Literaturdatenbank
Literaturdatenbank |
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Wilbur, H. M. (1975). A growth model for the turtle chrysemys picta. Copeia, 1975(2), 337–343.
Added by: Admin (18 Jul 2009 11:46:28 UTC) |
| Resource type: Journal Article BibTeX citation key: Wilbur1975a View all bibliographic details  |
Categories: General Keywords: Chrysemys, Chrysemys picta, Emydidae, Habitat = habitat, Nordamerika = North America, Physiologie = physiology, Schildkröten = turtles + tortoises Creators: Wilbur Collection: Copeia |
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| Abstract |
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A growth law for a Chrysemys picta population in southeastern Michigan is deduced from observations of individually marked turtles of known age and from growth increments recorded by annual rings on the pectoral shield. This model can be used to assign ages to turtles for demographic studies. A 3 × 2 × 4 analysis of covariance compares the annual growth increment as a function of plastron length and age in adult males, females and immatures in two ponds during four growing seasons. Only body size and sex are significant components of this linear, additive model. The insignificant components are pooled with the error component and a new model relating the length of the plastron to the logarithm of age is fitted to all the growth data for turtles with a known sex. This logarithmic model adequately describes growth from birth through the first few years of adult life, but overestimates the predicted size of 42 turtles marked by Owen Sexton in 1953-1957 and recaptured in 1968-1972. After about age ten turtles probably grow at a linear rate of approximately 0.55 mm a year. The evolutionary significance of these growth patterns are analyzed as responses to predation and reproductive demands.
Added by: Admin |