A5042013909- Turtle Biology and Conservation
- Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities
- Animal Behavior and Reproduction
- Sexual Differentiation and Disorders
- Reproductive biology and impacts on aquatic species
- Amphibian and Reptile Biology
- Sperm and Testicular Function
- Bird parasitology and diseases
- Avian ecology and behavior
- Wildlife Ecology and Conservation
- Hormonal and reproductive studies
- Marine animal studies overview
- Ichthyology and Marine Biology
- Evolutionary Psychology and Human Behavior
- Fish Ecology and Management Studies
- Leech Biology and Applications
- Veterinary Medicine and Surgery
- Primate Behavior and Ecology
- Marine and coastal plant biology
- Marine Ecology and Invasive Species
- Race, Genetics, and Society
- Wildlife Conservation and Criminology Analyses
- Species Distribution and Climate Change
- Wildlife-Road Interactions and Conservation
- Demographic Trends and Gender Preferences
University of Alabama at Birmingham
2005-2021
University of Exeter
2017
The University of Texas at Austin
1989-1995
Texas A&M University
1990-1992
Abstract Temperature sensitivity and gonadal differentiation were studied in a turtle, Trachemys scripta , with temperature‐dependent sex determination. Sex determination was sensitive to both the duration magnitude of incubation temperature. exerted an “all or none” effect on ovarian testicular nature most gonads, but affected length ovaries graded fashion. Collectively, results indicate that is controlled by quantitative temperature during period beginning prior (histologically detectable)...
Abstract In many egg‐laying reptiles, the incubation temperature of egg determines sex offspring, a process known as temperature‐dependent determination (TSD). TSD is an “all or none” and intersexes are rarely formed. How external signal transduced into genetic that gonadal channels sexual development? Studies with red‐eared slider turtle have focused on physiological, biochemical, molecular cascades initiated by signal. Both male female development active processes—rather than...
Abstract Treatment of developing embryos two diverse species reptiles with fadrozole (a potent and specific nonsteroidal inhibitor aromatase activity in mammals) resulted the induction male sex determination. In first experiment, males were produced an all-female parthenogenic lizard ( Cnemidophorus uniparens ). second determination was induced a turtle Trachemys scripta ) temperature-dependent The results support hypothesis that endogenous production oestrogen may represent pivotal step...
Abstract In many reptiles, the temperature at which eggs are incubated determines sex of hatchlings. Administration estradiol will counteract masculinizing effects a male‐producing temperature, resulting in female To address whether and estrogen biologically equivalent, two experiments were conducted with red‐eared slider turtle, Trachemys scripta . first experiment, varying dosages administered Stage 17 (the middle temperature‐sensitive window) to maintained temperatures, 26°C (which...
Abstract A variety of sex determination systems exists in reptiles, including temperature‐dependent (TSD). While the precise physiological basis TSD is unknown, numerous past studies have provided a general characterization this phenomenon. The period thermosensitivity encompasses middle one third to half embryonic development. It has been shown that several species reptiles starts prior (histologically defined) gonadal differentiation and extends time when specific changes are becoming...
ABSTRACT The specificity of steroid hormone-induced sex determination was investigated in the red-eared slider, Trachemys scripta , a turtle with temperaturedependent determination. All eggs were incubated at either female-producing temperature (31 °C) or male-producing (26 and received control experimental treatments stage 17–18 embryonic development. A variety induced female maleproducing temperature. Oestradiol-17β, diethylstilboestrol (DES) (an oestrogen agonist) norethindrone (NET) (a...
The leatherbacks nesting at Bird's Head Peninsula, Papua Barat, Indonesia, account for 75% of the total leatherback in western Pacific and represent last sizeable population entire Pacific. Sporadic nest counts Jamursba Medi Beach have indicated a declining trend from 1980s through 2004, although relatively high amount has recently been documented Wermon Beach, located 30 km east Medi. We used expanded year‐round surveys 2005 to 2011 these two primary beaches obtain more robust estimates...
Incubation temperatures in loggerhead sea turtle (Caretta caretta) nests were examined as a method for predicting hatchling sex ratios. recorded 40 that laid on Hutchinson Island, Florida. Small temperature data loggers placed directly (in the center of egg mass) and programmed to record every 1.2 h entire incubation period. Nests during early, middle, late portions peak nesting period (June July) examined. The equally distributed an untreated beach had been artificially supplemented with...
Abstract This study is a quantitative evaluation of historic nesting levels the Kemp's ridley sea turtle ( Lepidochelys kempii ) in 1947 based on (1) Herrera film arribada, (2) Hildebrand's report regarding arribada shown film, (3) documentation and (4) current characteristics related to size relative total nests for season. Using this information approach, we estimate approximately 26 916 during recorded by Herrera. Based trends, also predict that would equate 121 517 season (range 82...
The sex ratio of immature loggerhead sea turtles, Caretta caretta, inhabiting the Atlantic coastal waters Florida was investigated. Blood samples were obtained from 223 turtles that captured in intake channel a power plant on Hutchinson Island. A serum androgen sexing technique utilized to individual turtles. (2.1 female: 1.0 male) differed significantly 1:1 and thus appears differ predictions allocation theory. These observations are consistent with those previous study, collectively...
We examined loggerhead nest temperatures and hatchling sex ratios in an effort to more accurately predict produced from 2 barrier islands the northern management unit (Blackbeard Island National Wildlife Refuge Wassaw Refuge, Georgia, United States) 2000 2004. Temperature data loggers were placed into 169 nests monitor incubation temperatures. Average critical period ranged 26.3°C 33.2°C (mean ± SE, 29.2° 0.1°C) indicated seasonal variation ratios. The of 669 hatchlings found dead was...
We developed a Kemp's ridley (Lepidochelys kempii) stock assessment model to evaluate the relative contributions of conservation efforts and other factors toward this critically endangered species' recovery. The demographic by Turtle Expert Working Group (TEWG) in 1998 2000 updated for binational recovery plan 2011 was modified use as our base model. TEWG uses indices annual reproductive population (number nests) hatchling recruitment predict future numbers nests on basis series assumptions...
Abstract In many reptiles, sex is determined by the temperature at which eggs are incubated (i.e., temperature‐dependent determination, or TSD). Past studies have shown that exogenous steroid hormones can override effects of and induce female determination. However, past attempts to male determination consistently failed. present study, was studied in a turtle with TSD. By utilizing an incubation regimen resulted approximately 1:1 ratio control group, be sensitive both androgen estrogen...
There is a variety of sex determining mechanisms among vertebrates. Many reptiles possess temperature-dependent determination (TSD), in which the incubation temperature egg determines hatchling. The red-eared slider turtle, <i>Trachemys scripta</i> has often been used as model system for examining physiology TSD. In current study, expression Dmrt1 was examined during TSD this turtle. putative regulator determination/differentiation and identified vertebrates, including fishes,...