Milky Way Shepherds Dung Beetles Away from Competitors

Dung beetle researchers have discovered that the diminutive insect orients itself relative to the light emanating from the Milky Way, an observation which may very well apply to other various species in the animal kingdom. Originally published in the journal Current Biology, the study asserts that this particular evolutionary trait may have developed to ensure that each individual beetle can quickly and efficiently secure its own ball of dung as far away from the original source as possible in order to avoid the competition.

Study co-author Eric Warrant of the University of Lund explains, "If they roll back into the dung pile, it's curtains. This is a complicated navigational feat-it's quite impressive for an animal that size."

Scientists originally believed that the insect used photoreceptors to track the moon at night, but their results contradicted their hypothesis. "We didn't know how to explain this all, says Warrant. "It occurred to us that maybe they were using the stars-and it turns out they were."

So, what are the implications of this study? UC Riverside entomologist Bradley Mullens suggests, "I would not be surprised if other nocturnal insects-or maybe other animal groups-might be able to use a diffuse but directional cue such as the Milky Way. Maybe this paper will stimulate more studies of that nature."

The University of Nebraska-Lincoln's resident dung beetle researcher Sean Whipple tells National Geographic, "If artificial light-from cities, houses, roadways, etc.-drowns out the visibility of the night sky, it could have the potential to impact effective orientation and navigation of dung beetles in the same way as an overcast sky."