Dung Beetles Navigate by the Stars

The Milky Way guides intrepid insects.

How do African dung beetles, nocturnal creatures with tiny brains, protect their next meal? Remarkably, they rely on the Milky Way. The galaxy’s light improves the insects’ getaway path, allowing them to walk a straighter line when they see it and quickly move the fecal balls they eat away from the source—and throngs of potential thieves. “If they roll around in circles, the chance of coming back to the pile is there,” says Marie Dacke, a researcher at Sweden’s Lund University who published the findings in the journal Current Biology. “Then they will have rolled around and made the ball for nothing. The only safe way is to move in a straight line.” Thousands of beetles might descend on a fresh pile of feces; each insect pushes its prize up to 60 feet away from the source and devours it over five days before flying off in search of more food. The discovery has broad implications, including shedding light on how moths or locusts might use the same technique to migrate at night, or understanding how insects with small eyes and brains (sensors and processors, as Dacke calls them) solve complex challenges.

This story originally ran in the May-June 2013 issue as "Walk This Way."