As discussed elsewhere in this volume (see Chapter 1), the Lepidoptera comprise one of the megadiverse orders of holometabolous insects with approximately 160,000 named species including many of the most economically important pests in agriculture and forestry (Powell 2003). Most moths and butteries are herbivores as larvae, and the order as a whole represents the single largest evolutionary lineage of animals specialized to consume living plants. Commensurate with this diversity is a similarly large community of natural enemies that prey upon Lepidoptera. The most species-rich of these natural enemies are parasitoid wasps (Hymenoptera). Almost all Lepidoptera are attacked by one or more species of parasitoid wasps, but the vast majority of parasitoids are specialists that parasitize a particular life stage of one or a few species of hosts (Whiteld 1998; Pennacchio and Strand 2006).