Responses of Cyprinodon maya and C. labiosus females to visual and olfactory cues of conspecific and heterospecific males

Premating isolating mechanisms, based on visual and olfactory cues, were studied in two members of a young species flock which is endemic to Lake Chichancanab in Mexico. The two species, Cyprinodon maya and C. labiosus, differ in morphological traits that may be associated with trophic differentiation, but show little genetic change. Female C. maya strongly preferred conspecific males over C. labiosus males, based on visual as well as olfactory cues. C. labiosus females discriminated between conspecific and heterospecific males based on olfactory cues but not visual ones. Asymmetries in the strength of female preferences for conspecific males in this species pair suggest that mate recognition systems based on visual and olfactory cues evolve at different rates and track the degree of genetic differentiation.