scholarly journals Incubation temperature causes skewed sex ratios in a precocial bird

2016 ◽  
Vol 219 (13) ◽  
pp. 1961-1964 ◽  
Author(s):  
Sarah E. DuRant ◽  
William A. Hopkins ◽  
Amanda W. Carter ◽  
Laila T. Kirkpatrick ◽  
Kristin J. Navara ◽  
...  
Keyword(s):  
Incubation Temperature ◽  
Sex Ratios ◽  
Precocial Bird

scholarly journals Consistent sex ratio bias of individual female dragon lizards

2006 ◽  
Vol 2 (4) ◽  
pp. 569-572 ◽  
Author(s):  
Tobias Uller ◽  
Beth Mott ◽  
Gaetano Odierna ◽  
Mats Olsson
Keyword(s):  
Genetic Variation ◽  
Sex Ratio ◽  
Incubation Temperature ◽  
Sex Ratios ◽  
Phenotypic Traits ◽  
Female Size ◽  
Offspring Sex Ratio ◽  
Phenotypic Differences ◽  
Sex Ratio Bias ◽  
Offspring Sex

Sex ratio evolution relies on genetic variation in either the phenotypic traits that influence sex ratios or sex-determining mechanisms. However, consistent variation among females in offspring sex ratio is rarely investigated. Here, we show that female painted dragons ( Ctenophorus pictus ) have highly repeatable sex ratios among clutches within years. A consistent effect of female identity could represent stable phenotypic differences among females or genetic variation in sex-determining mechanisms. Sex ratios were not correlated with female size, body condition or coloration. Furthermore, sex ratios were not influenced by incubation temperature. However, the variation among females resulted in female-biased mean population sex ratios at hatching both within and among years.

scholarly journals Population viability at extreme sex-ratio skews produced by temperature-dependent sex determination

2017 ◽  
Vol 284 (1848) ◽  
pp. 20162576 ◽  
Author(s):  
Graeme C. Hays ◽  
Antonios D. Mazaris ◽  
Gail Schofield ◽  
Jacques-Olivier Laloë
Keyword(s):  
Sex Determination ◽  
High Mortality ◽  
Egg Production ◽  
Incubation Temperature ◽  
Sea Turtles ◽  
Sex Ratios ◽  
Population Viability ◽  
Temperature Dependent ◽  
Population Extinction ◽  
The World

For species with temperature-dependent sex determination (TSD) there is the fear that rising temperatures may lead to single-sex populations and population extinction. We show that for sea turtles, a major group exhibiting TSD, these concerns are currently unfounded but may become important under extreme climate warming scenarios. We show how highly female-biased sex ratios in developing eggs translate into much more balanced operational sex ratios so that adult male numbers in populations around the world are unlikely to be limiting. Rather than reducing population viability, female-biased offspring sex ratios may, to some extent, help population growth by increasing the number of breeding females and hence egg production. For rookeries across the world ( n = 75 sites for seven species), we show that extreme female-biased hatchling sex ratios do not compromise population size and are the norm, with a tendency for populations to maximize the number of female hatchlings. Only at extremely high incubation temperature does high mortality within developing clutches threaten sea turtles. Our work shows how TSD itself is a robust strategy up to a point, but eventually high mortality and female-only hatchling production will cause extinction if incubation conditions warm considerably in the future.

scholarly journals Temperature-dependent sex-biased embryo mortality in a bird

2008 ◽  
Vol 275 (1652) ◽  
pp. 2703-2706 ◽  
Author(s):  
Yvonne A Eiby ◽  
Jessica Worthington Wilmer ◽  
David T Booth
Keyword(s):  
Low Temperatures ◽  
Incubation Temperature ◽  
Sex Ratios ◽  
Molecular Sexing ◽  
Temperature Dependent ◽  
Female Embryo ◽  
Male Embryo ◽  
Diverse Range ◽  
Embryo Mortality ◽  
Incubation Temperatures

Sex ratios have important evolutionary consequences and are often biased by environmental factors. The effect of developmental temperature on offspring sex ratios has been widely documented across a diverse range of taxa but has rarely been investigated in birds and mammals. However, recent field observations and artificial incubation experiments have demonstrated that the hatching sex ratio of a megapode, the Australian brush-turkey ( Alectura lathami ), varied with incubation temperature; more females hatched at high incubation temperatures and more males hatched at low temperatures. Here, we investigated the causes of this temperature-dependent sex-biasing system. Molecular sexing of chicks and embryos confirmed that male embryo mortality was greater at high temperatures while female embryo mortality is greater at low temperatures, with mortality in both sexes similar at intermediate incubation temperatures. Temperature-dependent sex-biased embryo mortality represents a novel mechanism of altering sex ratios in birds. This novel mechanism, coupled with the unique breeding biology of the brush-turkey, offers a potentially unparalleled opportunity in which to investigate sex allocation theory in birds.

scholarly journals Influence of short-term temperature drops on sex-determination in sea turtles

2021 ◽  
Author(s):  
Ellen Porter ◽  
David T Booth ◽  
Col J Limpus
Keyword(s):  
Sex Determination ◽  
Heavy Rainfall ◽  
Incubation Temperature ◽  
Sea Turtles ◽  
Sex Ratios ◽  
Temperature Drop ◽  
Sea Turtle ◽  
Short Term ◽  
Sand Temperature

All sea turtles exhibit temperature-dependent sex-determination, where warmer temperatures produce mostly females and cooler temperatures produce mostly males. As global temperatures continue to rise, sea turtle sex-ratios have become increasingly female-biased, threatening the long-term viability of many populations. Nest temperatures are dependent on sand temperature, and heavy rainfall events reduce sand temperatures for a brief period. However, it is unknown whether these short-term temperature drops are large and long enough to produce male hatchlings. To discover if short-term temperature drops within the sex-determining period can lead to male hatchling production, we exposed green and loggerhead turtle eggs to short-term temperature drops conducted in constant temperature rooms. We dropped incubation temperature at four different times during the sex-determining period for a duration of either 3 or 7 days to mimic short-term drops in temperature caused by heavy rainfall in nature. Some male hatchlings were produced when exposed to temperature drops for as little as 3 days, but the majority of male production occurred when eggs were exposed to 7 days of lowered temperature. More male hatchlings were produced when the temperature drop occurred during the middle of the sex-determining period in green turtles, and the beginning and end of the sex-determining period in loggerhead turtles. Inter-clutch variation was evident in the proportion of male hatchlings produced, indicating that maternal and or genetic factors influence male hatchling production. Our findings have management implications for the long-term preservation of sea turtles on beaches that exhibit strongly female-biased hatchling sex-ratios.

scholarly journals Incubation temperature affects the metabolic cost of thermoregulation in a young precocial bird

2011 ◽  
Vol 26 (2) ◽  
pp. 416-422 ◽  
Author(s):  
Sarah E. DuRant ◽  
William A. Hopkins ◽  
Amanda F. Wilson ◽  
Gary R. Hepp
Keyword(s):  
Incubation Temperature ◽  
Metabolic Cost ◽  
Precocial Bird

scholarly journals Incubation temperature influences the behavioral traits of a young precocial bird

2018 ◽  
Vol 329 (4-5) ◽  
pp. 191-202 ◽  
Author(s):  
Sydney F. Hope ◽  
Robert A. Kennamer ◽  
Ignacio T. Moore ◽  
William A. Hopkins
Keyword(s):  
Incubation Temperature ◽  
Behavioral Traits ◽  
Precocial Bird

scholarly journals The Impact of Temperature-Dependent Sex Determination on the Population Dynamics of Green Sea Turtles (Chelonia mydas)

Bionatura ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 1029-1038
Author(s):  
Candy Herrera ◽  
Evelyn Guerra ◽  
Andrea Rosas ◽  
Yingying Wei ◽  
Jack Pringle ◽  
...  
Keyword(s):  
Incubation Temperature ◽  
Sea Turtles ◽  
Sex Ratios ◽  
Chelonia Mydas ◽  
Continuous Model ◽  
Sea Turtle ◽  
Green Sea Turtle ◽  
Green Sea Turtles ◽  
Turtle Population ◽  
The Impact

The sex of the turtles is determined by the incubation temperature of the eggs during the mid-trimester of development. In green sea turtles (Chelonia mydas), recent studies show that sex ratios are changing, producing a female-biased sex ratio within the population. We developed a novel continuous model to analyze the dynamics of the green sea turtle population long-term. We determine the safe operating space for the proportion of eggs that become male at which the population of green sea turtle can exist without going to extinction. When the proportion of male eggs leaves this range the overall turtles’ population collapses. Additionally, we examined how temperature changes affect the sex ratios of the green sea turtle population.

Effects of pre-chilling, incubation temperature and light on seed germination of Saponaria officinalis

Planta Medica ◽  
2015 ◽  
Vol 81 (16) ◽  
Author(s):  
YA Jeon ◽  
HS Lee ◽  
ES Park ◽  
YY Lee ◽  
JS Sung ◽  
...  
Keyword(s):  
Seed Germination ◽  
Incubation Temperature ◽  
Saponaria Officinalis
Sign in / Sign up

Export Citation Format

Share Document