The other bagworm

Two bagworm moths live around these parts.  One, the very small and oft unseen Dahlica triquetrella (seen in the first image here) never grows longer than about half an inch/twelve millimeters.  Being so thin and so well camouflaged, they’re usually mistaken for small bits of dirt or wood.

The other species, the evergreen bagworm moth (Thyridopteryx ephemeraeformis), can have bags up to two inches/50 mm in length, yet their size does little to make them more obvious.  Take this one as an example:

An evergreen bagworm moth (Thyridopteryx ephemeraeformis) hanging from a tree limb (2009_07_04_025856)

Hanging on a tree like that, they easily can be confused with some kind of seed pod or cone growing from the tree itself.

An evergreen bagworm moth (Thyridopteryx ephemeraeformis) attached to the side of a building (2009_07_04_025850)

But when they’re stuck to the side of a building—or in this case, the side of an outhouse—even the best camouflage fails to hide the fact that something more than plant material lurks beneath all that collected debris.

Which brings me to the sky is falling…

As I stood in the riparian woods along Dixon Branch watching a yellow-crowned night-heron (Nyctanassa violacea), something dropped ever so slowly onto the top of my head.  I reached up and gently lifted it out of my hair.

An evergreen bagworm moth (Thyridopteryx ephemeraeformis) hanging from a thread of silk (2009_07_25_027685)

Ah, an evergreen bagworm moth.  It dangled from a tether of silk that stretched some 30 feet/ten meters into the treetops.  Given the length of thread and the light weight of the larva, slight breezes that I couldn’t even feel sent the little critter swinging like a pendulum.  And that its descent was painfully slow meant it spent more time swinging than it did dropping toward the ground.

An evergreen bagworm moth (Thyridopteryx ephemeraeformis) dangling from a thread of silk (2009_07_25_027686)

From that heavily cropped version of the previous image you can see the larva leaning its head back through the top of the bag.

It is unfortunate that when I decided to swap lenses for better close-ups, the camera likewise decided to die.  Very dead.  And why did that happen?  Sweat.

I apparently had been dripping large amounts of sweat from my forehead directly onto the seams of the camera body.  How much I don’t know, but I do know I had to blow-dry the innards for 15 minutes before it would even power on.  Lesson learned.

8 thoughts on “The other bagworm”

  1. I can’t see the larvae in the first photos – is it visible? Great camouflage, regardless.

    I can see just enough of that second one to make me want to see the whole larvae. Argh.

    Dude, bummer about your camera, but at least you were able to revive it. Sure has been muggy these last few days – wonder what full-on summer will bring…

    1. Oh no, I should have mentioned that, Amber. In the first photo the larva is behind the tree needles and in the second it’s already closed the bag so it can pupate.

      Funny thing about these moths: the females (legless and wingless as adults) never leave their bags and the males tear off most of their wing scales when they leave theirs. Seeing the whole larva seems to require removing them from the bag.

      And I’m SO not looking forward to summer given how warm and humid it’s been this spring. Ugh!

  2. This is all quite new for me, I am not familiar with this particular moth. In the first couple of photos I would not have recognized it as such – probably a seed pod. But in the last two there is definitely a larva popping out…

    Sucks about the camera. That is useful info, though. I think my new camera is similar to yours, I’ll try not to perspire in it.

    1. I really should have thought about all the sweat, Amar. I was drenched and it was dripping everywhere, and I was also holding the camera to my face for long periods of time. Somehow I had a mental disconnect on what that might mean.

  3. Oh I love this kind of thing. The moth as an artist. There’s a larvae here… can’t remember which… that lives in the water. It too makes its protective carapace from detritus. As children we’d catch and put them in jam jars strewn with tiny class beads so that the industrious little creatures would adorn themselves in glittering sheathes like 1920’s demi monde. Hmmm. An intervention too far I fear, but afterwards we always carefully returned them to where they’d come from. so they could re-camouflage themselves in silt and gravel.

    Yet again you show us the curious and the wonderful Jason. Thank you.

    1. That is a great story, Clive! Sure, in hindsight it might seem to have been too far, but at the time it was probably delightful fun. Just giving nature a hand with its fashion sense…

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