Cosmic Compass: How Insects Use the Milky Way to Navigate Across Vast Distances
Dung beetles are also known to consult the Milky Way to roll their dung balls directly away from a pile of droppings and avoid competition, as reports . However, these are extremely short distances. Bogong moths, on the other hand, travel hundreds of kilometers. Until now, researchers assumed that the moths native to Australia orient themselves on their journeys using the Earth’s magnetic field and only perceive larger visual stimuli in the night sky, such as the moon. Now, a new study shows that magnetism probably plays a much smaller role in the moths’ navigation than previously thought.
“Even the tiniest creatures look to the stars — proving that nature’s greatest journeys often follow a cosmic path.”
Researchers at Lund University in Sweden used a Helmholtz coil system to cancel the Earth’s magnetic field in a test environment, a kind of flight simulator, to study the orientation abilities of Bogong moths. They then showed the moths various constellations. The result: The moths continued to fly in the direction they were supposed to according to the prevailing season. But when the researchers randomly arranged the points of light in the night sky, the moths lost their orientation.
Therefore, according to the researchers, it’s clear that they don’t simply fly to the brightest light, as Science Alert notes . Rather, bogong moths are the first known invertebrates to use a star compass for navigation. In spring, Bogong moths fly in huge swarms toward the Australian Alps, where they spend the summer in cool caves. They fly for hours, but only at night, covering distances of up to 1,000 kilometers.
In the fall, they return to the exact same location from which they left, produce offspring, and die. The next generation then flies back toward the cool caves in the spring. Because Bogong moths only live for one year, it’s impossible for them to pass on the route to their offspring. The researchers discovered that the moths’ brains have specialized neurons that respond to their orientation relative to the starry sky. When the animal faces south, the neurons fire most strongly.
A sign that “the brain of the Bogong moth encodes celestial information in an astonishingly sophisticated way,” as Eric Warrant, lead author of the study published in the journal Nature , explains.
The Milky Way likely plays a crucial role in helping moths navigate during their long migratory journeys, much like it does for dung beetles. While dung beetles use the starry band of the Milky Way to roll their dung balls in a straight line away from the competition, moths appear to rely on the same celestial guide to travel vast distances across Australia. This surprising discovery highlights that even insects can use complex visual cues from the night sky to find their way, suggesting that the cosmos serves as a universal map for many creatures, regardless of size or intelligence.
