10.5061/DRYAD.7M0CFXPT5
Ritchot, Yanny
0000-0001-7007-0723
Université de Sherbrooke
Pelletier, Fanie
Université de Sherbrooke
Festa-Bianchet, Marco
Université de Sherbrooke
Coltman, David
University of Alberta
Data from: Determinants and long-term costs of early reproduction in males
of a long-lived polygynous mammal
Dryad
dataset
2021
FOS: Natural sciences
age at first reproduction
intra-specific competition
Life histories
Male reproductive success
bighorn sheep (Ovis canadensis)
polygyny
2022-03-26T00:00:00Z
2022-03-26T00:00:00Z
en
84022 bytes
3
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
In long-lived polygynous species, male reproductive success is often
monopolized by a few mature dominant individuals. Young males are
generally too small to be dominant and may employ alternative tactics,
however, little is known about the determinants of reproductive success
for young males. Understanding the causes and consequences of variability
in early reproductive success may be crucial to assess the strength of
sexual selection and possible long-term trade-offs among life-history
traits. Selective pressures driven by fluctuating environmental conditions
may depend on age-class. We evaluated the determinants of reproduction in
male bighorn sheep (Ovis canadensis) aged 2-4 years using 30 years of
individual-level data. These young males cannot defend estrous ewes and
use alternative mating tactics. We also investigated how the age of first
detected reproduction was correlated to lifetime reproductive success and
longevity. We found that reproductive success of males aged three years
was positively correlated to body mass, to the proportion of males aged
2-4 years in the competitor pool and to the number of females available
per adult male. These results suggest that reproductive success depends on
both competitive ability and population age-sex structure. None of these
variables, however, had significant effects on the reproductive success of
males aged 2 or 4 years. Known reproduction before the age of five
increased lifetime reproductive success but decreased longevity,
suggesting a long-term survival cost of early reproduction. Our analyses
reveal that both individual-level phenotypic and population-level
demographic variables influence reproductive success by young males and
provide a rare assessment of fitness trade-offs in wild polygynous males.