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Life History Phenomena in Two Populations of the Lizard Sceloporus undulatus in Southwestern New Mexico
Marian B. Vinegar
The American Midland Naturalist
Vol. 93, No. 2 (Apr., 1975), pp. 388-402
Published by: The University of Notre Dame
Stable URL: http://www.jstor.org/stable/2424171
Page Count: 15
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Fecundity, survivorship and population characteristics were determined for the lizards Sceloporus undulatus consobrinus and S. u. tristichus in southwestern New Mexico. Sceloporus u. consobrinus lays at least four clutches per year with a mean clutch size of 9.9 eggs. Sceloporus u. tristichus lays at least two clutches per year with a mean clutch size of 7.2 eggs. The deviations about the regressions of clutch size on snout-vent length were significantly different between the two subspecies. In S. u. tristichus, eggs are heavier, survivorship higher, predation (as estimated by tail loss frequency) lower, mean adult size smaller, and the population is more dense than in S. u. consobrinus. The S. u. tristichus population is probably closer to K (environmental carrying capacity) than that of S. u. consobrinus. The life history and population characteristics of other populations of the S. undulatus group were compared in light of current concepts of r- and K-selection, and these concepts were evaluated.
The American Midland Naturalist © 1975 The University of Notre Dame