When steering balls of poop, dung beetles use the stars to navigate

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FACT: Dung beetles use the Milky Way to steer their poop balls 

By Christie Taylor

A dung beetle is a deceptively humble creature. Humble, in the sense that they literally eat and raise their young in poop. Deceptive in the sense that they perform incredible feats of strength, play an underappreciated ecological role, and can even (in some cases) appreciate our place in the cosmos.

Dung beetles are all members of the scarab family. And if the word “scarab” evokes ancient Egypt for you, there’s a reason. The scarab-headed god Khepri was, in fact, a dung beetle. Ancient Egyptians had seen these beetles rolling balls of dung, and connected them to the sacred, dung ball-like orb of the sun itself, as well as concepts of renewal and rebirth.

In any terrestrial ecosystem, a fresh pile of poop is an entire universe. Beetles eat dung, flies lay eggs, other insects come to eat the larvae of these animals. It’s a beautiful stinky circle of life.

It’s also dangerous and competitive, which is why one group of dung beetles has a strategy for success: get some poop, pack it into a ball, and roll it the hell out of there. These balls are sometimes 50 times their weight, and they’ll move them as far away as 200 meters before burying them underground.

First, though, they dance: the dung beetle hops atop their fresh-rolled ball of poop and performs one or more rotations before they then push their precious cargo to a safe hiding place. It likely plays a role in these beetles’ orientation to landmarks in the sky–which may be one way these beetles avoid rolling in circles and ending up right back where they started, in poop central. Signals like the rising or setting sun, the wind, and polarized moonlight are in the arsenal of dung beetles’ compass cues, without which they struggle to orient and travel in wobbly, circular paths.

And for at least one nocturnal species, the vital clue on a moonless night seems to be our own Milky Way. In 2013, a research team took some specimens of Scarabeus satyrus (and some poop) to a planetarium in Johannesberg, South Africa, and tested their navigational skills with and without a projection of our galaxy’s trademark diffuse band of light. Remarkably, the beetles steered straight–and floundered when fitted with tiny cardboard hats to block their eyes. 

Later research suggested these beetles are using the differences in brightness along the Milky Way, as opposed to individual star patterns, to find their way. And other research has found these nocturnal dung-haulers may be vulnerable to increasing light pollution, as bright lights provide confusing new landmarks, and diffuse light washes out the Milky Way’s vital contrasts.

Why does it matter if a beetle runs its poop in a straight line? Dung beetle success is crucial to healthily dispersing animal waste in ecosystems by bringing nutrients directly into the soil. There’s a citation-less figure floating around the internet that in some parts of Texas, dung beetles bury 80 percent of manure from cattle ranching–either way, these insects can absolutely demolish an individual cowpat.  And in so doing, they may help reduce methane and even CO2 emissions from livestock manure. 

And by burying and eating dung, they reduce the opportunities for flies and other pests to propagate–a lesson Australians learned the hard way when native dung beetles proved poorly adapted to assisting with the dung of colonists’ influx of cows and sheep. Thankfully for Australians, a government program to introduce and appreciate cow poop-eating beetles has been active since the 1960s.

FACT: Bananas might be the secret to better beer

By Laura Baisas 

Bananas might be the secret to a better beer. In 2022, a team of microbiologists in Belgium reported that they could improve contemporary beer’s flavor by genetically engineering a type of yeast. They focused on a gene for a banana-like flavor, “because it is one of the most important flavors present in beer, as well as in other alcoholic drinks.” The brewing of beer has a fascinating scientific, culinary, and sociological history, with women serving as brewmasters for centuries. Listen to this week’s episode to learn more! 

FACT: Made up animals can help us understand how language evolves online—and how resistant people are to censorship

By Rachel Feltman

In recent years, folks have started talking about a phenomenon often called “algospeak.” It’s where users of social media platforms like Instagram and TikTok come up with code words to help them avoid algorithms that suppress or outright ban certain topics of discussion. But this kind of linguistic innovation is far from new. In fact, researchers have been studying a similar tactic among Chinese internet users for more than a decade. 

The classic example of this phenomenon is discussion of an animal called the “grass mud horse.” Despite having millions of results on Google, the animal doesn’t exist. Its name is a sort of homophone you can only play with in a tonal language like Mandarin or Cantonese. By shifting tones, you turn cǎonímǎ—grass mud horse—into cào nǐ mā, which is a very profane insult. Talking about this made up animal (and an assortment of other imaginary species) allowed internet users to curse, discuss topics considered taboo by the algorithm, and criticize government officials and their policies without risking censorship. You can see a great visualization of how this kind of wordplay works here. 

In some cases this has led to seemingly random words being banned. For example, the name of the band Hoobastank became a stand-in for the censored word “tank,” and is now itself flagged! 

Chinese social media platform Weibo recently pledged to crack down on this kind of pun-based censorship evasion for good. But luckily they’ve got their work cut out for them, because people just keep upping their wordplay game.