M. sexta has a short life cycle, lasting about 30 to 50 days. In most areas,
M. sexta has about two generations per year, but can have three or four generations per year in Florida.
Eggs M. sexta eggs are spherical, approximately 1.5 millimeters in diameter, and translucent green. The
hemolymph (blood) of this species contains insecticyanin, a blue-colored
biliprotein. When the larva feeds on its normal diet of plant foliage, it ingests
pigmentacious carotenoids, which are primarily yellow in hue. The resulting combination is green. Under laboratory conditions—when fed a wheat-germ-based diet—larvae are turquoise in color due to the lack of carotenoids in their diet. The
caterpillar stage of the tobacco hornworm is quite similar in appearance to that of the closely related
tomato hornworm. The larvae of these two species can however be readily distinguished by their lateral markings. Specifically, the
M. sexta caterpillar has seven white diagonal lines with a black border at the first seven abdominal segments, and the horn is red or green with a red tip. The
M. quinquemaculatacaterpillar has V-shaped white markings with no borders at all eight of its abdominal segments, and the horn is dark blue or black in color. During the larval stage,
M. sexta caterpillars feed on plants of the family
Solanaceae, principally tobacco, tomatoes and members of the genus
Datura.
M. sexta has five larval instars, which are separated by
ecdysis (molting), but may add larval instars when nutrient conditions are poor. Near the end of this stage, the caterpillar seeks a location for
pupation, burrows underground, and pupates. This searching behavior is known as "wandering". The imminence of pupation—suggested behaviorally by the wandering—can be anatomically confirmed by spotting the
heart (aorta), which is a long, pulsating vessel running along the length of the caterpillar's dorsal side. The heart becomes visible through the skin just as the caterpillar is reaching the end of the final instar. A common
biological control for hornworms is the
parasitic braconid wasp Cotesia congregata, which lays its eggs in the bodies of the hornworms. The wasp larvae feed internally and emerge from the body to spin their
cocoons. Parasitized hornworms are often seen covered with multiple white, cottony wasp cocoons, which are often mistaken for large eggs. A
wasp species,
Polistes erythrocephalus, feeds on hornworm larvae. Tobacco Hornworm 1.jpg Manduca sexta larval stage.jpeg|In the larval state its back end might be confused as its head. Tobacco Hornworm 1 by Max Wahrhaftig.jpg|With parasitic wasp cocoons Manduca Pupae.jpg|Pupa
Pre-pupa Before the larva pupates, it goes through a stage called the pre-pupa, where it shrinks considerably and prepares to pupate. Often people mistake this stage for a dead or dying caterpillar.
Pupa The pupal stage lasts approximately 14–18 days under laboratory conditions (17 hours light, 7 hours dark, 27 °C). When reared on a short-day
photoperiod (12 hours light, 12 hours dark), pupae enter a state of
diapause that can last several months. During the pupal stage, structures of the adult moth form within the pupal case, which is shed during
eclosion (adult emergence).
Adult Adult
M. sexta have narrow wings with a wing span of approximately 9.5-12 cm.
M. sexta moths are
nectarivorous and feed on flowers, demonstrating a remarkable ability to hover. Adults are
sexually dimorphic. Males are identifiable by their broader
antennae and the presence of
claspers at the end of the abdomen. Female moths are typically ready to mate one week after
eclosion, and do so only once. Males may mate many times. Mating generally occurs on a vertical surface at night, and can last several hours, with the male and female facing in opposite positions, their posterior ends touching. After mating, females deposit their fertilized eggs on foliage, usually on the underside of leaves. Manduca sexta MHNT CUT 2010 0 104 Caranavi, La Paz Bolivia male dorsal.jpg|Male Manduca sexta MHNT CUT 2010 0 104 Caranavi, La Paz Bolivia male ventral.jpg|Male underside Manduca sexta MHNT CUT 2010 0 104 Dos Amates Catemaco VeraCruz Mexico female dorsal.jpg|Female Manduca sexta MHNT CUT 2010 0 104 Dos Amates Catemaco VeraCruz Mexico female ventral.jpg|Female underside
Laboratory rearing Like
Drosophila melanogaster,
M. sexta is commonly used as a
model organism for experiments. They are frequently studied in the laboratory due to their large size and relative ease of rearing. They may be reared on host plants, such as tobacco and tobacco relatives, tomato plants, or wheat-germ-based artificial diet. Their rearing is straightforward, provided they receive a long daylight cycle (e.g., 14 hours) during development to prevent
diapause. Eggs are rinsed for one to five minutes in dilute household bleach for disinfection. Eggs are placed on diet cubes or host plants. The eggs hatch and develop at different speeds depending on temperature. The larvae are moved to a fresh diet or leaves as their food spoils or is consumed. When they start to "wander", they are about to pupate, so are placed in a pupation chamber. Pupation chambers are holes drilled into a wood board. The
Manduca larvae are sealed in the chamber using a stopper and allowed to pupate. After pupation, the pupae are placed in a breeding or colony chamber to
eclose. Providing a cup of sugar water and a tobacco (or related) plant will allow mated females to
oviposit fertile eggs, which can then be reared. When fed an artificial diet,
Manduca larvae do not consume the
xanthophyll -which is a yellow pigment- needed to produce their green coloration; instead they appear blue. On some diets, they have very little pigment and pigment precursors, so are a very pale blue-white. As vitamin A and other
carotenoids are necessary for the visual pigments (
rhodopsin), an artificial-diet-reared hornworm may have poor vision due to lack of carotenoids in the diet.
As pet food Captive-bred hornworms fed on an artificial diet are often given to insectivorous exotic animals, such as certain reptiles, fish and small mammals. They are preferred over wild-collected hornworms, which may
bioaccumulate poisonous substances found in dietary plants. Hornworms, though originally bred for laboratories, are also farmed for this purpose. They are often sold already packed into pods that include everything the larvae need, including food. Care is relatively easy, and animals seem to relish their bright color and flavor. == Animal model ==