美国国家公共电台 NPR Scientists Find Out How Leaping Maggots Leap（在线收听）

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This is the time of year when goldenrod blooms. It's that yellow flower you often see growing along highways. A scientist was recently studying goldenrods and discovered something phenomenal. As NPR's Nell Greenfieldboyce reports, it's a small creature that has no arms, legs or wings but nonetheless performs a remarkable feat.

NELL GREENFIELDBOYCE, BYLINE: Plants defend themselves from hungry insects, and Mike Wise studies that at Roanoke College in Virginia. A few years ago, he was dissecting tumor-like swelling on goldenrod. These growths form around little maggot-like things that are the larvae of developing flies.

MIKE WISE: And the larvae get as big, when they're full grown, as a small grain of rice.

GREENFIELDBOYCE: They look like bright orange tiny worms.

WISE: And generally I take the larvae out and put them in a little dish next to my microscope, and they barely move. They may wiggle around just a little bit.

GREENFIELDBOYCE: On this day, he'd spend about an hour removing a dozen or so. But then he looked in the dish, and they were gone.

WISE: I was wondering what was going on. And then I caught out of the corner of my eye a little bit of motion, a little orange larva jumping across my table.

GREENFIELDBOYCE: The larvae were leaping.

WISE: I looked on the floor, and there had been some that had jumped all the way to the wall.

GREENFIELDBOYCE: But how? They don't have anything critters normally use to jump. To understand this, he brought bouquets of goldenrod to Sheila Patek. She's a biologist at Duke University who studies small extremely fast things like the deadly strike of the mantis shrimp or the snapping bite of trap-jaw ants.

SHEILA PATEK: I know that sounds super quirky, but it turns out that this arena of biology is a very interesting one.

GREENFIELDBOYCE: Because these creatures do stuff that engineers can only dream of. Her lab filmed Wise's leaping larvae with some of the world's best high-speed cameras.

PATEK: You know, he'd get one out and put it in a tray. And I'd be like, oh, OK, yeah, well, there it is. And the next thing you know, this tiny little thing is curling up into a loop. And the next thing you know, it's gone.

GREENFIELDBOYCE: Curling up into a loop turns out to be critical. Patek says, if you were one of these little guys, you'd first curl up so that a special patch of hair on your head sticks to a patch of hair on your rear end. Then you'd need to squeeze fluid through your soft body to stiffen up the part that's against the ground.

PATEK: And you keep doing that, and you keep doing that, and you keep doing that until suddenly you've generated enough force that it unsticks the hairs between your head and the tail, and you are suddenly airborne.

GREENFIELDBOYCE: The findings in the Journal of Experimental Biology have impressed Sarah Bergbreiter. She's a mechanical engineer at Carnegie Mellon University who says there's a lot of interest these days in robots that are soft instead of rigid and clanky (ph).

SARAH BERGBREITER: One of the really cool things about it is that these are soft-bodied jumpers. That means they're squishy, and they can jump over 30 body lengths.

GREENFIELDBOYCE: She says that's comparable to fleas, which we think of as great jumpers.

Nell Greenfieldboyce, NPR News.