A laboratory study was conducted to examine the efficacy of a novel protein marking technique on insect parasitoids. Adult parasitoids were marked with the mammal protein, rabbit immunoglobulin G (IgG), by three different application methods. Adult parasitoids were marked internally by feeding them a honey solution "spiked" with rabbit IgG and externally by contact exposure or topical mist. Marked individuals were then assayed using a sandwich enzyme-linked immunosorbent assay (ELISA) for the presence of the protein marker using an antibody specific to rabbit IgG. Data indicate that the protein marker was retained throughout the entire adult lifespan in almost every (>95%) individual parasitoid assayed, regardless of the species examined and the application method used.