Last updated March 6, 2017 at 10:13 am
Scientists love putting animals on treadmills. Not to get fit, but to work out other things about them. Usually they’re built for larger-sized animals, however this week details have been released of a treadmill for ants.
It wasn’t simply a shrunken version of what you might find in a gym. Instead, the ant was placed on top of a super-lightweight polystyrene ball which allowed them to scurry forwards, backwards, stop and change direction as they would normally. The ball was suspended in a blowing airstream to minimise resistance. Keeping the ant in place was a fine thread of dental floss attached to the ant’s back – strong enough to keep them on top of the ball, yet fine enough to not impede the ant’s movement and natural gait.
While spherical treadmills have been used for many years to study small animals, previously they haven’t been sensitive enough to track the quick movements of ants and their tiny legs. However, this new design uses optical sensors from computer mice to accurately and finely track the movements of the ball.
The researchers claim the experience for the ants being studied is not too different from their natural desert surroundings. They apparently just don’t realise they are on a futile journey and continue as they normally would.
So if the aim isn’t to get the ants fit, why create this contraption? The treadmill is being used to discover the secrets of how desert ants from the Sahara navigate. The ants usually travel about 10 m from their nest in search of food, mapping their route using the number of steps they’ve taken and the sun and polarisation of light for orientation. When the ants were at the farthest point from their nest the researchers nabbed them and placed them on their treadmill.
Despite this relocation, the ants tried to return to their nest as if they were still running along the ground, and the treadmill was able to record their movements. The ants proceeded quickly and directly back towards where the nest was thought to be, but when they couldn’t locate the nest and realised they were lost (because they were on the treadmill), they changed into a looping search pattern. These patterns match what researchers have observed in real life.
Now the researchers have developed their treadmill and confirmed the ants still behave as if they were on the ground returning to their nest, they can begin doing more in depth tests. These might include looking at the brain patterns of the ants as they navigate and switch to the search pattern. Eventually this kind of information could be used to develop navigational software, and even used to create robotic insects which could be used as artificial plant pollinators.