Mate Choice by Both Sexes Maintains Reproductive Isolation in a Species Flock of Pupfish (Cyprinodon spp) in the Bahamas

Female and male mate choices can reinforce reproductive isolation after sympatric speciation. Using a binary choice design, we examine the importance of visual cues in female mate choice in all three sympatric species of pupfish on San Salvador Island. We also examine the importance of olfactory cues in female choice of the hard‐shelled invertebrate specialist (Cyprinodon brontotheroides). We examine male mate choice in two of the three species, the scale eater (C. desquamator) and the detritivore (C. variegatus). Females of all three species use visual cues and prefer conspecific males. C. brontotheroides females do not use olfactory cues to discriminate between conspecific and heterospecific males. Males of C. desquamator and C. variegatus also preferentially court conspecific females. Thus, mutual mate choice, where both females and males exhibit mate choice, acts as a strong behavioral pre‐mating isolation mechanism in these sympatrically speciated pupfish.