Changes in plasma oestradiol, testosterone an progesterone concentrations during an annual reproductive cycle in wild Aldabra giant tortoises (Aldabrachelys gigantea)
| Autor: | Marcus Clauss, Jean-Michel Hatt, Richard Baxter, Gabriela F. Mastromonaco, Maya S. Kummrow, Nancy Bunbury, Dennis M. Hansen |
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| Přispěvatelé: | University of Zurich |
| Rok vydání: | 2020 |
| Předmět: |
Aldabrachelys gigantea
geography 10253 Department of Small Animals geography.geographical_feature_category 630 Agriculture Ecological Modeling Endangered species Atoll Zoology Testosterone (patch) Biology 10127 Institute of Evolutionary Biology and Environmental Studies Population decline Habitat Seasonal breeder 570 Life sciences biology IUCN Red List Animal Science and Zoology Ecology Evolution Behavior and Systematics Nature and Landscape Conservation |
| Zdroj: | Herpetological Journal. :197-201 |
| ISSN: | 0268-0130 |
| DOI: | 10.33256/hj30.4.197201 |
| Popis: | Aldabra giant tortoises (Aldabrachelys gigantea) are currently listed as Vulnerable on the IUCN Red List of Threatened Species. However, negative impacts of sea-level rise are predicted to result in an overall population decline of 40-65 % over the next 100 years, rendering the species Endangered. Captive propagation is an important tool for in- and ex-situ species conservation, but breeding success outside the tortoises’ native island habitats has been very limited. Until now, the reproductive cycle of Aldabra tortoises has only been described in anatomic and behavioural studies. During a one-year period, plasma of four female and four male wild tortoises on Aldabra Atoll were examined monthly for levels of gonadal steroid hormones (oestradiol, testosterone, progesterone). Plasma oestradiol and testosterone values as well as meteorological data of the sampling period corresponded to previously published reports on seasonal changes in anatomy, behaviour and climate on the Aldabra Atoll. Seasonal changes in plasma testosterone were evident in males, with high values from January through April, reflecting previously described testicular growth and breeding season, followed by a nadir in August and September. In females, plasma oestradiol levels displayed seasonal changes, coinciding with reported ovarian growth from January to May. The obtained data provide prerequisite knowledge for endocrinological monitoring of reproductive processes and management of breeding programs, both ex-situ as in-situ, to establish reserve- and rewilded populations. |
| Databáze: | OpenAIRE |
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