Butterfly & Moth Rearing

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Butterfly & Moth Needs

Rearing Habitat

  • An aquarium or wide mouthed jar with a the lid for the stem.
  • For larvae: A food plant vase made from film can or 1/2 pint container with "x" cut in lid.
  • For pre-pupal larvae: When the larvae are done eating they will wander around the container searching for a place to pupate.
  • If you do not know what kind of lepidopteran you have, provide each of the following. 1.) Several sticks securely leaning against the side of the container for spinning a cocoon or securing a chrysalis. 2.) Moist paper toweling or 1"-2" of moist sand or soil for species which pupate in the soil (usually moths).
  • For Pupa: Paper toweling taped to the top of the jar and hanging down to the bottom, and a moist pad of paper toweling in the container to keep humidity high. When the adult emerges, it will climb onto the towel to allow wings to expand and dry.
  • Pruning shears or heavy scissors are helpful to gather plant material and cut it for feeding.

Most larvae of butterflies and moths eat plants. Since they are often very selective about what they will eat, it is important to note the plant on which they are found and keep fresh plant material available at all times. Depending on their size, the larvae will eat one or more leaves of their food plant every day. Keep cuttings from the food plant fresh by placing the cut ends in narrow mouthed bottles of water. Cuttings can also be stored in a plastic bag misted with water in the refrigerator. Always recut ends and quickly insert into water after cutting and when transferring to a new container. When replacing old food plant, gently remove leaves or stems that the larvae are not sitting on and replace with fresh material. If the larvae are not eating, you either have identified the wrong food plant or the plant is too dry and undesirable. Replace it with fresh food plant or a selection of plants found from around where it was gathered. Adults usually feed on the nectar of flowers, but some do not feed at all. Unless you know what flowers the adults frequent, it may be difficult to feed the adults.

Larvae do not need water. They obtain all of the water they need from the food plant. The pupal stage does not feed or drink, but periodic light misting to prevent desiccation is important. When the adult emerges from the pupa, a humid environment is required to allow the wings to expand normally. Keeping a damp sponge in the cage when adult emergence is expected will usually provide sufficient humidity. If the containerŐs lid is screened, place a piece of plastic over it to increase humidity. Make sure that mold does not become established in this environment.

Taking Care
Lepidopteran larvae are eating machines and consequently pooping machines. Frass (droppings) needs to be removed to discourage mold. Gently remove water container and dump out frass. Every time you change the food plant, rinse out container and dry. Periodically wash the water container for the food plant. Young larvae may be hard to see, so make sure you count how many larvae are present in the container and record this number. This will also assist in assessing how much food plant the larvae are consuming.

Larvae of most Lepidoptera are harmless. Some larvae react to being touched by rearing up one end of the body, and some may expose odoriferous glands, which are harmless to humans. Both actions are intended to repel predators. Newly hatched larvae can be transferred by using a small paint brush. Adults have delicate wings that can be damaged by handling.

Raising Young
In most cases you will be starting with eggs or caterpillars. In a petri dish or vial, allow eggs to hatch and then transfer the larvae to a container. Several days before the adult will emerge, the pupa will darken and the patterns of the adult may be visible. Keep good records on how many insects you have. It is important to note the plant that the eggs or caterpillar is found on. The adults that emerge from pupa raised in the classroom should be released only if you found the larvae or eggs locally. Species that are ordered in a catalog or acquired from other locations should not be released unless you are certain the species occurs in the area.

Other Concerns

  • Some larvae have branched spines that cause sting. Hairy larvae such as the woolly bears, which have abundant straight hairs, are harmless. Single spines are not a problem.
  • Do not handle the container or larvae when they are molting. They are very susceptible to damage during this vulnerable transition. The same applies to the larva when it is becoming a pupa.
  • Make sure that the holes in the water container are not too big. Lepidoptera larvae are not particularly wary and young larvae may wander down the stem and drown.

Special Considerations
If the larva pupates in the fall, it is likely it will diapause (a period of dormancy during adverse environmental conditions) until the spring or summer. Remember the pupa is still alive. Do not allow it to dry out. It will squirm if it is alive. Dead pupa are dry, hard, and very dark.

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Lesson Plans Information Sheets Rearing Sheets Bibliography
Center for Insect Science Education Outreach The University of Arizona
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