UPDATE: Cambridge University has a longer but very lucid description of these results on its research publicity page.
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I always read the original paper before reporting on a new scientific finding, but this time I didn’t, for I just want to show a cool video of a Great Leap by a Small Mantis filmed by Malcolm Burrows et al. and given as supplementary material in their new paper in Current Biology (reference and link to summary below). First, the relevant part of the paper’s abstract, which of course is opaque to most of us, including me—except for the part about mutilating the insects and forcing them to crash:
We show that when making targeted jumps, juvenile wingless mantises first rotated their abdomen about the thorax to adjust the center of mass and thus regulate spin at takeoff. Once airborne, they then smoothly and sequentially transferred angular momentum in four stages between the jointed abdomen, the two raptorial front legs, and the two propulsive hind legs to produce a controlled jump with a precise landing. Experimentally impairing abdominal movements reduced the overall rotation so that the mantis either failed to grasp the target or crashed into it head first.
Here’s the video, with an explanation from Eurekalert below; see if you can notice all the movements described in the piece:
To watch a young, wingless praying mantis jump is a truly remarkable thing. The jump from take-off to landing lasts less than a tenth of second–literally faster than the blink of a human eye. During a jump, the insect’s body rotates in mid-air at a rate of about 2.5 times per second. And yet, according to researchers who report their observations in the Cell Press journal Current Biology on March 5, the mantises’ jumps are precise. When mantises jump, they land on target every time.
“This is akin to asking an ice skater who is rotating at the same speed as these mantises to stop suddenly and accurately to face a specific direction,” says Malcolm Burrows of the University of Cambridge.
. . . “We could not scare them into jumping or get them to jump away from a threatening stimulus,” Sutton says. “So instead we offered them a target to jump towards and found that they would do this consistently and accurately.”
. . . What the researchers saw was this: in preparation for a jump, first the insects sway their heads sideways, scanning for their targets. Then they rock their bodies backward and curl their abdomens up, tip pointed forward. [JAC: That part’s already over when this video begins.]
With a push from their legs, the mantises’ bodies launch into the air, spinning in controlled fashion. The insects rotate three distinct body parts–the abdomen, front legs, and hind legs–independently and in a complex sequence. As the mantises sail through the air, the spin is transferred from one body segment to the next, keeping the body as a whole level and right on target. [JAC: Yep, this is all visible.]
“Maintaining stability so that the body does not rotate uncontrollably in mid-air is a difficult task,” Burrows says. “When the movement is rapid, as it is in a jump, and you don’t have wings, then the task is even more difficult. Nevertheless, a praying mantis moves rapidly and controls the rotation of its body so that it lines up precisely with a target, and does all of this in less than 100 milliseconds.” (That’s a tenth of a second.)
This kind of jumping control is rather unusual in the insect world. Most insects lose all control once their legs leave the ground, the researchers say, spinning in unpredictable directions with frequent crash landings.
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Burrows, M., et al. Mantises Exchange Angular Momentum between Three Rotating Body Parts to Jump Precisely to Targets. Current Biology, online, http://dx.doi.org/10.1016/j.cub.2015.01.054
h/t: Su
Neat video. Mantids are endlessly fascinating.
Ow – sounds painful but I hope it wasn’t!
Fascinating! Would’ve been great to see a view from behind.
I also saw this on the internet.
If I understand correctly, it looks like one thing they do is to swing their upwardly arched abdomen down after they have launched, and this shift in the center of gravity helps cause their body to rotate to a more vertical orientation.
I sometimes raise Chinese mantises from eggs. That is a lot of work, btw. Anyway, it is pretty amazing how jumpy they are.
Yeah, I’ve raised those successfully only once. I don’t know what species, I bought the egg case from a local nursery. I put it on a light on one of my aquariums so it kept warm and humid. But it hatched when I was on a fishing trip and my poor wife had to deal with hundreds of those little buggers scurrying around the aquarium and room. She managed to move some outside, but most ended up in the vacuum. 🙁 I wasn’t thinking ahead, obviously.
They were probably the big Chinese mantis (Tenodera sinensis), or the related narrow winged mantis (Tenodera angustipennis). Both are introduced species that now live in the U.S. The egg cases are commonly sold commercially.
Well, no, because of cube/square scaling. Picture a skater made of styrofoam spinning in extreme slo-mo and you might have some idea of what it’s like for the insect.
The cube/square scaling also figures prominently in the apparent comfort with which the mantis bangs its body against the target before wrapping its legs around it. An acrobat (or just an ape) would land with his/her hands and feet and use muscles to cushion the landing).
Yeah, you can take some pretty hard knocks if your guts have negligible inertia.
I too had a hard time thinking that the mantis had “stuck the landing” when its legs went past the twig and its body hit it, but you may have the explanation – it doesn’t matter as long as you land grasping the twig: your body doesn’t care as long as you don’t end up in someone else’s mouth.
This is a little bit like the “drop a mouse down a well and it walks away, drop an elephant down the same well and it explodes” scaling. I remember that from many (50 or so) years ago; but I bet there is something out there on the Internet now.
You’re probably thinking of this quote from J.B.S. Haldane:
I was bitten on the neck by one of these things, Vampire mantis! Hurt like hell.
And now – You roam the night, turning others into Vampire Mantis/Human hybrids.
Bite me. And I mean that b/c I want to be a vampire mantis.
Checking other films by the author, I found several more that elaborate on the body english. This one contains 3 jumps “acrobatic”. Likable especially because, Strauss.
https://www.youtube.com/watch?v=JhLBqrl3n9M
I find it interesting that they seem to be taking the impact on their femurs, while letting the tibia and tarsus slide past the perch. I wonder why.
Yeah I wondered about the same thing
Are PMs known to have mood swings? I recently found a big one (at least four inches long) in my house. With a little nudging, it climbed slowly into a paper bag, showing no signs of fear. I left the bag on the patio, and that was that. It seemed like a gentle creature that might make a nice pet for a child if it weren’t so delicate.
Sub