Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

With Their Amazing Necks, Ants Don’t Need “High Hopes” to Do Heavy Lifting

11.02.2014
Ants can lift up to 5,000 times their own body weight, new study suggests

High hopes may help move a rubber tree plant (as the old song goes), but the real secret to the ant’s legendary strength may lie in its tiny neck joint.


Micro-CT scans of an Allegheny mound ant. Ohio State University engineers studied the ant's neck region, shown in more detail to the right. Images courtesy of Ohio State University.

In the Journal of Biomechanics, researchers report that the neck joint of a common American field ant can withstand pressures up to 5,000 times the ant’s weight.

“Ants are impressive mechanical systems—astounding, really,” said Carlos Castro, assistant professor of mechanical and aerospace engineering at The Ohio State University. “Before we started, we made a somewhat conservative estimate that they might withstand 1,000 times their weight, and it turned out to be much more.”

The engineers are studying whether similar joints might enable future robots to mimic the ant’s weight-lifting ability on earth and in space.

Other researchers have long observed ants in the field and guessed that they could hoist a hundred times their body weight or more, judging by the payload of leaves or prey that they carried. Castro and his colleagues took a different approach.

They took the ants apart.

“As you would in any engineering system, if you want to understand how something works, you take it apart,” he said. “That may sound kind of cruel in this case, but we did anesthetize them first.”

The engineers examined the Allegheny mound ant (Formica exsectoides) as if it were a device that they wanted to reverse-engineer: they tested its moving parts and the materials it is made of.

They chose this particular species because it’s common in the eastern United States and could easily be obtained from the university insectary. It’s an average field ant that is not particularly known for it’s lifting ability.

They imaged ants with electron microscopy and X-rayed them with micro-computed tomography (micro-CT) machines. They placed the ants in a refrigerator to anesthetize them, then glued them face-down in a specially designed centrifuge to measure the force necessary to deform the neck and eventually rupture the head from the body.

The centrifuge worked on the same principle as a common carnival ride called “the rotor.” In the rotor, a circular room spins until centrifugal force pins people to the wall and the floor drops out. In the case of the ants, their heads were glued in place on the floor of the centrifuge, so that as it spun, the ants’ bodies would be pulled outward until their necks ruptured.

The centrifuge spun up to hundreds of rotations per second, each increase in speed exerting more outward force on the ant. At forces corresponding to 350 times the ants’ body weight, the neck joint began to stretch and the body lengthened. The ants’ necks ruptured at forces of 3,400-5,000 times their average body weight.

Micro-CT scans revealed the soft tissue structure of the neck and its connection to the hard exoskeleton of the head and body. Electron microscopy images revealed that each part of the head-neck-chest joint was covered in a different texture, with structures that looked like bumps or hairs extending from different locations.

“Other insects have similar micro-scale structures, and we think that they might play some kind of mechanical role,” Castro said. “They might regulate the way that the soft tissue and hard exoskeleton come together, to minimize stress and optimize mechanical function. They might create friction, or brace one moving part against the other.”

Another key feature of the design seems to be the interface between the soft material of the neck and the hard material of the head. Such transitions usually create large stress concentrations, but ants have a graded and gradual transition between materials that gives enhanced performance—another design feature that could prove useful in man-made designs.

“Now that we understand the limits of what this particular ant can withstand and how it behaves mechanically when it’s carrying a load, we want to understand how it moves. How does it hold its head? What changes when the ant carries loads in different directions?”

One day, this research could lead to micro-sized robots that combine soft and hard parts, as the ant’s body does. Much work in robotics today involves assembling small, autonomous devices that can work together.

But a difficult problem will emerge if the researchers try to create large robots based on the same design, Castro explained.

Ants are super-strong on a small scale because their bodies are so light. Inside their hard exoskeletons, their muscles don’t have to provide much support, so they are free to apply all their strength to lifting other objects. Humans, in contrast, carry comparatively heavy loads due to our body weight. With our muscles supporting our body weight, we don’t have as much strength left over to lift other objects.

On a human-sized scale, though, ants are overcome by basic physics. Their weight increases with their overall volume (dimensions cubed), while the strength of their muscles only increases with surface area (dimensions squared). So a human-sized ant, were it to exist outside of a horror movie, would likely not be so successful in carrying extreme loads at a human scale.

A large robot based on that design might be able to carry and tow cargo in microgravity, though, so it’s possible that we may one day employ giant robot ants in space, “or, at least, something inspired by ants,” Castro said.

Meanwhile, the engineers will study the ant’s muscles closely—perhaps using magnetic resonance imaging. Computer simulations will also help answer the question of how to scale up similar structures.

Blaine Lilly, associate professor of mechanical and aerospace engineering, began this work with former student Vienny Nguyen. Nguyen earned her master’s degree with this project, and is now a robotics engineer at Johnson Space Center, where she is helping to design NASA’s Valkyrie robot for the DARPA Robotics Challenge. Ohio State undergraduate student Hiromi Tsuda recently joined Castro’s team, and she is analyzing the ant’s surface textures in more detail. Castro and Lilly have also begun collaborations with Noriko Katsube, also a professor of mechanical and aerospace engineering, and an expert in mechanical modeling of biomaterials.

Funding for this work came from Ohio State’s Institute for Materials Research and Nguyen’s National Science Foundation graduate research fellowship. Computing resources were provided by the Ohio Supercomputer Center; structural modeling software support by Simpleware Ltd.; and micro-CT by the laboratory of Richard Hart, professor and chair of the Department of Biomedical Engineering at Ohio State.

Contact: Carlos Castro, (614) 292-2662; Castro.39@osu.edu
Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu
Editor's note: Images are available from Pam Frost Gorder.

Pam Frost Gorder | EurekAlert!
Further information:
http://www.osu.edu

More articles from Life Sciences:

nachricht World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>