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

Xiphophorus pygmaeus males do not have a vertical bar pigment pattern and s o female preference for the bars was determined by giving females a choice between pairs of X. multilineatus males without bars (all bars removed by f reeze-branding) and with bars (freeze-branded between the bars). Female X. pygmaeus had a significant preference for male X. multilineatus without bar s over males with bars, and this preference was significantly different fro m the preference for bars detected in X. nigrensis and X. multilineatus. Th e implications of the results are discussed in regard to models for the evo lution of female preference. (C) 1998 The Fisheries Society of the British Isles.