SREL Reprint #2036

The effect of food limitation on lipid levels, growth, and reproduction in the marbled salamander, Ambystoma opacum

David E. Scott and Michele R. Fore

Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA

Abstract: Assimilated food energy is partitioned into four compartments: maintenance, growth, reproduction, and stored energy in the form of lipids. Food availability is limited in many natural systems, so organisms face trade-offs in allocating energy to these competing compartments. We conducted a dietary study with female marbled salamanders, Ambystoma opacum, to examine the relationship between food level and energy allocation patterns. Feeding treatments produced differences in total lipid amounts, growth rates, and reproductive traits. Females in the high-food treatment group exhibited larger body size, higher lipid levels, greater proportions of total lipids, and larger clutch size than low- and medium-food animals. In addition, 60% of the high-food females were reproductive at the end of the experiment, compared to 42% of the females sustained at medium-food levels and 12% on the low-food regimen. After removal of an apparent outlier from analyses, a female's mean egg size and egg lipid investment per egg depended on food level through its effect on body size; larger females tended to have bigger eggs. Collectively these results suggest that food availability affects traits related to individual fitness and may also influence the population dynamics of a species.

Keywords: Ambystoma opacum; Egg size; Fecundity; Food stress; Growth; Lipids; Reproduction; Reproductive frequency; Resource allocation; Salamander

SREL Reprint #2036

Scott, D.E. and M.R. Fore. 1995. The effect of food limitation on lipid levels, growth, and reproduction in the marbled salamander, Ambystoma opacum. Herpetologica 51:462-471.

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