The delayed effect on fertility of preadult crowding is incorporated into a model of competition between two species. Using the symmetric case of the exponential version of the Lotka-Volterra function, equilibrium solutions are examined for two life stages: adults, .cxa.N, and eggs, .cxa.n. It is found that, when looking at adult numbers, this delayed effect can give the appearance of competitive interactions quite different from the true relationships and in the extreme, can result in apparent mutualism between strong competitors.