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Legless, Leaping Larvae

Jump, little maggot, jump!

Show the world that not only the finely muscled and strong-boned can defy gravity, but also the soft-bodied and wormy.

Squish your body into a loop, hook your front to your back, pump up the internal pressure and fling yourself skyward in an exhilarating, tumbling arc.

This is not about a new Marvel superhero, although if any film producers are interested in a “Wonder Worm” treatment, I have a few ideas. This is research, several years of it, and all that attention couldn’t come to a nicer larva.

This lively leaper is the young, wriggly form of an insect called the gall midge. It is found in galls, or bumps on plants, not in rotting meat — so that’s a plus. And it’s so tiny, only a tenth of an inch long.

We knew the little fellows could jump, we being the scientific community that studies the quick and surprising movements of soft-bodied cylindrical insect larvae. But only with a video camera recording at 20,000 frames per second, and the use of scanning electron microscopes, did researchers come up with a detailed analysis of just how the marvelous maggots move. Earlier recordings were no faster than 54 frames per second.

The fairly obvious part, which had been figured out, more or less, is that the larva bends its soft body into a springy loop and launches itself across distances up to 30 times its body length. But there are some surprises, a research team reported Thursday in the Journal of Experimental Biology.

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The larva uses two patches of microscopic hairs that bond to each other to form a latch that links its front and rear end together. And it forms kind of a temporary leg to aid its launch. When the latch is released, the maggot flies.

Sheila Patek, who heads a lab at Duke University that studies links between physics and evolution, led the team that studied the movements of gall midge larvae. She is known for work on other quick microscopic movements, like the jaws of the trap jaw ant or the hammer of the mantis shrimp.

She said a friend and one of the authors of the new paper, Michael Wise of Roanoke College, brought the gall midge maggots to her attention.

Her lab doesn’t often find a new subject, she said, and the maggots were “really, really small, and really fast and hard to study.”

But the work paid off. The larvae did not use an anatomical feature called a spatula, which they use to burrow, in order to link front and back. Instead, those patches of microscopic hairs adhered to each other because of so called van der Waals forces, which involve electric attraction and repulsion.

And to help with the launch, the maggots formed a temporary leg of sorts by making a portion of their bodies particularly rigid. The researchers also found that for the larvae, jumping was much more efficient than crawling.

That may be why the larvae leap — to explore spots to burrow. Or it could be to escape predators. Until scientists come up with an answer, we are free to imagine that they jump for joy.

David Hu, a mechanical engineer at Georgia Tech who often studies animal movements but was not involved in this research, said the paper was “full of surprises,” such as the latch: “It’s a soft latch, composed of thousands of microscopic parts, that can shoot a soft larva like its being shot out of a cannon.”

Dr. Patek said the research shows “what you can do with a tiny, worm-shaped body,” and noted that “engineers are extremely interested in soft robotics.”

Earlier reporting on how things moveHow Spiders FlyJun 26, 2018A Sea Snail That Moves Like a Flying InsectFeb 22, 2016Slithering Through the Air With the Greatest of EaseFeb 19, 2014Why Is This Ostrich Wearing an Extra Set of Wings?May 2, 2019Never Mind Walking; Some Insects Can Jump on WaterAug 3, 2015


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