Mate Choice and Behavior of Xiphophorus hellerii and X. maculatus in a Sexual Selection System

Abstract

Females select for a variety of male traits. More often than not, females prefer conspecific traits to those found in heterospecific species in order to prevent hybridization. However within these trials, Xiphophorus maculatus females have shown preference for the heterospecific “sword” ornament of X. hellerii males, in addition to weak a selection for conspecific olfactory cues. X. hellerii females exhibited a strong conspecific olfactory preference, meanwhile demonstrated a weak conspecific preference towards males in visual trials and even a slight heterospecific majority choice with the presence of UV light. These two species are quite similar in courting and mate selection factors, thus possess weak premating isolation barriers. Though evidence of hybridization in the wild between these two species has yet to be found, the possibility of hybridization in the future is likely.