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Dung beetle uses Milky Way to navigate; Will scientists discover more insects that do the same?

Researchers from Lund University in Sweden have discovered the secret to dung beetle navigation, according to a news release from Cell Press. Researchers found that dung beetles use the Milky Way galaxy to navigate at night.

Scientists have known for years that birds and humans navigate by the stars, but this findings is the first believable evidence for a similar ability in insects, according to researchers. This is also the first known evidence of any animal navigating via the Milky Way as opposed to the stars.

“Even on clear, moonless nights, many dung beetles still manage to orientate along straight paths,” said Marie Dacke of Lund University in a statement. “This led us to suspect that the beetles exploit the starry sky for orientation—a feat that had, to our knowledge, never before been demonstrated in an insect.”

Dacke and her colleagues were amazed by the discovery. They pointed out that their findings reveal that even some of the simplest creatures in the animal kingdom have the ability to perform complex actions.

“It’s just another example of how wonderful the animal kingdom is, how the most amazing things have evolved,” said co-author Eric Warrant of Lund University.

Dacke and her team of researchers discovered that dung beetles move their dung balls along straight paths under a starlit sky but lose the ability to do so under overcast conditions. When placed in a planetarium, the dung beetles moved their dung balls along straight paths equally well under a full starlit sky and one exhibiting only the Milky Way.

While the night sky is littered with stars, most of them are probably too dim for the dung beetles’ tiny compound eyes to see, say researchers.

“Dung beetles are known to use celestial compass cues such as the sun, the moon, and the pattern of polarized light formed around these light sources to roll their balls of dung along straight paths,” Dacke added. “Celestial compass cues dominate straight-line orientation in dung beetles so strongly that, to our knowledge, this is the only animal with a visual compass system that ignores the extra orientation precision that landmarks can offer.”

Researchers think that other nocturnal insects may also look to the stars to help them navigate at night. The ability to use the stars for orientation gives the dung beetle a unique advantage. After locating a good pile of dung, the beetles shape a piece of dung into a ball and roll it away along a straight path. The ability to navigate using the stars means that that they will not return to the same dung pile and risk having their ball taken away by other beetles.

“They always roll straight. If they don’t roll straight, something is wrong,” said Warrant. “They have to get away from the dung pile as fast as possible, or the balls they roll will be stolen by other beetles.”

The study’s findings will be published online on January 24 in Current Biology.