Chelonian exhibit temperature dependent sex determination, and ex situ incubation of eggs in conservation hatcheries may render a gender bias. The gender of juvenile Painted terrapins (Batagur borneoensis) produced at a conservation hatchery in Malaysia was determined by endoscopy of the gonads. Circulating reproductive hormones (testosterone, progesterone and estradiol) were profiled for 31 juveniles and nine captive-reared non-breeding adult terrapins. Endoscopy revealed a gender bias of 96.8% (30/31) females. Testosterone levels in the juvenile females (2.49 ± 1.29) were significantly lower than that of the adult females (12.20 ± 4.29), and lower than values in the juvenile male (9.36) and adult males (27.60, 35.62). The progesterone levels in the juvenile females (107.12 ± 68.68) were significantly higher than that of the adult females (51.13 ± 24.67), but lower than values in the juvenile male (33.27) and adult males (3.43, 8.51). Estrogen levels were significantly lower in the juvenile females (1.57 ± 1.35) compared to the adult females (77.46 ± 53.45). Negative correlations were observed between levels of progesterone and testosterone, and progesterone and estrogen. A positive correlation was noted between estrogen and testosterone. The present study constitutes the first attempt to determine the gender and reproductive hormone profiles of juvenile Painted terrapins produced by ex situ incubation, and captive non-breeding adults. Endoscopy of the gonads is a useful techniques for gender determination among juvenile turtles, while the use of testosterone as a gender biomarker warrants further investigation.
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http://dx.doi.org/10.1292/jvms.19-0477 | DOI Listing |
J Wildl Dis
March 2025
Wildlife Epidemiology Laboratory, Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Veterinary Medicine Basic Sciences Building, 2001 South Lincoln Avenue, Urbana, Illinois 61802, USA.
Sulawesi tortoise adenovirus (STADV) has been implicated in a mortality event involving three endangered species of tortoises and detected in free-living painted turtles (Chrysemys picta); however, the epidemiology of this virus in North American turtles remains unclear. The specific objectives of this study were to 1) estimate the prevalence of STADV in free-living Blanding's turtles (Emydoidea blandingii), painted turtles, and red-eared sliders (RES; Trachemys scripta elegans) in Illinois, US, using quantitative PCR (qPCR) and 2) determine if qPCR prevalence is associated with location, sex, age class, blood parameters, or clinical signs across these three species. Oral-cloacal swabs from 581 Blanding's turtles, 137 painted turtles, and 82 RES sampled across three counties from 2017 to 2022 were evaluated via qPCR.
View Article and Find Full Text PDFJ Wildl Dis
March 2025
Wildlife Epidemiology Laboratory, Department of Veterinary Clinical Medicine, College of Veterinary Medicine, Veterinary Medicine Basic Sciences Building, University of Illinois, 2001 S. Lincoln Ave., Urbana, Illinois 61802, USA.
Morbidity and mortality associated with adenoviruses (AdVs) have been reported in multiple taxa, including chelonians. Adenoviruses of a distinct testudinoid origin have been detected in both managed and free-ranging turtles in North America and Europe; however, the prevalence and impact of AdVs in free-ranging turtle populations have yet to be determined. A multispecies investigation to detect novel or existing AdVs in Blanding's turtles (Emydoidea blandingii; n=1,359), painted turtles (Chrysemys picta; n=270), and red-eared sliders (Trachemys scripta elegans; n=205) was performed across four counties in Illinois (with one site reaching into Wisconsin), USA, from 2016 to 2022.
View Article and Find Full Text PDFJ Wildl Dis
January 2025
One Welfare & Sustainability Center, The Ohio State University College of Veterinary Medicine Department of Veterinary Preventive Medicine, Sisson Hall, 1920 Coffey Road, Columbus, Ohio 43210, USA.
Am J Physiol Cell Physiol
January 2025
Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada.
Turtle hepatocytes are a nonexcitable model for metabolic depression during low-temperature and/or anoxic overwintering conditions. Cytoskeletal structure and mitochondrial distribution are continuously modified in cells, and we hypothesized that metabolic depression would inhibit such processes as cell attachment and spreading and promote withdrawal of cell protrusions and peripheral mitochondria. After developing a methodology for culturing painted turtle hepatocytes, two-dimensional (2-D) area and maintenance of cell attachment after a media change were used as indicators of structural rearrangement and spreading/volume.
View Article and Find Full Text PDFEcol Evol
November 2024
Departments of Fisheries and Wildlife & Integrative Biology, W.K. Kellogg Biological Station Michigan State University Hickory Corners Michigan USA.
Sex-ratio theory predicts that parents can optimise their fitness by producing offspring of the rare sex, yet there is a dearth of empirical evidence for adaptive sex allocation in response to the adult sex ratio (ASR). This is concerning, as anthropogenic disruption of the sex ratios of reproductive individuals threatens to cause demographic collapse in animal populations. Species with environmental sex determination (ESD) are especially at risk but may possess the capacity to adaptively influence offspring sex via control over the developmental environment.
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