Dung Beetle Navigation

hook
Short and sweet, this hook engages the reader with a personal story and an intriguing question.

Black Lives Matter @GeneticJen 路 Aug 14

So today I was talking about evolution being amazing and literally every animal being awesome and I'm told the dung beetle isn't. Thread 馃憞

mechanism narrative
This tweetorial starts with an internal, mechanistic narrative, where the dung beetle is the main character. This narrative describes how the dung beetle, motivated to avoid conflict with other dung beetles, must find a way to quickly roll its dung away.

Black Lives Matter @GeneticJen 路 Aug 14

"It rolls poo". Yeah so lemme talk about that for a second. You can either roll poo, or you wait to ambush another beetle rolling poo

Black Lives Matter @GeneticJen 路 Aug 14

So if you're rolling poo, you wanna roll it the hell out of there as fast as possible in case you're going to get ambused

Black Lives Matter @GeneticJen 路 Aug 14

Fastest way to get somewhere? A straight line. So dung beetles push their ball in as straight line as possible. Simple, right?

discovery narrative
The reader accompanies the scientist Marie Daeke as she figures out the mystery of dung beetle navigation. The dung beetle remains a secondary character in this narrative, but now the focus in on Marie Daeke's process of learning from experiments, finding contradictions, and then resolving those contradictions through new discoveries.

Black Lives Matter @GeneticJen 路 Aug 14

How do dung beetles keep such a straight line? Marie Dacke, a biologist at Lund University in Sweden found they observed the sun and moon

Black Lives Matter @GeneticJen 路 Aug 14

During the day they watch the sun and during the night they use polarised light from the moon. This was back in 2003. Good so far https://t.co/eFBWlIGD8K

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Black Lives Matter @GeneticJen 路 Aug 14

If you put the beetle in a walled area so it can't see surroundings, it uses the moon. Takes 20 secs to get to a wall

Black Lives Matter @GeneticJen 路 Aug 14

Put a lid on top so it can't see the moon and now it takes 2 mins on average to hit a wall because they can't keep a straight line

Black Lives Matter @GeneticJen 路 Aug 14

This is what happens if you have a light source at the top turned on and then turn on the one at 90 degrees instead. It changes course https://t.co/3mpZjBvlwf

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Black Lives Matter @GeneticJen 路 Aug 14

Marie Dacke observed something weird in the following years. If the beetle can see the sky but it's a moonless night, it still does well

Black Lives Matter @GeneticJen 路 Aug 14

40 seconds with moonless night sky rather than expected 2 minutes. Was she wrong? Is it not really about the moon? So she studied further

Black Lives Matter @GeneticJen 路 Aug 14

They can't be using the stars because the beetle's eyes are too shit for that. Where you see a star they see darkness. So what gives?

Black Lives Matter @GeneticJen 路 Aug 14

She did things like turn only the brightest stars on, or only dimmer ones, and all sorts of weird experiments to see what the beetle did

Black Lives Matter @GeneticJen 路 Aug 14

Get this, the dung beetle can't see an individual star but it CAN see the Milky Way. Our spiral galaxy. It orients itself by our galaxy https://t.co/68sIhnLrtx

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payoff
The author returns to the hook and answer its question: why are dung beetles so cool? The author then zooms out to highlight the beauty in how something so small interacts with something so big.

Black Lives Matter @GeneticJen 路 Aug 14

Dung beetles might be lowly, smelly, poo-pushers but hey they're the only insect we know that observes our galaxy and I think that's cool

Black Lives Matter @GeneticJen 路 Aug 14

We think of bio as small and astronomical objects as huge and separate but things interact even at these differences in scale https://t.co/JowHzbEXAt

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