Tuesday, June 21, 2011

Compost critters, Part II

The little moths I found in my compost pile (see yesterday's post) puzzled me. What were they doing there? What moth pupates in rotting leaves? None that I knew of.

I had captured one. It was tiny, about 1 cm. long, with feathery wings, golden and shiny. It looked vaguely familiar.

I took a couple of quick photos, and foolishly released the moth. Later, examining the photo, I remembered. It looked like the Shy Cosmets that I hatched a couple of years ago. But they live down on the marshes, not here.

Shy Cosmet moth, 2008. A careful photo, and a tidy moth, but it matches  in all the essentials.

Head shot, 2008.

A bit of background is in order here.  In March of 2008, Seabrooke Leckie, in Ontario, brought home a cattail head, following the example of Gerry Wykes in Detroit, who had found the larvae of the Shy Cosmet protected from the January weather inside one. (Bug in a Cat-tail Rug.) Seabrooke examined hers and found one larva. (Her post: Cotton candy for blackbirds.)

In April, I brought home my own cattail head. (Blanket on a stick.) I found dozens of caterpillars; they looked like Seabrooke's, even though the shy one is an eastern species. After I photographed them, I left them in closed containers and forgot about them until August. When I examined them then, I found the moths. And they were Shy Cosmets. (Pure Gold!)

Back to the present. The Shy Cosmet is a marsh dweller, feeding on cattail seeds, and being eaten, in turn, by red-wing blackbirds. The larvae winter inside a downy blanket of cattail fluff and emerge as adults in June or July. If my compost moths were Shy Cosmets, what were they doing up here on the hills, so far from home?

I needed a better photo. I went out and raked around the edges of the place where the compost pile had been. Under a mat of dead nettle, I found about a half bucket of unsorted compost, which I dumped on the tarp and examined for moths. There were two; one flew away as soon as I saw it, the other waited until my hand was a few inches away, then led me on a merry chase around the lawn, into the cedars and then the rhododendrons before I lost it. Uncooperative beast! I think I heard it giggling.

So I sorted the compost, as I had the rest, pulling out all the sticks and rhodo leaves.  When I pulled apart one clump, it contained a fist-full of creamy fluff. Fresh, undecomposed cattail fluff!

Cattail "down", 2008


Now I remember; Laurie brought home a cattail a few months ago. I must have tossed it in the compost when it started to break up. And I didn't notice it was carrying dozens of healthy little caterpillars.  Mystery solved. And it seems that the moths have decided to stay in BC. Can't blame them; the weather's better here.


  1. What a wonderful bit of sleuth work you did on the compost!!! Maybe you will see offspring of these moths around you next year!

  2. That's how critters travel all over the the world I guess. - Margy

  3. Clytie, I don't think they'll be able to breed around here. Maybe down the hill a bit, in Burns Bog. They need the cattails.
    (Or maybe I should go plant some in the creek on the vacant lot across the street.)

    Margy, Hitchhiking takes you places!


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