Living Organism Care Guide: Hornworms | Carolina.com

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Living Organism Care Guide: Hornworms

Living Care Information

Manduca sexta

commonly known as tobacco hornworm,
goliath worm, Carolina sphinx moth,
tobacco hawk moth

Quick Start Information

We ship hornworms in the egg, larval, and pupal life stages. These care instructions are organized by stage.

  • For a shipment of eggs, begin with the instructions under Eggs.

  • For a shipment of larvae, begin with the instructions under Larvae.

  • For a shipment of pupae, begin with the instructions under Pupae.

  • For the care of adults, refer to the instructions under Moths.

About the Organism

  • The organism’s entire life cycle (egg to adult moth) lasts 30 to 50 days.
  • The name hornworm comes from the presence of a small, pointed horn on the posterior end of the larva.
  • The tobacco hornworm is capable of metabolizing nicotine from the tobacco plant and uses the nicotine for defense against predators.
  • As a defense mechanism, hornworm larvae emit short clicking sounds from their mandibles when they are attacked.
  • Adults can hover over a nectar-producing flower.
  • Hornworms are an agricultural pest species and should not be released under any circumstances.
  • Domain: Eukarya
  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Lepidoptera
  • Family: Sphingidae
  • Genus: Manduca
  • Species: sexta

Preparation

Our Hornworm Nursery Kit provides all the materials necessary to raise a population of hornworms from eggs to adults.

Housing

Eggs

Your hornworm eggs will arrive in a small, plastic vial. It is best to hatch eggs on an artificial diet. You can easily construct a hatching chamber for 30 to 50 eggs using a plastic cup with a lid. Either pour liquid diet into the bottom of the cup or use a spoon to add a layer of solid diet to the bottom of the cup. Pack down the solid diet until it creates a good seal in the bottom of the cup. Whether liquid or solid, the layer of food should be no deeper than 7 to 10 mm (about ¼ to ⅜") deep. Allow liquid diet to solidify in the cup before continuing.

Place plastic netting in the cup with one end extended into the food. The netting helps support the food when the cup is inverted and allows a surface for the larvae to climb to reach the food.

Use a paper hole punch or other instrument to punch 4 holes through the lid. Invert the lid—inside facing up—on a table and line it with 2 sheets of tissue paper, filter paper, or paper towels. Put the eggs on the paper and reposition the cup (containing the solidified food and netting) over the lid. Gently work the lid back onto the chamber. Take care not to invert the cup so the eggs remain on the paper.


Place the hatching chamber, lid down, on a wire rack or use spacers (pennies) to elevate the lid slightly above a solid surface. This will allow air to circulate through the holes in the lid. Place the hatching chamber in a warm location at approximately 27° C (81° F) with a relative humidity of 40 to 50%. The eggs should hatch in about 3 days.



Eggs will also hatch on members of the Solanaceae (nightshade) family of plants. Suitable plants include tomato, eggplant, tobacco, and jimsonweed. Once hornworm larvae have fed on plants, few will accept an artificial diet. Larvae imprint on the first species of plant they feed upon and are voracious eaters. If you choose to hatch larvae on a suitable plant, you will need a plentiful supply of that plant before beginning your work. Place a leaf on a piece of damp filter paper in a petri dish and place the eggs on the leaf. Incubate as described above. Replace any material that becomes visibly moldy. Once the delicate larvae hatch and eat the leaf, use a small, clean brush to transfer them to additional leaves in petri dishes or directly onto plants.

It is easy to damage the young larvae by handling, so do not remove them from the hatching chamber until they are at least 2 cm long. Once the larvae have reached an appropriate size, remove them from the hatching chamber and into individual containers as described in the Larvae section.


Larvae

If you ordered hornworm larvae, they will arrive in a plastic cup with a small amount of media on the bottom of the cup. The larvae can live in their shipping container for several days, but it is best to move them to separate containers as soon as possible. Hornworm larvae grow quickly, and growth can be best observed when housed in individual containers. The larvae are 5 to 6 days old when you receive them and will complete their life cycle in 4 to 5 weeks.

It is easy to damage young larvae when handling, so do not remove them from the shipping cup until they are at least 2 cm long.


Remove the larvae from the shipping cup and put 1 larva into a housing vessel containing artificial diet. Carolina sells pre-poured vials containing diet in packs of 12 or packs of 50.


Do not put more than 1 larva into each vial. Lay the vials on their sides and place a lamp with a 100-W bulb (or equivalent energy-saving bulb) about 25 cm above them. Regulate the temperature by moving the lamp toward or away from vials. Check the temperature several times until it has stabilized around 27° C (81° F); thereafter, check it at least twice a day. Larvae must receive constant light to prevent their pupal stage lasting several months (diapause).

If you’re not using our Hornworm Nursery Kit or prefilled food vials, you’ll need to obtain some plastic containers with lids. An 8-ounce deli cup should be large enough to raise 1 hornworm larva. You will also need a supply of prepared diet. We sell a ready-to-use diet and a dry medium. Prepared diet should be stored in an airtight container in the refrigerator until use.


Pupae

Hornworm pupae are shipped in a roll of packing material. Gently unwrap the pupae and handle them carefully. Do not break the tongue cases, or the pupae will die. Place the pupae in a flight cage or other suitable container. Adult moths will emerge in 1 to 3 weeks.

To prepare mature hornworm larvae for pupation, remove each larva from its vial and wash any remaining culture medium from the vial with a jet of water. Do not use soap or detergent.

Hornworm larvae pupate underground. You can create a simulated, underground pupation chamber using the materials in your Hornworm Nursery Kit.

To simulate an underground environment, place a mature larva in a clean chamber and cover it with dry inert material (e.g., shredded paper, sawdust, potting soil) until the vial is about half full, then recap. Do not overfill or pack the vial; the larva needs space to pupate. Next, wrap each vial containing the larva and inert medium in newspaper and secure with rubber bands.

Place pupation chambers in an area where they will remain undisturbed. Do not remove the larvae from the vial until pupation has been completed. A pupa’s cuticle or exoskeleton is transparent at first, revealing its bright green inner tissues. During this time, the pupa is soft and can be easily damaged or killed. Gradually, the cuticle turns reddish-brown, then becomes opaque and hardens. The hardening process is known as sclerotization. The color of the pupa continues to deepen and darken to a dark brown or black as emergence approaches. Typically, mature larvae require 7 to 8 days to pupate. We advise that pupae be removed from their pupation chambers at days 10 through 12 to ensure that the cuticle has had sufficient time to harden and the pupae will not be damaged when they are examined or transferred. Place the pupae in a flight cage or other well-ventilated container. Adults should begin to emerge within 1 to 3 weeks.


Moths

To prepare for the moths to emerge, place fully formed pupae in a flight cage or other container. Maintain them at room temperature and expose them to a normal day/night cycle. The cage must have a vertical surface (cardboard, newspaper) that the moths can climb and cling to, or their wings will crumple as they unfold, and they will be unable to fly. Adult moths should emerge in 7 to 14 days.

Feeding

Larvae

The pre-poured vials provided in the Hornworm Nursery Kit contain enough food to sustain 1 larva to the pupal stage. If you’re not using vials, place one spoonful of prepared media in each housing container. Start by feeding each larva 1 teaspoon every other day and increase to feeding 1 teaspoon daily as the larvae mature. Both varieties of diet that we sell contain enough media to raise 30 larvae to maturity.

You can also maintain larvae on plant material, but larvae hatched on plants are best kept on plants. If mold should appear in the medium, remove the larva, wipe excess moisture from the vial or container, and remove the mold with the point of a knife. Replace the larva.


Pupae

No further feeding is necessary for pupae.


Moths

Once the moths emerge, place a shallow dish of cotton balls soaked in sugar water in the cage for them to feed on. To prepare the sugar water solution, mix 2 teaspoons of white or brown sugar with 1 cup of water.

Maintaining and culturing

Larvae

To complete the life cycle in 30 days, larvae must receive constant light, or their pupal stage could last several months (diapause). Maintain a temperature of about 27° C (81° F) throughout the larval stage. Lower temperatures can prolong the life cycle, while temperatures over 32° C (90° F) can kill the organism.


The larvae should be ready to pupate 18 to 21 days after hatching from eggs. At maturity, larvae are often over 7 cm (2 ¾") long and will develop a dark, pulsating line with nodes on the dorsal surface of their body. This is the dorsal aorta. Every day, examine each larva for the appearance of a dark dorsal aorta; oftentimes, it initially appears just anterior to the horn. Once the line first becomes visible, prepare the larvae for pupation. Delay at this point often results in the death of the larvae. Note that mature larvae raised on plants will burrow into soil to pupate if not removed from the plants.


Pupae

Maintain the larva at 27° C (81° F). If necessary, use a lamp or an incubator. A dish of water in an incubator will help maintain the necessary humidity. Pupation should be complete in 7 days. The strange appearance of this stage fascinates students. Examine the pupae, if desired. Many are surprised to learn that although the pupae seem rigid and inactive, their abdomens move when gently touched. Be sure to warn your students about this—many are startled when the pupae begin to wiggle in their palms. The pupae can be easily damaged if students drop them. No later than 14 days after the larvae have been prepared to pupate, remove them from their pupation chambers to prepare them for adult emergence.


Moths

Once the moths emerge, mist the cage with water daily to keep airborne wing scale to a minimum. Adult moths will begin to lay eggs around day 3 after hatching. Provide a tobacco or related plant for females to lay eggs. Female moths will deposit eggs on the underside of the leaves of host plants. Eggs can be carefully collected to start the life cycle over again.

Disposal

Hornworms are an agricultural pest species and should not be released under any circumstances. Place unwanted organisms in a sealable container and freeze for 48 hours. Dispose of the organisms in the regular solid waste. Unwanted eggs can be frozen or placed in alcohol.

Biosafety

Hornworms are an agricultural pest species and should not be released under any circumstances.

Video

FAQs

Since hornworms are a crop pest, how should I dispose of them?

It is best to dispose of hornworms by freezing them for 48 hours.

After emerging from the pupal case, how long until the adult females begin to lay eggs?

The female moth usually begins depositing eggs on the third night after emerging from the pupal case.

Where does an adult female moth typically place an egg?

The female hovers about a host plant and touches the upper surface of a leaf (near its margin) with her leg. She quickly flexes her abdomen underneath the leaf until it touches the lower leaf surface. A single egg is extruded from the ovipositor, placed near the edge of the leaf, and the moth flies away.

What are some plants that hornworm larvae will eat?

Hornworm larvae eat leaves from a wide range of solanaceous plants including jimsonweed (Datura), ground cherry (Physalis), tomato (Lycopersicon esculentum), eggplant (Solanum melongena), Jerusalem cherry (Solanum pseudo-capsicum), potato (Solanum tuberosum), pepper (Capsicum annuum), and tobacco (Nicotiana tabacum).

Is there a way to tell when the eggs are about to hatch?

The smooth, pale-green egg is about 1 mm in diameter and almost spherical. The color fades, becoming almost white before hatching. Eggs will hatch in 3 to 8 days depending on temperature.

Can hornworms be sexed?

Hornworm pupae can be sexed. Examine the ventral tip of the abdomen with a hand lens. Males exhibit 2 small bumps on segment 9, the next to last segment. Segment 9 is smooth on females, and there is a thin groove on segment 8.

How do I know if my pupa is still alive?

If your larvae pupate during the fall, they may enter an extended pupal stage called diapause. Pupae will remain in diapause until spring or summer (when conditions are more favorable). However, if you keep a light on the larvae during their development, they will not enter diapause. You will know your pupa is dead if it does not move and squirm. Dead pupae are dry, hard, and very dark. You can prevent pupae from drying out by maintaining the appropriate humidity.

Need help?

We want you to have a good experience. Orders and replacements: 800.334.5551, then select Customer Service. Technical support and questions: caresheets@carolina.com

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