PHASE SWITCHING IN POPULATION-CYCLES

Oscillatory populations may exhibit a phase change in which, for examp le, a high-low periodic pattern switches to a low-high pattern. We pro pose that phase shifts correspond to stochastic jumps between basins o f attraction in an appropriate phase space which associates the differ ent phases of a periodic cycle with distinct attractors. This mechanis m accounts for two-cycle phase shifts and the occurrence of asynchrono us replicates in experimental cultures of Tribolium.