Each year in Australia, millions of Bogong moths make an amazing migration. In spring, the moths hatch from eggs in their breeding grounds in Australia’s southeast. They then fly 1,000 kilometers (621 miles) south to spend a few months in the cool caves of the Australian Alps. Then in the fall, they fly back to their breeding grounds, where they mate, lay eggs, and die.
How do the moths know how to make the journey from their birthplace to the Australian Alps? The moths never meet their parents, so they do not learn the route from them. Also, moths do not have GPS or Google Maps! Previously, researchers learned that Bogong moths use Earth’s magnetic field and an unknown landmark to reach the Alps.
Now, scientists have discovered that Bogong moths rely on bright stars and the Milky Way to guide their migrations.
To figure this out, researchers captured migrating Bogong moths and took them to a lab. They placed the moths in a special enclosure with no magnetic field and projected a night sky onto the ceiling. They recorded the moths’ flight directions.
The team found that when they projected the natural starry sky and the Milky Way as they exist in nature, the moths flew in their correct migratory directions. When the researchers rotated the star patterns, the moths turned with the rotated patterns. When the star map was scrambled, and the Milky Way and constellation patterns were lost, the moths became disoriented.
Eric Warrant, one of the moth researchers, explains: “This proves they are not just flying towards the brightest light or following a simple visual cue. They’re reading specific patterns in the night sky to determine a geographic direction, just like migratory birds do.”
David Brown adapted this story for Mongabay Kids. It is based on an article by Shreya Dasgupta, published on Mongabay News.
