Dung beetles navigate using the Milky Way and other facts about ‘nature’s recyclers’

Science Friday
Rainbow scarab beetle

A rainbow scarab beetle, a type of dung beetle native to North America, is shown here. 

StingrayPhil/CC BY 2.0 (image cropped)

You may not envy what dung beetles and carrion beetles dine on, but you live in a world that they help keep clean. Think of the insects as “nature’s recyclers,” decomposing waste and returning all kinds of nutrients back into the ecosystem.

At a recent live show in Wichita, Kansas, Science Friday host Ira Flatow talked with Rachel Stone and Emmy Engasser, graduate researchers at Wichita State University’s biodiversity lab, about this powerful natural cleanup crew. Here are some surprising takeaways from their conversation:

Dung beetles navigate using the Milky Way

“There have been studies where scientists put, if you can imagine, adorable little hats that covered [the beetles’] eyes,” Stone said. “They could no longer navigate and they would wander in circles. But whenever those are removed, they can go in a straight path using the sun and using the Milky Way at night.”

Carrion beetles have a 'dead-on' sense of smell

“Carrion beetles can detect up to 1 to 2 miles away — they can smell the rotting carcasses,” Engasser said. “I know the American burying beetle can fly almost 1 kilometer [over half a mile] in a night. So, they're actively searching for that carrion, those dead animals to eat.”

Dung beetles have favorite, er, foods — just like we do

“There's dung beetles that have a really broad palate — you know, they'll eat any kind of dung they can find,” Stone said. “There's others that are more persnickety. For example, there are dung beetles that eat only the dung from sloths.”

Carrion beetles can smell pretty rank themselves

“They, a lot of times, have these orange or yellow patches on them, and that's a warning coloration because what they want to do is deter predators from eating them because they stink like rotting flesh,” Engasser said. “And so, they're trying to get those predators to not eat them.”

And finally, have you ever wondered why some dung beetles roll balls of dung?

“You have to imagine [dung] like it's this incredible resource,” Stone said. “It's like you're in the desert; there's no food at all, and somebody drops this tray of cheeseburgers on the ground and everybody is rushing all at once and they're greedy. They want their fair share of this really limited resource.”

“And so this is just one strategy that dung beetles show. But what he's doing is he's trying to tear a hunk off for himself and take it away from all the chaos of that pile of cheeseburgers — or poo — and he's taking it away so he can have it himself.”

Curious? There’s more! Take a beetle-catching field trip with Stone, Engasser, and the SciFri production team here. You can also listen to the full interview this segment is based on, from Science Fridays recent live show at the Orpheum Theater in Wichita, Kansas.

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