title: The effect of size and hormonal state on the establishment of dominance in young males of Tilapia mariae (Pisces: Cichlidae).
abstract: Pairs of young males of Tilapia mariae were allowed to establish dominance in an aquarium large enough for one territory only. The fishes differed in size and/or in the androgenic hormonal state, which was measured by the size of the male genital papilla. The fish with a larger papilla won most of the encounters. Overall size was decisive for winning only if the genital papillae sizes of the contestants were equal, or if the differences between the genital papillae were small, but there was a large overall size difference. It is concluded that in these encounters dominance is assessed mostly by asymmetries in pay-offs (state of reproductive readiness) and not by asymmetries in resource holding potentials (size).
authors.affiliation: Department of Zoology, Division of Ethology, University of Stockholm, Box 6801, S-113 86 Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Schwanck