Female Choice and Male Courtship Behaviour in the Beaugregory Damselfish

Abstract

AbstractDuring courtship in the beaugregory (Stegastes leucostictus), a coral reef fish, males turn the dorsal half of their bodies from dull brown to bright yellow, and perform a series of rapid dipping movements in front of females. To look for evidence that females select males on the basis of these characteristics, we provided males with artificial breeding sites in the field, measured their reproductive success, and videotaped courtship. Reproductive success was measured by monitoring both the number and size of egg clutches present in the breeding site that was defended by the male. Both unmanipulated and experimentally induced courtship events were videotaped in separate groups of 88 (of which 32 were videotaped courting females) and 30 males, respectively. Experimental induction of courtship was done by placing a female in a clear plastic cylinder 0.5 m away from the breeding site of a territorial male; each of the 30 males received 8 different female presentations, but never more than one a day, and with a different female every time. We compared (i) the cumulative amount of eggs and number of clutches with the amount of yellow colouration and dipping rate for individual males in both the observational and experimental groups, (ii) individual variation in percentage yellow and dipping rate (for the experimental group only) with reproductive success on the same day when courtship was videotaped, and (iii) egg survivorship (ratio of final to early stage eggs) with yellow colouration and dipping rate, to see if these characteristics indicate male parental ability. Individual variation in courtship characteristics was not correlated with reproductive success on that day. In contrast, however, mean values of percentage yellow and dip rate were correlated with both the number of clutches and amount of eggs, for both the observational and experimental group of males, indicating that females preferentially spawn with males that have the brightest yellow colouration and the highest dip rate. Percentage yellow colouration was correlated with egg survival in the unmanipulated males, but not in the experimental group, while dipping rate was not correlated with egg survival in either group. We argue here that female assessment of male courtship is part of a complex process of female choice, in which females either simultaneously or sequentially examine territorial, breeding site, and male characteristics, and thereby attempt to enhance the survivorship of their offspring.