Did you ever notice…

…one of these clinging to a tree?

Bagworm Moth Case

A tiny little case, maybe only 1/4 to 1/2 inch long, made of plant or some other organic material held together with silk.  I have seen them secured to the tree…  I have also seen them moving along the bark!  Those of you familiar with stream and pond life may be wondering what a Caddis Fly larva is doing in the woods on a tree.  That’s what I thought, the first time I saw one!  But this is not a Caddis Fly.

There is a family of moths called Psychidae, or Bagworm Moths whose larva build these cases.  There are around 600 species found worldwide and individual species’ stories vary.  (Some tropical species build cases as long as 6 inches!)  In general, as the larva eats and grows, the case is enlarged.  Eventually, the critter anchors its case to something solid – a tree or rock, for example, and pupates.  The adult male is reported to be a strong flyer and will search via pheremones for the wingless female adult, still inside the case.  After mating, the female may lay her eggs inside the case before dying, or not.  In some species, the female dies and the larva emerge from eggs that are still inside the mother’s body.

Some species cause quite a problem by defoliating trees.  If you choose to google them, you will find many websites that deal with how to manage them.

I suppose I should have included this one in my story about Lepidoptera in Winter!

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5 thoughts on “Did you ever notice…

  1. Haha! So funny that you should post this, I have a few photos of my own lined up in my queue. I was going to put them into tonight’s post, but then decided to split it into two, and didn’t. The ones I found were clinging to the inside of my parents’ windowpanes. I thought it was just debris when I first noticed it, then realized it was much too organized to be debris. I hadn’t done much research yet; you’ve provided some interesting info on them.

  2. After watching a chickadee foraging on the side of our home ,upon closer examination I could see that it was after the bagworms scattered about, the first I had ever seen. Interesting how birds can recognize a food source that really does not look like food at all.

    Speaking of foraging,but on a grander scale, do not miss the Hunter I & II of the most recent Nature Remains posts — facinating !! Thanks to the light snow, it is amazing how much one can learn about a fox’s activities that would otherwise be unknown.

  3. I see bag worms (I think its the same) here quite often–using the scales of the red cedar branches for their houses. As long as they choose to attach themselves within the cedar, they’re nicely camouflaged. But every so often I see one hanging off the tip of a maple branch.
    They should know better than that!!

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