Male pipefish prefer dominant over attractive females

Animals may obtain information guiding their choice between potential partn ers from observing competitive interactions and displays between them, or f rom displays directed at the choosing individual. In the sex-role reversed pipefish Syngnathus typhle females display a temporary ornament (a color pa ttern) to other females as well as to males. We have previously shown that display of female ornaments per se is attractive to males. Here we show tha t information from competitive displays can override such direct attraction displays as signals in the partner choice process. In a mate choice experi ment, an enclosed male could choose between two females. On the first exper imental day, females could interact freely, while on the second day they we re isolated from each other. When female-female competition was allowed, th e ornament display was directed more to the other Female than to the male: Time competing, rather than time courting the male, correlated with ornamen t display duration. However, ornament display under competition and ornamen t display in the absence of competition did not correlate significantly. In fact, females competing more intensively on day one displayed the ornament less on day two. Furthermore, the ornament display during the first, but n ot the second, day predicted male mate choice on the second day. Thus, male s remembered previous information from competitive displays and used it rat her than immediate information from displays in the absence of female-femal e competition. We suggest that competitive displays more reliably signal fe male quality as compared to noncompetitive ones, and that males benefit fro m mating with dominant females.