Abstract
Summary: To express the degree of hunger during both of feeding and unfeeding periods of spiders, equations for the amount of ingestion and food disappearance from the gut were presented using three components: capacity of gut, rate of ingestion and rate of food disappearance. The degree of hunger was expressed by the rate of unfilled capacity of gut to the capacity of gut based on these equations.The rates of ingestion and food disappearance were estimated from the results of experiment with a wolf spider, Pardosa laura. The equations obtained well applied to the experimental result. By changing values of these rates, it was revealed that the ratio of rates of ingestion to food disappearance determine the amount of ingestion.