This creates an initial spread, even though, once evolved, warning color is beneficial because by definition it reduces the number of prey eaten during predator learning. This selection against rarity makes it easy to understand why warning-colored races are normally fixed and sharply separated by narrow overlap zones from other races, but in turn makes it hard to understand how geographic races diversified in the first place. If it weren't for unpalatability, mimicry would never be possible. Unpalatability is defined as any trait that acts on predators as a punishment, and that causes learning leading to a reduction in attacks. Being unpalatable has both its advantages and disadvantages.
Individuals incur costs in synthesis or processing of distasteful chemistry.
Individuals are also likely to incur damage, while other members of the population mostly benefit from predator learning. Also, benefits are shared among kin, and many believe that kin selection is responsible for the evolution of unpalatability. Recent research has found that being unpalatable may not be that costly after all. Although expensive to process distasteful secondary compounds, in some cases the same biochemical machinery is required to exploit available food. Other advantages include the fact that most time predators taste test their food, and in addition the production of toxic chemicals adds to the resiliency of the individuals exterior, causing limited harm.