Manduca sexta, the tobacco hornworm, is used for a variety of entomological studies. An artificial diet is available making it relatively easy to rear in the laboratory. It is a relatively large moth which makes it easier to do many physiological experiments. The adult hornworms are Sphinx Moths of the family Sphingidae. Sphinx moths are known for their ability to hover while collecting nectar from flowers.
Scientists who are interested in the aerodynamics and flight mechanics of hovering study Manduca as a model for developing flying mechanical robots with the the ability to hover. The ability to hover in a relatively small space allows the flight to be captured on video.
Hovering also allows entomologists to study the interactions between hawkmoths and the flowers they pollinate. The Manduca hawkmoth flies at night and often visits flowers in the nightshade family. Some flowers such as flowering tobacco (nicotiana) open at night to attract the night flying moths that pollinate them. These flowers are fragrant. Experiments have demonstrated that these hawk moths respond to both the odor and visual cues of the flowers.The odors attract the moth to the flower location from longer distances. At short range, the moth uses visual cues provided by the flower to guide its proboscis (long sucking mouthpart) into the flower to contact the nectar. Some pollen from the flower sticks to the proboscis and is carried to neighboring flowers. It is possible to use artificial flowers baited with odor to investigate the visual cues used by the moths. The artificial flowers can be constructed with patterns or even be clear so the moth cannot see the flower. Seeing the flower is necessary to elicit extension of the proboscis by the hawk moth. Other patterns help the moth direct its proboscis to the source of the nectar.
Hawk moths can “learn” where to locate nectar in relation to the patterns. Hawk moths are also able to track flowers that are moving up to about 3 cycles per second. This ability is important when a breeze causes the flowers to move. The hawk moth can move while hovering and adjust its flight to hit the moving target.
The Manduca hawk moths are strong fliers. I have seen and heard them flying at night, attracted to flowering tobacco ornamentals in my front yard. Their low distinctive buzzing sound can easily be heard on warm summer nights.