Stability of the Interaction Between Didinium and Paramecium: Effects of Dispersal and Predator Time Lag

Experiments to test effects of dispersal ability and predator time lag on the stability of the interaction between the predatory Didinium nasutum and Paramecium caudatum were performed in depressions which could be connected by capillary tubes. The basic interaction is shown to be unstable. Dispersal rates are variable, but generally high; dispersal does not alter stability in a 2-compartment system but increases stability in a multicompartment system. Predaton numerical time lag to changed food supply decreases stability to a small extent, but dispersal time lag may increase stability. The results suggest that spatial or temporal complexity is necessary for stability of this predator-prey interaction; the latter probably controls dynamics in natural conditions.