The use of artificial diets for rearing natural enemies is an expensive technique with negative implications in the development of parasitoids. The aim of this study was to determine the effects on the development of the parasitoid Chelonus insularis Cresson (Hymenoptera: Braconidae) using as the host Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) larvae reared on castor bean (Ricinus communis L.) and maize (Zea mays L.) leaves. Twenty-five egg masses of S. frugiperda were exposed to adult parasitoids of C. insularis. One hundred twenty-three larvae were fed with castor bean leaves and 309 larvae with maize. Survival of S. frugiperda larvae and emergence of healthy adults of C. insularis were recorded. Durations of the developmental stages, weight per parasitoid, length of the radial cell, and total length of the forewing also were recorded. No significant differences were determined between the two host plants with respect to survival of S. frugiperda larvae or the emergence of healthy adults of C. insularis. Durations of the developmental stages of the parasitoid were longer on castor bean leaves than on maize. The length of the radial cell and the total length of the forewing were greater on parasitoids that emerged from castor bean-reared larvae than those reared on maize for both females and males. The weight per parasitoid did not differ. Chelonus insularis can be maintained in S. frugiperda larvae reared on castor and maize leaves but, based on these results, the use of castor bean leaves favors the size of the parasitoid.