Testosterone identifies hatchling sex for Mojave desert tortoises (Gopherus agassizii).

Autor: Walden MA; Department of Natural Resources and Environmental Science, University of Nevada, Reno, Reno, NV, USA. mar.walden@gmail.com.; Department of Fisheries Biology, California State Polytechnic University, Humboldt, Arcata, CA, USA. mar.walden@gmail.com., Loope KJ; Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, USA.; Department of Biology, Georgia Southern University, Statesboro, GA, USA., Hunter EA; U.S. Geological Survey, Virginia Cooperative Fish and Wildlife Research Unit, Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, USA., Divers SJ; Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA., Comolli JR; Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.; Department of Veterinary Services, Miami Seaquarium, Key Biscayne, FL, USA., Esque TC; U.S. Geological Survey, Western Ecological Research Center, Boulder City, NV, USA., Shoemaker KT; Department of Natural Resources and Environmental Science, University of Nevada, Reno, Reno, NV, USA.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2023 Sep 08; Vol. 13 (1), pp. 14818. Date of Electronic Publication: 2023 Sep 08.
DOI: 10.1038/s41598-023-41677-2
Abstrakt: The threatened Mojave desert tortoise (Gopherus agassizii) exhibits temperature-dependent sex determination, and individuals appear externally sexually monomorphic until sexual maturity. A non-surgical sex identification method that is suitable for a single in situ encounter with hatchlings is essential for minimizing handling of wild animals. We tested (1) whether plasma testosterone quantified by enzyme-linked immunosorbent assay differentiated males from females in 0-3 month old captive hatchlings, and (2) whether an injection of follicle-stimulating hormone (FSH) differentially elevates testosterone in male hatchlings to aid in identifying sex. We validated sex by ceolioscopic (laparoscopic) surgery. We then fit the testosterone concentrations to lognormal distributions and identified the concentration below which individuals are more likely female, and above which individuals are more likely male. Using a parametric bootstrapping procedure, we estimated a 0.01-0.04% misidentification rate for naïve testosterone samples, and a 1.26-1.39% misidentification rate for challenged (post-FSH injection) testosterone samples. Quantification of plasma testosterone concentration from small volume (0.1 mL) blood samples appears to be a viable, highly accurate method to identify sex of 0-3 month old hatchlings and could be a valuable tool for conservation measures and investigation of trends and variation in sex ratios for in situ wild nests.
(© 2023. Springer Nature Limited.)
Databáze: MEDLINE
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