Amazing ants ‘fly’ when they fall

By Robert Roy Britt

Senior writer

updated 1:30 p.m. ET Feb. 9, 2005

Add ants to the list of animals that can fly. Worker ants, the wingless kind.

Scientists call it gliding, or directed aerial descent. But just as one might say that flying squirrels fly, so do a type of ants called Cephalotes astratus. They live in rain forest treetops, and their newly discovered ability is a lifesaver.

Stephen Yanoviak of the University of Texas Medical Branch and University of Florida made the discovery by accident about two years ago while collecting mosquitoes for an unrelated project in the rain forest canopy near Iquitos, Peru.

The finding was announced Wednesday.

"When I brushed some of the ants off of the tree trunk, I noticed that they did not fall straight to the ground," Yanoviak told LiveScience. "Instead, they made a J-shaped cascade leading back to the tree trunk."

Yanoviak immediately suspected that his observation was something "new and exciting," but figured someone must have scooped him years ago. However, a quick read of past research revealed that his observation was novel.

So paint them
Yanoviak started marking the ants with paint to follow their amazing journeys up and down the trees. He discussed the findings with Michael Kaspari of the Smithsonian Tropical Research Institute in Panama and the University of Oklahoma. A third colleague, Robert Dudley, with the University of California and also the Smithsonian, was brought in to create high-speed videos of the gliding wonders, among other things.

The team found that the ants downward journey comes in three phases: a 2- to 3-yard freefall and attempt to slow down, followed by a rapid midair turn back toward the tree trunk, and finished off with a steep but directed glide to the tree trunk.

The remarkably adapted ants are the first animals found to consistently glide backwards, other than microbes, some of which spend their entire lives gliding in directions hard to call backwards or forwards.

Yanoviak and his colleagues discovered that the gliding ants are able to return to their home tree trunk 85 percent of the time.

Once they make contact again with the trunk, the ants either cling to it with their sticky toes (called "tarsi" in ants) or fall a few more yards before gaining a foothold — at which point they begin their march back up the tree, often returning to the exact point from which they dropped, and typically within 10 minutes of their initial fall. Experiments done with blinded ants found that they rely on their vision to detect the tree trunk and guide their descent.

Smaller ants fell shorter distances. The scientists also found that ants called Pseudomyrmecinae were able to glide, but other arboreal ants they tested could not.

These results are published in Thursday's issue of the journal Nature.

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