Raising Lunas: Cocoons

Once Luna caterpillars make their cocoons, the waiting starts (Hint: it always takes them longer to emerge than you want them too).

Like all moths/butterflies, Lunas emerge with fat bodies and small, crumpled wings. Once they emerge, they pump fluid from their bodies into the wings. They need space to do that.

If a cocoon is hanging from a branch, that will be fine. You can also put cocoons at the bottom of a cage or other enclosure, as long as there’s something for the Lunas to climb when they emerge. If they’re in a net cage, the net will work. If it’s somewhere with slicker sides, add a stick or two.

Lunas can be pretty active inside their cocoons – even when they’re hibernating. If you hear them rustling around periodically, that’s just what they do. It’s also fine if you don’t hear them rustle – like babies, some are more active than others.

You’ll know they’re on their way out when you hear a steadier, more purposeful rasping sound. They’re using a sort of tooth to cut their way out of the cocoon. It takes a while.

Once emerged, they’ll start expanding their wings. It takes about 30 minutes for the wings to fully expand, and a couple of hours for them to dry.

If your Luna has thin antennae and a rotund, goddess-like body, she’s a female full of eggs. (thanks to Ann Doss Helms for the photo).

Lunas with larger, more feathery antennae are males.

The crazy thing about big silk moths like Lunas and Cecropias – they don’t eat as adults. They don’t even have mouths. They have one goal – to mate and lay eggs.

If your Luna emerges in the morning, as they often do, you can release it that evening, after the birds have gone to bed (they make delicious bird snacks). Or you can wait until the next evening. Since your Luna doesn’t eat, it won’t get hungry. But regardless of what you do, it will only live about a week.

When you release a Luna it will sometimes excrete a milky fluid and/or fall down to the ground and start flopping around. Both these things are normal defensive mechanisms. It will fly off soon enough.


Given their short lifespan, Lunas have to be pretty efficient about getting together. The way they do it: the female finds a place to sit and sends pheromones out into the air. Males can sense them from as far as a mile away

It’s this system that makes it possible to breed Lunas. There are a variety of ways to do it, but I usually take a female and make her a harness out of dental floss. Then I tie her to a stick so she can’t fly away, and set her out on my front porch late at night (you want a wild male because you need a fresh set of genes).

I go out to check about 4 a.m. or so, and she’s usually got a beau. I put a cage over them, so they don’t get munched by birds.

That evening, I let him go and put her in a paper bag. She’ll lay her eggs on the inside of the bag. The next day, I’ll release her near a sweetgum or other host tree where she can finish laying. A female Luna can lay 200 eggs.

About 10 days later the cycle starts again.