Birds and humans use stars to navigate (at least, our pre-GoogleMaps ancestors did), but can insects map their routes?
For dung beetles, a new study says the answer is yes. The African insects appear to find their way via the Milky Way. It’s the first evidence that any insect can orientate themselves with the sky, and the first evidence that any animal uses the Milky Way as a map of sorts.
“Even on clear, moonless nights, many dung beetles still manage to orientate along straight paths,” said Marie Dacke of Lund University in Sweden. “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.”
Dung beetles are so named because they search out piles of dung to roll into balls (yes, that’s dinner). They roll the balls in a straight line so that they won’t risk having their meal stolen by other beetles.
To test their navigation, researchers watched the beetles in a planetarium under a starry sky, a sky showing only the Milky Way, and an overcast sky. The beetles had no problem maintaining their straight lines under the first two skies, but couldn’t do it when the Milky Way was indistinguishable.
Most stars are probably too dim for the insects’ eyes, the researchers said in the study published online in Current Biology.
One question may remain unanswered: Is it more fascinating that these creatures navigate by the Milky Way, or eat dung for dinner?
Photo: Emily Baird