preferential mating

Rundle HD, Chenoweth SF & Blows MW 2009 The diversification of mate preferences by natural and sexual selection. J Evol Biol 22:1608-1615.

• perhaps surprisingly, natural selection in the absence of sexual selection had no consistent effect on the evolution of mate preferences
• natural selection alone may be unlikely to cause preference evolution during the early stages of ecological speciation
• this may seem to contradict a wealth of past speciation experiments in which assortative mating has been observed to evolve as a by-product of divergent natural selection
• sexual selection was unconstrained in all of these experiments, making its contribution unknown
• the operation of sexual selection may be critical for mate preferences evolution after this particular change in environment