SREL Reprint #2036
THE EFFECT OF FOOD LIMITATION ON LIPID LEVELS, GROWTH, AND REPRODUCTION IN THE MARBLED SALAMANDER, AMBYSTOMA OPACUM
DAVID E. SCOTT1 AND MICHELE R. FORE 1,2
1Savannah 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.
Key words: Arnbystoma opacum; Egg size; Fecundity; Food stress; Growth;
Lipids; Reproduction; Reproductive frequency; Resource allocation; Salamander
2 PRESENT ADDRESS: Aquatic Ecology Laboratory, The Ohio State
University, Columbus, OH 43212: USA.
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.
