ROLE OF FOOD IN POPULATION-DYNAMICS OF ORCHESELLA-CINCTA (LINNE) (COLLEMBOLA)

The feeding activity of the collembolan species O. cincta (L.) was studied in the laboratory and the field. In the laboratory, at any one time, only about 50-60% of the animals were feeding; the remainder were occupied with molting activities. Most of the time similar values were obtained in the field but during winter and during dry summer periods high percentages of empty guts could be demonstrated, indicating an absence or inaccessability of food. When favorable weather returned, high feeding activity was again observed. Laboratory experiments and field observations indicate that temporary starvation periods are followed by synchronization of the molting and reproductive rhythms and an apparent increase in longevity. These phenomena are important for the restoration of the population after unfavorable periods but reduce the stabilizing force of food scarcity.