Opportunity for sexual selection and effective population size in the lek-breeding European treefrog (Hyla arborea)
Résumé
Sexual selection in lek-breeding species might drastically lower male effective population size, with potentially important consequences
for evolutionary and conservation biology. Using field-monitoring and parental-assignment methods, we analyzed
sex-specific variances in breeding success in a population of European treefrogs, to (1) help understanding the dynamics of genetic
variance at sex-specific loci, and (2) better quantify the risk posed by genetic drift in this species locally endangered by habitat
fragmentation. The variance in male mating success turned out to be markedly lower than values obtained from other amphibian
species with polygamous mating systems. The ratio of effective breeding size to census breeding size was only slightly lower in
males (0.44) than in females (0.57), in line with the patterns of genetic diversity previously reported from H. arborea sex chromosomes.
Combining our results with data on age at maturity and adult survival, we show that the negative effect of the mating
system is furthermore compensated by the effect of delayed maturity, so that the estimated instantaneous effective size broadly
corresponded to census breeding size. We conclude that the lek-breeding system of treefrogs impacts only weakly the patterns of
genetic diversity on sex-linked genes and the ability of natural populations to resist genetic drift.
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...