Parasitoid wasps are often part of the rich invertebrate communities in decaying organic matter where their hosts are found. However, little is known about what adults of these parasitoids eat. Most parasitoid wasps parasitize herbaceous insects, so nectar from flowers often is readily available. The present study examined feeding by adult Spalangia cameroni Perkins (Hymenoptera: Pteromalidae), a species that burrows through manure, where it finds and parasitizes pupae of filth flies. Feeding on host fluids occurs in many parasitoid wasps, including S. cameroni. In the laboratory, these wasps also readily feed on honey or a sucrose solution, which increases their longevity. When given more realistic food choices, compared to just water, longevity was increased by buckwheat inflorescences, but not by cow manure, silage, milk, sweet alyssum, or dandelion inflorescences. Free sugars, lipids, and glycogen in wasps were determined with colorimetric tests in two experiments. The first experiment had two wasp treatments: 1) wasps given water for 2 d and then fed for 1 d and 2) same-aged wasps given just water. Wasps given buckwheat had significantly lower lipid levels. Wasps given hosts had significantly lower sugar and lipid levels. Wasps fed honey had significantly lower lipid levels and higher glycogen and sugar levels. In a second experiment, energy stores were examined 4 d after feeding, rather than immediately after, and patterns were different. Compared to water only, wasps fed buckwheat had significantly lower sugar levels and higher glycogen levels. Wasps given a host did not differ in sugar, lipid, or glycogen level from wasps given water
