Literaturdatenbank
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Mitchell, J. C. (1985). Female reproductive cycle and life history attributes in a virginia population of stinkpot turtles, sternotherus odoratus. Copeia, 1985(4), 941–949.
Added by: Admin (24 Aug 2008 19:37:38 UTC) Last edited by: Beate Pfau (01 Aug 2009 08:37:58 UTC) |
| Resource type: Journal Article BibTeX citation key: Mitchell1985 View all bibliographic details  |
Categories: General Keywords: Fortpflanzung = reproduction, Habitat = habitat, Kinosternidae, Nordamerika = North America, Schildkröten = turtles + tortoises, Sternotherus, Sternotherus odoratus Creators: Mitchell Collection: Copeia |
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| Abstract |
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Sternotherus odoratus The female reproductive cycle and life history attributes of a central Virginia population of Sternotherus odoratus were studied over a two-year period. Ovarian cycles were phenologically similar between years. Ovarian mass and follicle size are maximal in spring, decrease through the egg-laying period (mid-April-mid-July) and reach minimal mass and size in Aug. Vitellogenesis is underway in Aug. and most is completed by winter brumation. Females matured at four years of age and at carapace lengths of 66-77 mm. Clutch size averaged 3.2 eggs and did not differ significantly between years. Several females each year produced multiple clutches and, although second clutches tended to be smaller than first clutches, they were not significantly different from each other. Clutch size is significantly related to female carapace length and age. A multiple regression model explained only 64% of the variation in clutch size using the variables carapace length, egg length, egg width, egg mass, month and year. This result and the lower within-female clutch variance compared to within-population variance supports Gibbon's (1982) conclusion that environmental factors affect clutch size more than genetic or age-specific components. Egg mass and egg width were significantly correlated with carapace length. Within-female egg width is less variable than egg length. Comparison of the ovarian cycle with that of a syntopic population of Chrysemys picta studied concurrently reveals concordance in most aspects. Differences occur in length of the quiescent period, egg-laying season and patterns of follicle growth. Average adjusted clutch size for S. odoratus is significantly higher than that for C. picta. A relationship between minimum egg size and length of overwintering time is suggested. Added by: Admin Last edited by: Beate Pfau |