It never fails to amaze me how little we know about our neighbors here. I’ve been noticing these curled-leaf cocoons on spicebushes for years, but never realized that they were most likely the work of the promethea moth, A.K.A. spicebush silkmoth. In fact, I’m embarrassed to admit that we initially mis-identified this mating pair on a spicebush next to the barn as cecropia moths — one of the three or four other species of giant silkmoths that occur on the mountain.
The female eclosed sometime this morning. Our neighbors Troy and Paula, who are painting the barn for us, spotted her clinging to her newly vacated cocoon around noon. Late in the afternoon, Troy called to say that a smaller, darker moth had joined her — literally. So presumably she had been busy releasing pheromones, broadcasting her presence to any male in the vicinity. As the Wikipedia article about moths of their family, the Saturniidae, puts it,
Adult females emerge with a complete set of mature ova and “call” males by emitting pheromones (specific “calling” times vary by species). Males can detect these chemical signals up to a mile away with help from sensitive receptors located on the tips of their featherlike antennae. The males will fly several miles in one night to locate a female and mate with her; females generally will not fly until after they have mated.
Since the mouthparts of adult saturniids are vestigial and digestive tracts are absent, adults subsist on stored lipids acquired during the larval stage. As such, adult behavior is devoted almost entirely to reproduction, but the end result (due to lack of feeding) is a lifespan of a week or less once emerged from the pupa.
I’m not sure why they’re named after Prometheus, but whoever named many of the most spectacular North American silkmoths (luna, cecropia, polyphemus, io) seems to have had a thing for Greek mythology. Perhaps the female’s coloration suggested fire?
Spicebush isn’t the only host plant for promethea moth larvae, but we have many of the others, too, including sassafras, tuliptree and white ash. This does show the value of landscaping with natives, I think — I’ve planted spicebushes all around the place. This one was a volunteer, but I made sure it wasn’t crushed when they took down the old corncrib last year. It currently hosts six other silkmoth cocoons, possibly all prometheas. Here’s how it looked the autumn before last, when it was covered with berries:
Those berries are not only highly sought-after by birds, but they taste just like allspice, and can be dried, crushed and used as such. I’ve used both the berries and the leaves to flavor beer. In fact, I included spicebush leaves in the herbal mix for the batch of homebrew I’m drinking now — I had to prune the bush next to my front walk and didn’t want to waste the prunings. They joined juniper berries, yarrow tops and ginger root, plus a blend of wheat and barley malts, for a refreshing summer ale.
Spicebush is also the namesake of, and one of the main hosts for, the spectacular spicebush swallowtail butterfly. So I’d better be careful and not pick too many leaves for my own use. A lot of hungry caterpillars and silkworms will be needing them soon.