Bolker and Pacala recently introduced a model of an evolving population
in which an individual's fecundity is reduced in proportion to the
"local population density." We consider two versions of this model and
prove complementary extinction/persistence results, one for each version.
Roughly, if individuals in the population disperse sufficiently quickly
relative to the range of the interaction induced by the
density dependent regulation, then the population
has positive chance of survival, whereas, if they do not, then the population
will die out.