none Apanteles flavipes is a gregarious endoparasitoid of Porthesia scintillans . A new method for the estimation of energy available to the parasitoid is presented and used to prepare an individual energy budget for A. flavipes. A. flavipes consumes 13.9 J of the host tissue and assimilates 13.4 J. Production amounted to 10.1 J. Efficiencies of assimilation and production are 96.2 and 75.3% respectively. Metamorphic metabolic rate was 0.555 kJ/g/day.