Physiological characterization of the compound eye in monarch butterflies with focus on the dorsal rim area

Abstract The spectral, angular and polarization sensitivities of photoreceptors in the compound eye of the monarch butterfly (Danaus plexippus) are examined using electrophysiological methods. Intracellular recordings reveal a spectrally homogenous population of UV receptors with optical axes directed upwards and ‡10°to the contralateral side. Based on optical considerations and on the opsin expression patter