Caterpillars can be reared a variety of ways. Depending on the species you will quickly establish which methods will work. Luna moths for instance tolerate dense rearing conditions were as Cecropia do not. Part of this has to do with their tolerance to disease and the need for air circulation.

The easiest method to rear larva is to place them in a sleeve directly onto the host plant. The obvious advantage here is that the food is still attached to the host. Provided you do not overload the sleeve sometimes you can leave the sleeve the entire season unattended. In situations where you will rear larger numbers of larva you will need to ensure that the sleeve is moved prior to complete defoliation. Select a branch that has clean lush grown and shake it vigorously to free it of potential predators such as spiders or stink bugs. Make sure you do not select a branch that is far longer or wider than the sleeve you will be using. Also make sure the sleeve is large enough to allow proper flow of air around the leaves. They should not be packed so densely that it would inhibit air movement or promote mold or moisture. Slide the sleeve onto the branch first and then place the larva in the center of the branch and tie the base of the sleeve firmly to the branch. You want to make sure you tie it tightly otherwise on windy days you risk the sleeve pulling loose and blowing off the tree. Birds are remarkable hunters and once they have identified a food source they will keep coming back till all the larva have been consumed. Wasps can also prove to be a problem, however this is typically more the case in late summer when there are large numbers of them. After the first week you should examine the sleeve and look at the lowest side for the presence of caterpillar frass. As time goes on the amount of frass should continue to increase. If you don’t see this then something may have happened to the larva and you will want to open it up for inspection. It is especially important to check sleeves after storms or heavy rainfall. Most caterpillars are well adapted to tolerate summer storms, however sleeves heavy will frass may promote disease or snap the limb. To avoid this you should always try and empty the sleeve of frass prior to a storm. Once the larva are fully grown you will often need to check the sleeve daily to harvest cocoons or remove mature larva if you intend for them to spin up elsewhere. Often by the time the larva are ready to spin their cocoons there is not that much foliage left and they will frequently use the sleeve material instead.

The next method is to cut fresh plant material to supply the growing caterpillars. This can prove challenging if the material used to supply the larva is not close or limited. Always make sure that you do not rear more caterpillars than you have food or time to handle. When rearing indoors you want to make sure that the temperature is not too cool nor too hot. The regulation of humidity is also important. If the air is too dry it can cause the food plant to prematurely dry as well as causing molting issues. Plastic totes work very well for rearing larva. You can utilize a lid or screen depending on the environment. When rearing larva in this type of contained method be sure to empty the frass and waste often. Also make sure your checking the water source for your branches or plant material. It’s astonishing how much water cut stems will utilize in a day. Make sure to place stems through tin foil or other material that prohibits the larva from having direct contact with the water. Caterpillars will walk right down the stem into the water and drown themselves. A tip for working with woody plant material is to first cut the stem on the sharpest angle possible then split up the stem several times. You can also purchase a florist product called QUICK DIP and this helps open up the phloem to keep the leaves nice and turgid. The main thing to remember when container rearing is to always keep the food fresh and to monitor waste and humidity.