Rosalita Cormier
BI - 114
January 26, 2015
Getting to Know Your Model Organism: Tobacco Hornworm
Common Name: Tobacco hornworms are commonly called the tobacco hornworm or the goliath worm.
Scientific Name: Manduca sexta is the scientific name of the tobacco hornworm. Manduca, from the Latin word for “glutton”, represents the tobacco hornworm’s excessive appetite through the larval stage of growth. Sexta means six-fold, representing the six pairs of orange spots lining the stomach of mature moths.
Habitat Information: The tobacco hornworm is a land dweller in areas of rich vegetation such as tobacco fields and vegetable gardens. They are most commonly found in the southern region of United States, particularly the Gulf Coast, Mexico,…show more content… Larva develops through the process of molting, which includes discarding the previous exoskeleton and growing a new one. The larva molts five times during a period of approximately 20 days through stages known as instars. Larva remains a solid white color when it emerges and progressively changes into a blue-green color with black and white diagonal lines streaking along each side of it’s body. The larva has a distinguishing dorsal spine on the final abdominal segment. Along with the three pairs of thoracic legs, the caterpillar has five pairs of prolegs structured on the abdominal segment. The prolegs are plumper and contain several miniature pegs called crochets that permit the larva to fasten themselves onto its host…show more content… When fully developed, the pupa of the hornworm is a dark, reddish-brown and reaches roughly 40-60 millimeters in length. The hornworm undergoes metamorphosis for about 7 days.
The adult hornworm emerges as a moth. The adult hornworm is a fairly large thick bodied being with a wingspan up to 4 inches. The moth is dark gray with clear bands on the rear wings and six orange spots beside each surface of the abdomen. The life expectancy of an adult tobacco hornworm is typically only 2 weeks. In just one year, the hornworm population can give birth to two generations.
Behavior: Nicotine is known to be poisonous to numerous animals that rely on their muscles for movement. Yet, the tobacco hornworm is able to absorb nicotine from the tobacco plant and use it as defense and protection against predators. The hornworm does this without harming itself. The released nicotine is a defence mechanism used to discourage spiders.
Physiology:
Nicotine is toxic to most insects, but the tobacco hornworm is resistant. They have a special mechanism for secreting the nicotine and using the nicotine as a defense mechanism. A portion of nicotine exhaled by the hornworm’s spiracles and put into the atmosphere. The released nicotine is a defence mechanism used to ward off
