Featured Research

from universities, journals, and other organizations

It's A Bug's Life: MIT Team Tells Moving Tale

Date:
September 29, 2005
Source:
Massachusetts Institute of Technology
Summary:
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.

The larva of a waterlily leaf beetle gets ready to propel itself up onto a leaf using a technique recently discovered by MIT researchers.
Credit: Photo courtesy Hu and Bush, 2005

MIT mathematicians have discovered how certain insects canclimb what to them are steep, slippery slopes in the water's surfacewithout moving their limbs -- and do it at high speed.

Related Articles


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

For the last four years, Hu and JohnBush, an associate professor in the department, have been studying thenovel strategies these insects use to navigate their environment. To doso, they took high-speed video of the creatures using a camera providedby MIT's Edgerton Center, then digitized and analyzed the images.

In2003, the two and Brian Chan, a graduate student in the Department ofMechanical Engineering, reported in Nature how some of these creatureswalk on water. Both that paper and the current one were Nature coverstories.

Now Bush and Hu are describing how three species ofinsects are able to climb the slippery slopes, or menisci, that arisewhen the water surface meets land, floating bodies or emergentvegetation.

Why would they want to leave the water? "There are many reasons, such as laying eggs or escaping predators," said Hu.

Menisciare all around us--picture the slight upward curve of water in a glasswhere it meets the side. "But we don't notice them because they're sosmall, only a few millimeters in height," said Hu. But if you're acreature that's much smaller than that, those slopes "are likefrictionless mountains," Hu said. "Plus, it's slippery."

In theseconditions, the insects' normal modes of propulsion won't work. Hu andBush took high-speed video of insects trying to ascend menisci with arunning start and found they got partway up, then slid back down.

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

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

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

Bushexplains that the insect is actually "generating tiny menisci" with itsfront and hind legs. Since menisci are attracted to other menisci, thecumulative effect is to pull the insect up and over the meniscus at thewater's edge.

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

Thelarva of the waterlily leaf beetle solves the same problem a differentway. The sluglike creature simply arches its back, creating menisci ateach end. The effect has the same end result, propelling the larva upthe slope.

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

Hu will be defending his thesis on Sept. 28.

This work was sponsored by the National Science Foundation.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Institute of Technology. "It's A Bug's Life: MIT Team Tells Moving Tale." ScienceDaily. ScienceDaily, 29 September 2005. <www.sciencedaily.com/releases/2005/09/050929082253.htm>.
Massachusetts Institute of Technology. (2005, September 29). It's A Bug's Life: MIT Team Tells Moving Tale. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2005/09/050929082253.htm
Massachusetts Institute of Technology. "It's A Bug's Life: MIT Team Tells Moving Tale." ScienceDaily. www.sciencedaily.com/releases/2005/09/050929082253.htm (accessed October 26, 2014).

Share This



More Plants & Animals News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) — Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) — Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) — One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) — Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins