Modulation of Reproductive Behavior of Diaphania indica (Lepidoptera: Pyralidae) by Preferred and Non-preferred Host Plants

Abstract

The cucumber moth, Diaphania indica (Lepidoptera: Pyralidae), is one of the most destructive pests of cucurbitaceous plants all over the world. Previously, we showed that volatile organic compounds (VOCs) from cucumber plants play a crucial role in guiding gravid D. indica females to oviposition sites, whereas watermelon VOCs did not, and females significantly prefer cucumber over watermelon for oviposition. It remained unclear, however, whether preferred and non-preferred host plants also affect moth reproductive behaviors. In the present study we investigated the effect of preferred and non-preferred host plants on female calling, male attraction to female sex pheromone, and mating behavior in D. indica. In the presence of cucumber, virgin females engaged in significantly more calling on the first night than in either the watermelon treatment or the control. Also, we found that the mean time per bout on the first night in the cucumber plant treatment was significantly higher than that of the other two groups. The combination of cucumber foliage with female pheromone significantly increased the attraction and landing of males compared to either watermelon or the control in the wind tunnel. Furthermore, for one-day-old insects mating occurred only in the cucumber treatment. All insects in the cucumber treatment exhibited their first mating on one of the first three nights, but in the watermelon treatment only by night four had all insects mated. We also found that the duration of first mating in cucumber was significantly greater than in either watermelon or control. Overall, our study provides evidence that preferred and non-preferred host plants affect reproductive behaviors in D. indica.