The coevolution of sexual imprinting by males and females

Sexual imprinting is the learning of a mate preference by direct
observation of the phenotype of another member of the population. How
preferences are learned can affect trait evolution and speciation rates.
Sexual imprinting can be paternal, maternal or oblique if individuals learn
to prefer the phenotypes of their fathers, mothers or other members of the
population, respectively. Models of polygynous systems suggest that
females should evolve to imprint on their fathers, because paternal
imprinting helps females to choose mates that will provide offspring that
are both viable and sexy. Sexual imprinting by males has also been
observed, but a theory for the evolution of sexual imprinting by males does
not exist. We developed a model to study the conditions under which
sexual imprinting by males or by both sexes can evolve, and to ask which
sexual imprinting strategies maximise the fitness of the choosy sex. We
found that when only males imprint, maternal imprinting is the most
advantageous strategy. When both sexes imprint, it is most advantageous
for both sexes to use paternal imprinting. Previous theory suggests that, in
a given population, either males or females but not both will evolve
choosiness in mating. We show how environmental change can lead to the
evolution of sexual imprinting behaviour by both sexes in the same
population.