Rare-Earth Magnets Influence Movement Patterns of the Magnetically Sensitive Nudibranch Tritonia exsulans in Its Natural Habitat

Abstract

Overview

The study focuses on the nudibranch Tritonia exsulans, previously known as Tritonia diomedea, which exhibits behaviors and neural responses that are sensitive to alterations in the Earth's magnetic field. The aim was to examine how this magnetic perception might function in their natural environment.

Methodology

An exploratory study was conducted using underwater video footage to analyze the crawling patterns of Tritonia exsulans. Magnets with varying strengths were placed in the substrate to observe potential effects on movement.

• A paired comparison approach was used.
• Track measurements were taken from distances both close to (0-25 cm) and further from (25-50 cm) the magnets.

Findings

Most measurements, including track length, displacement, velocity, and tortuosity, showed no significant differences with varying magnet strengths. However, notable effects were observed in the variability of track headings, with increased heading variability when the nudibranchs moved closer to stronger magnets.

Conclusion

The findings support the hypothesis that Tritonia exsulans might use its magnetic sense continuously to maintain its navigation in straight lines. The results prompt further specific tests to explore this potential animal compass sense.