In this Experiment, students design an experiment to examine intraspecific and interspecific competition using two species of parasitoid wasps (Nasonia vitripennis and Melittobia digitata). Students examine the effect of both types of competition on reproductive output in the wasps. One or two females are placed on a single host: alone, or a competitor of the same species (intraspecific), with a competitior of the other species (interspecific), or with competitors of both species (intraspecific and interspecific). Students gather data on the number of offspring produced by females under each of the treatments. The resulting data are used to estimate the parameters of the Lotka-Volterra competition model. The predictions of the model are then compared to the outcome of interspecific competition treatments. Information is included on how to use the appropriate statistical analyses to compare the relative importance of interspecific and intraspecific competition on reproduction. Several extensions of this experiment (other questions that can be investigated using the same materials) are also described.