Visual pigments are the light-absorbing molecules that mediate vision. They consist of an apoprotein, opsin, covalently linked to cis-retinal. Upon white light stimulation, is internalized into the rhabdomere membranes. Phosphorylated on some or all of the serine and threonine residues present in the C-terminal region. Each Drosophila eye is composed of 800 facets or ommatidia. Each ommatidium contains 8 photoreceptor cells (R1-R8), the R1 to R6 cells are outer cells, while R7 and R8 are inner cells. Belongs to the G-protein coupled receptor 1 family. Opsin subfamily.