Male fertility and sex ratio at birth in red deer.
Efforts to test sex ratio theory have focused mostly on females. However, when males possess traits that could enhance the reproductive success of sons, males would also benefit from the manipulation of the offspring sex ratio. We tested the prediction that more-fertile red deer males produce more sons. Our findings reveal that male fertility is positively related to the proportion of male offspring. We also show that there is a positive correlation between the percentage of morphologically normal spermatozoa (a main determinant of male fertility) and the proportion of male offspring. Thus, males may contribute significantly to biases in sex ratio at birth among mammals, creating the potential for conflicts of interest between males and females.
Gomendio
Montserrat
M
Reproductive Ecology and Biology Group, Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales [Consejo Superior de Investigaciones Científicas (CSIC)], 28006-Madrid, Spain. montseg@mncn.csic.es
Malo
Aurelio F
AF
Soler
Ana J
AJ
Fernández-Santos
Maria R
MR
Esteso
Milagros C
MC
García
Andrés J
AJ
Roldan
Eduardo R S
ER
Garde
Julian
J
D000818:Animals; D003670:Deer / Q000502:physiology*; D005260:Female; D005298:Fertility; D005306:Fertilization; D008297:Male; D012098:Reproduction; D012744:Sex Ratio; D013081:Sperm Motility; D013094:Spermatozoa / Q000166:cytology; D014960:X Chromosome; D014998:Y Chromosome