preferential mating
Tinghitella RM & Zuk M 2009 Asymmetric mating preferences accommodated the rapid evolutionary loss of a sexual signal. Evolution 63:2087-2098.
- for a sexual signal to change, the change must be favorable for the signaler, but must also be accommodated by the receiver's perception and preferences
- selective pressure by a deadly parasitoid fly favored a wing mutation in Hawaii (flatwing) that eliminates males' singing ability altogether
- females from ancestral, unparasitized Australian and Pacific Island populations as well as parasitized Hawaiian populations, will mate with silent flatwing males
- suggesting this behavioral option predates the change in sexual signal
- ancestral Australian females discriminate against flatwing males more severely than island females
- island colonization favored females with relaxed mating requirements (Kaneshiro's effect) facilitating the rapid evolutionary loss of song in Hawaii
- Kaneshiro's hypothesis (1976, 1980, 1989)
- the initial stages of island colonization, when population size is very small, impose strong selection for females who are less discriminating in mate choice
- extremely choosy females would be unlikely to mate under these circumstances
- this, he argued, would relax selection on sexual signals, favoring divergence and premating reproductive isolation
- Kaneshiro's hypothesis predicts a characteristic mating asymmetry whereby ancestral females discriminate against derived males (who may lack elements of the courtship repertoire), but derived females discriminate less strongly between ancestral and derived males
