Dung beetles use balls of feces away for food and brooding chambers. To do so, they (specifically the 10% nicknamed “rollers“) hide the dung from the other greedy beetles by rolling it away from the location they found it.
However, this presents a unique problem: how to roll the ball away without doubling-back to your original location. Strangely enough, these scarabs can travel disorderly and indirect routes to the source of dung while still able to make a straight path to their home once more!
To accomplish this interesting feat, dung beetles use the Sun and Moon to guide their travel. The light from the sun gives them a bearing during the day (or the moon at night) telling them if they are facing the right direction. Even polarized light from these sources is utilized, as dung beetles can perceive these light sources that we cannot!
However, when the sun goes down and the moon isn’t out, how do the beetles travel in a straight line? It was determined that, unlike crabs who use individual stars to find their way, dung beetles use the Milky Way to orient themselves! The light of the Milky Way across the sky guides the beetles in any direction they want to go; in the same manner as they would use the sun or moon. This makes the scarab the only insect known to use stars for direction, and the only creature to use the Milky Way.
I highly recommend this TedX lecture at Wits University for more fascinating information on the topic: