Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

It’s a bug’s life: MIT team tells moving tale

29.09.2005


MIT mathematicians have discovered how certain insects can climb what to them are steep, slippery slopes in the water’s surface without moving their limbs -- and do it at high speed.



Welcome to the world of the tiny creatures that live on the surface of ponds, lakes and other standing bodies of water. There, "all the rules change," said David Hu, a graduate student in the Department of Mathematics and first author of a paper on the work to appear in the Sept. 29 issue of Nature.

For the last four years, Hu and John Bush, an associate professor in the department, have been studying the novel strategies these insects use to navigate their environment. To do so, they took high-speed video of the creatures using a camera provided by MIT’s Edgerton Center, then digitized and analyzed the images.


In 2003, the two and Brian Chan, a graduate student in the Department of Mechanical Engineering, reported in Nature how some of these creatures walk on water. Both that paper and the current one were Nature cover stories.

Now Bush and Hu are describing how three species of insects are able to climb the slippery slopes, or menisci, that arise when the water surface meets land, floating bodies or emergent vegetation. Why would they want to leave the water? "There are many reasons, such as laying eggs or escaping predators," said Hu.

Menisci are all around us -- picture the slight upward curve of water in a glass where it meets the side. "But we don’t notice them because they’re so small, only a few millimeters in height," said Hu. But if you’re a creature that’s much smaller than that, those slopes "are like frictionless mountains," Hu said. "Plus, it’s slippery."

In these conditions, the insects’ normal modes of propulsion won’t work. Hu and Bush took high-speed video of insects trying to ascend menisci with a running start and found they got partway up, then slid back down.

The solution? The creatures adopt special postures that create forces that pull them up the slope at speeds of almost 30 body lengths per second (for comparison, an Olympian sprinter moves at about five body lengths per second).

For example, Hu and Bush found that two species of water treaders have retractable claws on their front and hind legs that allow them to "grasp" the surface of the water and pull it into a miniscule peak. The insect simultaneously presses down on the water with its central pair of legs, forming dimples in the water surface that bear the creature’s weight.

Because the insects are so small, these perturbations create forces that suck them up the slope, similar to the way champagne bubbles rise to the edge of a glass.

Bush explains that the insect is actually "generating tiny menisci" with its front and hind legs. Since menisci are attracted to other menisci, the cumulative effect is to pull the insect up and over the meniscus at the water’s edge.

Remember the champagne bubbles? Each essentially forms its own meniscus, hence the attraction to the edge of the glass.

The larva of the waterlily leaf beetle solves the same problem a different way. The sluglike creature simply arches its back, creating menisci at each end. The effect has the same end result, propelling the larva up the slope.

Bush and Hu got involved in this work because they wanted to explain how these creatures do what they do. Bush notes, however, that "the physics is also of interest to people working in nanotechnology because they, too, are concerned with problems at very small length scales."

Hu will be defending his thesis on Sept. 28.

Elizabeth Thomson | EurekAlert!
Further information:
http://www.mit.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>