Dec 13, 2011, 17:51 PM by User Not Found

Discovery Magazine
Discoblog
http://blogs.discovermagazine.com

The Weird Wingless Ant That Glides About, Upside-Down and Backwards

Ants do well in rain forest canopies. Edward O. Wilson once catalogued 43 species of ants in a single Peruvian tree, which is “about equal to the entire ant fauna of the British isles.” But what if they fall? Ending up on the ground—far removed in distance and ecosystem niche—could be fatal. So hundreds of species of canopy-dwelling ants evolved the ability to direct their fall in a number of impressive ways, as a post in The Why Files explains. For example, the gliding ant Cephalotes atratus can:

• Fly backwards, even though backward movement is rare among animals (house cats and hummingbirds being among the exceptions)
• Control their position with their hind legs, flipping backwards at first, then rotating in the last 3 to 5 milliseconds to land legs-down and head-first
• Descend at about 75°, which looks like a controlled crash, but is sufficient to return the ants to the home tree
• Exceed the expectations of an ant-size nervous system by performing these presto-chango mental manipulations

Researcher Robert Dudley tells The Why Files that this type of “controlled aerial descent” evolved hundreds or thousands of times in arthropods alone . This includes wingless aphids and flat spiders that can glide at an angle of 45 degrees.

These arthropods don’t have wings or even partial wings that show up in the fossil record, which could put the evolution of controlled descent—some of the first evolutionary developments towards flight—earlier than researchers thought. Controlled gliding, Dudley says, “preceded the origin of wings, and so the evolution of flight is more about control than about the formation of wings.”

Some other animals can also glide for long distances without proper wings, like the gliding lizard Draco sumatranus, or Wallace’s flying frog.

This video shows researchers dropping a non-gliding control ant, followed by the gliding C. atratus, which makes it back to the tree’s trunk.