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ABSTRACTThe introduction of exotic species often results in a loss of biodiversity. Mexico has 4 invasive species of freshwater cyclopoid copepods: Thermocyclops crassus, Mesocyclops aspericornis, M. thermocyclopoides, and M. pehpeiensis. The Asian cyclopoid M. pehpeiensisis now established in several lakes and rivers in Mexico, but how it might compete with native species and potentially change the structure of plankton communities is unknown. Some insights might be obtained from a study of its demography compared to that of a native species. We compared the life cycle parameters of the native Mesocyclops longisetusand the exotic invasive species M. pehpeiensisin separate cultures. Four treatments were set up with 2 densities of Plationus patulus(Rotifera) individuals (1 and 4 mL−1) and 2 concentrations of Scendesmus acutus(Chlorophyte) cells (0.5 × 106and 1.5 × 106mL−1). Both species survived and reproduced in the treatment of 4 mL−1of P. patulusindividuals  +  0.5 × 106mL−1of S. acutuscells. Mesocyclops pehpeiensishad common characteristics in successful invasive species: short generation time, high reproductive capacity, and a wide dietary range. At low rotifer densities, M. pehpeiensishad a higher population growth rate (0.12 d−1) compared to M. longisetus(0.08–0.10 d−1). M. pehpeiensisis likely to outcompete M. longisetus,especially under food-limited conditions, and most likely expand its range in Mexico.