The role of sexual selection in the loss of sexually selected traits in the swordtail fish Xiphophorus continens

摘要: Swordtail fish have been studied extensively in relation to several exaggerated male traits that evolved due sexual selection. However, one species of swordtail fish, Xiphophorus continens, lacks all these traits. Males this are relatively small, lack swords and do not possess any the pigment patterns found throughout swordtails platyfish. In study we compared mating behaviour X. continens behaviours other determine whether a relaxation selection may played role loss large size pattern vertical bars. We lacked courtship present species, female preference for response bars were significantly weaker than tested. addition, results staged male–male interactions suggested neither nor under strong competition. did detect polymorphism bars, suggesting has evolutionarily retained even though trait was lost. Based on what is known about body across northern swordtails, hypothesize selection, whereas not.