Reproductive success of males in polyandrous crosses of Barbus meridionalis (Cyprinidae) revealed by microsatellite genotyping

Using microsatellite genotyping in Barbus meridionalis, we tried to assess the identity of fathers of progeny produced during four experimental polyan drous crosses involving the same four males and one or two females. The poo led analysis revealed that males had significantly different reproductive s uccesses. We found no conspicuous causes explaining differential reproducti ve success in the behavioural data or in the physical characteristics of th e males but a genetic determinism is the most parsimonious hypothesis to ac count for this variability. We argue that this conclusion is compatible wit h the hypothesis that the reproductive strategy of barbels, which involves large aggregations of males, is a result of sexual selection. This study pr ovides guidelines for future interspecific crosses and constitutes the prel iminary experiment of an investigation of the origin of a hybrid zone betwe en Barbus barbus and Barbus meridionalis.