Zooming in on Beetles' Knees, Biologists Find Tiny Screws and Nuts

By Valerie Ross | June 30, 2011 4:31 pm

Scanning electron micrograph images of the nut (A,B)
and screw (C, D) in the leg joint of a Papuan weevil

What’s the News: Biologists spend lots of time poring over nature’s nuts and bolts. Now, for the first time, they’ve found a biological screw and nut—previously thought to be an exclusively human invention. The legs of beetles called Papuan weevils, researchers report today in Science, have a joint that screws together much like something you’d find in the hardware store.

How the Heck:

  • The researchers took x-ray microtomography scans of museum specimens of the beetle.
  • One part of the joint (called the coxa) resembled a nut, with a thread along its inner surface covering 345°. The other part (the trocanter) resembled a screw, with an external thread spiraling around it for 410°—more than a full turn.
  • The beetles’ muscles pull on the leg to turn the screw. The beetles don’t turn their legs a full 345°, however; they can rotate their front legs by 90°, and their hind legs by 130°.
  • When the scientists expanded their search, they found the same mechanism in the legs of several other species. “The screw-and-nut system appears to be widespread among weevils,” they wrote, “and may indeed represent a basic character of the family.”
  • These joints may provide additional flexibility, useful to the beetles as they feed on leaves and twigs, as well as help them keep steady when at rest.

What’s the Context:

Reference: Thomas van de Kamp, Patrik Vagovič, Tilo Baumbach, & Alexander Riedel. “A Biological Screw in a Beetle’s Leg.” Science, June 30, 2011. DOI: 10.1126/science.1204245

Image: van de Kamp et al., Science

  • Brian Too

    These beatle’s knees are the bees-knees!

  • http://discovermagazine.com Iain

    ‘Nuff said dude! LOL!

  • Jeffrey

    I sure hope no one will ever find nuts when zooming in on my knees, even when I get real old…

  • JMW

    Interesting. I wonder if, as the weevil walks, the screw makes the leg move closer to the body, or further away. I wonder if there is some evolutionary advantage to having the leg have a slight movement inward or outward as it walks…it should probably produce a slight right-left motion of the body as it walks, even though the feet move straight forward and backward.

  • John Lerch

    “Nuts” seems to be a misnomer. Screw is correct since screw describes any function associated with a male spiral thread. But nut is specific to a female spiral thread that holds something in place. As best as I can tell the “nut” is a female worm gear.

  • YUGI

    another amazing proof that their is a “Grand Designer”.

  • Barry Johnstone.

    Yugi – I think you are WRONG! This may be a proof that there ISN’T a “Grand Designer”. I think ID is complete and utter B/S!

  • http://minimalistphotography101.com Steve

    Yugi – in your case he or she probably needs to look at their quality control setup.

  • jim

    The great spaghetti monster uses corkscrew pasta for its legs, so why wouldn’t its creations be in its image?

  • Jennifer Angela

    Nature seems to have the answers to all of our questions. And whatever we invented all by ourselves isn´t healthy – take plastic as an example. I am not saying it isn´t useful. I am just saying that nature always has better answers to everything in general.

  • http://www.sydneytranslation.com.au Translation Agency

    The context of this says it all… nature is beautiful and perfect engineering….

  • Douglas R Dexheimer

    Has anyone tested the handed-ness of the threads on these joints. i.e., are they all right handed threads, or are the threads on the left side, left handed, (legged)?
    Taking off on comment No. 4 above: would the gait of the insect be left-right-left-right on each pair of legs? If the leg ‘unscrewed’ and moved out when moving forward on the right leg, does the left leg have a left handed screw, so that the left leg moves outward when that leg moves forward on each step.
    The creature would have a crazy dance step if his hip joints accordion-ed with each step. If the threads are all right handed, the creature would zig-zag back and forth with each cycle of its legs.
    I’d like to see a video of one of these beetles walking!

  • http://www.mehandidesigns4girls.blogspot.com/ Nanains

    wow what a great information for me….

  • http://urfunnytube.blogspot.com/ Shahzad

    Awesome post…nice article… informative news…again thankx

  • jojo

    YUGI, please don’t have children.

  • Idlewild

    Wow, some posters are really overreacting to Yugi. He/she didn’t attack anyone, just showed their view on this discovery. I think Yugi is wrong, but that doesn’t mean they’re a defective person who shouldn’t procreate just because they don’t believe what I do.

    Personally, I don’t see how this discovery is proof either way for intelligent design. It reminds me of a picture in an old Time Life book showing an armored man compared to an armadillo, and a pickaxe compared to the tusks of a boar. There are only so many shapes that work well for their purpose. It’s not surprising to see that supposedly human inventions exist in nature serving similar purposes.

  • Ironbear

    I wonder if screw-together legs facilitate quicker repairs? Speaking as someone waiting to get his knees replaced I can say that it’s an interesting concept.

  • Geack

    @ Jennifer Angela,

    Why the assumption that we aren’t part of nature? And “whatever we invented by ourselves isn’t healthy”? How do you figure? We have absolutely nothing to learn from EXCEPT nature. We closely study what happens when things burn, and we make rockets and combustion engines. We closely study what happens when sand melts, and we make glass. We closely study what grows in a puddle full of excrement, and we learn to build sewers to keep from dying. Using your example, “plastic” isn’t unhealthy. Throwing tons of plastic into the oceans every year is pretty bad for everything else living on the planet, but failing to clean up after ourselves doesn’t make the plastic itself unhealthy or “unnatural”. After all, petroleum is just really thorough compost – people seem to forget that… Humanity’s (and the planet’s) problems aren’t due to our inventions being unhealthy – they’re due to our inability to control ourselves.

  • Geack

    @Idlewild –

    Just to explain the strong reactions to Yugi: Intelligent Design is anti-science pretending to be science. ID doesn’t make predictions, or present testable hypotheses. The people who write ID “research” basically just point out something that we haven’t figured out yet, and say “See, this is too complicated for current science to explain; therefore Magic Designer did it”. As soon as you bring in the idea of the Magic Designer, you’ve essentially ended any effort to study the topic further. Science is figuring things out, constantly testing what you think you know against what we see in the real world. ID is just throwing up your hands and saying “It must be something we’ll never understand”. But IDers hide their anti-science behind sciency-sounding language in order to confuse those who aren’t paying much attention (like school boards). So the whole topic generates a lot of anger when someone throws it onto a board dedicated to real science. My guess is Yugi was just trolling anyway…

  • YUGI

    I guess you are right Geack — I am just trolling… but one thing I am sure is, their is a Grand Designer even Einstein believe it. And about “As soon as you bring in the idea of the Magic Designer, you’ve essentially ended any effort to study the topic further” — on the contrary, further study of such matter with an aim to relate how what you called as “Magic Designer” has created it is a way of showing how humans credit this work of art that HE indeed created…

    I can’t explain my side any further because I am not good in English or lack of vocabulary…

    Sorry for my English again….

  • Deacon.James

    We all have sinned, Jesus paid that sin with his death on the cross. His Father did create all that is seen and unseen. We can try as humans to deny our creator, but when it comes time to stand before him, your only hope of salvation is in the finished work of Jesus, not in our own inteligence or good deeds. Thank you YUGI for standing up in what you believe is right. We do not try to dismiss what we do not know and call it God, we do however know that God knows, and the fact that he has given us the inteligence to figure it out on our own is a gift. I for one will always and continually pray that your eyes will be opened to the saving grace of our heavenly Father through Jesus Christ his son by the power of the Holy Spirit. Hope you all have a great day!

  • Geack

    @ YUGI,

    Your English is quite good, no need for apologies. Never would have guessed you aren’t a native speaker. And I know you didn’t specifically mention “Intelligent Design”. But you got some very harsh, dismissive responses to your comment, and I thought it would be useful to provide some explanation. If your belief in a grand designer drives you to study the world, you’re in good company – most of history’s great scientists were believers of one type or another. But you should know that the idea of a “designer” in biology, here in the States and elsewhere, is currently tied up with the deeply dishonest “Intelligent Design” movement, which as I noted previously uses fake science as a political tool, in order to try to force a literal interpretation of the Christian bible into public-school science classes. Its supporters crop up on this site regularly, starting arguments about God that have little to do with the cool discoveries being reported, and many of the commenters here are tired of it. Thus the anger and dismissal.

  • Geack

    @ Deacon James,

    Please preach elsewhere.

  • David

    Geack said to Deacon James, “Please preach elsewhere”.

    I agree. Preferably in his own bedroom closet.

    And for YUGI; how is this discovery “PROOF” of a Grand Designer? You might want to “BELIEVE” it, but there is not a HINT of proof here for your belief.

  • YUGI

    I do not like ID base on the meaning of it in wikipedia they believe in HIM but they avoid to know HIM.

    And GEACK i like your comment “We have absolutely nothing to learn from EXCEPT nature”. it is related to a text found in the Bible….

    “Ask, please, the domestic animals, and they will instruct you; also the winged creatures of the heavens, and they will tell you. Or show your concern to the earth, and it will instruct you; and the fishes of the sea will declare it to you.”—JOB 12:7, 8.
    (by the way BIOMIMETICS is COOL)

    Consider this, the engineer who designs a safer, more efficient aircraft wing would deserve to receive credit for his design. Likewise, the inventor who devises a more versatile bandage—or a more comfortable clothing material or a more efficient motor vehicle—deserves credit for his or her design. In fact, a manufacturer who copies someone else’s design but fails to acknowledge or credit the designer may be viewed as a criminal.
    Does it seem logical to you, then, for highly trained researchers who crudely mimic systems in nature to solve difficult engineering problems to attribute the genius of devising the original idea to unintelligent evolution? If the copy requires an intelligent designer, what about the original? Really, who deserves more credit, the master artist or the student who imitates his technique?

  • Hollybelle

    This is about science. It is not a forum for religious rhetoric. Please marvel at the discoveries, comment on it, ponder it…. share your thoughts. Let respect be the rule and keep theological debate out of it. Thank you.

  • David

    Hollybelle is right. Yugi, you are welcome to your religious beliefs but take them somewhere else. There are thousands of blogs made for your thoughts. This is a Science forum,

  • YUGI

    Then I must say sorry… all I want is to give credits to God.

    Sorry again.

  • Delta

    I bet HollyBelle is an atheist. No need to be sorry YUGI you credited the right person. :)

  • David

    YUGI doesn’t need to be sorry about his beliefs. But preaching and bible quotes have no place on a Science blog. Let’s get back to the original point: What’s in the News – biologists and beetles

  • Robert

    I think to say that, “This is about science. It is not a forum for religious rhetoric.” Is slightly on the ignorant side. The whole of science is to study, understand, and explain phenomenon. Ethics applied to the scientific fields are not created themselves by science. It is not science that asks,”Is this right? Should we do this?” Those questions are created by the unseen beliefs and ideas held by the scientists, created by their religion or philosophy.

    Saying the two do not intermingle strips away the conscience, the questions of right and wrong.

  • David

    Robert – Bringing ethics into a scientific discussion could have its place, but an article about the structure of beetles’ knees does not lend itself to religious rhetoric and bible quotes. I think Yugi’s beliefs are wrong, but I have nothing against him believing them. But if he wants to promote ID, this scientific blog is not the place. There must be tens of thousands of relevant places he can put those ideas forward for debate.

  • Truth

    Yugi, there is no need to apologize for your belief in the truth. what the posters here who are complaining about your comment forget is that there is no proof of evolution, yet they accept Darwin’s early theories of it as if it were the absolute truth, though even he redacted his theory prior to his death. If they would read “On the Origin of species or the Preservation of Favoured Races i the Struggle for Life” properly, they would quickly realize it was a piece of propoganda written to “explain” that the caucasian race was superior to others. Peace be with you.

  • http://www.dhoward.us dahowa

    Great Caesar’s Ghost!! Can we have a discussion of science without someone bringing religion into it? Go to a baseball game and every time someone gets a hit or fields a ball or swings and misses, proclaim “That’s proof that baseball is just a part of God’s plan.” See how long it takes before the entire section turns on you. Just go away and have your discussion at your next bible study.

  • Truth

    dahowa, interesting that you talk about ghosts but are angered at the mention of God. God’s gift to us was free will, we do what we want with our lives.

  • Hollybelle

    I’m not an atheist. I believe in the Great Spaghetti Monster! Ever hear of Dr. Bart D. Ehrman? (Sorry, I just couldn’t help myself).

    But I do think these beetles have really cool knees – no matter how they came by them.

    Do you think the cork screw joint is found in all of the legs or just certain ones? I also think the screw and nut description is erroneous since there really is no “nut”, rather isn’t it more like a simple spiral bearing? That is something used for continuous motion.


  • Hollybelle

    To all readers, I want to apologise for my reference to FSG. I am not in the habit of mocking anyone’s religious beliefs. I was working quite late and after reading through the discussion I made a poor decision. I respect everyone’s right to believe what they will and I expect the same courtesy. I just ask that no one starts to quote passages from the Bible because – out of respect – not everyone believes in the Bible. This discussion is about the wonder of nature, the biology, of learning new things. Can we please focus on how interesting these findings are?

  • http://cort.as/14lp acuvue oasys rebate

    Good stuff, loved this submit


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles covering the day's most compelling topics.

See More

Collapse bottom bar