THE INFLUENCE OF CONSTANT AND CYCLIC ACCLIMATION TEMPERATURES ON THE METABOLIC RATES OF PANOPEUS HERBSTII AND UCA PUGILATOR

¹ Belle W. Baruch Institute for Marine Biology and Coastal Research, University of South Carolina, Columbia, South Carolina 29208 USA

The comparative influence of acclimation to constant and cyclic temperatures on the metabolic rates of the mud crab, Panopeus herbstii, and the fiddler crab, Uca pugilator, was observed. Although interspecific differences were observed, cyclic acclimation temperatures significantly depressed oxygen consumption in the 15°- 25° C temperature range in both species when compared to rates of animals subjected to constant acclimation rates. Since this depression of metabolic rates occurs over that portion of the yearly temperature range within which the animals are most active, it is suggested that these organisms utilize energy more efficiently when subjected to natural cyclic temperature conditions than when subjected to constant temperature environments. This difference in metabolic data would be significant in analyzing the role of the yearly energy budgets of crabs in ecosystem energetics.