Natural selection and the reinforcement of mate recognition

Natural selection on mate recognition may often contribute to speciation, resulting in reproductive character displacement. Field populations of Dro-sophila serrata display reproductive character displacement in cuticular hydro-carbons when sympatric with Drosophila birchii. We exposed Þeld sympatric and allopatric populations of D. serrata to experimental sympatry with D. birchii for nine generations. Cuticular hydrocarbons of Þeld allopatric D. serrata pop-ulations evolved to resemble the Þeld sympatric populations, whereas Þeld sympatric D. serrata populations remained unchanged. Our experiment indi-cates that natural selection on mate recognition resulted in the Þeld pattern of reproductive character displacement. A direct role for natural selection in the gen-eration of reproductive isolation during spe-ciation is highly controversial (1–6). Natural selection may rapidly increase divergence in mate recognition between sympatric popula