Male and female parasitoids often have different motivations for dispersal which can result in different dispersal behaviors. Males of the specialist parasitoid, Macrocentrus grandii, are attracted to females by a pheromone. Female M. grandii are attracted to their host, the European corn borer, Ostrinia nubilalis, by host frass and plant volatiles. We tested whether male and female parasitoids displayed different dispersal behaviors when presented with a choice of high and low host density corn fields. We marked parasitoids developing on O. nubilalis using foliar applications of rubidium chloride to corn plots. Marked parasitoids were presented with transgenic corn fields, which had low populations of both female M. grandii and hosts, and non-transgenic corn fields, which had relatively higher populations of female M. grandii and hosts. The dispersal of the wasps was monitored using sticky traps. Marked wasps were identified by their rubidium concentration. Preliminary results show that males are less likely to disperse into low host density fields than females.