Even though you're farmin' just one slim acre, there are the routine morning chores. I tend the chickens first, release them from the coop into the run, make sure they have food and water (old farm tenet: "Feed and water your animals first, then go to breakfast"). After they're flushed from the coop, I check their food supply, watering "trough," and scatter about the run a handful or two of hen scratch and sunflower seed. Then it's on to the potted plants, see to their irrigation needs before the day heats up. Perhaps I'll hoe a weed or two....
This summer, however, I've added one more task to the morning's routine. I mosey past the chickens out to the willow tree and gather a bundle of leaves, this season's growth, lush and tender, pasturage, you might say for my summer's strange experiment: tending caterpillars, a project that began when my environmentally sensitive friend Nancy L brought me a large moth she found clinging to some new construction she had going. Instead of dispatching the moth in the deep freeze overnight, I left it in the jar in which it came. Next morning I was dismayed to find during the night the moth had tried to escape its confines (Moths? Creatures of the night? I should have known better...) and badly frayed one of its forewings. Before its escape attempt the moth deposited nearly four dozen bluish- green eggs on the bottom of the jar. Thus began my ongoing project.
A bit of research turned up a website for
PNW moths (Plate III) and as I knew my specimen belonged to the family
Sphingidae (sphinx moths), it took little time to find the moth among its cousins. My bug was a blind-eyed sphinx moth (
Paonias excaecatus), a misnomer because the moth wasn't sightless (most likely named for the eye spots on the hindwings). More research revealed the moth's host plants were willow, cottonwood, and poplar, helpful information should the eggs prove viable which at this point I had no way of knowing. (Sometimes under stress the unmated female will lay eggs, her last ditch effort to reproduce.)
Checking the jar each morning became routine. Four mornings passed. The eggs remained unchanged, cemented to the bottom of jar as deposited. Day five I noticed a few eggs had lost their color, were white, translucent. Curled next to the shells and not much larger than a point 12 font comma were a half dozen larvae. I had read that a caterpillar's first meal is usually a portion of the egg case from which it emerged. Nonetheless, I headed for the pussywillow bush for some fresh leaves for the 'pillars' main course. Over the span of a week the other eggs hatched and I had some three dozen little wrigglies to tend.
I wasn't sure the little hatchlings would feed on the willow. My Pennsylvania friend Ron who has had considerable experience rearing moths suggested I include some cherry and apple leaves as well, both of which I added to the willow. Whether the tiny larvae were feeding on these provisions I had no way of knowing until a couple mornings later I noticed tiny specks of "frass" (caterpillar "poop") on the bottom of the jar. Next, ragged little notches in the young leaves of the willow, which, I learned, were the preferred browse of the larvae; the apple and cherry leaves were ignored.
The caterpillars' voracious appetites put me in mind of Eric Carle's children's book
The Very Hungry Caterpillar, whose principal character's gustatory behavior was represented by larger and larger holes in the cardboard pages. The larvae consumed handfuls of fresh leaves daily, leaving only twigs and stems behind. The stage where they were able to escape through the toothpick holes in their saran wrap ceiling lasted only a few days. I soon had to transfer them to a larger container and chose a gallon bucket covered in tulle netting. The growing larvae continued to consume quantities of leaves and sometimes required two feedings per day.
In the early stages of my caterpillar tending I remained in contact with Ron, asking his advice on how best to tend the fast growing larvae. The larval stage of the moth, as with most insects, is the second of four stages in the metamorphosis cycle (egg, larva, pupa, adult).
My moth species, Ron told me, pupates in the ground (unlike butterflies that pupate above ground, hanging by an integument beneath a leaf, twig or stem); the sphinx moth larva burrows into the soft soil at the base of the host plant and there evolves into a pupa or chrysalis.
In order to accommodate the larvae's subterranean rite of passage, I had to provide a third container for their convenience and chose a wooden nuc box in which I had received a small colony of honeybees this past spring. I filled the bottom with five or so inches of loose compost, an excellent medium for whatever burrowing they needed to do. First supplying the larvae with a bundle of fresh willow leaves, I transferred them to their third container.
(Note: In the world of Nature infant butterflies and moths have an astounding mortality rate: less than one percent complete the cycle from egg to adult. In addition to the whims of weather, floods, fires, parasitic wasps and parasitoid ichneumon flies ravage eggs, the larvae, the chrysalids, the latter two literally eaten from the inside out by the ravenous larvae of the parasites.
It was my intent to boost the survival rate through human intervention by providing the caterpillars a secure incubator. As some of these parasites are tiny themselves, I worry that some might enter the nuc box through the small gauge ventilation mesh. As things stand, whether for lack of food or water or natural mortality, some larvae have already perished; only two dozen or so survived for the third transfer.)
As of this posting there are fewer than a dozen of the fat grubs feasting on the leaves, and I have yet to see any deceased wrigglies lying on the soil. It is my hope the others have burrowed in, exchanged their soft exteriors for the carapace-like shells of the chrysalis. When the last larva has disappeared, I'll store the box in the shed, hopefully protecting any chrysalids from marauding parasites. This fall I'll sift through the compost and retrieve whatever (if any) chrysalises lie beneath the surface. I'll follow Ron's instructions: "Layer them in paper towels in a large container, mist the contents once in a while and be sure to include something for the adults to climb and cling to while their wings inflate and dry." I'm crossing my fingers that the fall harvest will include at least a pair of pristine sphinx moths, wings unfrayed, to join their mother in her collecting case. The surplus, if any, I'll set free in the Valley night.
