Surprise Moth Survival

Happy National Moth Week, all. To celebrate, I thought I'd share my experience raising a Promethea Moth, and how it seemingly came back from the dead.

Last summer I tried my hand at raising some moth caterpillars in addition to my usual Black Swallowtail butterflies. I have several spicebushes (Lindera benzoin) in my yard, and there’s more in the park down the street. So when I found this cluster of stripey caterpillars on the underside of a spicebush leaf, I was very intrigued!

The young caterpillars feed together early in their development, when they're striped like this.

Later the caterpillars changed their appearance and behavior. Rather than stripes, they now had black and yellow knobs on them, and no longer clustered together. Apparently this is common for this species: my guidebook says that Promethea Moths are gregarious when young, then wander off solo as they get older.

They also eat a lot of spicebush in order to grow so big and fat!

Only one of the three caterpillars made it all the way to cocoon; I’m not sure why. In fact, I only had two butterfly chrysalids to overwinter as well, one Spicebush Swallowtail and one Black Swallowtail. To be honest, I can’t remember why, although since I did finish up my Masters degree last fall I might have been too busy to check the garden as often as I usually do! 

Anyway, fast forward to this spring. In April, when the nights here are generally above freezing (usually about 40) but the days are starting to warm up, I put any overwintering chrysalids outside (I described this HERE). I put all three of my pupae in a single cage and hung it on our front porch. I thought I had it well secured, but my set-up couldn’t withstand the insane winds that came with a week of storms in May. (Neither could our roof, but that’s another story.)

I didn’t realize the cage was gone right away, but toward the end of the week I suddenly noticed it was missing. It took us a few days of searching before we finally found it next door, in a deep puddle in our neighbor’s yard. The cage was nearly flattened as well. When I opened the cage to see if anything was salvageable, I found two soggy, lifeless butterflies. They must have eclosed shortly after the cage blew away, but of course were trapped inside with no way to get food. Poor things. The moth cocoon still seemed intact, even if it too was soaking wet. I put it in a clean, dry cage and set that in my office, hoping just maybe the pupa was still alive.

I kept checking the cage every few days, but there were no signs of life for almost two months. I had just about decided that the pupa must have drowned after all. But then while tidying my office, I accidentally bumped the cage. Suddenly a large, very agitated moth was flying around inside! I had given up too soon on my pupa, but luckily hadn’t gotten around to putting it outside for decomposers to pick over. For once, procrastination comes to the rescue!

Anyway, I shouted for Victor to grab the camera, and we went outside to free the moth. After a brief exploration of my leg, the moth decided to perch on an antique bike that hangs on our front porch. Although its camouflage wasn’t as effective here as it would have been on a tree branch, the moth stayed there peacefully for several hours through the heat of the day. It wasn’t until mid-afternoon that it took off, when I inadvertently disturbed it by whistling for one of our cats. (I wonder if whistling normally bothers moths? Interesting.)

"Hmm, not quite right for my first day out."

"Ahh... that's better."

Check out those fantastic antennae! Gorgeous.

I'm pretty sure my moth was a male. Males are dark brown, with markings along the edge of their wings, where females are reddish with markings on their entire wings, as shown & described here and here.

I last saw the moth flying up over my house, toward the canopy of an oak tree that grows in between our house & the next house. An oak tree is a much better place for a moth to spend the rest of the daylight, anyway. I hope it did well! Silkmoths like the Promethea don't live terribly long in adult form. In fact they don't even have mouthparts, since they don't eat anymore once metamorphosing! No wonder they are such little pigs as larvae. Should my moth find a mate, of course, the spicebushes are ready and waiting to feed plenty of caterpillars. I'll certainly update here if I get a second generation.

So even though I failed to overwinter butterflies this year, I succeeded with my very first moth attempt! Pretty cool. Hope you had a good National Moth Week too!