Literaturdatenbank
Literaturdatenbank |
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Nagle, R. D., Lutz, C. L., & Pyle, A. L. (2004). Overwintering in the nest by hatchling map turtles (graptemys geographica). Canadian Journal of Zoology, 82(8), 1211–1218.
Added by: Sarina Wunderlich (30 Jun 2012 22:01:38 UTC) |
| Resource type: Journal Article DOI: 10.1139/z04-096 BibTeX citation key: Nagle2004 View all bibliographic details  |
Categories: General Keywords: Emydidae, Graptemys, Graptemys geographica, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises, Zeitigung = incubation Creators: Lutz, Nagle, Pyle Collection: Canadian Journal of Zoology |
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| Abstract |
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We monitored 75 natural nests of Graptemys geographica (Lesueur, 1817) in central Pennsylvania to determine the tactics and patterns of hatchling emergence. Following incubation, all hatchlings in 95% of nests delayed emergence from their natal nest cavities throughout autumn and winter until the following spring. Nests were constructed in a variety of substrates ranging from loose sand or coal to hard-packed clay mixed with gravel. Time from egg deposition to natural hatchling emergence averaged 333 days. During winter, hatchlings tolerated subzero temperatures as low as –8 °C, which are lethal to hatchlings of some sympatric species. Emergence occurred from 10 April to 25 May, and most hatchlings were found during morning following rain. There was an interactive effect of minimum daily air temperature and rainfall level 1 day prior to emergence on the number of hatchlings emerging each day. One half of all hatchlings found dead were contained in nests in which autumn emergence had apparently occurred. We speculate that autumn emergence by hatchlings of some turtle species may be an adaptive response to nest conditions likely to provide poor environments for successful overwintering.
Added by: Sarina Wunderlich |