The intrinsic rate of increase of a population in terms of fecundity, developmental time, and longevity, is known to affect the colonizing ability of species. We present evidence that Polistes dominulus, an invasive European paper wasp introduced to the United States, exhibits life-history traits that predispose it to successful colonization. This predisposition is not simply due to the more frequent pleometrosis of P. dominulus. Many authors have speculated, based on cursory observations, that P. dominulus is replacing native species including P. metricus. The possibility of replacement in light of the data is discussed.