Mimicry

In the 1870s, Fritz Müller theorized a different type of mimicry. His idea, also based on sets of butterfly species, was that several species, all somewhat distasteful, would evolve to look like each other. Such an evolutionary strategy would, in effect, reduce predation on any of the species because the predator would learn to avoid a single color pattern, but since all of them had the same pattern, they would all be safe from predation. The rarer form, say species 1, would eventually converge to look like the more common form, species 2, as the individuals that looked too different from species 2 would be rapidly selected out by predators. Since species 2 was more common, the predator would have had more experience with it and would have had more opportunity to learn to avoid it than with species 1, the rare species. Individuals of species 1 that resembled species 2 would benefit from the predator's learned avoidance of species 2, and thus would proliferate. The species would evolve to share a similar pattern as relative frequencies shifted. If the two species were equal in abundance, Müller reasoned, it would not be possible to distinguish mimic from model, as both had converged on a common phenotype, or appearance.