Can house flies see the colour red?
While humans have three types of pigment molecules used in color reception (corresponding to the primary colors), most insects only have two. One absorbs green/yellow light and the other absorbs blue/ultraviolet light. Some insects do have a third pigment molecule that allows them to see into the red color range. This is especially common in pollinators that can cue in on flowers in this color range. Other insects don’t have this molecule because they do not need it for survival. House flies do not likely see red because they are not major flower pollinators. I can’t think of any other reason why they would need to see red.
