Why I talk about moths

Those following me here or on Twitter will notice a pronounced uptick in invertebrate conversation in the next couple of months. This is because my partner raises moths.

Each year the terrariums come back into the dining room and living room. Filled with leaves, eggs, cocoons, and caterpillars, they are home to three different species of moths. This year she’s raising Cecropias, Lunas, and probably Prometheas. (Last year we raised Polyphemous, but not Luna.)

Here’s how this goes.

In the early summer the adult moths emerge from their over-wintering cocoons. The males, on emerging, fly around looking for a female. The females get free and sit, broadcasting scent to attract a male. They mate, and a few days later the female lays eggs. Both adults go forth to die after mating. Mostly they are eaten by birds.

After a few days or weeks the eggs hatch. The caterpillars grow for weeks. They start out eating leaves, a few every couple of days. After five weeks or so the caterpillars are inches long and need fresh leaves twice a day, at least. The Cecropias in particular get to be huge — three or four inches long, and as big around as a thumb. Sometime around the middle of August the caterpillars spin cocoons.

These are moth caterpillars. They spin cocoons. Butterflies do not spin cocoons. They chrysalize. They molt their caterpillar skin, leaving a hard chrysalis attached to a branch. We raise moths. They spin cocoons, attaching them to branches.

I harp on this because children’s books completely confuse this, leaving otherwise educated people under the impression that all caterpillars spin cocoons. They don’t.

The cocoons over-winter. That is to say, we clean out the water and the dead leaves, and we put the tanks of cocoons in the garage in the fall. They sit out there all winter, through the snow and the ice and the subzero temperatures. That’s how these particular species work.

In the spring, J hauls the tanks out into the fresh air. She puts a tarp over them in rain, so the cocoons don’t drown. In late spring or early summer — right around now, in fact — the cocoons hatch and adult moths emerge.

Female Cecropia Moth, May 2012

J lets the males go. The females, she keeps in a mesh container. At around 3:45 in the morning she opens the mesh. The adult female stays in the enclosure, calling for a male. A male comes by most of the time and the two moths mate. The male leaves. J puts fresh leaves in and zips the enclosure shut. This way the female will lay eggs in a location J can find later.

Thus we begin all over again.

The most labor-intensive part of this is the late summer, when the caterpillars need fresh leaves two or three times a day. In August the dining room is filled with the constant noise of chewing. Endless, endless chewing. The most amusing part, to me, is the late spring wheeling and dealing among the neighborhood moth breeders. Envelops of eggs are left in mailboxes, tupperware containers of cocoons left on front steps. I find this very funny.

Why do we do it?

Well, because we can. Because all life is interesting, not merely the charismatic megafauna. Because Cecropias and Lunas are stunningly gorgeous, and huge, and otherworldly to human eyes. Because my kids see our involvement with the natural world. Because we are part of a community of people re-populating native moth species in our urban forest. Because birds need to eat, too. Because we are massively outnumbered as a species on this planet, and we would do good to remember that.

Endless, endless, relentless chewing. And in the early summer, at 4:00 in the morning, a quivering moth unfurling its wings for the first time in the pre-dawn light.

3 Responses

  1. A note of context for that photo that Sig posted: That is the hand of an adult woman who has long fingers. The wing span for an adult Cecropia moth is between 5 and 7 inches across, and sometimes bigger. Stunningly large and equally beautiful creatures.

  2. Super cool! We have a few caterpillars in containers as we speak – hoping to see one container of some common Minnesota moth and one of monarchs – fingers crossed!

  3. @Sarah Do you have milkweed in your yard? That’s a sure way to get monarchs!

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