Relationships of Lipids to Ovum Size in Amphibians

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.

The interspecific range size–body size relationship in Australian frogs

“…Despite a significant relationship between clutch size and range size in single‐predictor regressions using both cross‐species and independent contrasts analyses, clutch size was clearly not important in explaining residual variation in the range size–body size relationship after accounting for the other predictor variables. The correlative evidence reported here supports the argument that species with increased colonization capacity through the production of small eggs with comparatively fast development (Komoroski et al ., 1998) are more likely to be widespread, compared with those producing large eggs. Since clutch size could not account for significant variation in range size over and above body size, the idea that species with large clutches and the associated colonization advantage are geographically widespread was not supported for Australian frogs.…”

“…Gaston & Blackburn, 1996b). In amphibians, the developmental period of small eggs is shorter compared to that of large eggs (Komoroski et al ., 1998), and in general, rapid development is a defining feature of highly colonizing species (Begon et al ., 1996).…”

Morphological Diversity and Evolution of Egg and Clutch Structure in Amphibians

“…Differences in the rate or pattern of release of eggs from a female also can influence clutch structure. Oviposition site, ovum number and size (Bernardo, 1996;Pombal and Haddad, 2005;Salthe and Duellman, 1973;Summers et al, 2007), energy content (e.g., Komoroski and Congdon, 2001;Komoroski et al, 1998), pigmentation, subsequent characteristics of development, larval ecomorphology, and other such factors are not directly considered in this review. In part, this is because the functional roles of oviductal (e.g., Greven, 2002Greven, , 2003 and especially ovipositional (e.g., Aronson, 1943) factors are not understood in sufficient detail.…”

Altitudinal variation in maternal investment and trade‐offs between egg size and clutch size in the Andrew's toad

“…This finding is in accordance with previous findings from intra‐specific comparisons of species with wide geographical ranges, supporting the idea that larger eggs are produced in colder localities where egg survival is presumably low (Berven & Gill, ). The reasons are that increasing energetic requirements posed by physiological stress or limited resources may be overcome by a larger amount of yolk and nutrients (Komoroski, Nagle & Congdon, ). Moreover, a lower loss of sodium resulting from a smaller surface‐to‐volume ratio of larger eggs is the major physiological impact of low temperature stress in larvae (Roff, ).…”