ants movement characteristics. Summary statementWe investigated the impact of multimodal information on navigating ants. Ants showed flexible response to multimodal information depending on the sensori-motor contingencies of the navigation task.