image: Flying desert locust under the blue sky illustrating the pattern of polarization created by the sun just outside the image on the upper right side. view more
Credit: Image credit: Keram Pfeiffer
A study explores how desert locusts integrate two different and complementary internal compasses to navigate using the sky. The desert locust has two compass systems, relying on both the position of the sun and the polarization pattern of the sky. The polarization pattern is created as sunlight is scattered by air molecules and changes depending on the position of the sun. Uwe Homberg and colleagues investigated how these two systems are integrated in the locust brain by recording intracellular activity of neurons in response to polarized light traveling across the entire visual field. The authors measured the activity of 23 neurons in response to polarized light shone at 33 different points. In large parts of the insects' virtual sky, neurons were sensitive to the angle of polarization and tuned to match the polarization patterns of the sun in various positions. Using injected tracers, the authors localized the neurons responsible for encoding the horizontal position of the solar locations to the protocerebral bridge in the locust's central complex. Neurons in the protocerebral bridge encoded 360 degrees of space. The central complex thus acts as a hub for navigation, combining available cues from the sky to develop a compass signal, according the authors.
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ARTICLE #20-05192: "Matched-filter coding of sky polarization results in an internal sun compass in the brain of the desert locust," by Frederick Zittrell, Keram Pfeiffer, and Uwe Homberg.
MEDIA CONTACT: Uwe Homberg, University of Marburg, GERMANY; e-mail: homberg@staff.uni-marburg.de
Journal
Proceedings of the National Academy of Sciences