Batesian Mimicry in butterflies

    Viceroy (Papilio) and Monarch (Limenitis) butterflies [left] are not closely related, but have evolved similar orange & black wing pattern (notice slight differences in wing venation & the distribution of white spots of the tips of the front wings). Monarchs feed on milkweed plants, which makes them distasteful to avian predators. When a scrub jay eats a distasteful Monarch (left), it vomits (right). Thereafter, the jay will avoid eating Monarchs, as well as the similarly-patterned Viceroys, even though the latter are not distasteful. The Viceroys gain a selective advantage by evolving a wing pattern that closely mimics the Monarchs.

    Batesian mimicry requires that the mimics remain at a relatively low density with respect to the models in order to obtain the advantage of mimicry If the mimic becomes too common, predators will not learn to avoid the pattern.