Chaos and population control of insect outbreaks

We used small perturbations in adult numbers to control large fluctuations in the chaotic demographic dynamics of laboratory populations of the flour beetle Tribolium castaneum. A nonlinear mathematical model was used to iden tify a sensitive region of phase space where the addition of a few adult in sects would result in a dampening of the life stage fluctuations. Three exp erimental treatments were applied: one in which perturbations were made whe never the populations were inside the sensitive region ("in-box treatment") , another where perturbations were made whenever the populations were outsi de the sensitive region ("out-box treatment"), and an unperturbed control. The in-box treatment caused a stabilization of insect densities at numbers well below the peak values exhibited by the out-box and control populations . This study demonstrates how small perturbations can be used to influence the chaotic dynamics of an ecological system.