Literaturdatenbank
Literaturdatenbank |
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Fehrenbach, A. K., McFadden, S., & Lindeman, P. V. , Reproductive allometry of the sabine map turtle (graptemys sabinensis) in southwestern louisiana - abstract. Unpublished paper presented at Program and Abstracts of the Tenth Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles.
Added by: Sarina Wunderlich (06 Jul 2014 16:10:43 UTC) |
| Resource type: Conference Paper BibTeX citation key: Fehrenbach2013 View all bibliographic details  |
Categories: General Keywords: Emydidae, Emys orbicularis, Fortpflanzung - reproduction, Habitat - habitat, Nordamerika - North America, Schildkröten - turtles + tortoises Creators: Fehrenbach, Lindeman, McFadden Collection: Program and Abstracts of the Tenth Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles |
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| Abstract |
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Optimal egg size theory states that as females grow larger, they produce more eggs of an optimum size rather than larger eggs. However, many turtle species show a correlation of egg size with female body size. This phenomenon can be explained by the anatomical-constraints hypothesis, under which smaller females are unable to lay eggs of the optimum size because of the restricted size of the caudal gap of the shell and the pelvic aperture. We collected data on female body size, clutch size, and egg width for populations of Sabine map turtles (Graptemys sabinensis) in the Mermentau and Calcasieu drainages in southwestern Louisiana. The data were logarithmically transformed to perform correlation analyses addressing isometry and allometry. There was a nonsignificant positive and hypoallometric correlation of clutch size with female body size. Significant positive correlations of mean and maximum egg width with female body size, consistent with the concept of the anatomical-constraints hypothesis, also were hypoallometric (i.e., egg size increased at a slower rate than body size). These results are consistent with studies of other Graptemys in showing that as females grow larger, they partition the extra reproductive effort they achieve between increased egg size and increased clutch size, such that neither can increase isometrically. There were significant differences between the two drainages in mean and maximum egg width, with Calcasieu females having wider eggs after statistical correction for the influence of female body size, but whether anatomical differences that facilitate this difference exist between the drainage populations is unknown.
Added by: Sarina Wunderlich |