Closed-Economy Energetics

Rashotte, Michael E. Closed-economy energetics. Appetite (2002) 38, 149–154. When the behavioral cost of access to food is increased in the 24 h closed-economy procedure, the number of meals per day decreases, the amount consumed per meal increases, and the total daily food intake remains relatively constant. This “Collier function” is found widely in individuals of different species and poses interesting questions about the mechanisms by which behavioral cost achieves these effects on feeding. Data from experiments with pigeons are reviewed which show that: (a) behavioral costs that differentially alter inges tive behavior are not differentiated by energetic costs (VO2), (b) the effects of a rise in behavioral cost of food require several days for full expression in ingestive behavior, (c) a bimodal distribution of feeding activity across the active phase is conserved when increased costs reduce the number of meals per day, (d) when ingestive behavior fails to supply a satisfactory nutrient load, physiological and behavioral energy-saving responses occur during the inactive phase. Mechanisms responsible for behavioral-cost effects on feed ing will need to $make provision for development of the effects across days, conservation of within-day distribution of feeding activity, and apparent lack of differential feed back from energy expenditure related to the differential behavioral costs. A complete energetic picture of life in a closed economy will include the inactive phase of the day and consideration of the effects of ambient temperature.