The visual pigment of a stomatopod crustacean,Squilla empusa

Summary Stomatopod crustaceans are visually active animals which have large, mobile compound eyes of unique design. Aspects of their ecology and behavior suggest they may be able to discriminate hues. Isolated rhabdoms of the squillid stomatopod,Squilla empusa, were investigated using microspectrophotometry and fluorometry. A single rhodopsin, of _max507 nm, exists in the main rhabdom. Its stable metarhodopsin, with _max503 nm, possesses typical arthropod fluorescence characteristics. No evidence was found for a visual pigment with peak absorption in the ultraviolet. Vision in this animal might therefore be monochromatic.Abbreviation ASW artificial sea water