Navigation Links
Tiny muscles help bats fine-tune flight, stiffen wing skin
Date:5/23/2014

PROVIDENCE, R.I. [Brown University] A new study of bats reveals a capability within their wondrous wings that may help them fine-tune their flight.

Bats employ a network of nearly hair-thin muscles embedded in the membrane of their inherently floppy wing skin to adjust the wings' stiffness and curvature while they fly, Brown University researchers report. Birds and insects have stiff wings, but the new evidence suggests bats have evolved this muscular means of preserving or adjusting wing shape.

"Aerodynamic performance depends upon wing shape," said Brown biology graduate student Jorn Cheney, lead author of the newly published paper in Bioinspiration and Biomimetics. "The shape of a membrane wing might initially begin flat but as soon as it starts producing lift it's not going to remain flat because it has to deform in response to that aerodynamic load.

"The shape it adopts could be a terrible one it could make the animal crash or it could be beneficial," Cheney said. "But they are not locked into that shape. Because bats have these muscles in their wings, and also bones that can control the general shape as well, they can adopt any number of profiles."

Membrane muscle measurements

Cheney wasn't sure what to make of the tiny muscles, called plagiopatagiales, heading into the experiments reported in the paper. They have been known for more than a century but their function has never been demonstrated.

When Cheney considered the muscle function, he estimated that each individual muscle would be too weak to reshape the wing. That led him to form two competing hypotheses: either that the muscles would activate together to enhance force or that these oddly shaped, weak muscles might exist solely as sensors of stretch.

Only experiments could settle the question, so Cheney attached electrode sensors to a few muscles on the wings of a few Jamaican fruit bats and filmed them as they flew in the lab's wind tunnel.

Three key findings emerged from the data. They all point to the plagiopatagiales modulating skin stiffness.

One result was that the muscle activation and relaxation follows a distinct pattern during flight: They tense on the downstroke and relax on the upstroke.

"This is the first study showing that bats turn these muscles on and off during a typical wingbeat cycle," said co-author Sharon Swartz, professor of biology at Brown.

Another finding was that the muscles don't act individually. Instead they exert their force in synchrony, providing enough collective strength to stiffen the wing.

Finally, Cheney found, the muscles appeared to activate with different timing at different flight speeds. As the bats flew faster, they tensed the muscles sooner in the upstroke-downstroke cycle.

In other words, the data suggested that the muscles do not behave passively but actively and collectively in keeping with conditions of flight.

None of the data, however, preclude the muscles from serving a sensory function as well.

Technological insight, too

Cheney's findings fit into a larger program of research at Brown between the labs of biologist Swartz and co-author Kenneth Breuer, professor of engineering, in which, as Breuer puts it, they are "using biology to inspire engineering and using engineering to inspire biology."

In parallel with studies of real bats, the team has also built a robotic bat wing that incorporates their biological observations. Then they use the wing to generate data from experiments that they could never do with living creatures, such as precisely varying kinematic parameters like wingbeat frequency and amplitude, or the degree of wing folding during flapping.

In a separate paper in the same edition of Bioinspiration and Biomimetics, Swartz, Breuer, and former student Joe Bahlman report on how energy costs and aerodynamic forces changed as they varied several kinematic parameters in the robotic bat wing. They found that to generate a given force, such as lift, each of several parameters requires about the same amount of energy, but that the timing and extent of wing folding varies the ratio between lift and power significantly.

The group is now improving the robotic wing by integrating the new findings about how plagiopatagiales impact wing stiffness and shape.

"When one tries to build an engineered flying vehicle, you want to have control over its aerodynamic properties," Breuer said. "This is one more knob that we have to turn now. To be able to use these membrane wings and be able to control the properties in the way that we suspect bats do, using these muscles, is a great opportunity for biomimetic systems."

The group has a paper in press showing that controlling membrane tension in this way controls aerodynamic properties.


'/>"/>

Contact: David Orenstein
david_orenstein@brown.edu
401-863-1862
Brown University
Source:Eurekalert

Related medicine news :

1. Turning back the clock on aging muscles?
2. Strengthen Your Gym’s Business Muscles with Mobile Marketing: CallFire's Health & Fitness Webinar Week – Jan 13th to Jan 17th
3. "Home Remedies For Sore Muscles," a New Article on Vkool.Com, Teaches People How to Treat Muscle Soreness Naturally - V-kool
4. Wayne State receives grant to examine exercises effects on proteins in muscles
5. Knockout mouse grows larger, but weaker, muscles
6. Icahn School of Medicine at Mount Sinai Grants Exclusive License to Cellular Dynamics International for Development of a Cellular Therapy for Cardiac Muscles
7. Building Lean Muscle
8. How “Muscle Imbalances Revealed” Helps People Build Muscles Quickly – V-kool
9. Rapid Fat Loss
10. How “Start Plan One Program” Helps People Lose Fat And Achieve Muscles Quickly – Tony Nguyen
11. Weight Lifting Exercises
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/14/2016)... ... February 14, 2016 , ... In honor of ... Nurses (AAHFN) is promoting healthier living with heart failure by providing educational materials ... Living with Heart Failure will kick-off February 14 and includes tips on keeping ...
(Date:2/13/2016)... ... February 13, 2016 , ... Many individuals looking to lead a healthy lifestyle ... reasons. IsoPasta by Isolator Fitness has delved into this niche allowing those giving ... high-carb repercussions. IsoPasta has 30 grams of protein and only 7 grams of ...
(Date:2/13/2016)... ... ... an Au Pair comes all the way around the world to provide child ... are often worried things won’t go well. More often than not, however, they find out ... the Year winner’s all commented how their Au Pairs have become a part of the ...
(Date:2/12/2016)... ... 2016 , ... The law firm of Morrow, Morrow, Ryan & Bassett is ... these scholarships is to encourage applicants to pursue a degree in their field of ... parishes. , “We have available jobs in St. Landry and Evangeline Parishes that ...
(Date:2/12/2016)... ... February 12, 2016 , ... Each year, the American Physical ... in Anaheim, CA at the Anaheim Convention Center. Almost 10,000 physical therapists across the ... products in action, learn more about their chosen field and network with their colleagues. ...
Breaking Medicine News(10 mins):
(Date:2/12/2016)... , 12 februari 2016 ... een toonaangevende leverancier van productie en ontwikkeling ... industrieën, kondigt vandaag een uitbreiding aan van ... haar locatie in Charleston, SC ... geleid tot meerdere recente investeringen. ...
(Date:2/12/2016)... , Ungarn, February 12, 2016 ... das sich auf den ungedeckten medizinischen Bedarf ... positive Ergebnisse seines klinischen Forschungsprogramms bekannt. Das ... beschäftigt, ergab Verbesserungen ihrer respiratorischen Funktionen und ... ltd , ein Medizintechnikunternehmen, das sich auf ...
(Date:2/11/2016)... NEW YORK , Feb. 11, 2016 ... - Companion Diagnostics in Personalized Medicine and Cancer ... Markets. - High-Growth Diagnostic Testing Markets. - ... Cancer Testing. - Molecular Diagnostics in Genetic Testing. ... - Molecular Diagnostics Markets. - Over-the-Counter Diagnostic Products ...
Breaking Medicine Technology: