How ant brains use moonlight for navigation

Ants use polarized light from both the sun and the moon to navigate. Polarized light, which is light waves vibrating in a specific direction, serves as a natural compass. Ants can detect this pattern and adjust their direction based on the orientation of the light.

In this study, foragers responded to shifts in the direction of the polarized light, whether from the sun during the day or from the moon at night, helping them find their way home.

When navigating at night, ants rely on polarized moonlight in a similar way they use sunlight. Their behavior showed that they adjust their path by integrating the direction of the polarized light into their ongoing journey.

Impact of lunar phases on navigation
The ants' ability to detect and respond to the moon's polarized light was most effective during the waxing phase of the moon.

This ability to adjust their direction even under varying moon phases suggests that their brain can process and use lunar polarized light for long-distance navigation, just as they do with sunlight during the day.

However, when the moon was waning or absent, their responses were weaker. This reduction suggests that the ants' path integration system relies heavily on continuous access to the polarized light pattern, and any interruption, like a moonless sky, could disrupt their navigation abilities.

These findings show that the ants' ability to navigate is influenced by how well they can track the movement of celestial objects, especially the moon.

This research suggests that their brains integrate these cues into a long-term “path integrator,” allowing them to navigate accurately even over long distances.

The study opens the door to understanding how ants, and possibly other animals, use both visual and environmental cues to guide their movement in complex landscapes.

About the scientific paper:

First author:  Cody A Freas, Australia
Published: Elife, December 2024.
Link to paper: https://elifesciences.org/articles/97615