The host-feeding parasitoid Ooencyrtus nezarae Ishii accepted 0–7 d eggs of Riptortus clavatus Thunberg. Host acceptance behavior was divided into four different behavioral phases: examining, drilling, host feeding, and ovipositing. The amount of feeding and number of eggs laid per host decreased with increasing host age. Females often rested during the host-feeding phase on 0-d hosts. Times of examining, feeding, and resting on 0-d hosts were longer than on the older hosts. Females appeared to regulate the amount of feeding and number of eggs laid based on host value, which decreases with increasing host age.