Butterflies use warning colors and concentrations of poison within their bodies to ward off predators. They also utilize camouflage, large eye spots, mimicry and flight to avoid being eaten.
Poisonous butterflies, such as monarch butterflies, consume toxic plants. In the case of the monarch, the toxic plant of choice is milk weed. The butterflies are immune to the poison, but they sequester it in their bodies rather than excrete it, so that if a predator eats them, they become sick and develop an aversion to any other butterfly that resembles the one that made them ill.
Poisonous butterflies have flashy wings to reinforce the association between appearance and illness. Some non-poisonous butterflies mimic the appearance of poisonous ones to imply that they too make predators sick.
Other species have enormous spots on their wings that resemble eyes. These eye spots make the animal look much larger when their wings are spread, scaring off and surprising potential predators.
Some butterfly wings are designed to resemble vegetation or tree bark. Some species even have transparent wings. These adaptations serve as camouflage, making it easy for the insects to avoid predators by going unseen.
Finally, butterflies can be fast fliers, and their distinct fluttering motion makes it difficult for predators to determine where they will go next, making pursuit difficult. Butterflies called skippers have been recorded at more than 30 miles per hour.