Influence of Sibling Competition on Nestling Sex Ratios of Sexually Dimorphic Birds

1986 ◽  
Vol 127 (4) ◽  
pp. 495-507 ◽  
Author(s):  
Gary R. Bortolotti
Keyword(s):  
Sex Ratios ◽  
Sibling Competition ◽  
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

Sexual Size Dimorphism and Sibling Competition: Implications for Avian Sex Ratios

1991 ◽  
Vol 138 (3) ◽  
pp. 623-641 ◽  
Author(s):  
Hugh Drummond ◽  
Jose Luis Osorno ◽  
Roxana Torres ◽  
Cecilia Garcia Chavelas ◽  
Horacio Merchant Larios
Keyword(s):  
Sexual Size Dimorphism ◽  
Sex Ratios ◽  
Sibling Competition ◽  
Size Dimorphism

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

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
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