Dung beetles Use the Sky to Navigate and Move in Straight Lines, This is How They Do it
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A 2009 study showed that humans, taken to the Sahara Desert for the experiment, moved around in circles when they could not see the sun. Moreover, the blindfolded participants moved in circles only 20 metres wide.
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- Last Updated: January 04, 2021, 18:24 IST
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The dung beetles have a fascinating ability to move in a straight line. Their sense of direction comes from sources such as the sun, moon and even wind. It is this ability that made the ancient Egyptians believe that a dung beetle drives the movement of the sun. It is, however, the other way round.
Around 600 of the over 8,000 known species of dung beetles roll tiny balls of animal dung away for about six minutes, before burying them in the ground where they can eat peacefully. During this process, they follow a path that reflects the sun’s movement across the sky, a report published in The Wire Science said.
Traveling in a straight line is not as easy as it seems, especially without any point of reference. A 2009 study showed that humans, taken to the Sahara Desert for the experiment, moved around in circles when they could not see the sun. Moreover, the blindfolded participants moved in circles only 20 metres wide.
The dung beetles, however, move straight despite not being able to see where they are headed. They push the dung balls with their hind legs while moving backwards and their heads point at the ground.
In a study conducted by entomologists at the University of the Witwatersrand in Johannesburg, the team presented the reflection of sun from a mirror while hiding the actual sun from the participating creatures’ view. They found that the beetles followed the path of the reflected sun. Similar results were arrived at using LED.
During noon, when the sun is directly overhead, making it an unreliable source for navigation, the beetles make use of the wind instead. This was found in a 2019 study conducted using the South African dung beetle, Scarabaeus lamarcki.
Apart from sun, which is only available in daytime, the nocturnal species can take their cue even from the moon.
When light from the sun hit the tiny particles suspended in the atmosphere, some of it gets polarized, resulting in waves that ripple in the same direction. This is what is perceived by the beetles, bees, ants and other insects. However, the dung beetles are the first ones known to do it using the moonlight, which is about a million-times-dimmer.