Name: 墨西哥跳豆為什麼會跳？（Why Did the Mexican Jumping Bean Jump? | Deep Look）
Uploaded: 2021-09-27T14:32:44.000Z
Duration: 4 min 16 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

What if you spent most of your life in near  darkness, surrounded by the same walls,  

That's life inside a Mexican jumping bean…  and that's just how these creatures like it.

They're the same jumping beans you find in  markets all over Mexico and exported worldwide.

But they're not something you'd want  to eat. They aren't beans at all.

They're seeds of this scraggly shrub.  

It primarily grows in Mexico, in  the mountains of the Sonoran Desert.

There are three of them that make up this fruit.

Some of these sections have a stow-away –  

a tiny moth larva that burrowed into the  seed while it was still on the plant.

The larva devours the inside of the seed,  

hollowing out its new pad to  make room for its growing body.

Over the next 8-10 months our squirmy friend  lines the walls with a comfy layer of silk.

Just enough air and moisture sneak in  through tiny holes in the seed walls.

That heat can dry out and  kill our sweet little larva. 

A few hops out of the sun can mean  the difference between life and death.

Luckily, it's got wheels – well sort of.

The seed's shape – with two flat sides  

and one curved – even allows the  jumping beans to travel uphill.

With its back legs, it grabs onto the silk lining  and thrashes its head against the seed wall.

Researchers think these headbangers  aim themselves in the right direction  

using a finely-tuned sense of temperature.

Check out this experiment. One side  of the pan is warmed by a heat lamp,  

Over time, the larvae move away from the heat.   

It's not always a smooth trip. If the seed  gets damaged, the larva springs into action,  

repairing holes with a dense patch of silk.

But the larva can't stay in  its comfort zone forever.

With sharp mandibles, it cuts a circular door  in the seed wall. But it doesn't open it.

And then transforms into an adult moth. It simply pushes itself through the  

pre-cut exit door – which is handy,  because now its mandibles are gone.

The liberated moth has mere  days, maybe a few weeks,  

to quickly mate and lay eggs before it dies.

But after all, freedom isn't  really what this animal lives for.

For most of life, it's totally fine being  a young larva trapped inside a seed,  

just hoping – and hopping  – for a place in the shade.

Hi, it's Laura. It's hard to grow  up. You know what's also hard?  

Giving birth. A female tsetse fly pushes out a  single squiggly larva almost as big as herself,  

which she nourishes with her own milk. That's  right: fly milk. Enjoy and see you soon.

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墨西哥跳豆為什麼會跳？（Why Did the Mexican Jumping Bean Jump? | Deep Look）

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