ABSTRACT Release-recapture experiments using Drosophila pseudoobscura and D. persimilis strains of different karyotypes were performed in a heterogeneous environment. The heterogeneity was due to both spatial variation and the species of yeast used to attract the released flies. No karyotypic-specific habitat preferences were detected. However, in all releases, different strains did behave differently with respect to one or both of the heterogeneous factors. These results indicate there is variation for dispersal behavior in these species that is most likely based on genotype-dependent habitat preferences.