Functioning 'mechanical gears' seen in nature for the first time

Sep 12, 2013
This image shows cog wheels connecting the hind legs of the plant hopper, Issus. Credit: Burrows/Sutton

a plant-hopping insect found in gardens across Europe - has hind-leg joints with curved cog-like strips of opposing 'teeth' that intermesh, rotating like mechanical gears to synchronise the animal's legs when it launches into a jump.

The finding demonstrates that gear mechanisms previously thought to be solely man-made have an evolutionary precedent. Scientists say this is the "first observation of mechanical gearing in a ".

Through a combination of anatomical analysis and high-speed video capture of normal Issus movements, scientists from the University of Cambridge have been able to reveal these functioning natural gears for the first time. The findings are reported in the latest issue of the journal Science.

The gears in the Issus hind-leg bear remarkable engineering resemblance to those found on every bicycle and inside every car gear-box.

Each gear tooth has a rounded corner at the point it connects to the gear strip; a feature identical to man-made gears such as bike gears – essentially a shock-absorbing mechanism to stop teeth from shearing off.

The gear teeth on the opposing hind-legs lock together like those in a car gear-box, ensuring almost complete synchronicity in leg movement - the legs always move within 30 '' of each other, with one microsecond equal to a millionth of a second.

This is critical for the powerful jumps that are this insect's primary mode of transport, as even miniscule discrepancies in synchronisation between the velocities of its legs at the point of propulsion would result in "yaw rotation" - causing the Issus to spin hopelessly out of control.

Photograph of an Issus nymph. Credit: Malcolm Burrows

"This precise synchronisation would be impossible to achieve through a nervous system, as would take far too long for the extraordinarily tight coordination required," said lead author Professor Malcolm Burrows, from Cambridge's Department of Zoology.

"By developing mechanical gears, the Issus can just send nerve signals to its muscles to produce roughly the same amount of force - then if one leg starts to propel the jump the gears will interlock, creating absolute .

"In Issus, the skeleton is used to solve a complex problem that the brain and nervous system can't," said Burrows. "This emphasises the importance of considering the properties of the skeleton in how movement is produced."

"We usually think of gears as something that we see in human designed machinery, but we've found that that is only because we didn't look hard enough," added co-author Gregory Sutton, now at the University of Bristol.

"These gears are not designed; they are evolved - representing high speed and precision machinery evolved for synchronisation in the animal world."

Interestingly, the mechanistic gears are only found in the insect's juvenile – or 'nymph' – stages, and are lost in the final transition to adulthood. These transitions, called 'molts', are when animals cast off rigid skin at key points in their development in order to grow.

It's not yet known why the Issus loses its hind-leg gears on reaching adulthood. The scientists point out that a problem with any gear system is that if one tooth on the gear breaks, the effectiveness of the whole mechanism is damaged. While gear-teeth breakage in nymphs could be repaired in the next molt, any damage in adulthood remains permanent.

This video is not supported by your browser at this time.
Spontaneous jump of a nymph viewed from the side. The images were captured at a rate of 5,000 images s-1 and with an exposure time of 0.03 ms and are replayed at 30 frames s-1 . Credit: Malcolm Burrows

It may also be down to the larger size of adults and consequently their 'trochantera' - the insect equivalent of the femur or thigh bones. The bigger adult trochantera might allow them to can create enough friction to power the enormous leaps from leaf to leaf without the need for intermeshing gear teeth to drive it, say the scientists.

Each gear strip in the juvenile Issus was around 400 micrometres long and had between 10 to 12 teeth, with both sides of the gear in each leg containing the same number – giving a gearing ratio of 1:1.

Unlike man-made gears, each gear tooth is asymmetrical and curved towards the point where the cogs interlock – as man-made gears need a symmetric shape to work in both rotational directions, whereas the Issus gears are only powering one way to launch the animal forward.

While there are examples of apparently ornamental cogs in the animal kingdom - such as on the shell of the cog wheel turtle or the back of the wheel bug - gears with a functional role either remain elusive or have been rendered defunct by evolution.

The Issus is the first example of a natural cog mechanism with an observable function, say the scientists.

Explore further: 'Femme fatale' emerald ash borer decoy lures and kills males

More information: "Interacting Gears Synchronize Propulsive Leg Movements in a Jumping Insect," by M. Burrows et al Science, 2013.

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Lorentz Descartes
1.8 / 5 (10) Sep 12, 2013
Neat! Perhaps there even is a wheeled beetles out there?
JohnGee
2.1 / 5 (7) Sep 12, 2013
As the great prophet Sagan (pbuh) said, we are molecular machinery.
DistortedSignature
1 / 5 (1) Sep 12, 2013
VSauce did a good video about the lack of wheels in nature www.youtube.com/w...EOKAG0zw

I'd postulate from there by saying it'd only come about in a colony/hivemind sort of species.
xrayrrman
4.2 / 5 (5) Sep 12, 2013
There are examples of continuous motion in the flagellum of bacteria. A sort of wheel if you like.
Lorentz Descartes
1 / 5 (8) Sep 12, 2013
Yeah the molecular space is full of rotating stuff. ATP synthase http://www.youtub...dO4nNaKY for example. Weird to think we digest food, in essence, by splitting of the hydrogens and stuffing them in sack until it is full to bursting, then generate energy by driving molecular water wheels. To a 14th century European it must've seemed quite natural.

But are there any macroscopic wheels? All i can think of are those rollie pollie garden bugs
Gmr
2.6 / 5 (5) Sep 12, 2013
If you want to be super technical, the dung beetle represents a wheel for the purposes of a wheel to use minimum contact and rotational momentum to reduce friction and resistance to motion.

Oh! And tumbleweeds - who combine a nearly spherical shape and windeborne transportation.
Gmr
3 / 5 (6) Sep 12, 2013
I dunno about wheels but we already know about http://livingwith...oint/... Just another evidence of Big blind watchmaker.


Is this an extension of the old "God is love and love is blind therefore God is blind?" I'm confused.
DonGateley
3.7 / 5 (3) Sep 12, 2013
"'The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe without Design' is a 1986 book by Richard Dawkins."

Wouldn't you just love to see a time lapse movie of that thing evolving. It looks to me like it reveals something else despite the fact that I "know" better. :-)
Howhot
2 / 5 (4) Sep 12, 2013
That SEM photo just blew my mind!
ohyeah
3.3 / 5 (7) Sep 12, 2013
oh yea of little faith, dont doubt evolution because something 'looks' designed. We all know that a partial gear is more beneficial to the evolving nymph than no gear. keep the faith.

meerling
not rated yet Sep 13, 2013
I guess all I can add to the wheel talk is this:
http://en.wikiped..._systems
Torbjorn_Larsson_OM
3 / 5 (6) Sep 13, 2013
Neat! Not unexpected, just predictably rare.

As for macroscopic rolling animals: http://en.wikiped..._animals

BTW, creationists trolling science are hilarious. And they make deconverts from religion too, see Dawkins's Convert's Corner.

In this case intermediates is the basic evolutionary prediction (descent by modification), and "half an eye" or something similar creationist idea doesn't work after Darwin explicitly showed how intermediates appears. Have been repeated for major organs (legs, wings, et cetera) as well as for important molecular mechanisms (hereditary mechanism, cell division, pores, flagella/archella, et cetera).

Here, a partial gear still works as partly synchronized legs at jumping, so as for eyes, legs, wings it is easy, except for dummies, to see that intermediates have fitness advantages and therefore are fixated by evolution. It is the molecular mechanisms that needs genomic and/or biochemical elucidation, they aren't always obvious.
Lurker2358
1.4 / 5 (11) Sep 15, 2013
oh yea of little faith, dont doubt evolution because something 'looks' designed. We all know that a partial gear is more beneficial to the evolving nymph than no gear. keep the faith.


No, no, remember, Dawkins' theory is that the gear did something else while it was in transition, so for example, he might claim it was once a propeller for when it was in the water, before it became attached to the legs, or maybe he'd claim it was once a helicopter propeller instead. Maybe it was a fan to keep the insect cool during the day time.

This is the same fool who also believes the universe came from absolute nothingness, but wait, it came from a particular type of conditional nothingness, but wait, that's a contradiction, and he knows it, but you know, gotta stick with the faith, er, faithlessness.
Lurker2358
1.4 / 5 (10) Sep 15, 2013
Anyway, the Watchmaker made a set of gears in nature in order to keep time for this insect's body functions.

Incredible, isn't it?

Well, now that we know God did it, one thing I admit the scientists are good at is stealing God's designs after the fact, so I imagine they will be interested in the genetic basis of this system for use in synthetic biology or organic nanotechnology.

Lol. God did it. lol.
Gmr
2.6 / 5 (5) Sep 15, 2013
Lol?

Oh, yes - the idea that God did it is, in fact, laugh-out-loud ridiculous.

The idea that it would hide its handywork not in its allegedly pentultimate pet project, man; but rather only in the nymph stage of an inconsequential insect and at a level that requires scanning electron microscopy to see...

Funny thing is, if it was truly a goddiddit moment, it would violate the primacy of Christianity being primarily a revealed faith-based institution. If it is emperically demonstrable, it becomes quantifiable, and then you have apostasy meters at all the airports and it all goes to hell from there.

By the way, all it would take to start this transition is a single tooth- whichever started first would kick the other into almost synch. So it still is not proof of a magical judgemental voyeur in the sky who likes child sacrifice.
Gmr
2.6 / 5 (5) Sep 15, 2013
I have to add, just like the physics cranks, you don't "win" if you show a flaw with current theory. It isn't a pageant with your runner-up showing up to claim the prize.

Your theory has to have something that explains everything current theories do, is quantifiable and demonstrable as current theories are, and provides the same predictions as current theory.

Science is not a debate where one side or the other wins. There are no sides. If your model provides more explanation, demonstrably and in a testable fashion... see, that's where creationism and all of its evolved ilk fall flat. It is not testable if you claim invisible, undetectable, acting-without-pattern willed forces are at work that can't be pinned down to a mechanism of action. They can be removed from an equation and make no difference, ergo, as far as theory goes they can be ignored with no consequence. They provide no explanation at all.
nowhere
3 / 5 (2) Sep 15, 2013
This is the same fool who also believes the universe came from absolute nothingness

The theory goes back so far as the singularity. At this point all matter is compacted into a single point and both time and space have no meaning. Our theories break down at this origin and since time is a property of our universe, there is no before the singularity. So there is no 'absolute nothingness'.
, but wait, it came from a particular type of conditional nothingness,

There is no nothingness, and there is no special condition. Everything that is probable is and everything that isn't isn't.

but wait, that's a contradiction, and he knows it, but you know, gotta stick with the faith, er, faithlessness.

What's the difference between god and a contradiction? Well a contradiction exists.
Lurker2358
1.7 / 5 (12) Sep 15, 2013
Funny thing is, if it was truly a goddiddit moment, it would violate the primacy of Christianity being primarily a revealed faith-based institution. If it is emperically demonstrable, it becomes quantifiable, and then you have apostasy meters at all the airports and it all goes to hell from there.


No, that's the lie people like Dawkins want you to believe about the Bible.

If you try READING the Bible, you'll find places like in the Proverbs, and two places in the New Testament which deal with naturalism, and proof.

The word "Faith" does not mean what you have been brainwashed to think it means.

Finding something microscopic, which is not previously known, is in fact a revelation. You seem to think God was/is somehow required to share all knowledge with all humanity ahead of time, and he obviously isn't. The universe is designed in such a way that when people are ready for something, it naturally comes about most of the time. Not always though.
DonGateley
2.7 / 5 (7) Sep 15, 2013
"The word "Faith" does not mean what you have been brainwashed to think it means."

I particularly like Tom Robbins definition, "Faith is believing something you know isn't true."
Gmr
1.8 / 5 (5) Sep 16, 2013
The universe is designed in such a way that when people are ready for something, it naturally comes about most of the time. Not always though.


Except in the few outlier cases where it doesn't have to happen exactly as it didn't.

Useless. Completely useless. Even if true, completely useless.

That's the point: faith-based "science" does nothing. There is nothing to discover, but what we hope will be revealed? Why do research? Why question anything? At most it looks ex post facto for codes in the English botched translation of the Greek transcriptions of the Hebrew or Aramaic recording of oral traditions influenced by heavily Mesopotamian context.
triplehelix
1.4 / 5 (10) Sep 16, 2013
Lurker, I have read the Bible, dozens of times. It's accuracy in terms of a physical, chemical, geological and biological case point is, absolutely hilarious.

You find nothingness becoming something basic absurd. But you find nothingness becoming an all powerful being with infinite knowledge wisdom and power completely fine and okay.

Righto.

How can God also be omnipotent and omniscient at the same time? That's a contradiction in itself. Everyone knows a vehicle with a nearly broken gearbox can still work, just badly, but hey, a vehicle with a nearly broken gearbox can go faster than something without a nearly broken gearbox.

In biology you don't need something to fit perfectly for it to be advantagous. In fact most biological systems, even highly specialised ones, are far from perfect, and man can usually use them as ideas and progress onwards with designed technology.
triplehelix
1.4 / 5 (10) Sep 16, 2013
2 people voted 1/5 for my comment. my god the human race is screwed lol
TheGhostofOtto1923
1.5 / 5 (8) Sep 16, 2013
My god jesus was a mechaniic not a carpenter!
This is the same fool who also believes the universe came from absolute nothingness, but wait, it came from a particular type of conditional nothingness, but wait, that's a contradiction, and he knows it, but you know, gotta stick with the faith, er, faithlessness
Leave it to an idiot godder to decide god did it before we really know.

Consider Lrrkrr, that these were 2 intersecting plates which originally interacted by friction. And then consider that subsequent generations worked better when bumps developed on the plates and were thus selected for.

This is only a wild guess but it is much better than your gutless and brainless leap of faith.
Estevan57
2.2 / 5 (17) Sep 16, 2013
Don't worry about the votes, triplehelix, those are just Otto's latest sock-puppets. They follow everyone that Otto disagrees with.
TheGhostofOtto1923
1 / 5 (5) Sep 16, 2013
Don't worry about the votes, triplehelix, those are just Otto's latest sock-puppets. They follow everyone that Otto disagrees with.
Hey there termite. This is not true And per my profile page it is obvious who the liar is yes?
http://phys.org/p...tto1923/
mtwzzyzx
1 / 5 (8) Sep 16, 2013
nowhere (Sep 15, 2013),

"This is the same fool who also believes the universe came from absolute nothingness"

"The theory goes back so far as the singularity. At this point all matter is compacted into a single point and both time and space have no meaning. Our theories break down at this origin and since time is a property of our universe, there is no before the singularity. So there is no 'absolute nothingness'."

So if there was a singularity and time and space didn't exist, what caused the eruption of a time/space dependent universe from that singularity? Something was created at that moment- or you're going to tell me that the probability for this universe existed in that singularity, but then you've got to deal with who created the probability? Probability in those terms (and philosophically) is a thing too. From whence hath it come?

Also, if no html is allowed here, how does one blockquote? Thanks!
nowhere
3 / 5 (2) Sep 18, 2013
So if there was a singularity and time and space didn't exist, what caused the eruption of a time/space dependent universe from that singularity?

Answering that would require a theory of how singularities work.

Something was created at that moment

Nothing was created, the total energy for the system was and still is zero.

- or you're going to tell me that the probability for this universe existed in that singularity

Probably.

, but then you've got to deal with who created the probability?

No you don't for two reasons. First is, assuming there exists a creater who made probability is less likely than only assuming there is probability. Second is that it may be there is no probability. All things that can exist do and all that can't don't.

Also, if no html is allowed here, how does one blockquote? Thanks!

[ q ] [ /q ] seems to work for me.
animah
2.3 / 5 (3) Sep 18, 2013
1. Man invented gears
2. Insect found to have 1/8th of a gear (i.e. an interlock not even a real gear)
3. Therefore God exists!

Useless. And dangerous because:

4. I am a man of God
5. God is a despot
5. Therefore I must rule.

Even if God existed and was everything you hoped, I would still not be attracted to your dim and utterly dull quest for dominion.

But oh the things we would ask the bearded man about!
Howhot
2.3 / 5 (3) Sep 19, 2013
The conversation doesn't need to turn to god for an answer to something as amazing as this is. We humans are surrounded by amazing things everyday. Our stereo vision is just one example. Our RGB vision system is another. Each part of our bodies has some logical function, so why shouldn't logic extend into the insect world, and the microscopic design of a gear mechanism? I find it an amazing freak of nature. Not God.

DonGateley
2 / 5 (4) Sep 19, 2013
I think being an engineer puts me in an awkward position. With all the consideration and investigation that's been given to it by many really exceptional people, I can't even entertain the thought that the modern theory of evolution is fundamentally wrong. At the same time I believe that this thing was designed and cannot shake that belief because it comes from somewhere really deep. Go figure. :-)