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Shy Cosmet Moth Larvae Overwintering In Cattails

9-30-16-shy-cosmet-moth-larva-20160924_3140If you look at the seedheads of a bed of cattails in the fall, some are in pristine condition while others have places where their seeds have started to burst from the stem. Such a “fluffed out” seedhead can indicate that something (s) is living within the 250,000 or so packed seeds. A bit of investigation into these heads often reveals tiny, tan larvae (as well as larval skins and frass) that have burrowed their way into the depths of the seedhead, where they overwinter. These are the larvae of the Shy Cosmet (Limnaecia phragmitella), a slender tan moth. Come spring they will pupate and emerge as adults.

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2 responses

  1. Marilyn

    Earlier this year I lopped off the brown heads of the cattails which have invaded my little pond, to see what effect this would have. Some birds seem to like the cattails, and I apologize to them. Now I know that this Shy Cosset will be missing their winter shelter. Hmm.

    October 5, 2016 at 8:11 am

  2. Such a wonderful winter shelter…I’ve looked for these little larvae since learning about them from Sam Jaffe, but without success. Lest others get discouraged in a hunt through those frowsy cattail heads, bear in mind that the foaming spew of cattail seeds can also be caused by pecking birds, thrashing about in strong winds, or the prying fingernail of a curious passerby. Thoreau was fascinated by this spilling forth of thousands of seeds and wrote about it several times in his Journal.

    October 5, 2016 at 12:17 pm

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