The function of aposematic coloration is to prevent attack by warning potential predators that the prey animal has defenses such as being unpalatable or poisonous.
Visual warnings like bright colours, with high contrast patterns such as stripes are patterns used as honest indication of noxious prey. Thus the brighter and more conspicuous the organism, the more toxic it usually is.
The most common and effective colours are red, yellow, black and white. These colours provide strong contrast with green foliage, resist changes in shadow and lighting, and provide distance dependent camouflage.