Friday, May 29, 2009

May Wonders 5: Tent Caterpillars

On the way back from watching the herons, I spied a nest of tent caterpillars. Never in my life have I regarded them with anything other than revulsion. On this unnaturally buoyant day, however, it occurred to me that there were some lovely patterns in this writhing mass of leaf-eating larvae.


And so it was that I approached my afternoon walk to the pond—and through the valley of the caterpillars—with a new kind of curiosity. It's hard to believe that an entire canopy's worth of verdant foliage is being rapidly devoured. But it is.

The first spring I walked here, I noticed a strange, steady sound as I walked under the leaves. It's something like the the noise of tiny air bubbles bursting on the sand as a wave recedes, or maybe the small but vigorous pop of a jewelweed pod.

"Those are the tent caterpillars," G. groaned.

Later, when we drove around, she pointed out the barren hillsides, their trees as leafless as in autumn. That was the work that was in progress as I walked under the trees.



I
didn't ask G. exactly what the caterpillars were doing that made the noise. Eating, I suppose, was what I assumed. But something about that didn't seem right: Could I really be hearing whatever jaws they had slicing through the the leaves?

On my walk down the hill, I began to focus on the rocks. I noticed that there were small black dots everywhere, about the size of poppy seeds. It occurred to me, then, that these might be caterpillar droppings.

And they are. Wikipedia says: "Fecal pellets dropping from treetops in which the caterpillars are feeding create the auditory illusion of rainfall."

So there I was, walking through a downpour of caterpillar pellets. They probably showered my clothes, my hair. Somehow, on that day, it didn't bother me at all. When I got home, I looked up the good things about tent caterpillars.

One of my 1920s field guides remarks that "both species of Cuckoo, the Vireos, Orioles, Chipping Sparrows, Goldfinches, and several Warblers come to the caterpillars' webs either to get food or to procure web to use in the construction of their nests."

A Washington State University Web site notes that when some taller trees are defoliated, "the shrubs and trees below receive increased sunlight, giving some of them a boost in growth." The pellets "break down easily, returning nutrients to the forest floor." True, the weak trees may die under a caterpillar onslaught, but "healthy trees will leaf out again."

On my way back from the pond, I began to notice something else. Caterpillars kept landing on my clothes, my arms. I'd suspended disgust, and it turned out I didn't really mind how they felt, marching up my skin. They even had a pretty, bluish stripe.

Where were they coming from? As I walked, I realized, I'd been periodically waving my hands, clearing something from around my arms or face, unthinkingly brushing away webs. As I came into a sunnier glade, I saw the lattice of caterpillar filaments extended across the trail.

The caterpillars dangled in the light.


They were acrobats in the breeze.


They danced.


I was in ecstasy. Again.

1 comment:

Gerry Gomez Pearlberg said...

Another fab post, though I don't know that I can ever share your enthusiasm: you're more highly evolved than I am.

Funnily, I just came upon a related post at another of my favorite blogs. Have not read it yet, but thought you'd like to know about it.

http://themarvelousinnature.wordpress.com/2008/05/02/tenting-it-with-the-family/