Every spring in southeastern Australia, billions of bogong moths take flight — guided not by instinct alone, but by the stars above.
The Agrotis infusa, or bogong moth, migrates from its birthplace across vast distances to the cool caves of the Australian Alps. What’s remarkable? These moths are flying to a place they’ve never seen before, using nature’s most ancient maps.
Now, scientists confirm a stunning truth: these tiny invertebrates use a dual navigation system.
How it works:
- Star-based navigation — the moths orient themselves using the starry night sky, even detecting the Milky Way.
- Magnetic field alignment — they use Earth’s magnetic field when clouds block the stars.
Using a flight simulator, researchers exposed moths to artificial night skies and magnetic fields. The moths consistently flew in the correct direction — south in spring, north in autumn. When either visual or magnetic cues were removed, they lost their way.
Brain recordings even showed neurons reacting to star patterns, proving moths interpret the sky for guidance — a trait previously seen only in birds, seals, and humans.
Why two systems? Stars work best on clear nights; Earth’s magnetic field provides backup during cloud cover or solar storms. Evolution built redundancy into their natural GPS.
But there’s a catch. Bogong moth numbers are declining rapidly. Light pollution from cities disrupts their stellar navigation, threatening their entire migratory journey.
Protecting this phenomenon means protecting dark skies. These moths follow the stars — let’s not turn them off.