Further examination of female preference for vertical bars in swordtails:preference for 'no bars' in a species without bars

摘要

Xiphophorus pygmaeus males do not have a vertical bar pigment pattern and so female preference for the bars was determined by giving females a choice between pairs of X. multilineatus males without bars (all bars removed by freeze-branding) and with bars (freeze-branded between the bars). Female X. pygmaeus had a significant preference for male X. multilineatus without bars over males with bars, and this preference was significantly different from the preference for bars detected in X. nigrensis and X. multilineatus. The implications of the results are discussed in regard to models for the evolution of female preference.