scholarly journals Mechanisms that influence sex ratio variation in the invasive hymenopteran Sirex noctilio in South Africa

2019 ◽  
Vol 9 (14) ◽  
pp. 7966-7973 ◽  
Author(s):  
Joséphine Queffelec ◽  
Amy L. Wooding ◽  
Jaco M. Greeff ◽  
Jeffrey R. Garnas ◽  
Brett P. Hurley ◽  
...  
Keyword(s):  
South Africa ◽  
Sex Ratio ◽  
Sirex Noctilio ◽  
Ratio Variation

scholarly journals Population sex ratio variation in a monogamous long-lived bird, the wandering albatross

2005 ◽  
Vol 74 (2) ◽  
pp. 285-291 ◽  
Author(s):  
HENRI WEIMERSKIRCH ◽  
JOELLE LALLEMAND ◽  
JULIEN MARTIN
Keyword(s):  
Sex Ratio ◽  
Ratio Variation ◽  
Wandering Albatross

The effect of drought stress on the sex ratio variation ofSilene otites

2000 ◽  
Vol 35 (2) ◽  
pp. 203-210 ◽  
Author(s):  
Leo L. Soldaat ◽  
Helge Lorenz ◽  
Annette Trefflich
Keyword(s):  
Drought Stress ◽  
Sex Ratio ◽  
Ratio Variation

scholarly journals Internest sex-ratio variation and male brood survival in the ant Pheidole pallidula

1996 ◽  
Vol 7 (3) ◽  
pp. 292-298 ◽  
Author(s):  
Laurent Keller ◽  
Serge Aron ◽  
Luc Passera
Keyword(s):  
Sex Ratio ◽  
Brood Survival ◽  
Ratio Variation ◽  
Male Brood ◽  
Pheidole Pallidula

Evolution of Sex Ratio Variation in Aphids

1993 ◽  
pp. 346-368 ◽  
Author(s):  
Nancy A. Moran
Keyword(s):  
Sex Ratio ◽  
Evolution Of Sex ◽  
Ratio Variation

scholarly journals SEX RATIO VARIATION AMONG GYNODIOECIOUS POPULATIONS OF SEA BEET: CAN IT BE EXPLAINED BY NEGATIVE FREQUENCY-DEPENDENT SELECTION?

Evolution ◽  
2009 ◽  
Vol 63 (6) ◽  
pp. 1483-1497 ◽  
Author(s):  
Mathilde Dufay ◽  
Joël Cuguen ◽  
Jean-François Arnaud ◽  
Pascal Touzet
Keyword(s):  
Sex Ratio ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Ratio Variation ◽  
Negative Frequency Dependent Selection

scholarly journals Facultative primary sex ratio variation: a lack of evidence in birds?

2004 ◽  
Vol 271 (1545) ◽  
pp. 1277-1282 ◽  
Author(s):  
John G. Ewen ◽  
Phillip Cassey ◽  
Anders P. Møller
Keyword(s):  
Sex Ratio ◽  
Primary Sex Ratio ◽  
Ratio Variation

scholarly journals SEX-RATIO VARIATION IN THE GYNODIOECIOUS SHRUB HEBE STRICTISSIMA (SCROPHULARIACEAE)

Evolution ◽  
1990 ◽  
Vol 44 (1) ◽  
pp. 134-142 ◽  
Author(s):  
Lynda F. Delph
Keyword(s):  
Sex Ratio ◽  
Ratio Variation

scholarly journals Patterns of Sex Ratio Variation in House Sparrows

The Condor ◽  
2002 ◽  
Vol 104 (3) ◽  
pp. 598-609 ◽  
Author(s):  
David F. Westneat ◽  
Ian R. K. Stewart ◽  
Emily Halpin Woeste ◽  
Johnny Gipson ◽  
Latifat Abdulkadir ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Passer Domesticus ◽  
Pcr Amplification ◽  
Population Level ◽  
Significant Heterogeneity ◽  
House Sparrows ◽  
Female Body Size ◽  
Ratio Variation ◽  
La Mancha ◽  
Size Condition

Abstract PCR amplification of a sex-linked gene was used to assay the sex ratio of nestling House Sparrows (Passer domesticus) from five consecutive breeding seasons. We tested several predictions from sex ratio theory, including that at the population level, sparrows should produce a 1:1 sex ratio. Of 1162 nestlings, 53% were male, which is not significantly different from 50%. We did find a significant skew toward males in two of the five years, and significant heterogeneity in sex ratio among seasons. There was no evidence that brood sex ratios were skewed from a binomial distribution, despite a modest excess of all male broods. We found that male nestlings weighed significantly more (0.5 g) than their female siblings. We tested the possibility that females produce males when conditions are good. Sex ratio was not associated with nest attempt, despite some evidence that conditions varied seasonally. Clutch size was negatively associated with date of first egg, but neither nestling weight nor sex ratio showed any correlation with date. We also tested an array of female characteristics; sex ratio was not associated with female body size, condition, or age. Females that hatched a larger proportion of eggs produced more males, a consistent pattern in all five seasons. However, the female's mate's characteristics (size, condition, age, or size of throat patch) did not influence sex ratio. These data contribute to a growing number of studies that provide an inconsistent picture of sex ratio variation in birds. Patrones de Variación en la Proporción de Sexos de Passer domesticus Resumen. Un gen ligado al sexo, amplificado por PCR, fue usado para examinar la proporción de sexos de pichones de Passer domesticus provenientes de cinco temporadas de apareamiento consecutivas. Se probaron varias predicciones de la teoría de proporción de sexos, incluyendo que a nivel poblacional, los gorriones deberían producir una proporción de sexos 1:1. De 1162 pichones, 53% fueron machos, lo cual no difiere significativamente de 50%. Se encontró un sesgo significativo hacia machos en dos de los cinco años y una heterogeneidad significativa en la proporción de sexos entre estaciones. No hubo evidencia de que la proporción de sexos de la camada se desviara de una distribución binomial, a pesar de un moderado exceso de crías macho. Se encontró que los pichones machos pesaron significativamente más (0.5 g) que sus hermanas. Se examinó la posibilidad de que las hembras producen machos cuando las condiciones son benignas. La proporción de sexos no estuvo asociado con el momento de anidación dentro de la temporada, a pesar de que algunas evidencias sugieren que las condiciones variaron estacionalmente. El tamaño de la camada estuvo negativamente asociado con la fecha de puesta del primer huevo, pero ni el peso del pichón ni la proporción de sexos mostró correlación con dicha fecha. Se examinaron además un serie de características de la hembra; la proporción de sexos no estuvo asociada con el tamaño del cuerpo, la condición o la edad de la hembra. Las hembras que empollaron una mayor cantidad de huevos produjeron más machos, un patrón consistente en las cinco temporadas. Las características de las parejas de las hembras (tamaño, condición o tamaño de la mancha del cuello) no influyeron la proporción de sexos. Estos datos contribuyen al creciente número de estudios que presentan una descripción contradictoria de la variación de la proporción de sexos en aves.

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