Mimicry that exploits a polymorphism for palatability to predators. In the monarch butterfly, for example, unpalatability arises from the food plants which are chosen by the ovipositing female. After hatching, the feeding larvae take in substances that are toxic to birds but not to the insects themselves. This renders them unpalatable. The situation is used to advantage by palatable members of the species, which mimic the coloration of the unpalatable ones and so obtain protection. The polymorphism is frequency-dependent, and the unpalatable insects must be more abundant (and hence more frequently encountered by the bird predators) than the palatable insects.
Subjects: Zoology and Animal Sciences — Ecology and Conservation.