| Abstract: | Previous experiments on Betta splendens have shown that energy expenditures related to aggression are under social control. The present paper examines the biochemical energetics of social cohabitation in groups of Macropodus opercularis. The species is closely related to Betta splendens, however, dominants use somewhat different behavioral tactics against intruders. In contrast to Bettas, submissive Macropoduses are not harassed by dominants, but are confined to the bottom of the tank. This results in a reduced rate of oxygen consumption in defeated animals (Anabantid fish mainly use atmospheric oxygen). The only metabolic change, compared to isolated controls, is a reduction in hepatic glycogen content. Submissive animals have shifted carbohydrate metabolism towards anaerobic glycolysis. Substantial reductions in muscle proteins, lipids, and glycogen occurred in submissive Betta splendens. Thus, the sharp difference in behavioral strategy results in a sharp difference in the energetic consequences of aggression. A theory is presented regarding the possible role of energetic constraints in the control of behavior. © 1996 Wiley-Liss, Inc. |
