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Intraseasonal variation in reproductive effort: young males finish last

Mason, T.H.E.; Stephens, P.A.; Willis, S.G.; Chirichella, R.; Apollonio, M.; Richards, S.A.


T.H.E. Mason

R. Chirichella

M. Apollonio

S.A. Richards


Age-dependent reproductive timing has been observed in females of a number of species; older females often breed earlier in the season and experience higher reproductive success as a result. However, to date, evidence for within-season variation in reproductive effort (RE) for males has been relatively weak. Males are expected to time RE in light of intraseasonal variations in the availability of receptive females and competition with other males. Young males, which are typically smaller and less experienced, might benefit from breeding later in the season, when male-male competition is less intense. Using a long-term data set of Alpine chamois Rupicapra rupicapra, we sought to evaluate the hypothesis that younger males allocate highest RE late in the breeding season, at a time when older male RE has decreased substantially. Our results support this hypothesis, which suggests that intraseasonal variation in RE may be an adaptive life-history trait for males as well as females.


Mason, T., Stephens, P., Willis, S., Chirichella, R., Apollonio, M., & Richards, S. (2012). Intraseasonal variation in reproductive effort: young males finish last. The American Naturalist, 180(6), 823-830.

Journal Article Type Article
Acceptance Date Jul 5, 2015
Online Publication Date Oct 30, 2012
Publication Date 2012-10
Deposit Date Aug 20, 2012
Journal American Naturalist
Print ISSN 0003-0147
Electronic ISSN 1537-5323
Publisher The University of Chicago Press
Peer Reviewed Peer Reviewed
Volume 180
Issue 6
Pages 823-830