Spodoptera frugiperda(J. E. Smith) larvae parasitized byOphion flavidusBrulle continued to feed after parasitoid oviposition. Consumption of a pinto bean diet was measured from parasitoid oviposition to parasitoid emergence or until pupation by control larvae. ParasitizedS. frugiperdalarvae of two size groups consumed 17 and 22% less diet, respectively, than control larvae. Parasitized larvae consumed less food, gained less weight, and produced less feces than unparasitized larvae at 48 and 72 h after exposure to a female parasitoid. Parasitized larvae had significantly larger (P<0.05) approximate digestibility index values and significantly smaller efficiency of conversion of digested food index values at 48 h than control larvae.