Philosophy
These pesky, blood-sucking critters are a nuisance...but, they do exhibit some interesting physics as ants and their lifting power.
Cambridge University scientists have solved the mystery of how fleas jump so far and so fast.
It was known that the energy to catapult a flea over a distance up to 200 times its body length lay in a spring-like structure in its body.
But scientists did not understand how they transferred this energy to the ground in order to jump.
High-speed footage now reveals that the secret lies in the way fleas use their hind legs as multi-jointed levers.
This "lever-effect" allows fleas to drive their feet onto the ground, and the sudden release of the "coiled spring" hurls the insect forwards and upwards, scientists report in the Journal of Experimental Biology .
Jumping controversy
Half a century ago two groups of researchers first discovered that the energy for the insects' jumping ability was contained in an internal spring, rather than in the fleas' miniature muscles.
This discovery led to two competing theories about the insects' agility. While one group surmised that fleas bounced upward from their knees, the other said that the recoil of the spring acted through the joints of the hind legs, pushing the flea's feet onto the ground. From this "crouch" position, the insect could spring upwards.
Dr Gregory Sutton and Professor Malcolm Burrows from the University of Cambridge, who led the new research, wanted finally to end this controversy.
Dr Sutton, whose research was funded by the Human Frontiers Research Program, hopes ultimately to design robots that can jump as high as the insects.
"If you look at the actions and movements animals can generate, they are so much better than modern machines," he told BBC News. "So I was interested in studying exactly how they generate these movements."
Like his predecessors, Dr Sutton drew his first clues from detailed anatomical studies of the fleas.
These revealed relatively large spines near the insects' feet; structures that suggested that it was these areas that gripped the ground for traction.
Filming fleas
The biggest revelation came from high-speed footage, which was painstakingly shot throughout a week where the researchers had to work out how to persuade a flea to jump at the right time, in shot and in focus.
"We finally figured out that the fleas wouldn't jump if it was dark," Dr Sutton explained. "So we'd turn off the lights, move the camera and chamber to get the flea in plane, then zap the lights on and the flea would jump along the plane of the camera."
When the researchers modelled the trajectory of each flea's jump, it matched exactly the trajectory that was worked out in 1967 by a British scientist named Henry Bennet-Clark.
"That was the smoking flea," said Dr Sutton. "Our data was an exact match with the Bennett Clark data."
Some aspects of the flea's agility is still unclear.
"They always jump in the same direction and so we think they may be limited," he told BBC News. "And we don't know how the flea locks its legs into position when it's charging the spring."
Dr Sutton added: "This just shows us how little we know about [the abilities of] very common insects."
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Philosophy
The jumping flea
These pesky, blood-sucking critters are a nuisance...but, they do exhibit some interesting physics as ants and their lifting power.
"Flea's jumping ability explained"
by
Victoria Gill
February 10th, 2011
BBC News
by
Victoria Gill
February 10th, 2011
BBC News
Cambridge University scientists have solved the mystery of how fleas jump so far and so fast.
It was known that the energy to catapult a flea over a distance up to 200 times its body length lay in a spring-like structure in its body.
But scientists did not understand how they transferred this energy to the ground in order to jump.
High-speed footage now reveals that the secret lies in the way fleas use their hind legs as multi-jointed levers.
This "lever-effect" allows fleas to drive their feet onto the ground, and the sudden release of the "coiled spring" hurls the insect forwards and upwards, scientists report in the Journal of Experimental Biology .
Jumping controversy
Half a century ago two groups of researchers first discovered that the energy for the insects' jumping ability was contained in an internal spring, rather than in the fleas' miniature muscles.
This discovery led to two competing theories about the insects' agility. While one group surmised that fleas bounced upward from their knees, the other said that the recoil of the spring acted through the joints of the hind legs, pushing the flea's feet onto the ground. From this "crouch" position, the insect could spring upwards.
Dr Gregory Sutton and Professor Malcolm Burrows from the University of Cambridge, who led the new research, wanted finally to end this controversy.
Dr Sutton, whose research was funded by the Human Frontiers Research Program, hopes ultimately to design robots that can jump as high as the insects.
"If you look at the actions and movements animals can generate, they are so much better than modern machines," he told BBC News. "So I was interested in studying exactly how they generate these movements."
Like his predecessors, Dr Sutton drew his first clues from detailed anatomical studies of the fleas.
These revealed relatively large spines near the insects' feet; structures that suggested that it was these areas that gripped the ground for traction.
Filming fleas
The biggest revelation came from high-speed footage, which was painstakingly shot throughout a week where the researchers had to work out how to persuade a flea to jump at the right time, in shot and in focus.
"We finally figured out that the fleas wouldn't jump if it was dark," Dr Sutton explained. "So we'd turn off the lights, move the camera and chamber to get the flea in plane, then zap the lights on and the flea would jump along the plane of the camera."
When the researchers modelled the trajectory of each flea's jump, it matched exactly the trajectory that was worked out in 1967 by a British scientist named Henry Bennet-Clark.
"That was the smoking flea," said Dr Sutton. "Our data was an exact match with the Bennett Clark data."
Some aspects of the flea's agility is still unclear.
"They always jump in the same direction and so we think they may be limited," he told BBC News. "And we don't know how the flea locks its legs into position when it's charging the spring."
Dr Sutton added: "This just shows us how little we know about [the abilities of] very common insects."
- If There Is A Comic God, Show Me A Sign
Brothers, Sisters, and Transgendered Comedists Everywhere, This weekend we talk about found comedy, those chuckles that one gets by tripping over something undeniably and unintentionally funny, specifically ones you find on advertising signs. As a child,...
- Scanning Electron Microscope Photos Of Creepy Things
Cat Flea Daddy Long Legs Dust Mite Flour Mite House Fly Yellow Dung Fly...
- Pest Control For Ancient Humans
It was inevitable. Like so many ancient discoveries...chance and reasoning. How many had to suffer or die before these discoveries. "Scientists say ancient human bedding used for pest control" by Ed Stoddard December 9th, 2011 Reuters Almost 80,000...
- Bug Food?
This will not work anytime soon except at weird partys. It is more than just making the insect palatable but convincing people of the concept. McDonald's new entree...the Happy Roach or Egg and Cricket Biscuit? "Replace cattle? Edible insects produce...
- Serendipity Again...in Massachusetts
This undated handout image shows what U.S. researchers say appears to be the oldest imprint of a prehistoric insect, made while the dragonfly-like creature was still alive. The fossilized remains were uncovered two weeks ago at a rocky outcrop near a...