Mating preference of female zebrafish, Danio rerio, in relation to male dominance

Mating success tends to be skewed toward dominant males, though female mate preferences may not always correlate with male dominance. In this study, we investigated the mating preferences of female zebrafish, Danio rerio, in the absence of male–male competition. We paired females sequentially with males of known dominance rank, using a nested, repeated measures design, with egg production as a measure of female mate preference. We predicted that females would spawn more frequently and produce larger clutches when paired with males of higher dominance rank. We found significant differences among females in the size of clutches produced and among males in the size of clutches received, but these differences were independent of male dominance rank. Male body size was not related to either dominance rank or clutch size received. These results indicate that females vary clutch size in relation to the males with which they are paired but that they do not favor dominant males. Thus, male competition may normally override female mate preference in zebrafish. Key words: assortative mating, mate choice, oviposition, pheromone, territoriality. [Behav Ecol] Sexual selection, that is, selection arising through competi-tion over mates and matings, results from differential mat-ing success among males (Darwin 1871). The strength of sexual selection depends on the sex difference in the variance in mating success for each sex; the greater the difference, the more opportunity there is for selection to operate (Shuste