In this paper the problem of chaos synchronization, and the related phenome
na of riddling, blowout and on-off intermittency, are considered for discre
te time competition models with identical competitors. The global propertie
s which determine the different effects of riddling and blowout bifurcation
s are studied by the method of critical curves, a tool for the study of the
global dynamical properties of two-dimensional noninvertible maps. These t
echniques are applied to the study of a dynamic market-share competition mo
del.