Want to breed your own insects? Check out our YouTube Channel for video tutorials.

How to Keep Hornworms after getting them in the Mail

Posted by Critter Depot on

Table of Contents

What are Hornworms?

The tobacco hornworm (Manduca sexta) (Lepidoptera: Sphingidae) is an economically important insect pest of many solanaceous (nightshade) crops, such as tobacco, tomato, peppers, and potato. As a contrast to its destructive nature as a caterpillar, adult moths are beneficial pollinators. This insect can be distinguished by its posterior red horn and abdominal markings that look like cigarettes. Like Bombyx mori and Drosophila melanogaster, the tobacco hornworm is also used as a model insect in many scientific studies.

Life Expectancy

This species is holometabolous, meaning that they go through a complete metamorphosis—egg, larva, pupa, and adult. The average lifespan of a hornworm about 40 days. On average, the insect remains a caterpillar for about 20 days, and it lives for about 10 days as an adult. The hornworm has five instars, or growth stages.

The duration for each stage is as follows:

  • 2–3 days for the first stage
  • 2–3 days in the second stage
  • 2–3 days in the third stage
  • 3–4 days in the fourth stage
  • 6–8 days in the fifth stage.

After the fifth instar, the larvae will begin to pupate, which takes about 7 days.

How to Keep Hornworms

After you receive your hornworms in the mail, you'll need to keep them alive until you feed them to your bearded dragon or leopard gecko.  Storage of your hornworms is best carried out in large plastic containers lined with cardboard in rooms where temperature, relative humidity, and photoperiod can be controlled.


For optimal growth, it is best to store hornworms at temperatures of 78°F (26°C), with a relative humidity of at about 80%, and a photoperiod of 16 hours light to 8 hours dark. Research suggests that lower temperatures will inhibit physiological functions, thus delaying molting and preventing pupation. Therefore, temperatures of 68°F (20°C) can be safe for the insect and can possibly delay growth by a week.

Remember that insects are cold-blooded animals, meaning that they rely on the environment to control their body temperature. If storage temperatures fall below 68°F (20°C), physiological processes are slowed and will lead to hornworms that are too weak to survive and increase their susceptibility to various diseases. On the other hand, temperatures that are too great (>95°F [35°C]), can directly affect the health of hornworms, causing heat stress and death.

Hornworm Poop

Caterpillars are voracious eaters, and they will also excrete a comparable amount of waste (frass). It is recommended that the container is cleaned after every molt (day estimates listed above); however, in the later instars (fourth and fifth), the container might need two cleanings. If you have a garden, be sure to save that frass, as it can be used as a biofertilizer—research suggests that the trace amounts of chitin present may induce disease resistance in plants.

You may also want to consider putting in a few sticks or twigs in your container to help with molting. When molting, some caterpillars climb to high places and hang upside-down to go into the next instar.


As you rear your hornworms, you will find that they constantly eat—only stopping to molt. Although in nature, the tobacco hornworm’s choice food is nightshade leaf material (e.g. tomato leaves), caterpillars that have fed on any nightshade-related leaves should not be fed to reptiles. Those hornworms will be poisonous because they will have accumulated toxic compounds.

The hornworm has been shown to feed on other plants outside of Solanaceae. (nightshade). Research has suggested that hornworms can subsist on leaves of cabbage and cowpea. Be aware, however, that cowpea leaves will prolong the larvae reaching pupation; likely due to its poor nutritional content. Hornworms are also known to feed upon sliced tomatoes and peppers. Although, if you are unable to acquire leaf tissue and solanaceous fruits, artificial diets for hornworms can be purchased online. Be aware that artificial diet is more nutrient-rich than leaf tissue and fruit, meaning that larvae will likely be fatter and molt faster.

To keep your insects healthy, it is best to keep them fed at all times, removing dried/moldy leaf material, fruit, or diet as necessary. At about 20 days, you can expect hornworm caterpillars to reach weights over 3 g before beginning pupation. Be advised that while research has suggested that starvation might prolong the larval stage (specifically keeping fifth instar hornworms under 3 g), this is not recommended. Stress of this type can lead to malnourished hornworms, increasing mortality and making insufficient feed for your reptile.


It must be stated that while suggestions can be given for the care of hornworms, one must remember that these are living creatures, and each will act differently with specific stimuli.

It is recommended to keep your hornworms fed at all times and clean their container after every molt. It is also recommended to keep your hornworms at temperatures of 78F (26C), with humidity levels of about 80%. Although, to prolong the larval stage of your insects, you might find success at keeping the temperature around 68°F (20°C).

Article Author

Colin Bonser, Entomology PhD

Primary Sources

Beck, G., S. Cardinale, L. Wang, M. Reiner, and M. Sugumaran. 1996. Characterization of a defense complex consisting of interleukin 1 and phenol oxidase from the hemolymph of the tobacco hornworm, Manduca sexta∗. J. Bio. Chem. 271(19): P11035–11038.

Grunert L.W., J. W. Clarke, C. Ahuja, H. Eswaran, and H. F Nijhout. 2015. A quantitative analysis of growth and size regulation in Manduca sexta: the physiological basis of variation in size and age at metamorphosis. PLoS ONE. 10(5): e0127988.

Hussa, E., and H. Goodrich-Blair. 2012. Rearing and injection of Manduca sexta larvae to assess bacterial virulence. J. Vis. Exp. 70.

Jacobson, D. J. 2021. Manduca sexta experience high parasitoid pressures in the field but minor fitness costs of consuming plant secondary compounds. Ecol. Evol. 11(20): 1388413897.

Reinecke, J. P., J. S. Buckner, and S. R. Grugel. 1980. Life cycle of laboratory-reared tobacco hornworms, Manduca sexta, a study of development and behavior, using time-lapse cinematography. Biol. Bull. 158(1): 129–140.

Reynolds, S. E., and S. F. Nottingham. 1985. Effects of temperature on growth and efficiency of food utilization in fifth-instar caterpillars of the tobacco hornworm, Manduca sexta. J. Insect. Physiol. 31(2): 129–134.

Safranek, L., and C. W. Williams. 1984. Critical weights for the metamorphosis in the tobacco hornworm, Manduca sexta. Biol. Bull. 167(3).

Traugott, M.S., and N. E. Stamp. 1996. Effects of chlorogenic acid-and tomatine-fed caterpillars on the behavior of an insect predator. J. Insect Behav. 9: 461–476.

Villaneuva, R. 1998. Tobacco Hornworm, Manduca sexta (Linnaeus), and Tomato Hornworm, Manduca quinquemaculata (Haworth), (Insecta: Lepidoptera: Sphingidae). University of Florida Extension.

Secondary Sources

Byron, M. A., and J. L. Gillett-Kaufman. 2017. Tobacco hornworm. Featured Creatures, University of Florida, Department of Entomology and Nematology.

Feeding Nature. 2022. What do hornworms eat? < https://feedingnature.com/ what-do-hornworms-eat/ >.


Leave a comment

Please note, comments must be approved before they are published