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91.
Recent studies have demonstrated male mate choice for female ornaments in species without sex-role reversal. Despite these empirical findings, little is known about the adaptive dynamics of female signalling, in particular the evolution of male mating preferences. The evolution of traits that signal mate quality is more complex in females than in males because females usually provide the bulk of resources for the developing offspring. Here, we investigate the evolution of male mating preferences using a mathematical model which: (i) specifically accounts for the fact that females must trade-off resources invested in ornaments with reproduction; and (ii) allows male mating preferences to evolve a non-directional shape. The optimal adaptive strategy for males is to develop stabilizing mating preferences for female display traits to avoid females that either invests too many or too few resources in ornamentation. However, the evolutionary stability of this prediction is dependent upon the level of error made by females when allocating resources to either signal or fecundity. 相似文献
92.
93.
Sexual selection is thought to drive the evolution of sexually dimorphic traits that increase male reproductive success. Despite a large degree of sexual dimorphism among haplorhine primates, phenotypic traits that may influence the reproductive success of males are largely unstudied due to long life spans and the difficulties in quantifying such traits non-invasively. Here we employ digital photogrammetry of body length and crest size, as well as ranking of the gluteal muscle size, to test whether these sexually dimorphic traits are associated with long-term measures of male reproductive success in western gorillas. Among 19 adult male gorillas monitored for up to 12.5 years, we found that all three phenotypic traits were positively correlated with the average number of mates per male, but only crest size and gluteal muscle size were significantly correlated with offspring survival and the annual rate of siring offspring that survive to weaning age. We discuss why such sexually dimorphic traits might be under ongoing selection in gorillas and other species. 相似文献
94.
Chen G Wang Y Qiu L Qin X Liu H Wang X Wang Y Song G Li F Guo Y Li F Guo S Li Z 《Journal of Proteomics》2012,75(10):2824-2834
IgG functions rely on interactions of the Fc region with other proteins, which are optimized by tailoring of a conserved N-linked glycosylation at Asn-297. We conducted a study involving 735 control individuals and 138 thyroid cancer patients. Here we demonstrated that previously described age-related change in Fc-glycosylation was further characterized by definite sex specificity. In females, the incidences of most of glycosylated forms began to pose characteristic changes at ages of puberty or menopause. In addition, glycan-glycan relationships existed extensively within Fc glycosylation, which were characterized to be altered upon different states of subjects, such as age, sex and thyroid cancer. In thyroid cancer patients, detailed comparison of glycosylation incidences with control individuals yielded insight into aberrant change in IgG(1) Fc-glycosylation. This aberrant pattern was also featured by remarkable specificities of both age and sex. The receiver operating characteristic curve analysis was used to determine diagnostic values of Fc glycosylation. Finally, clinical measurement of two major female sex hormones estradiol and progesterone was conducted to determine potential associations of hormones with IgG Fc glycosylation. This study provided an important view to the associations of IgG Fc N-linked glycosylation with age, sex, female sex hormones and thyroid cancer. This article is part of a Special Issue entitled: Proteomics: The clinical link. 相似文献
95.
David A. Puts Lisa L.M. WellingRobert P. Burriss Khytam Dawood 《Evolution and human behavior》2012,33(1):1-9
It has been hypothesized that female orgasm evolved to facilitate recruitment of high-quality genes for offspring. Supporting evidence indicates that female orgasm promotes conception, although this may be mediated by the timing of female orgasm in relation to male ejaculation. This hypothesis also predicts that women will achieve orgasm more frequently when copulating with high-quality males, but limited data exist to support this prediction. We therefore explored relationships between the timing and frequency of women's orgasms and putative markers of the genetic quality of their mates, including measures of attractiveness, facial symmetry, dominance, and masculinity. We found that women reported more frequent and earlier-timed orgasms when mated to masculine and dominant men—those with high scores on a principal component characterized by high objectively-measured facial masculinity, observer-rated facial masculinity, partner-rated masculinity, and partner-rated dominance. Women reported more frequent orgasm during or after male ejaculation when mated to attractive men—those with high scores on a principal component characterized by high observer-rated and self-rated attractiveness. Putative measures of men's genetic quality did not predict their mates' orgasms from self-masturbation or from non-coital partnered sexual behavior. Overall, these results appear to support a role for female orgasm in sire choice. 相似文献
96.
Marie-Line Maublanc Eric Bideau Romain Willemet Clara Bardonnet Georges Gonzalez Lionel Desneux Nicolas Cèbe Jean-François Gerard 《Comptes rendus biologies》2012,335(12):735-743
We studied the ranging behaviour and spatial relationships between seven roe deer during more than 4 years in a partly wooded 14.2-ha enclosure. The animals (three young males, four adult females) were monitored with GPS telemetry collars. As expected, the surface area and overlap of the males’ bimonthly ranges decreased, and the distance between their arithmetic centres increased, as they became adult and, for two of them, territorial. Unexpectedly, females also tended to space out, the surface area and overlap of their bimonthly ranges being minimal in May to June, i.e. during the birth period. The distance between their arithmetic centres reached its maximum at the same time. Overlap between females’ ranges was consistently lower than those between males and females’ ranges, or between 1-year old males’ ranges. Our results raise the questions of female seasonal territoriality and of independence of the spacing systems of the two sexes in roe deer. 相似文献
97.
98.
The energetic incubation constraint hypothesis (EICH) for clutch size states that birds breeding in poor habitat may free
up resources for future reproduction by laying a smaller clutch. The eider (Somateria mollissima) is considered a candidate for supporting this hypothesis. Clutch size is smaller in exposed nests, presumably because of
faster heat loss and higher incubation cost, and, hence, smaller optimal clutch size. However, an alternative explanation
is partial predation: the first egg(s) are left unattended and vulnerable to predation, which may disproportionately affect
exposed nests, so clutch size may be underestimated. We experimentally investigated whether predation on first-laid eggs in
eiders depends on nest cover. We then re-evaluated how nesting habitat affects clutch size and incubation costs based on long-term
data, accounting for confounding effects between habitat and individual quality. We also experimentally assessed adult survival
costs of nesting in sheltered nests. The risk of egg predation in experimental nests decreased with cover. Confounding between
individual and habitat quality is unlikely, as clutch size was also smaller in open nests within individuals, and early and
late breeders had similar nest cover characteristics. A trade-off between clutch and female safety may explain nest cover
variation, as the risk of female capture by us, mimicking predation on adults, increased with nest cover. Nest habitat had
no effect on female hatching weight or weight loss, while lower temperature during incubation had an unanticipated positive
relationship with hatching weight. There were no indications of elevated costs of incubating larger clutches, while clutch
size and colony size were positively correlated, a pattern not predicted by the ‘energetic incubation constraint’ hypothesis.
Differential partial clutch predation thus offers the more parsimonious explanation for clutch size variation among habitats
in eiders, highlighting the need for caution when analysing fecundity and associated life-history parameters when habitat-specific
rates of clutch predation occur. 相似文献
99.
Theoretical and empirical evidence suggests that avian females are able to manipulate the offspring sex ratio at birth. Although
mating with an attractive male may induce females to skew the sex ratio toward males, the balance between the benefits of
producing attractive sons and the costs of competing with other females for mates could vary with female age, a possibility
that had not been previously explored. In this paper we increment experimentally the attractiveness of males of the polygynous
spotless starling (Sturnus unicolor) by adding green plants to their nests, a trait involved in courtship, and look for female age-differential effects on offspring
primary sex ratio. Young and middle aged females produced more sons in experimental than in control nests, as expected, but
old females showed the opposite tendency. To explain this novel result, we speculate that older females are limited to produce
the most costly sex because the physiological drawbacks imposed by ageing reduce their ability to compete with younger ones
for the non-shareable resources offered by males. We discuss that this evolutionary scenario may be widespread in avian polygynous
systems. 相似文献
100.
安徽滁州雌性丽斑麻蜥繁殖特征 总被引:1,自引:1,他引:0
在安徽滁州地区丽斑麻蜥(Eremias argus)年产两窝卵。窝卵数及窝卵重与雌体体长呈正相关,相对窝卵重与雌体体长无关,卵重与窝卵数无关。窝卵数、窝卵重及卵重在窝序间无明显的差异。卵长径与卵短径呈正相关,卵长径与窝卵数呈负相关,而卵短径与窝卵数无关。雌体主要通过增加窝卵数增加繁殖输出。 相似文献