colour can be used in advertising. some butterflies have eyespots on their wings. these make no effort at concealment, but may startle a potential predator into trying elsewhere. the western skink has a distinctive blue tail. if the skink cannot escape from a predator by concealment or flight, it can afford to lose its tail in order to escape with its life. similarly, some species of grasshopper are well-camouflaged when at rest but flash vivid colouration when flying. the grasshopper thus avoids being eaten while the potential predator hunts in vain for the brightly coloured insect it saw.