Guided by the Stars 

Each spring, billions of Bogong moths take to the night skies of southeastern Australia, flying hundreds of miles to reach their cool alpine retreats. 

For years, scientists have wondered how these unremarkable-looking insects manage to return to the same cool caves in the Snowy Mountains year after year. Earlier research showed that the moths rely on Earth’s magnetic field to make their 600-mile journey. 

Now, a new study has found that Bogong moths (Agrotis infusa) also navigate by the stars. 

Researchers found that the moths use a stellar compass – relying on constellations and the Milky Way itself – to guide their nocturnal migration, making them the first known invertebrates to use star patterns for long-distance travel. 

“Bogong moths are incredibly precise,” senior study author Eric Warrant said in a statement. “They use the stars as a compass to guide them over vast distances, adjusting their bearing based on the season and time of night.” 

To test their theory, Warrant and his team created a miniature flight simulator, suspending the moths on tungsten rods inside a magnetic vacuum to isolate celestial cues. When a realistic night sky was projected above them, the moths consistently flew in the correct migratory direction. 

But when researchers rotated the sky image 180 degrees, the moths changed course accordingly – demonstrating they were using the stars for orientation. When the star patterns were scrambled, the moths became completely disoriented. 

“That was, for us, like the final proof, more or less, that they actually indeed use the stars for navigation,” co-author David Dreyer told NBC News. 

The team also found that the moths combine this stellar guidance with their internal magnetic compass, giving them a robust dual navigation system – even in cloudy weather. 

“This proves they are not just flying towards the brightest light or following a simple visual cue,” Warrant added in the statement. “They’re reading specific patterns in the night sky to determine a geographic direction, just like migratory birds do.” 

The researchers hope their findings not only reveal the remarkable sophistication of insect navigation but also support conservation efforts. 

Bogong moth populations have plummeted in recent years: In 2021, it was added to the International Union for Conservation of Nature Red List as a vulnerable species.