The hyperparasitoid Trichomalopsis apanteloctena (Crawford) is an idiobiont ectoparasitoid that uses the prepupa or pupa of the primary parasitoid Cotesia kariyai (Watanabe), which is paralyzed by venom at parasitization. Changes in nutrient quality of the primary parasitoid were evaluated during its development. The primary parasitoid C. kariyai was available as a host for 5 d, because C. kariyai eclosed at 5 d after emergence. The lipid contents of the primary parasitoid decreased during these 5 d. The size of individual T. apanteloctena progeny paralleled the available nutritional resources of these primary parasitoids. A decrease in body mass, that is, the change in the quality of the fat body in the primary parasitoid development affected the adult size and sex ratio of the hyperparasitoid. The hyperparasitoid had no preference of developmental stage of the primary parasitoid. However, adult sizes of the individual progeny that parasitized at 4 d after pupation were smaller and the sex ratio was male biased.