For people in southern Australia, the Bogong Moth is a familiar friend. Every spring, some 4 million Bogong moths migrate, sometimes over 1000km, from southern Queensland to the high-altitude regions in the Dividing Range. They can be difficult to spot – with their brown and grey camouflage wings, but they may occasionally ascend on houses, attracted to the light, while making their annual journey south.
New research from Nature has, in a world-first discovery, revealed how these humble invertebrates make this vast journey – by combining celestial navigation with Earth’s magnetic field to pinpoint a specific destination it has never visited before.
“Until now, we knew that some birds and even humans could use the stars to navigate long distances, but this is the first time that it’s been proven in an insect,” says Lund University Professor of Zoology, Eric Warrant.
“Bogong moths are incredibly precise. They use the stars as a compass to guide them over vast distances, adjusting their bearing based on the season and time of night.”
Using sophisticated flight simulators and brain recordings in controlled, magnetically neutral environments, the researchers tested how moths orient themselves under different sky conditions.
When shown natural starry skies with no magnetic field, the moths still flew accurately in their correct seasonal direction — south in spring, north in autumn. Rotating the sky 180 degrees flipped the moths’ direction. When stars were scrambled or hidden, the moths became disoriented.
“This proves they are not just flying towards the brightest light or following a simple visual cue,” says Warrant. “They’re reading specific patterns in the night sky to determine a geographic direction, just like migratory birds do.”
Interestingly, when stars were obscured by clouds, the moths maintained their direction using only the Earth’s magnetic field, ensuring reliable navigation even in poor flying conditions.
Even more extraordinary, the researchers pinpointed specialised neurons in the moths’ brains that respond to celestial orientation. These cells, located in regions responsible for navigation and steering, fired most strongly when the moths faced southward.
“This kind of directional tuning shows that the Bogong moth brain encodes celestial information in a surprisingly sophisticated way,” says Warrant. “It’s a remarkable example of complex navigational ability packed into a tiny insect brain.”
Researchers say the discovery could inform technologies in robotics, drone navigation, and even conservation strategies for species threatened by habitat loss or climate change.
“This is not just about a moth – it’s about how animals read the world around them,” says Warrant. “The night sky has guided human explorers for millennia. Now we know that it guides moths, too.”