Host exploitation behavior in two hyperparasitoids, Lysibia nana and Gelis agilis, was compared in single cocoon clusters of their primary parasitoid host, Cotesia glomerata. L. nana reproduces sexually, is fully winged, does not host-feed and matures eggs quite rapidly after eclosion, whereas G. agilis possesses opposite traits. Cohorts of individual hyperparasitoid females of differing age and physiological state were given access to single cocoon clusters of C. glomerata that also varied in age. These results reveal that the reproductive biology of L. nana is well matched to exploit cocoon broods in C. glomerata, suggesting strong a co-evolutionary history with this host. By contrast, G. agilis is much less efficient at exploiting host cocoons and is probably a generalist species that attacks other hosts in nature.