Age-dependent sexual selection in bighorn rams

摘要: Although mating systems and sexual selection have been intensively studied in ungulate model systems, very few studies combined genetic paternity analysis with individual phenotypic data over several breeding seasons. We used microsatellite to determine the parentage of 83 bighorn sheep (Ovis canadensis) born between 1995 2000 at Ram Mountain, Alberta, Canada. could assign 64 lambs a high level statistical confidence (95%). Within each season, most successful ram sired an average 35.5% assigned paternity, single 26.1% all six large-horned, mature (age 8+ years) rams had reproductive success, younger ca. 50% lambs. Mixed-effects models indicated that success increases as nonlinear function age, horn length increasingly positive correlation older rams. These results indicate young or small possibly achieve through alternative tactics are less dependent on body weapon size, such coursing blocking. Sexual is therefore likely age-dependent effects traits agility, size.