none Considering the growth of parasitized host after parasitization, a new method was developed to estimate the bioenergetic parameters of parasitic insects. Spodoptera exigua Hubner parasitized by Apanteles prodeniae Viereck was taken as the model system. A. prodeniae consumes 16.5 J, excretes 0.53 J, assimilates 15.97 J and produces 11.37 J. Rates of feeding, assimilation, production and metabolism can be estimated using this method. Nutrition; Diet; Life cycle and development; Development; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts Spodoptera exigua (Noctuidae); Hymenopteran parasites; Apanteles prodeniae; Parasite food consumption & energetics model; Host parasite relationships; Hymenopteran parasite food consumption & energetics model Apanteles prodeniae (Braconidae); Quantity of food consumed; Energy sources; Energy content of lepidopteran host, energetics model; Food utilization; Lepidopteran host parasitoid energetics model; Growth; Energetics of parasite in lepidopteran host; Lepidopteran hosts; Spodoptera exigua; Parasite food consumption & energetics model; Host parasite relationships; Parasite food consumption & energetics model in lepidopteran host