01850nas a2200121   4500008004100000245010800041210006900149260001600218520140700234100002201641700002201663856004301685       2017                        eng d00aReproductive character displacement of female, but not male song discrimination in an avian hybrid zone0 aReproductive character displacement of female but not male song   cNov-05-20173 a<p>Divergence of male sexual signals and female preferences for those signals often maintains reproductive boundaries between closely related, co-occurring species. However, contrasting sources of selection, such as interspecific competition, can lead to weak divergence or even convergence of sexual signals in sympatry. When signals converge, assortative mating can be maintained if the mating preferences of females diverge in sympatry (reproductive character displacement; RCD), but there are few explicit examples. Pied flycatchers (Ficedula hypoleuca) are sympatric with collared flycatchers (F. albicollis) on the Baltic island of &Ouml;land, where males from both species compete over nestboxes, their songs converge, and the two species occasionally hybridize. We compare song discrimination of male and female pied flycatchers on &Ouml;land and in an allopatric population on the Swedish mainland. Using field choice trials, we show that male pied flycatchers respond similarly to the songs of both species in sympatry and in allopatry, while female pied flycatchers express stronger discrimination against heterospecific songs in sympatry than in allopatry. These results are consistent with RCD of song discrimination of female pied flycatchers where they co-occur with collared flycatchers, which should maintain species assortative mating despite convergence of male sexual signals.</p>
1 aWheatcroft, David1 aQvarnström, Anna  uhttp://doi.wiley.com/10.1111/evo.13267