mimicry, if the mimic is less common than the model, then the rare mimic phenotype is selected for because the predator has continued reinforcement that the prey is harmful or unpalatable. As the mimic becomes more common than the model, the situation reverses and the mimic is preyed upon more often. Therefore, dishonest signals in prey can be selected for or against depending on predation pressure. An example of apostatic selection by birds was observed by Allen and Clarke (1968) in ground-dwelling passerines when they presented wild birds in their natural habitat with artificial, dimorphic prey. The two colors of prey were presented in 9:1 ratios, and then the prey were switched so both colors had an opportunity to be over or underrepresented. In all four of the passerine species that were observed, the more common morph of the artificial prey was consumed more frequently regardless of its color. This study also had a second component in which they allowed the birds to become familiar with one color of the prey, and then presented the dimorphic prey in equal amounts. In this case, the passerines consumed more of the prey that they were accustomed too. This is consistent with the idea that the search image influences apostatic selection: the familiar form that has been encountered more frequently is the preferred prey. Apostatic selection has also been studied in cichlid fish, which presents a rare polymorphism: the gold ('Midas') colour morph. Torres-Dowall et al. (2017) discussed how apostatic selection is a plausible mechanism for the maintenance of this Midas morph. They concluded that the rare morph is established by a difference in the predator's probability of detecting the Midas morph. One limitation of this study was that the morphs in the wild were not able to be manipulated. See also Frequency dependent selection Polymorphism (biology) References Behavioral ecology Selection