A parasitoid fly, Sturmia bella (Diptera: Tachinidae), parasitizes more than 20 species of lepidopterans. In this study, oviposition preference and learning ability of the female were examined using Marsdenia tomentosa (Mt; Asclepiadaceae, heart-shaped leaf, a food plant of Parantica sita) and Oryza sativa (Os; Poaceae, needle-shaped leaf, a food plant of Parnara guttata) in the laboratory. In the first experiment, we released a naive female fly in a cage with two leaves of both Mt and Os without any host larvae, and recorded the number of eggs laid on leaves of each plant on the first day (Day 1). On Day 2, we presented Mt with a P. sita larva and Os without any host larvae in the same way. On Day 3, we presented two plants without any host larvae again. As a result, females laid more eggs on Os, Mt and Mt on Days 1, 2 and 3, respectively. We also presented two types of paper leaf models, needle-shaped and heart-shaped ones, to naive and conditioned females which experienced a P. sita larva on Day 2 of the first experiment. Naive females laid more eggs on needle-shaped than heart-shaped models, while conditioned females laid more eggs on heart-shaped than needle-shaped ones. The results show that this species has an ability to learn the leaf shape in connection with existence of the host larva.