Abstract

Chaos is reported in laboratory populations of the flour beetle Tribolium. A nonlinear demographic model was used to predict the population dynamics and to establish the experimental protocol that would reveal chaotic behavior. With the adult mortality rate experimentally set high, the dynamics of animal abundance changed from equilibrium to quasiperiodic cycles to chaos as adult stage recruitment rates were experimentally manipulated. These transitions in dynamics correspond to those predicted by the mathematical model. Phase-space graphs of the data together with the deterministic model attractors (shown projected onto the larval, adult-plane) provide convincing evidence of transitions to chaos.