Estimating the sex ratio of loggerhead turtle hatchlings at Mon Repos rookery (Australia) from nest temperatures

2008 ◽  
Vol 56 (1) ◽  
pp. 57 ◽  
Author(s):  
Cuong The Chu ◽  
David T. Booth ◽  
Colin J. Limpus
Keyword(s):  
Sex Ratio ◽  
Constant Temperature ◽  
Loggerhead Turtle ◽  
Temperature Fluctuations ◽  
Daily Temperature ◽  
Nest Temperature ◽  
Emergence Success ◽  
Sand Temperature ◽  
Almost All ◽  
Equivalent Method

Sand temperatures and loggerhead turtle nest temperatures (Caretta caretta) at Mon Repos rookery (Australia) were monitored over the 2005–06 and 2006–07 nesting seasons and hatchling sex ratios of clutches were estimated using the Constant Temperature Equivalent method. Nest temperatures were positively correlated with the sand temperature and air temperature in both seasons. Both seasons produced a female-biased sex ratio, especially the 2005–06 season, when almost all hatchlings were predicted to be female. Hatch success rate was not affected by nest temperature and averaged 85%, but hot nests from 2005–06 had a reduced emergence success compared with other nests. Daily cyclic temperature fluctuations of 0.5–1.5°C were a feature of nests, with a tendency for greater daily amplitude in the 2005–06 season when the average daily temperature was hotter. These daily temperature fluctuations increased the constant temperature equivalent temperature by 0.1–0.5°C above mean nest temperature during the sex-determining period and resulted in an increased female bias in the estimated hatchling sex ratio.

Effect of nest temperature on hatchling phenotype of loggerhead turtles (Caretta caretta) from two South Pacific rookeries, Mon Repos and La Roche Percée

2012 ◽  
Vol 60 (6) ◽  
pp. 402 ◽  
Author(s):  
Tyffen Read ◽  
David T. Booth ◽  
Colin J. Limpus
Keyword(s):  
Thermal Tolerance ◽  
Hatching Success ◽  
New Caledonia ◽  
Loggerhead Turtle ◽  
Caretta Caretta ◽  
Nest Temperature ◽  
Genetic Stock ◽  
Upper Limit ◽  
Emergence Success ◽  
The Mean

La Roche Percée, in New Caledonia, is the most important loggerhead turtle rookery outside of Australia for the eastern Pacific genetic stock. The females nesting on this beach are genetically similar to the females found at the Mon Repos rookery in Queensland, Australia. This study shows how nest temperature affects the phenotype of genetically similar populations. During the 2010–11 breeding season, mean nest temperatures were significantly higher at La Roche Percée (31.8°C) than at Mon Repos (29.5°C) and the mean for the three-days-in-a-row maximum nest temperatures was also significantly higher at La Roche Percée (34.6°C), than at Mon Repos (31.7°C). Differences were found in mean hatching success (La Roche Percée 83 ± 3%, Mon Repos 96 ± 2%) and emergence success (La Roche Percée 76 ± 3%, Mon Repos 93 ± 3%). Hatchlings from La Roche Percée also had significantly lower fitness characteristics, having smaller carapace size (La Roche Percée 1565 ± 7 mm2, Mon Repos 1634 ± 5 mm2), slower self-righting times (La Roche Percée 4.7 ± 0.1 s, Mon Repos 2.7 ± 0.1 s) and slower crawling speed in terms of both absolute speed and body lengths per second (La Roche Percée 2.5 ± 0.2 cm s–1 or 0.57 ± 0.05 body lengths s–1, Mon Repos 4.6 ± 0.1 cm s–1 or 1.04 ± 0.02 body lengths s–1). Nest temperatures at La Roche Percée approached the upper limit of embryo thermal tolerance towards the end of incubation (34°C) and this condition may contribute to the lower hatching and emergence success and lower fitness characteristics of hatchlings at the La Roche Percée rookery.

scholarly journals Nest temperature fluctuations in a cavity nester, the southern ground-hornbill

2017 ◽  
Vol 66 ◽  
pp. 21-26 ◽  
Author(s):  
L. Combrink ◽  
H.J. Combrink ◽  
A.J. Botha ◽  
C.T. Downs
Keyword(s):  
Temperature Fluctuations ◽  
Nest Temperature

Analysis of Elemental Composition of the Eggshell before and after Incubation in the Loggerhead Turtle (Caretta caretta) in Oman

2011 ◽  
Vol 17 (3) ◽  
pp. 452-460 ◽  
Author(s):  
S.N. Al-Bahry ◽  
I.Y. Mahmoud ◽  
K. Melghit ◽  
I. Al-Amri
Keyword(s):  
Elemental Composition ◽  
Amorphous Material ◽  
Loggerhead Turtle ◽  
Middle Layer ◽  
Caretta Caretta ◽  
Exothermic Peak ◽  
Shell Membrane ◽  
Emergence Success ◽  
Significant Difference ◽  
Before And After

AbstractTo date, there are limited studies on loggerhead turtle (Caretta caretta) eggshell ultrastructure and its elemental composition. Eggs were collected from turtle nests immediately after oviposition and post hatching. Three eggshell layers were recognized. The outer calcareous layer consists of loose nodular units of different shapes and sizes with loose attachment between the units, resulting in numerous spaces and openings. Each unit consists of CaCO3crystals in aragonite (99%) and calcite (1%). The middle layer has several strata with numerous openings connecting the calcareous and the inner shell membrane. Crystallites of the middle layer are a mix of amorphous material with aragonite (62%) and calcite (38%). The inner shell membrane has numerous reticular fibers mixed predominantly with halite (NaCl) and small amounts of sylvite. Thermogravimetry analysis of the calcareous showed a low exothermic peak at 425°C, which corresponds to a transitional phase from aragonite to calcite. A high endothermic peak at 814°C corresponds to decomposition of calcite CaCO3to CaO and CO2. Electron diffraction confirmed the presence of NaCl halite crystal. A significant difference was found in the percentage of elements and crystal configurations in the three layers. This study has value in assessing the emergence success in this endangered species.

scholarly journals Response of Development and Body Mass to Daily Temperature Fluctuations: a Study on Tribolium castaneum

2016 ◽  
Vol 43 (3) ◽  
pp. 356-367 ◽  
Author(s):  
P. Kramarz ◽  
D. Małek ◽  
K. Naumiec ◽  
K. Zając ◽  
S. M. Drobniak
Keyword(s):  
Body Mass ◽  
Tribolium Castaneum ◽  
Temperature Fluctuations ◽  
Daily Temperature ◽  
Daily Temperature Fluctuations

A novel piezoelectric dynamometer based on double-sensor for thermal compensation

2016 ◽  
Vol 231 (23) ◽  
pp. 4479-4491 ◽  
Author(s):  
Yu Tian ◽  
Jun Zhang ◽  
Zong-jin Ren ◽  
Wei Liu ◽  
Zhenyuan Jia ◽  
...  
Keyword(s):  
Constant Temperature ◽  
Rocket Engine ◽  
Temperature Fluctuations ◽  
Measurement Precision ◽  
Thermal Compensation ◽  
Static Calibration ◽  
Maximal Output ◽  
Heat Conduction Differential Equation ◽  
Force Compensation ◽  
Over Time

A piezoelectric dynamometer can produce thermal forces because of temperature fluctuations, thus affecting measurement precision. To investigate the influence of the thermal force on the dynamometer, this article proposes a hypothesis of decreasing the conduction power and establishes the function of a thermal force over time in an ordinary dynamometer based on the heat conduction differential equation. A novel double-sensor thermal compensation dynamometer is designed, with static calibration in constant temperature and force/heat coupling experiments, to solve the problem of the thermal force. The experimental results indicate that the nonlinearity and repeatability of the double-sensor thermal compensation dynamometer are less than 1% full scale (FS) of the static calibration at a constant temperature; in the force/heat coupling experiments, at a heating rate of 0.4 ℃/s to 110 ℃ with a loading force of 500 N, the maximal output deviation is less than 1.06% (FS), realizing the unidirectional thermal force compensation of the structure. The double-sensor thermal compensation dynamometer can be utilized in sharp temperature fluctuations environment, like rocket engine forces measurement.

Going back to the roots: finding a strategy for the management of nesting loggerhead sea turtles in New Caledonia

2018 ◽  
Vol 66 (6) ◽  
pp. 394
Author(s):  
Tyffen C. Read ◽  
Marion Petit ◽  
Marion Magnan ◽  
David Booth
Keyword(s):  
Hatching Success ◽  
Incubation Temperature ◽  
New Caledonia ◽  
Loggerhead Turtle ◽  
Sea Turtle ◽  
Vital Role ◽  
Morning Glory ◽  
Root Penetration ◽  
Loggerhead Sea Turtles ◽  
Emergence Success

Incubation temperature plays a vital role in sea turtle life history because it influences embryonic growth, sex determination and hatchling attributes such as body size, residual yolk size, self-righting ability, crawling speed and swimming speed. For these reasons there is concern that predicted increases in air temperature, as a result of global warming, will increase nest temperatures and result in decreased hatching success, decrease or cease male hatchling production, and decreased hatchling quality. In a previous study examining incubation temperature at a loggerhead turtle (Caretta caretta) rookery located at La Roche Percée, New Caledonia, high nest temperatures and root invasion by beach morning glory (Ipomoea pes-caprae) were found to adversely affect hatching success and locomotor performance. In the current study, we relocated loggerhead turtle nests into shaded hatcheries. Shading nests decreased sand and nest temperatures and was predicted to increase male hatchling production slightly, but nest emergence success was decreased due to invasion of cottonwood (Hibiscus tiliaceus) roots into some nests. Using shaded structures is a viable and affordable management option to counteract the high sand temperatures found on some sea turtle nesting beaches, but these shade structures need to be located some distance from trees and other plants to ensure that root penetration into nests does not adversely affect nest emergence success.

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