Wednesday, 14 September 2016

Ants don’t just smell and count, they also look around

Ants are amazing navigators, they can find their homes even when their quite far away from their nests. This is really impressive, considering the small size of the ants. Scientists have finally found out how the ants can pull it off.

Counting and smelling
A desert ant

Scientists thought they knew all of the tricks ants use to find their way back home. Ants count their steps away from their nests, so they know exactly how far away they are from their home. Ants also have excellent smell, so they can smell other ants and follow them home in the case they accidentally lose count of their steps. This is also the reason ants like to move around in ‘trains’. By moving in trains, they can easily follow each other through their olfactory navigation. Though this method seems flawless, if you were to separate the front and back half of an ant train using a piece of cardboard, for example, the ants in the back half would get utterly disorientated. This would happen because they can’t smell their fellow ants anymore. If you remove the piece of cardboard, the ants will be able to smell their friends again and they can continue their journey back to their nest without any problems. However, a special species of ants called Cataglyphis desert ants are exceptionally good at navigating, better than these two methods can explain. This has left scientists puzzled over the mystery for ages, until now.

How flies see the world
Just use your eyes!
The answer isn’t really weird, or even surprising, desert ants simply look around to estimate distances and find out where they are. It’s the same principle as when you’re driving a car, trying to find your cousin’s new home in a labyrinth-like neighbourhood. Although this seems like a rather obvious answer for humans, it’s somewhat strange for insects like ants since insects have notoriously low vision. The reason for this is that they have so-called facet-eyes made from numerous smaller eyes. These work together to create one big picture. The problem is, insects’ brains aren’t that efficient at putting together all the information from the small eyes. This means that insects see the world in a distorted and pixelated way, which is why you can easily swat a fly with a fly swatter. Due to the holes in the swatter, the fly simply cannot see what’s coming for it. On the other hand, the desert ants can apparently see well enough to find their way back to their nest, even when their step counting and smelling methods fail.

Can the others see too?
Since Cataglyphis desert ants have three different methods of navigating; counting, smelling and looking around, they are some of the best navigators in the realm of insects. This is also due to the fact that they can find their way using each of those methods separately. Scientists already knew that flying insects such as flies, wasps or bees, use their eyes to navigate, but they didn’t know that walking insects, like ants could do the same. This opens all kinds of new, interesting research about the sight of all other kinds of walking insects, for example beetles.