Some Evolutionary Consequences of Pegmatypic Mating Systems (Imprinting)

On the Evolutionary Consequences of Sexual Imprinting

“…A stable polymorphic equilibrium can result, but the conditions under which this occurs are likely to be fairly restricted. This finding conflicts with those of earlier analyses (O'Donald 1960; Kalmus and Maynard Smith 1966;Seiger 1967), which suggested that sexual imprinting can result in a population splitting into two noninterbreeding, genetically distinct populations or that sexual imprinting is likely to maintain a stable polymorphism in the population. However, the validity of the assumptions that underlie these findings is open to question.…”

“…Moreover, the frequency with which mating types occur can be considered dependent on the frequency and strength of the preferences but also on the frequency ofthe trait phenotypes in the population. This latter assumption is consistent with recent models ofsexual selection (Kirkpatrick 1982;Heisler and Curtsinger 1990;Otto 1991) but distinct from that of Kalmus and Maynard Smith (1966). It is assumed that there is unlimited polygyny and that one sex dominates the matings (does the choosing).…”

“…Empirical studies universally find that imprinting generates a relative, rather than absolute, mating preference. The finding of previous studies, that sexual imprinting is a mechanism that is likely to establish and maintain a balanced polymorphism (Kalmus and Maynard Smith 1966;Seiger 1967), follows from a combination of the modeling of imprinting by restricting the types of matings that can occur, the assumption of absolute dominance, and the assumption that mating preferences for particular morphs are independent of the frequency of the morph in the population.…”

“…Moreover, Seiger considers only cases in which one allele is completely dominant and in which there is no viability selection. Kalmus and Maynard Smith (1966) conducted a slightly more sophisticated analytical investigation of the evolutionary consequences of sexual imprinting, which incorporated viability selection on the trait alleles. They found that when there are relative mating preferences (i.e., ifthere is an imprinted preference for the parental type but with some individuals mating with the alternative phenotype), a stable polymorphic equilibrium tends to result.…”

No evidence for differential survival or predation between sympatric color morphs of an aposematic poison frog

“…Because the red morph is more common, appears to be dominantly inherited, and shows a stronger tendency toward assortative mating in the wild (Richards-Zawacki et al 2012), the yellow morph might be expected to disappear from the population over time. However, if mating preferences are learned rather than innate, modeling studies suggest that this sort of polymorphism can be stable (Kalmus and Maynard Smith 1966;Seiger 1967) and even lead to sympatric speciation (Verzijden et al 2005).…”