Corticosterone Exposure during Embryonic Development Affects Offspring Growth and Sex Ratios in Opposing Directions in Two Lizard Species with Environmental Sex Determination

2009 ◽  
Vol 82 (4) ◽  
pp. 363-371 ◽  
Author(s):  
Daniel A. Warner ◽  
Rajkumar S. Radder ◽  
Richard Shine
Keyword(s):  
Embryonic Development ◽  
Sex Determination ◽  
Sex Ratios ◽  
Environmental Sex Determination ◽  
Lizard Species ◽  
Offspring Growth

WINDOWS OF EMBRYONIC SEXUAL LABILITY IN TWO LIZARD SPECIES WITH ENVIRONMENTAL SEX DETERMINATION

Ecology ◽  
2007 ◽  
Vol 88 (7) ◽  
pp. 1781-1788 ◽  
Author(s):  
Richard Shine ◽  
Daniel A. Warner ◽  
Rajkumar Radder
Keyword(s):  
Sex Determination ◽  
Environmental Sex Determination ◽  
Lizard Species

Nest site choice compensates for climate effects on sex ratios in a lizard with environmental sex determination

2006 ◽  
Vol 20 (4) ◽  
pp. 307-330 ◽  
Author(s):  
J. Sean Doody ◽  
Enzo Guarino ◽  
Arthur Georges ◽  
Ben Corey ◽  
Glen Murray ◽  
...  
Keyword(s):  
Sex Determination ◽  
Nest Site ◽  
Sex Ratios ◽  
Environmental Sex Determination ◽  
Climate Effects ◽  
Nest Site Choice

scholarly journals Do Covariances Between Maternal Behavior and Embryonic Physiology Drive Sex-Ratio Evolution Under Environmental Sex Determination?

2019 ◽  
Vol 110 (4) ◽  
pp. 411-421 ◽  
Author(s):  
Fredric J Janzen ◽  
David M Delaney ◽  
Timothy S Mitchell ◽  
Daniel A Warner
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Environmental Conditions ◽  
Oviposition Behavior ◽  
Thermal Sensitivity ◽  
Sex Ratios ◽  
Theoretical Work ◽  
Environmental Sex Determination ◽  
Turtle Species ◽  
Primary Sex Ratio

Abstract Fisherian sex-ratio theory predicts sexual species should have a balanced primary sex ratio. However, organisms with environmental sex determination (ESD) are particularly vulnerable to experiencing skewed sex ratios when environmental conditions vary. Theoretical work has modeled sex-ratio dynamics for animals with ESD with regard to 2 traits predicted to be responsive to sex-ratio selection: 1) maternal oviposition behavior and 2) sensitivity of embryonic sex determination to environmental conditions, and much research has since focused on how these traits influence offspring sex ratios. However, relatively few studies have provided estimates of univariate quantitative genetic parameters for these 2 traits, and the existence of phenotypic or genetic covariances among these traits has not been assessed. Here, we leverage studies on 3 species of reptiles (2 turtle species and a lizard) with temperature-dependent sex determination (TSD) to assess phenotypic covariances between measures of maternal oviposition behavior and thermal sensitivity of the sex-determining pathway. These studies quantified maternal behaviors that relate to nest temperature and sex ratio of offspring incubated under controlled conditions. A positive covariance between these traits would enhance the efficiency of sex-ratio selection when primary sex ratio is unbalanced. However, we detected no such covariance between measures of these categories of traits in the 3 study species. These results suggest that maternal oviposition behavior and thermal sensitivity of sex determination in embryos might evolve independently. Such information is critical to understand how animals with TSD will respond to rapidly changing environments that induce sex-ratio selection.

Environmental Sex Determination in Southern Brook Lamprey, Ichthyomyzon gagei

1993 ◽  
Vol 50 (6) ◽  
pp. 1299-1307 ◽  
Author(s):  
F. William H. Beamish
Keyword(s):  
United States ◽  
Sex Determination ◽  
Sex Ratios ◽  
Southeastern United States ◽  
Larval Density ◽  
Larval Growth ◽  
Age Groups ◽  
Differential Mortality ◽  
Environmental Sex Determination ◽  
Brook Lamprey

Sex ratios were determined for 20 populations of southern brook lamprey larvae, Ichthyomyzon gagei, collected from throughout much of their range in the southeastern United States. Ratios varied between 9 and 49% males. Differential mortality was an unlikely factor, as sex ratios were similar among age groups within each population. Environmental sex determination is suggested. Sex ratio varied with growth (expressed as length of larvae at specific ages), larval density, pH, and annual mean temperature of the natal stream. Generally, under conditions promoting rapid growth, the percentage of males varied directly with density and inversely with temperature. Where growth was slow, the percentage of males declined as larval density increased, the response being less at low than at high pH. Temperature had little effect when larval growth was slow. The percentage of males declined when growth was rapid under otherwise similar environmental conditions.

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