The Energetic Cost of Courtship and Aggression in a Plethodontid Salamander

Abstract

The aerobic and anaerobic energetic contributions to courtship and aggression between males were measured in the plethodontid salamander Desmognathus ochrophaeus in the laboratory. Average rate of oxygen consumption and average lactate content were increased significantly above resting levels during both courtship (O 2 : +0.029 mL°g — 1 °h — 1 ; lactate: +0.058 mg/g) and aggression (O 2 : +0.040 mL°g — 1 °h — 1 ; lactate: +0.172 mg/g). However, these are rather small increments, representing rises of only 38—56% in oxygen consumption and only 8—23% of anaerobic capacity. The cost of a courtship bout is estimated to be 2.70 J/courting pair and is derived 90% aerobically. This value represents °1% of the daily ingested energy and secondary productivity for this species, based on estimates in a previous study. It thus seems unlikely that the behavior patterns of courtship or aggression in this species are subject to energetic limtations.