How do scarab beetles use the light of the Milky Way?

The scarab beetles actually use the light strip from the Milky Way to navigate! They are the first animals to of been found to use the starlight to navigate. Scientists were amazed to find the beetles would roll their dung balls in a straight line at night leading them to conclude starlight had an impact on their movements. Sure enough, they found the beetles to not move in a straight line when the night was cloudy! Since the beetle's eyes are probably not strong enough to see individual stars they made the conclusion that it must be a cluster of stars and noticed that it lines up with the Milky Way! Cool stuff!

https://www.theguardian.com/science/2013/jan/25/dung-beetles-navigate-stars