Meeting Abstract
The only known or proposed mechanisms for color vision require either spectrally distinct photoreceptors or spectral filtering of a single photoreceptor type. Virtually all cephalopods (octopus, squid, and cuttlefish) have a single unfiltered photoreceptor type and lack the ability to determine color by comparing photon intensity across multiple spectral channels. Nevertheless, cephalopods dramatically change color both to produce chromatically-matched camouflage and to signal conspecifics. This presents a paradox – an apparent ability to determine color in organisms with a monochromatic visual system – that has been a long-standing puzzle. We demonstrate how chromatic aberration (focus variation with wavelength) can be exploited, especially through non-axial pupils, to obtain spectral information. This has potential applicability in any organisms with limited photoreceptor complements, such as spiders and dolphins.
