Ants run on tiny treadmills to help track their behavior
The machines had to be custom-built for the insects.
It's relatively easy to study animals' movement by plunking them on treadmills, but how do you do that with a creature as small and fragile as ants? Build a tiny custom treadmill, that's how. Scientists have crafted a contraption that let them study the homing behavior of ants on a treadmill for the first time. In many ways, it amounts to an optical mouse flipped on its back. An air-cushioned styrofoam ball serves as the actual running surface, giving the ant freedom to move as far as the tether (dental floss) allows without falling off; optical sensors from computer mice track their gait, speed and changes in direction.
The actual treadmill run revealed new insights into how ants behave. It confirmed existing techniques that ant use to get back to their nest, such as counting their strides and using the Sun's position as a guide. However, it also revealed that lost ants jump into a search pattern where they slow down and loop around until they have some sign of where to go.
While the machine was designed for a specific test, it's easy to see the broader possibilities. This should be useful for experiments where researchers want to study insects in controlled conditions without imposing too many restrictions on the critters in question. While ants and other species frequently act as collectives, this could shed a lot of light on what they do when they're on their own.
