SREL Reprint #2310

Relationships of lipids to ovum size in amphibians

Mark J. Komoroski1,2, Roy D. Nagle3, and Justin D. Congdon1,2

1Savannah River Ecology Laboratory, Drawer E, Aiken, South Carolina 29802
2Department of Ecology, University of Georgia, Athens, Georgia 30602
3Juniata College, Huntingdon, Pennsylvania 16652

Abstract: Relative to small embryos, large embryos may have longer developmental periods and, subsequently, relatively greater maintenance budgets. Because of the potentially increased metabolic costs of maintaining large embryos for long embryonic periods, Salthe and Mecham (1974) suggested that as ovum size increases among amphibians, ovum lipids (the primary stored metabolic energy reserves) should increase at a proportionally greater rate. To test Salthe and Mecham's hypothesis, we quantified egg lipids for 13 amphibian species from the southeastern United States. As ovum size increased among species, total, nonpolar, and polar lipids increased at rates uniform with or relatively lower than rates of increase in ovum size, in contrast to the hypothesis of Salthe and Mecham. However, variation in ovum lipids among species may be related to differences in breeding biology. Our results indicate that the amount of lipids allocated to ova do not merely depend on ovum size, but rather on the selective environments of the embryo and neonate.

SREL Reprint #2310

Komoroski, M.J., R.D. Nagle, and J.D. Congdon. 1998. Relationships of lipids to ovum size in amphibians. Physiological Zoology 71:633-641.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).