Predator exposure alters female mate choice in the green swordtail

Female green swordtails, Xiphophorus helleri, show a matingpreference for males with brightly colored, elongated swords.This preference is thought to be due to a preexisting receiverbias favoring longer sworded males. In this study, we examinedvariation in the expression of this sword bias in females. Specifically,we tested the hypothesis that an increase in perceived predationrisk will decrease female response to males with longer swords.We used a video playback experiment to evaluate female choicebetween two recordings of a displaying male that differed onlyin sword length. We scored responses of females to these recordingsimmediately before and after they had been exposed to a videorecording of a predation event between a cichlid and a malepossessing a long sword. We found that prior to exposure tothis predation event, females preferred the male with the longersword. However, after exposure to the predator, females alteredtheir mating response, preferring the male with the sword removed.Exposure to the predator also caused an increase in the frequencywith which females moved from potential mating positions toa neutral zone. The results presented here suggest that thefemale preference for males with longer swords can be modulatedbased on the perceived risk of predation.