Female-biased sex ratio of immature loggerhead sea turtles inhabiting the Atlantic coastal waters of Florida

1991 ◽  
Vol 69 (12) ◽  
pp. 2973-2977 ◽  
Author(s):  
Thane Wibbels ◽  
R. Erik Martin ◽  
David W. Owens ◽  
Max S. Amoss Jr.
Keyword(s):  
Sex Ratio ◽  
Coastal Waters ◽  
Sex Allocation ◽  
Sea Turtles ◽  
The United States ◽  
Loggerhead Sea Turtles ◽  
Blood Samples ◽  
Sex Allocation Theory ◽  
Biased Sex Ratio ◽  
Atlantic Coastal

The sex ratio of immature loggerhead sea turtles, Caretta caretta, inhabiting the Atlantic coastal waters of Florida was investigated. Blood samples were obtained from 223 turtles that were captured in the intake channel of a power plant on Hutchinson Island. A serum androgen sexing technique was utilized to sex individual turtles. The sex ratio of the turtles (2.1 female: 1.0 male) differed significantly from 1:1 and thus appears to differ from predictions of sex allocation theory. These observations are consistent with those of a previous study, and collectively the results suggest that the sex ratio of immature C. caretta inhabiting the Atlantic coastal waters of the United States is significantly female biased: approximately two females per male.

Pivotal temperature for loggerhead turtles (Caretta caretta) from Kyparissia Bay, Greece

2002 ◽  
Vol 80 (12) ◽  
pp. 2118-2124 ◽  
Author(s):  
N Mrosovsky ◽  
Stephanie Kamel ◽  
Alan F Rees ◽  
D Margaritoulis
Keyword(s):  
United States ◽  
Sex Ratio ◽  
Constant Temperature ◽  
Sea Turtles ◽  
Caretta Caretta ◽  
The United States ◽  
Loggerhead Sea Turtles ◽  
Incubation Duration ◽  
Different Populations ◽  
Pivotal Temperature

Pivotal temperature (the constant temperature giving 50% of each sex) for two clutches of loggerhead sea turtles (Caretta caretta) from Kyparissia Bay, Greece, was 29.3°C. Pivotal incubation duration (the time from laying to hatching giving 50% of each sex) was 52.6 days. These values are close to those obtained for this species in Brazil and the United States, providing further evidence that these characteristics are relatively conservative in different populations. Methodological differences between different experiments and limitations on accuracy of equipment make the detection of small differences problematic. Comparison of incubation durations in the field with the pivotal durations obtained here suggest that hatchling sex ratio on some Mediterranean beaches is female biased but probably varies considerably within this region.

Sex ratio of hatchling loggerhead sea turtles: data and estimates from a 5-year study

1992 ◽  
Vol 70 (3) ◽  
pp. 530-538 ◽  
Author(s):  
N. Mrosovsky ◽  
Jane Provancha
Keyword(s):  
Global Warming ◽  
Sex Ratio ◽  
Sea Turtles ◽  
Sex Ratios ◽  
Caretta Caretta ◽  
Loggerhead Sea Turtles ◽  
Loggerhead Turtles ◽  
Biased Sex Ratio ◽  
Nesting Season

Hatchling loggerhead sea turtles (Caretta caretta) were collected over three nesting seasons from a rookery at Cape Canaveral, Florida. From data on the distribution of nests over the season, we estimated that 92.6–96.7, 94.7–99.9, and 87.0–89.0% of the hatchlings produced on this beach in 1986, 1987, and 1988, respectively, were females. These skewed sex ratios were consistent with the fact that for most of the season, sand temperatures were above the pivotal level for loggerhead turtles. The present results show that the female-biased sex ratio reported previously by these authors for the 1986 nesting season at this site was not an isolated, atypical event. In addition to a total of 3 years of sampling for sex ratio, measurements of beach temperatures at the depth of turtle nests were extended to cover 5 years. These temperatures were commonly above the pivotal level. The strongly female-biased hatchling sex ratio found in this population of loggerhead turtles poses theoretical challenges. It may also complicate conservation efforts, since global warming might be expected to skew the sex ratio still further toward females.

scholarly journals 1 H-NMR metabolomic study of whole blood from hatchling loggerhead sea turtles ( Caretta caretta ) exposed to crude oil and/or Corexit

2017 ◽  
Vol 4 (11) ◽  
pp. 171433 ◽  
Author(s):  
Stasia A. Bembenek Bailey ◽  
Jennifer N. Niemuth ◽  
Patricia D. McClellan-Green ◽  
Matthew H. Godfrey ◽  
Craig A. Harms ◽  
...  
Keyword(s):  
Crude Oil ◽  
Whole Blood ◽  
Sea Turtles ◽  
Caretta Caretta ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Loggerhead Sea Turtles ◽  
Blood Samples ◽  
H Nmr ◽  
Whole Blood Samples

We used proton nuclear magnetic resonance spectroscopy ( 1 H-NMR) to evaluate metabolic impacts of environmentally relevant crude oil and Corexit exposures on the physiology of hatchling loggerhead sea turtles ( Caretta caretta ). Sample extraction and data acquisition methods for very small volume whole blood samples and sources of variation between individual hatchlings were assessed. Sixteen unclotted, whole blood samples were obtained from 7-day-old hatchlings after a 4-day cutaneous exposure to either control seawater, crude oil, Corexit 9500A or a combination of crude oil and Corexit 9500A. After extraction, one- and two-dimensional 1 H-NMR spectra of the samples were obtained, and 17 metabolites were identified and confirmed in the whole blood spectra. Variation among samples due to the concentrations of metabolites 3-hydroxybutyrate, lactate, trimethylamine oxide and propylene glycol did not statistically correlate with treatment group. However, the characterization of the hatchling loggerhead whole blood metabolome provides a foundation for future metabolomic research with sea turtles and a basis for the study of tissues from exposed hatchling sea turtles.

The Canadian-American Reciprocity Treaty of 1855 to 1866

1968 ◽  
Vol 28 (4) ◽  
pp. 598-623 ◽  
Author(s):  
Lawrence H. Officer ◽  
Lawrence B. Smith
Keyword(s):  
United States ◽  
North America ◽  
Free Trade ◽  
Coastal Waters ◽  
The United States ◽  
Free Access ◽  
British North America ◽  
British North American ◽  
Atlantic Coastal ◽  
St Lawrence River

The Reciprocity Treaty between the British North American Provinces (Canada) and the United States was ratified in February 1855 and terminated in March 1866. It provided for free trade in all natural products, free access for United States fisheries to the Atlantic coastal waters of British North America, and access to the St. Lawrence River for American vessels under the same tolls as native vessels.

Sex ratio variation in the yuma bat (Myotis yumanensis)

1993 ◽  
Vol 71 (5) ◽  
pp. 937-940 ◽  
Author(s):  
Barry N. Milligan ◽  
R. Mark Brigham
Keyword(s):  
British Columbia ◽  
Sex Ratio ◽  
Maternal Age ◽  
Sex Allocation ◽  
Sex Ratios ◽  
Ratio Variation ◽  
Sex Allocation Theory

Sex allocation theory predicts that monomorphic species should produce natal sex ratios near unity. We measured natal sex ratios in a maternity colony of approximately 1600 yuma bats (Myotis yumanensis) near Squilax, British Columbia, during June and July 1991. Overall, the natal sex ratio did not differ from unity but the sex ratio did vary significantly throughout the summer. Variation appears to be related to an interaction between maternal age and date of birth. This evidence suggests that facultative manipulation of the sex of the offspring by individual females may occur within the population.

Sexual size dimorphism and food requirements of nestling birds

1993 ◽  
Vol 71 (12) ◽  
pp. 2541-2545 ◽  
Author(s):  
David J. Anderson ◽  
Jo Reeve ◽  
Juan E. Martinez Gomez ◽  
Wesley W. Weathers ◽  
Siobhan Hutson ◽  
...  
Keyword(s):  
Gender Difference ◽  
Sex Ratio ◽  
Sex Allocation ◽  
Sexual Size Dimorphism ◽  
Positive Association ◽  
Size Dimorphism ◽  
American Kestrels ◽  
Sex Allocation Theory ◽  
Strong Positive Association ◽  
And Gender

The food requirements of dependent sons and daughters have important implications for evolution of the sex ratio, according to current sex allocation theory. We studied food requirements of nestling American kestrels (Falco sparverius), a moderately size-dimorphic falcon, by hand-feeding 61 birds from hatching to fledging. Daughters, the larger gender, consumed 6.99% more food than did sons. Sons did not have higher energy expenditure from higher effort during sibling competition than daughters did, so parents must supply more food to satisfy daughters' needs than to satisfy sons'. A review of all related studies shows a strong positive association between the degree of sexual size dimorphism and gender difference in food requirements.

The effect of operational sex ratio on sex allocation and neonate phenotype in a viviparous lizard Eremias multiocellata

2012 ◽  
Vol 33 (3-4) ◽  
pp. 485-493 ◽  
Author(s):  
Xiao-Long Tang ◽  
Feng Yue ◽  
De-Jiu Zhang ◽  
Xue-Feng Yan ◽  
Ying Xin ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Animal Species ◽  
Field Experiments ◽  
Maternal Investment ◽  
Tail Length ◽  
Operational Sex Ratio ◽  
Sex Allocation Theory ◽  
Female Investment ◽  
Eremias Multiocellata

Maternal investment in the production of male versus female neonates was approximately equal in most animal species. However, sex allocation theory predicts that under certain conditions, selection may favor the females’ ability to adjust the sex ratio of their offspring, which females tend to use more for an investment of the rare sex. The mechanism of operational sex ratio (OSR) influence on sex allocation is still unclear, and recent studies conducted on lizards have reached conflicting conclusions. Here, we selected a viviparous lizard Eremias multiocellata to test whether pregnant females could adjust the sex ratio of their offspring in response to OSRs. Our results showed that mothers did not adjust the sex ratios or phenotypes of neonates in the laboratory and field-based experiments, except tail length. However, the OSRs subsequently affected growth in both mass and SVL of the offspring in laboratory experiments; whereas only the mass was affected in the semi-nature field experiments. Our results, thus, contradict the predictions of sex allocation theory and challenge the idea that female investment in the scarcity sex might serve as a mechanism which is used for adjusting the population sex ratio.

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