Sun navigation requires compass neurons in Drosophila

To follow a straight course, animals must maintain a constant heading relative to a fixed, distant landmark, a strategy termed menotaxis. In experiments using a flight simulator, we found that Drosophila adopt arbitrary headings with respect to a simulated sun, and individuals remember their heading preference between successive flights—even over gaps lasting several hours. Imaging experiments revealed that a class of neurons within the central complex, which have been previously shown to act as an internal compass, track the azimuthal motion of a sun stimulus. When these neurons are silenced, flies no longer adopt and maintain arbitrary headings, but instead exhibit frontal phototaxis. Thus, without the compass system, flies lose the ability to execute menotaxis and revert to a simpler, reflexive behavior.One sentence summarySilencing the compass neurons in the central complex of Drosophila eliminates sun navigation but leaves phototaxis intact.