1:18pm

Wed April 27, 2011
The Picture Show

Water Can't Put Out A Fire-Ant Raft

You've seen ants. Thousands of them. And most of the time, you've seen them in colonies, living as a group. But have you seen them float as a group? Apparently a single fire ant will struggle in water, but a cluster of them can bob happily for months. A new study has used time lapse photography to figure out why — and how — that is.

The above fire ants, or Solenopsis invicta, have evolved so remarkably, that they can self-assemble into structural tools utilized by the entire colony. They have been known to build ladders, chains and walls — out of themselves — that ensure their colony remains intact.

To survive a flood, for example, they can link in a matter of seconds by mandibles, tarsal claws, and adhesive pads on their feet — to form, in essence, a raft. In short: by joining this way the ants are able to decrease their mean density as a whole and become a buoyant raft; if left alone they would sink.

Sightings of ant rafts were reported following flooding from Hurricane Katrina. These findings may contribute to future technologies for floating devices and waterproof materials. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.