The response of Melittia oedipus (Lepidoptera: Sessidae) to visual cues is increased by the presence of food source

In Guam, visual and olfactory cues in mediating short-distance orientation to different colors in the presence or absence of food were studied in Melittia oedipus Oberthur (Lepidoptera: Sesiidae), a biological control agent for the invasive weed Coccinia grandis (L.) Voigt (Cucurbitaceae). In the free choice tests, M. oedipus adults preferred the color yellow most followed by gray and white with honey-water added to each treatment. The colors red, blue, green, brown and black were the least preferred. The same trend was observed in no choice tests wherein each of the eight colors was individually tested; yellow paper with honey-water attracted significantly more M. oedipus adults than the other colors. The cumulative response of M. oedipus to different colored papers moistened with honey-water was significantly higher than those moistened with water alone. These results indicate that yellow paper moistened with honey-water increases the feeding rate of M. oedipus and can be incorporated in mass rearing programs to control C. grandis occurring in the field.