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

  • eating the same food, all alone?  

  • 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.

  • It's a cozy life.

  • Except for the sweltering desert sun.

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

  • So, of course, it starts jumping.

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

  • Luckily, it's got wheelswell sort of.

  • The seed's shapewith two flat sides  

  • and one curvedeven allows the  jumping beans to travel uphill.

  • Inside, the larva is working hard.  

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

  • The force topples the seed.

  • 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,  

  • the other cooled by an ice pack.

  • 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.

  • It's doing its future self a favor.

  • When it's done it turns into a pupa.

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

  • pre-cut exit doorwhich is handybecause 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 hopingand 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 outsingle squiggly larva almost as big as herself,  

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

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

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B2 中高級 美國腔

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

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    shihwun 發佈於 2021 年 09 月 27 日
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