Male phenotypic quality influences offspring sex ratio in a polygynous ungulate

Røed, Knut; Holand, Øystein; Mysterud, Atle; Tverdal, Aage; Kumpula, Jouko; Nieminen, Mauri

doi:10.1098/rspb.2006.0214

Cited by 48 publications

(41 citation statements)

References 52 publications

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“…However, in our study sex ratio only was affected by age class, while no other variable in hinds, such as body condition or weight, had any effect on it. Røed et al (2007) reported that females produce more sons when mating with an attractive male. Nevertheless, in our experiment male and female were housed separately during the non-mating season, when one female was near to be heat in rut season, then one male was introduced into the female's enclosure, and then taken back to its original enclosure after the female ended estrus.…”

Section: Discussionmentioning

confidence: 99%

Effect of reproductive rest on the subsequent breeding in Iberian red deer hinds (Cervus elaphus hispanicus)

et al. 2010

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Section: Discussionmentioning

confidence: 99%

Effect of reproductive rest on the subsequent breeding in Iberian red deer hinds (Cervus elaphus hispanicus)

et al. 2010

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“…The experimental reindeer herd at the Station amounts to around hundred winter animals which are free ranging within large seasonal grazing enclosures (altogether~40 km 2 ) (Holand et al 2006;Røed et al 2007;Mysterud et al 2009). Birch (Betula spp.)…”

Section: Study Areamentioning

confidence: 99%

Induced orphaning reveals post-weaning maternal care in reindeer

et al. 2012

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A common by-product of human harvesting is orphaning of calves in autumn. Despite this, there are few studies in northern and temperate ungulates evaluating the fate of orphaned calves and the potential benefits to offspring and costs to mothers of post-weaning maternal care. We manipulated orphaning and forage distribution during winter for two herds of reindeer (Rangifer tarandus): one nonfed and the other supplementally fed to increase level of interference competition. Both herds consisted of females with and without calves at heel and orphaned calves. We measured survival and somatic losses during winter and distances between mothercalves and adult females-orphans within the herds. All females survived the winter, and there was no evidence of post-weaning maternal cost in terms of female's mass loss. The winter mortality among calves was negligible and did not differ between orphans as compared to nonorphans. However, nonorphaned calves lost less mass and stayed closer to their mothers than orphans to adult females, suggesting that increased mortality might occur in harsher winters. This tended to be more marked in the fed group where interference competition was more likely due to feed being concentrated both in space and time. Reduced mass loss in nonorphans is therefore most likely due to mothers sharing and defending feeding resources and protecting their offspring from harassment by other herd members during their first winter. We conclude that hunting practise of northern and temperate ungulates where females having calf/calves at heel are intentionally or nonintentionally harvested, may have demographic side effects at least in harsh winters.

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“…There is evidence that offspring sex ratios may be adjusted in relation to the attractiveness of the father (Ellegren et al 1996). Similarly, in mammals offspring sex ratio is influenced by male body mass (Røed et al 2006). However, it is widely assumed that such manipulation is under female control.…”

Section: Male Fertility and Offspring Sex Ratiomentioning

confidence: 99%

Sperm traits and male fertility in natural populations

Gomendio¹,

Malo²,

Garde³

et al. 2007

Reproduction

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Male fertility has seldom been studied in natural populations because it has been assumed that strong selection would result in uniformly high values among males, and therefore mating success has been equated with fertilisation success. In contrast, male fertility has received much attention in studies of domestic livestock, where economic benefits rely on improving productivity, and in human infertility studies, where the efficiency of treatments depends on understanding which ejaculate traits explain reproductive failures and predict success at assisted conception. Despite years of efforts, no conclusive results have been obtained, probably because such studies have focused on opposite extremes of the range with little variation: domestic livestock have often been subject to strong artificial selection for high fertility, and human patients requiring treatment have compromised fertility. Recent findings from natural populations of red deer have shown that males differ markedly in their fertility, and have revealed the degree of variation found in different semen traits, both between and within males. Fertility trials have shown that male fertility is determined mainly by sperm swimming speed and the proportion of normal sperm, when sperm numbers are kept constant. Sperm design exerts a strong influence on sperm swimming speed, with faster swimming sperm having elongated heads, shorter midpieces and a longer principal plus terminal pieces in relation to total flagellum length. Thus, the large inter-male variation in sperm design found among natural populations underlies differences in sperm swimming speed which, in turn, determine differences in male fertility rates. Secondary sexual characters are honest indicators of male fertility, so males with large and elaborated antlers have larger testes and faster swimming sperm. Testosterone does not seem to mediate the relationship between antler size and semen quality, since it is associated with sperm production, but not with sperm quality or antler size. Finally, more fertile males produce a greater proportion of sons, who will inherit the semen traits which will enhance their fertility.

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Male phenotypic quality influences offspring sex ratio in a polygynous ungulate

Cited by 48 publications

References 52 publications

Effect of reproductive rest on the subsequent breeding in Iberian red deer hinds (Cervus elaphus hispanicus)

Effect of reproductive rest on the subsequent breeding in Iberian red deer hinds (Cervus elaphus hispanicus)

Induced orphaning reveals post-weaning maternal care in reindeer

Sperm traits and male fertility in natural populations

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