Spatial mapping influences navigation in Entomacrodus striatus

ABSTRACT

We tested the orientation capabilities during jumping in blackspotted rockskippers (Entomacrodus striatus). Amphibious fish routinely navigate between terrestrial and aquatic habitats and use either spatial mapping or visual cues to determine where to safely jump. We recorded jumping direction during three experiments: training, visual cue disruption, and spatial memory disruption. During the first round of training, the fish were able to jump to safety in a novel environment, regardless of starting orientation (p < 0.001). E. striatus were able to learn the terrain after repeated conditioning and continued to jump in the same direction after we moved rocks to the opposite side of the table (visual cue disruption), even if that meant jumping into a wall (p = 0.033). To test memory disruption, we injected the fish with NOS inhibitor L-NAME and found fish jumps became randomly distributed (p = 0.452). These results suggest blackspotted rockskippers entrain using visual cues and then rely on a mental map for subsequent jumps.

KEYWORDS:

• Amphibious fish
• blackspotted rockskipper
• visual cues

Acknowledgments

The authors acknowledge Dr Peter Niewiarowski for assistance with statistical analysis, Dr Petra Gruber for rockskipper photography, Grey Buo for data entry verification, and James Kirk Buo for figure creation. We thank the entire University of Akron Tropical Vertebrate Zoology class for assisting in rockskipper capture and the staff and scientists of CRIOBE station, Moorea, French Polynesia.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

CB is supported by the Integrated Biosciences program at The University of Akron. The research group was hosted by the CRIOBE facility on Moorea, French Polynesia.