Spatial learning through active electroreception in Gnathonemus petersii

Abstract

Navigation is a ubiquitous challenge to mobile animals as it is essential for finding mates, food and shelter. It can rely on self-generated (idiothetic) as well as external (allothetic) information. The contribution of either source of information depends on multiple factors, including the sensory modality. Far-range modalities such as vision have frequently been studied in the context of navigation, but the extent to which near-range sensory systems provide information for navigation is much less understood. Here we focused on spatial learning in the weakly electric fish Gnathonemus petersii. During their nocturnal excursions these fish typically rely on their short-range active electric sense to explore their environment. We addressed how these fish navigate and how electrosensory information is integrated in navigation. All fish learned to localize a target in a Barnes-like maze. In a series of transfer tests, we found that fish followed an idiothetic navigation strategy. When this strategy failed, fish were able to integrate electrosensory information to complete the task. Our results indicate that the active electric sense contributes to navigation in a resource-efficient and context-dependent manner. Together they show that weakly electric fish can incorporate highly localized sensory input in egocentric navigation. Extending these results will be important to reveal the sensory mechanisms of egocentric navigation in fish as well as to research whether and how spatially confined near-range sensory information might be used to form global representations of space.