Summary of the main findings.

<p>Frontal schematic diagram of the honeybee brain illustrates the main neuropils and the sky compass pathway. The dorsal rim area of the eye (DRA) is connected to the dorsal rim area of the medulla (MEDRA) through long visual fibers. Transmedulla neurons project from the MEDRA to the lower unit complex of the anterior optic tubercle (LUC). TuLAL1 neurons project from the LUC around the vertical lobe of the mushroom body (VL) to the median and lateral bulb (MBU, LBU). Three Types of TuTu1 neurons project to the contralateral LUC. Stippled grey lines in medulla (ME) indicate hypothetical unpolarized light input pathways. Also shown is immunoreactivity in the medulla to antisera against pigment dispersing factor (PDF) and 5HT (5HT). AL, antennal lobe; CBL, lower division of the central body; CBU, upper division of the central body; LA, lamina; LCA and MCA, lateral and medial calyx of the mushroom body; LO, lobula; PED, pedunculus. Scale bar: 200 μm.