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

Maternal age, paternal age, and litter size interact to affect the offspring sex ratio of German Shepherd dogs

2019 ◽  
Vol 135 ◽  
pp. 169-173
Author(s):  
Anna Carolina Lopes Martins ◽  
Marília Andreia Vaz ◽  
Max Mendes Macedo ◽  
Renato Lima Santos ◽  
Conrado Aleksander Barbosa Galdino ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Litter Size ◽  
Maternal Age ◽  
Paternal Age ◽  
German Shepherd ◽  
Offspring Sex Ratio ◽  
Offspring Sex

scholarly journals Fifty:Fifty Offspring Sex Ratios in Savannah Sparrows (Passerculus Sandwichensis)

The Auk ◽  
2003 ◽  
Vol 120 (1) ◽  
pp. 171-179
Author(s):  
Nathaniel T. Wheelwright ◽  
Rachel E. Seabury
Keyword(s):  
Sex Ratio ◽  
Sex Ratios ◽  
Strong Support ◽  
Population Level ◽  
Paternal Age ◽  
Bay Of Fundy ◽  
Offspring Sex Ratio ◽  
Passerculus Sandwichensis ◽  
Offspring Sex ◽  
Savannah Sparrows

Abstract Over a 14 year period, we determined offspring sex ratios in a population of Savannah Sparrows (Passerculus sandwichensis) breeding on Kent Island, an isolated 80 ha island in the Bay of Fundy, New Brunswick, Canada, based on morphological measurements of 318 independent juveniles and 361 returning adults of known parentage. The mean annual offspring sex ratio was exactly 1.00 (±0.23, range= 0.61–1.41, n = 14). In no year did offspring sex ratio deviate significantly from 50:50, regardless of the sex ratio of breeding adults. Offspring sex ratio did not vary as a function of the timing of breeding, maternal or paternal age, or parental mating status (monogamy vs. polygamy). Overall, our data provide strong support for 50:50 offspring sex ratios at the population level (Fisher 1930), but no support for the notion of adaptive modification of offspring sex ratios by individuals (Trivers and Willard 1973).

Breeding system can affect the offspring sex ratio in Syrian hamsters

2011 ◽  
Vol 45 (1) ◽  
pp. 55-57 ◽  
Author(s):  
M O M Chelini ◽  
N L Souza ◽  
E Otta
Keyword(s):  
Sex Ratio ◽  
Breeding System ◽  
Offspring Sex Ratio ◽  
Syrian Hamsters ◽  
Offspring Sex

scholarly journals Is biasing offspring sex ratio adaptive? A test of Fisher's principle across multiple generations of a wild mammal in a fluctuating environment

2018 ◽  
Vol 285 (1891) ◽  
pp. 20181251 ◽  
Author(s):  
Andrea E. Wishart ◽  
Cory T. Williams ◽  
Andrew G. McAdam ◽  
Stan Boutin ◽  
Ben Dantzer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
Adult Sex Ratio ◽  
Secondary Sex Ratio ◽  
North American Red Squirrels ◽  
Negative Frequency Dependent Selection ◽  
Fisher’S Principle

Fisher's principle explains that population sex ratio in sexually reproducing organisms is maintained at 1 : 1 owing to negative frequency-dependent selection, such that individuals of the rare sex realize greater reproductive opportunity than individuals of the more common sex until equilibrium is reached. If biasing offspring sex ratio towards the rare sex is adaptive, individuals that do so should have more grandoffspring. In a wild population of North American red squirrels ( Tamiasciurus hudsonicus ) that experiences fluctuations in resource abundance and population density, we show that overall across 26 years, the secondary sex ratio was 1 : 1; however, stretches of years during which adult sex ratio was biased did not yield offspring sex ratios biased towards the rare sex. Females that had litters biased towards the rare sex did not have more grandoffspring. Critically, the adult sex ratio was not temporally autocorrelated across years, thus the population sex ratio experienced by parents was independent of the population sex ratio experienced by their offspring at their primiparity. Expected fitness benefits of biasing offspring sex ratio may be masked or negated by fluctuating environments across years, which limit the predictive value of the current sex ratio.

Time of insemination within the cycle and offspring sex ratio

1998 ◽  
Vol 13 (11) ◽  
pp. 3280-3281 ◽  
Author(s):  
M. E. Bernstein
Keyword(s):  
Sex Ratio ◽  
Offspring Sex Ratio ◽  
Offspring Sex

Maternal Testosterone and Offspring Sex-Ratio in Birds and Mammals: A Meta-Analysis

2017 ◽  
Vol 45 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Thomas Merkling ◽  
Shinichi Nakagawa ◽  
Malgorzata Lagisz ◽  
Lisa E. Schwanz
Keyword(s):  
Sex Ratio ◽  
Meta Analysis ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
Maternal Testosterone
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