Scientists Reveal How Bogon Moths Navigate Using the Starry Night Sky as a Compass

Every spring, billions of Bogong moths (Agrotis infusa) migrate from their breeding grounds in southeastern Australia, covering distances of up to 1,000 km to reach previously unvisited locations.



The Bogong Moth utilizes stellar cues and Earth’s magnetic fields to develop a precise navigation system for long-distance night travel. Image credits: Lucinda Gibson & Ken Walker, Museum Victoria / CC by 3.0.

“While we already knew that certain birds and humans can navigate by stars, this is the first evidence showing that insects can do the same,” noted Professor Eric Warrant from the Australian National University and the University of South Australia.

“Bogong moths are remarkably precise navigators. They use stellar patterns as compasses, adjusting their course according to seasonal changes and the time of night.”

“Each spring, billions of Bogong moths emerge from their breeding sites in southeastern Australia, traveling up to 1,000 km to specific caves and rocky outcrops in the Australian Alps.”

“The moths remain dormant in cool, dark shelters throughout the summer and then return in autumn to breed and die.”

Researchers utilized advanced flight simulators and recorded brain activity in a controlled, magnetically neutral environment to study the moths’ navigation under various conditions.

Even without the natural starry sky or magnetic fields, the moths consistently flew in the correct seasonal direction.

They reversed their flight path when the night sky was rotated by 180 degrees, but became disoriented when the stars were jumbled.

“This demonstrates they aren’t merely flying toward the brightest light or relying on simple visual indicators,” Professor Warrant remarked.

“They interpret specific patterns in the night sky to establish their geographical bearings, similar to migratory birds.”

Remarkably, when the stars were obscured by clouds, the moths relied solely on Earth’s magnetic field for navigation.

This dual navigational system guarantees reliable orientation in diverse conditions.

https://www.youtube.com/watch?v=aqig_xbufe0

Professor Warrant and his team explored the neurological basis of this behavior and discovered specialized neurons in the moths’ brains that respond to star patterns.

These neurons, located in regions responsible for navigation and steering, are most active when the moth faces south.

“This directional tuning indicates that the Bogong moth’s brain encodes celestial information in an exceptionally sophisticated manner,” added Professor Warrant.

“This discovery exemplifies the complex navigational capabilities inherent in the brains of small insects.”

The findings could have implications for robotics, drone navigation, and conservation strategies for species threatened by habitat destruction or climate change.

Bogong moth populations have dramatically declined in recent years, prompting their listing as vulnerable.

This research underscores the necessity of protecting their migratory paths and the dark skies they depend on.

“This insight isn’t merely academic; it illustrates how animals perceive their surroundings,” Professor Warrant stated.

“The night sky has guided human explorers for millennia, and now we understand it also guides moths.”

This study was published this week in the journal Nature.

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D. Drayer et al. Bogong Moths utilize a star compass for long-distance navigation at night. Nature Published online on June 18th, 2025. doi:10.1038/s41586-025-09135-3

Source: www.sci.news

Australian Moths Navigate 1000 km Journeys Using the Stars as Their Compass

Bogong moths seek refuge in cooler caves during the summer

Ajay Narendra/Macquarie University, Australia

Traveling distances exceeding 1,000 kilometers to escape the summer heat, Australia’s moths have been identified as the first invertebrates to utilize stars for navigation on long migrations.

Every spring, billions of bogong moths (Agrotis infusa) embark from various regions of southern Australia, surviving the winter as caterpillars by feeding on vegetation before retreating to the cool caves of Australia’s Alpine regions. Once in the caves, they enter a state of dormancy known as estivation until they return to breeding grounds.

The recent decline of these moth populations has led to inquiries about their navigation methods in reaching high-altitude caves, as noted by Andrea Aden from the Francis Crick Institute in London.

Previous studies have demonstrated their ability to use Earth’s electromagnetic fields but only in conjunction with visible landmarks. Aden and her team sought to explore other potential cues that moths might use for navigation.

“When you venture into the Australian bush at night, one of the most striking visual markers is the Milky Way,” she explains. “We know that diurnal migratory birds rely on the sun, so testing whether moths use the starry sky seemed like a logical step.”

To investigate, the team employed light traps to capture moths during migration and transported them to a laboratory. There, they were placed in a Perspex arena with images of a night sky projected overhead. Moths were free to choose their flight direction based on the sky images while the Earth’s magnetic field was neutralized using a Helmholtz coil.

Experiments revealed that moths did utilize a stellar compass, according to team member Eric Warrant from Lund University, Sweden. “When the tethered moths were placed under a realistic starry sky, they oriented themselves towards their migratory direction,” he states. “They achieved this solely with the assistance of these stars, independent of other visual cues and the magnetic field.”

Caption: Aestivating moths in alpine caves during summer (roughly 17,000 per square meter, with millions in each cave) Copyright: Eric Warrant

Eric Warrant

When the simulated starry sky was rotated 180 degrees, the moth flew in the opposite direction. Randomizing the star placements in the image left them disoriented.

In a subsequent experiment, very thin electrodes were implanted in the moth’s brain, revealing changes in neural activity as the projected starfield was rotated.

While dung beetles are known to maintain a consistent bearing using the Milky Way, no other insect species has previously demonstrated this level of celestial navigation.

“The bogong moth is the first invertebrate documented with the ability to navigate long distances using stars as a compass—a phenomenon previously recognized only in certain birds and humans,” Warrant states. “This capability is truly remarkable.”

Another insect recognized for its extensive migrations, the Monarch butterfly (Danaus plexippus), primarily relies on the sun supplemented by the environment.

Cody Freas from Macquarie University in Sydney, Australia, emphasized the incredible efficiency of insect navigation, stating, “Stellar navigation showcases the remarkable visual acuity found in nocturnal insects, enabling them to utilize various cues (Sun, Moon, Stars) even in low-light conditions,” adds Freas.

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Source: www.newscientist.com