Animals, Animals, Genetically Modified, Arrestins, Blotting, Northern, Circadian Rhythm, DNA Probes, Drosophila Proteins, Drosophila melanogaster, Electrophoresis, Polyacrylamide Gel, Eye Proteins, Gene Expression, Immunoblotting, Phosphoproteins, Photoreceptor Cells, Invertebrate, RNA, Messenger, Rhodopsin