Literaturdatenbank
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Hofmeyr, M. D. (2004). Egg production in chersina angulata: an unusual pattern in a mediterranean climate. Journal of Herpetology, 38(2), 172–179.
Added by: Admin (14 Aug 2008 20:37:16 UTC) |
| Resource type: Journal Article BibTeX citation key: Hofmeyr2004 View all bibliographic details  |
Categories: General Keywords: Chelonia, Cheloniidae, Chersina, Chersina angulata, Fortpflanzung = reproduction, Habitat = habitat, Schildkröten = turtles + tortoises, Südafrika = Southern Africa, Testudinidae Creators: Hofmeyr Collection: Journal of Herpetology |
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| Abstract |
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Testudinidae The reproductive cycle and egg production of Chersina angulata females, maintained under natural climate conditions, were studied over 29 months using ultrasonography. Angulate tortoises initiated egg production in February (late summer) and were gravid through most of the year. A short nongravid period in January indicates a cyclic rather than continuous reproductive pattern. Chersina angulata females produced one egg at a time, and clutch frequency ranged from one to six per year. Annual fecundity was influenced by the date of reproductive onset and egg-retention time; early ovulation and a short retention time increased annual fecundity. Egg retention time was highly variable (23–212 days) and correlated to ambient temperature (inversely) and rainfall (positively). Temperature had no direct effect on oviposition, but rainfall served as an important exogenous cue, perhaps facilitating nesting. Oviposition and ovulation were synchronized and females prepared a new egg immediately after oviposition. This reproductive pattern is highly unusual for chelonians in Mediterranean climates. This pattern might facilitate reproduction in the different environments over the range of C. angulata.
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