LAPLANTE, L.H.; University of Connecticut: Social environment influences a nuptial signal displayed by female Halichoeres margaritaceus, the Pink-belly Wrasse

In conventional mating systems, females are �choosy� and not expected to have elaborate mating displays; nonetheless female nuptial signals (FNS) are observed in a wide variety of taxa. Factors leading to the evolution of FNS have been proposed for nest-brooding fish, but alternative explanations are needed for fish species having no parental care (i.e. broadcast spawners) since they are not subject to similar constraints. Halichoeres margaritaceus is a cryptic-colored wrasse that occurs in social groups on reef flats throughout the Indo-Pacific. Its mating system is polygynous and males and females spawn daily by simultaneously releasing gametes into the water column. Females of a wild population located in Okinawa, Japan, developed red belly coloration and performed conspicuous �bobbing� behavior as spawning approached. I examined whether changes in social environment influenced nuptial signal expression by comparing the intensity of nuptial signals (i.e. belly color rank and bobbing rate) displayed by females both before and after manipulating group size. Variation in FNS intensity was observed following the manipulation demonstrating that social environment plays an important role in FNS expression in Halichoeres margaritaceus and perhaps other wrasses as well.