The Effects of Polygyny and Domicility on Offspring Sex Ratio in Ghana

2007 ◽  
Vol 6 (4) ◽  
pp. 431-456
Author(s):  
Adansi Amankwaa
Keyword(s):  
Sex Ratio ◽  
Family Structure ◽  
Living Arrangements ◽  
Living Arrangement ◽  
Demographic And Health Surveys ◽  
Offspring Sex Ratio ◽  
Ratio Bias ◽  
Sex Ratio Bias ◽  
Offspring Sex ◽  
The Relationship

AbstractThis article explores how family structure and domicility influences offspring sex ratio bias, specifically living arrangements of husband in polygynous unions. Data from three Ghana Demographic and Health Surveys were used to examine the relationship between family structure and offspring sex ratio at birth, something that previous studies have not been able to do. This study estimate models of sex ratio offspring if the wives live together with husband present and wives live in separate dwellings and are visited by husband in turn. The results suggest that within polygynous marriages there are more male births, especially when husbands reside in the same dwelling as wives, than when husbands reside in separate dwellings from their wives. The analyses show that offspring sex ratio is related to the structure of living arrangement of husbands in polygynous unions. Indeed, the findings suggest that living arrangements and family structure among humans are important factors in predicting offspring sex ratio bias.

scholarly journals A father effect explains sex-ratio bias

2017 ◽  
Vol 284 (1861) ◽  
pp. 20171159 ◽  
Author(s):  
Aurelio F. Malo ◽  
Felipe Martinez-Pastor ◽  
Francisco Garcia-Gonzalez ◽  
Julián Garde ◽  
Jonathan D. Ballou ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Sex Ratio ◽  
Sex Chromosome ◽  
Sex Ratios ◽  
Sperm Nucleus ◽  
Equal Proportion ◽  
Offspring Sex Ratio ◽  
Ratio Bias ◽  
Sex Ratio Bias ◽  
Offspring Sex

Sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. The ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of X- and Y-chromosome-bearing sperm (CBS) in ejaculates due to segregation of sex chromosomes at meiosis. This expectation has been recently refuted. Here we used Peromyscus leucopus to demonstrate that sex ratio is explained by an exclusive effect of the father, and suggest a likely mechanism by which male-driven sex-ratio bias is attained. We identified a male sperm morphological marker that is associated with the mechanism leading to sex ratio bias; differences among males in the sperm nucleus area (a proxy for the sex chromosome that the sperm contains) explain 22% variation in litter sex ratio. We further show the role played by the sperm nucleus area as a mediator in the relationship between individual genetic variation and sex-ratio bias. Fathers with high levels of genetic variation had ejaculates with a higher proportion of sperm with small nuclei area. This, in turn, led to siring a higher proportion of sons (25% increase in sons per 0.1 decrease in the inbreeding coefficient). Our results reveal a plausible mechanism underlying unexplored male-driven sex-ratio biases. We also discuss why this pattern of paternal bias can be adaptive. This research puts to rest the idea that father contribution to sex ratio variation should be disregarded in vertebrates, and will stimulate research on evolutionary constraints to sex ratios—for example, whether fathers and mothers have divergent, coinciding, or neutral sex allocation interests. Finally, these results offer a potential explanation for those intriguing cases in which there are sex ratio biases, such as in humans.

Parental sex allocation and sex-specific survival drive offspring sex ratio bias in little owls

2019 ◽  
Vol 73 (6) ◽  
Author(s):  
Matthias Tschumi ◽  
Jolanda Humbel ◽  
Joscha Erbes ◽  
Julien Fattebert ◽  
Jochen Fischer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Offspring Sex Ratio ◽  
Ratio Bias ◽  
Sex Ratio Bias ◽  
Offspring Sex

scholarly journals Consistent sex ratio bias of individual female dragon lizards

2006 ◽  
Vol 2 (4) ◽  
pp. 569-572 ◽  
Author(s):  
Tobias Uller ◽  
Beth Mott ◽  
Gaetano Odierna ◽  
Mats Olsson
Keyword(s):  
Genetic Variation ◽  
Sex Ratio ◽  
Incubation Temperature ◽  
Sex Ratios ◽  
Phenotypic Traits ◽  
Female Size ◽  
Offspring Sex Ratio ◽  
Phenotypic Differences ◽  
Sex Ratio Bias ◽  
Offspring Sex

Sex ratio evolution relies on genetic variation in either the phenotypic traits that influence sex ratios or sex-determining mechanisms. However, consistent variation among females in offspring sex ratio is rarely investigated. Here, we show that female painted dragons ( Ctenophorus pictus ) have highly repeatable sex ratios among clutches within years. A consistent effect of female identity could represent stable phenotypic differences among females or genetic variation in sex-determining mechanisms. Sex ratios were not correlated with female size, body condition or coloration. Furthermore, sex ratios were not influenced by incubation temperature. However, the variation among females resulted in female-biased mean population sex ratios at hatching both within and among years.

scholarly journals Breeding ecology and bias in offspring sex ratio in little grassbirds (Megalurus gramineus)

2003 ◽  
Vol 51 (5) ◽  
pp. 505 ◽  
Author(s):  
Rebecca R. McIntosh ◽  
Romke Kats ◽  
Mathew Berg ◽  
Jan Komdeur ◽  
Mark A. Elgar
Keyword(s):  
Sex Ratio ◽  
Breeding Season ◽  
Salt Marshes ◽  
Sex Allocation ◽  
Breeding Ecology ◽  
Offspring Sex Ratio ◽  
Reed Beds ◽  
Primary Sex Ratio ◽  
Sex Ratio Bias ◽  
Offspring Sex

Little grassbirds (Megalurus gramineus) are small, sexually monomorphic passerines that live in reed beds, lignum swamps and salt marshes in southern Australia. The breeding biology and patterns of sex allocation of the little grassbird were investigated over a single breeding season. Our observations of this species in the Edithvale Wetland Reserve revealed a highly male-biased population sex ratio, with some breeding territories containing several additional males. Nevertheless, there was little compelling evidence that little grassbirds breed cooperatively. The growth rates of male and female nestlings were similar and, as predicted by theory, there was no overall primary sex ratio bias. However, the primary sex ratio was female-biased early in the breeding season and became increasingly male-biased later in the breeding season.

scholarly journals The Relationship Between Offspring Sex Ratio and Vasectomy Utilization

Urology ◽  
2017 ◽  
Vol 103 ◽  
pp. 112-116 ◽  
Author(s):  
Remy W. Lamberts ◽  
David P. Guo ◽  
Shufeng Li ◽  
Michael L. Eisenberg
Keyword(s):  
Sex Ratio ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
The Relationship

scholarly journals Covariance of paternity and sex with laying order explains male bias in extra-pair offspring in a wild bird population

2013 ◽  
Vol 9 (5) ◽  
pp. 20130616 ◽  
Author(s):  
Oscar Vedder ◽  
Michael J. L. Magrath ◽  
Marco van der Velde ◽  
Jan Komdeur
Keyword(s):  
Sex Ratio ◽  
Wild Population ◽  
Cyanistes Caeruleus ◽  
Offspring Sex Ratio ◽  
Bird Population ◽  
Male Bias ◽  
Laying Order ◽  
Offspring Sex ◽  
The Relationship ◽  
Blue Tits

It has been hypothesized that parents increase their fitness by biasing the sex ratio of extra-pair offspring (EPO) towards males. Here, we report a male bias among EPO in a wild population of blue tits ( Cyanistes caeruleus ). This resulted from a decline in both the proportion of males and EPO over the laying order of eggs in the clutch. However, previous studies suggest that, unlike the decline in EPO with laying order, the relationship between offspring sex ratio and laying order is not consistent between years and populations in this species. Hence, we caution against treating the decline in proportion of males with laying order, and the resulting male bias among EPO, as support for the above hypothesis. Variable patterns of offspring sex and paternity over the laying order may explain inconsistent associations between offspring sex and paternity, between and within species.

scholarly journals Maternal corticosterone exposure has transgenerational effects on grand-offspring

2016 ◽  
Vol 12 (11) ◽  
pp. 20160627 ◽  
Author(s):  
Nicola Khan ◽  
Richard A. Peters ◽  
Emily Richardson ◽  
Kylie A. Robert
Keyword(s):  
Reproductive Success ◽  
Sex Ratio ◽  
Hatching Success ◽  
First Record ◽  
Female Offspring ◽  
Adaptive Mechanism ◽  
Offspring Sex Ratio ◽  
Sex Ratio Bias ◽  
Offspring Sex ◽  
Unstable Environment

The hormone fluctuations that an animal experiences during ovulation can have lifelong effects on developing offspring. These hormones may act as an adaptive mechanism, allowing offspring to be ‘pre-programmed’ to survive in an unstable environment. Here, we used a transgenerational approach to examine the effects of elevated maternal corticosterone (CORT) on the future reproductive success of female offspring. We show that female zebra finches ( Taeniopygia guttata ) exposed to embryonic CORT produce daughters that have equal reproductive success (clutch sizes, fertility, hatching success) compared with the daughters produced from untreated mothers, but their offspring had accelerated post-hatching growth rates and were significantly heavier by nutritional independence. Although there was no significant effect on primary offspring sex ratio, females from CORT-treated mothers produced significantly female-biased clutches by nutritional independence. To the best of our knowledge, this is the first record of a transgenerational sex ratio bias in response to elevated maternal CORT in any avian species.

scholarly journals Does the Mother or Father Determine the Offspring Sex Ratio? Investigating the Relationship between Maternal Digit Ratio and Offspring Sex Ratio

PLoS ONE ◽  
2015 ◽  
Vol 10 (11) ◽  
pp. e0143054 ◽  
Author(s):  
Tae Beom Kim ◽  
Jin Kyu Oh ◽  
Kwang Taek Kim ◽  
Sang Jin Yoon ◽  
Soo Woong Kim
Keyword(s):  
Sex Ratio ◽  
Digit Ratio ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
The Relationship

Offspring sex ratio in moose Alces alces in relation to paternal age: an experiment

2004 ◽  
Vol 10 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Bernt-Erik Sæther ◽  
Erling J. Solberg ◽  
Morten Heim ◽  
John E. Stacy ◽  
Kjetill S. Jakobsen ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Alces Alces ◽  
Paternal Age ◽  
Offspring Sex Ratio ◽  
Offspring Sex
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