Are Skewed Fledgling Sex Ratios in Sexually Dimorphic Birds Adaptive?

1991 ◽  
Vol 138 (5) ◽  
pp. 1159-1172 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Kevin L. Teather
Keyword(s):  
Sex Ratios ◽  
Sexually Dimorphic

Prenatal sex ratios and expression of sexually dimorphic traits in three snake species

2006 ◽  
Vol 305A (8) ◽  
pp. 603-609 ◽  
Author(s):  
Patrick James Weatherhead ◽  
Kelley Joan Kissner ◽  
Sophie Jane Sommerer
Keyword(s):  
Sex Ratios ◽  
Sexually Dimorphic ◽  
Snake Species

scholarly journals Identification of sex-linked markers in the sexually cryptic coco de mer: are males and females produced in equal proportions?

AoB Plants ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Emma J Morgan ◽  
Christopher N Kaiser-Bunbury ◽  
Peter J Edwards ◽  
Mathias Scharmann ◽  
Alex Widmer ◽  
...  
Keyword(s):  
Sex Ratios ◽  
Differential Mortality ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
Determination System ◽  
Males And Females ◽  
Heterogametic Sex ◽  
Sex Determination System ◽  
Male Specific ◽  
Genetically Determined

Abstract Lodoicea maldivica (coco de mer) is a long-lived dioecious palm in which male and female plants are visually indistinguishable when immature, only becoming sexually dimorphic as adults, which in natural forest can take as much as 50 years. Most adult populations in the Seychelles exhibit biased sex ratios, but it is unknown whether this is due to different proportions of male and female plants being produced or to differential mortality. In this study, we developed sex-linked markers in Lodoicea using ddRAD sequencing, enabling us to reliably determine the gender of immature individuals. We screened 589 immature individuals to explore sex ratios across life stages in Lodoicea. The two sex-specific markers resulted in the amplification of male-specific bands (Lm123977 at 405 bp and Lm435135 at 130 bp). Our study of four sub-populations of Lodoicea on the islands of Praslin and Curieuse revealed that the two sexes were produced in approximately equal numbers, with no significant deviation from a 1:1 ratio before the adult stage. We conclude that sex in Lodoicea is genetically determined, suggesting that Lodoicea has a chromosomal sex determination system in which males are the heterogametic sex (XY) and females are homogametic (XX). We discuss the potential causes for observed biased sex ratios in adult populations, and the implications of our results for the life history, ecology and conservation management of Lodoicea.

Experimentally manipulated brood sex ratios: growth and survival in the black-headed gull (Larus ridibundus), a sexually dimorphic species

2005 ◽  
Vol 59 (2) ◽  
pp. 313-320 ◽  
Author(s):  
Wendt Müller ◽  
Ellen Kalmbach ◽  
Corine M. Eising ◽  
Ton G. G. Groothuis ◽  
Cor Dijkstra
Keyword(s):  
Sex Ratios ◽  
Sexually Dimorphic ◽  
Growth And Survival ◽  
Larus Ridibundus ◽  
Dimorphic Species

scholarly journals Sex ratios in sexually dimorphic umbelliferae

Heredity ◽  
1973 ◽  
Vol 31 (2) ◽  
pp. 239-249 ◽  
Author(s):  
David G Lloyd
Keyword(s):  
Sex Ratios ◽  
Sexually Dimorphic

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

The Relationship of Digit Ratio (2D:4D) and Gender-Role Orientation in Four National Samples

2007 ◽  
Vol 28 (2) ◽  
pp. 78-87 ◽  
Author(s):  
Stefan J. Troche ◽  
Nina Weber ◽  
Karina Hennigs ◽  
Carl-René Andresen ◽  
Thomas H. Rammsayer
Keyword(s):  
Gender Role ◽  
Sex Role ◽  
Role Orientation ◽  
Sexually Dimorphic ◽  
Gender Role Orientation ◽  
Left Hand ◽  
Fourth Finger ◽  
And Gender ◽  
Relationship Of ◽  
The Relationship

Abstract. The ratio of second to fourth finger length (2D:4D ratio) is sexually dimorphic with women having higher 2D:4D ratio than men. Recent studies on the relationship between 2D:4D ratio and gender-role orientation yielded rather inconsistent results. The present study examines the moderating influence of nationality on the relationship between 2D:4D ratio and gender-role orientation, as assessed with the Bem Sex-Role Inventory, as a possible explanation for these inconsistencies. Participants were 176 female and 171 male university students from Germany, Italy, Spain, and Sweden ranging in age from 19 to 32 years. Left-hand 2D:4D ratio was significantly lower in men than in women across all nationalities. Right-hand 2D:4D ratio differed only between Swedish males and females indicating that nationality might effectively moderate the sexual dimorphism of 2D:4D ratio. In none of the examined nationalities was a reliable relationship between 2D:4D ratio and gender-role orientation obtained. Thus, the assumption of nationality-related between-population differences does not seem to account for the inconsistent results on the relationship between 2D:4D ratio and gender-role orientation.

Chemogenetic inhibition of dopaminergic projections to the nucleus accumbens has sexually dimorphic effects in the rat gambling task.

2020 ◽  
Vol 134 (4) ◽  
pp. 309-322 ◽  
Author(s):  
Tristan J. Hynes ◽  
Jacqueline-Marie M. Ferland ◽  
Tanya L. Feng ◽  
Wendy K. Adams ◽  
Mason M. Silveira ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Sexually Dimorphic ◽  
Gambling Task
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