Last summer (2002), my husband, my kids and I raised 180 cecropia caterpillars in cages in our basement. We fed them wild cherry leaves, and a few ornamental weeping cherry leaves at the end. If you have never raised caterpillars before, I recommend you start small and raise fewer – say at most 20. I say this because I cannot over estimate the time it takes to gather food and take care of that many 5th instar caterpillars!

Bill Oehlke and his father, Don, had told me that cecropia are difficult to rear indoors. A couple of years earlier, I tried to raise cecropia caterpillars in plastic containers with disastrous results. None survived beyond the second instar stage. They all went limp and died very suddenly. By raising them in large well-ventilated cages with low humidity and fairly constant temperature, I think you may have good results. I only lost 2-3 caterpillars at the 2-3 instar stages and our biggest losses were due to drowning (8-9 caterpillars).

First, be sure you have an adequate food source to feed the caterpillars for 5-8 weeks. We offered our caterpillars a bouquet of walnut, cherry and hickory leaves, but they would only eat cherry leaves. I think cecropia will utilize other food sources, so check a reference (Bill Oehlke’s website or The Wild Silk Moths of North America by Tuskes et al) if you don’t have access to cherry.

You will also need time. I spent on average 45-60 minutes each day cleaning cages, gathering food and replacing branches when the caterpillars were at the 4-5 instar stage.

We began with about 200 eggs which have a reddish brown mottling of "glue" on them when deposited. The eggs hatched in early July over a five day period, about eleven to twelve days from deposition. We kept the hatchlings in small sealed Tupperware containers for 2-3 days and then we moved them, with a small artist’s paintbrush, to cherry branches in vases.

On day one, the black fuzzy caterpillars were .5 cm long and they grew, on average, to 8 cm (a little over three inches) at maturity. It took almost eight weeks (55 days), from the first hatch till the last caterpillar spun a cocoon. Larvae usually hatch in the morning about 11-12 days from egg deposition. Foliage should never be placed in a closed container with unhatched eggs. How does a 5mm caterpillar hatch out of a 2 mm egg? It's curled up around perimeter of egg shell and probably grows a bit as it eats its way out!

Second instar larvae are yelllow to green with black tubercles; third instar larva are much more colourful, with red thoracic scoli and blue lateral scoli and yellow dorsal scoli.

The period of time between the first to second, second to third and third to fourth instar stages was about 5-7 days each, but the period of time from the fourth molt to 5th instar stage and cocoon spinning was about 2-3 weeks. The caterpillars, as a group, developed at a uniform rate from 1-3rd instar, but developed at a less uniform rate from there on. I collected the first cocoon at 36 days from hatching, with peak cocoon spinning at around 43-47 days.

At first, I did not have the caterpillars in cages. They seemed content to stay on the foliage as long as there was food. This lasted till about the 3rd instar stage. By that stage they really like to do some walking and need to be contained in cages. I used Reptarium cages from Carolina Biological Supply Company (www.carolina.com or 1-800-334-5551). The cages have a very lightweight plastic frame with a removable, washable nylon mesh skin that has zippers for access. These cages are sort of expensive for what they are, but they are easy to clean, they are lightweight and they provide excellent ventilation. They also allow filtered light in. We covered the concrete basement floor with an old shower curtain to keep the floor clean. You could also use sheets of heavy plastic. Then we placed the vases, and later the cages on top of the plastic.

When the caterpillars were in vases alone, I covered the plastic with several sheets of newspaper to help clean up the frass. Later, I lined the bottoms of the cages with several layers of newspaper. Each day, I would roll up a layer or two of paper with frass and other debris and discard it. There was never any odor from the frass, or the caterpillars. We kept the caterpillars in three cages, about 60 caterpillars/cage.

Cecropia caterpillars don’t like bright sunlight, or high humidity. We raised the caterpillars on the cool concrete basement floor. The temperature in the basement was constant, about 70-75 degrees F. We also ran a dehumidifier in the basement 24 hours a day/7days a week. I would leave the overhead light on for them during the day and they also got a little filtered light from a basement window about 8-9 feet away. Interestingly, they often seemed to do their heaviest feeding at night in the dark!

From 1-3 instar stage you will need to replace foliage every 2-3 days. From 4th instar on I needed to replace it DAILY. I cut cherry branches daily and placed them in vases to keep the foliage fresh and hydrated. You MUST use vases or containers with a wide sturdy base to prevent tipping. Be sure to pack the opening of the vase around the branches with saran wrap or foil to keep caterpillars from marching down into the water and drowning. Check old foliage carefully for caterpillars before you discard the branches. You’ll be amazed by the noise of constantly munching caterpillars.

I’ve read in references that you should never disturb a molting caterpillar, but when you have to remove branches from the vases you really can’t avoid it. If caterpillars were molting, I would either just put the branch without leaves back into the vase or clip off that part of the branch with the molting caterpillar. Then I would put branches with molting caterpillars into a separate small container, oriented either horizontally or vertically, however they were originally.

Sometimes it would take 1-2 days for them to molt, but I never lost one with this method. Caterpillars getting ready to molt become quite still and stay in one spot for a long time. Sometimes they look a different color, either lighter or darker. Once you see them you’ll know what to look for. Twice, I found an aqua gel, (fluid from their bodies?), on either a branch or on the bottom of the cage from an injury or scratch, but none died.

When caterpillars are getting ready to spin they become very active, stop eating and walk around a lot. They will empty their intestinal tract (spill their guts). Don’t be alarmed to see watery reddish brown fluid in the cage. Spinning takes about a day.

Do not disturb cocoons for several days till the caterpillar has pupated. The caterpillars seemed to like to spin cocoons in the dark corners of the cages. The cocoons can be easily removed from the skin of the cage and the plastic tubing that forms the frame of the cage. Just gently start peeling from one edge and they will peal right off.

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