Researchers from the University of Marburg and the University of Würzburg have discovered how the “solar compass” works in the brains of the desert locust. In their paper published in the Proceedings of the National Academy of Sciences, Frederick Sittrell, Keram Pfeiffer and Uwe Homberg describe the study of how neurons respond to natural and polarized light in an insect brain, Science X Network reports.
Previous research has shown that one species of African Desert Locust (Schistocerca gregaria) can migrate long distances with incredible accuracy. It is also known that their behavior and purpose are genetically determined. But how the locusts manage to reach their destination has remained a mystery until now. Some experts in the field have suggested that locusts can use both natural sunlight and polarized light for navigation. In their new work, the researchers sought to find out if this was true, and if so, how the locust used both light sources as a solar compass for orientation.
The work involved first recording the response of neurons to light passing through the insect’s entire field of view. The researchers were able to measure the activity of 23 neurons that responded to polarized light coming from 33 different directions.
The researchers then introduced indicators that allowed them to identify the neurons responsible for encoding the sun’s horizontal position in the protocerebral bridge. They noticed that there neurons encode 360 degrees of space. By studying how the two types of light are processed in the brain, the scientists found that the central complex in it acts as a navigation center, taking signals from the sky and using them to create a “compass” that allowed locusts to navigate.