Deakin, SamuelFesta-Bianchet, MarcoMiller, Joshua M.Pelletier, FanieColtman, David W.2025-03-282025-03-28Scopus:85126845270PubMed:35317671https://dspace-test.anu.edu.au/handle/1885/733743901In polygynous species, secondary sexual traits such as weapons or elaborate ornaments have evolved through intrasexual competition for mates. In some species, these traits are present in both sexes but are underdeveloped in the sex facing lower intrasexual competition for mates. It is often assumed that these underdeveloped sexually selected traits are a vestige of strong sexual selection on the other sex. Here, we challenge this assumption and investigate whether the expression of secondary sexual traits is associated with fitness in female bighorn sheep. Analyses of 45 years of data revealed that female horn length at 2 years, while accounting for mass and environmental variables, is associated with younger age at primiparity, younger age of first offspring weaned, greater reproductive lifespan and higher lifetime reproductive success. There was no association between horn length and fecundity. These findings highlight a potential conservation issue. In this population, trophy hunting selects against males with fast-growing horns. Intersexual genetic correlations imply that intense selective hunting of large-horned males before they can reproduce can decrease female horn size. Therefore, intense trophy hunting of males based on horn size could reduce female reproductive performance through the associations identified here, and ultimately reduce population growth and viability.This research was supported by Natural Sciences and Engineering Research Council of Canada discovery grants to D.W.C., M.F.-B. and F.P., and scholarships to several students, Alberta Conservation Association, Universit? de Sherbrooke, Qu?bec Center for Biodiversity Science financed by Fonds de Recherche Nature et Technologie du Qu?bec and the Canadian Mountain Network. This research was supported by Natural Sciences and Engineering Research Council of Canada discovery grants to D.W.C., M.F.-B. and F.P., and scholarships to several students, Alberta Conservation Association, Universit\u00E9 de Sherbrooke, Qu\u00E9bec Center for Biodiversity Science financed by Fonds de Recherche Nature et Technologie du Qu\u00E9bec and the Canadian Mountain Network. AcknowledgementsEnglishPublisher Copyright: ©age of primiparitycranial weaponryfitnesslifetime reproductive successsecondary sexual traittrophy hunting202210.1098/rspb.2021.2534http://www.scopus.com/inward/record.url?scp=85126845270&partnerID=8YFLogxK