Flowering plant hosts of adult Hymenopteran parasitoids of central Illinois

We tabulated flowering plant species visited by 151 species of parasitic Hy menoptera. These data were extracted from records of C. Robertson who colle cted >15,000 insect visitors of flowering plants in central Illinois during a 33-yr period. Species diversity of parasitoids was highest on plant spec ies of the Apiaceae and Asteraceae. The most abundant parasitoids were 2 ti phiid and a scoliid species. Parasitoid species in 6 dominant families (Ich neumonidae, Braconidae, Chrysididae, Tiphiidae, Pteromalidae, and Eucoilida e) showed similar preferences for 10 plant species. Most parasitoid species visited a limited range of host plants, which may have implications for co nservation biological control and conservation biology.