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Whatever is a bag worm, do I hear you enquire?  Indeed, I didn't know myself (despite having often seen them ) until quite recently when I discovered one of these interesting creatures dragging its home laboriously behind itself across our gravelly path.  Fascinated,  I watched its action as it ventured, half out of its cocoon,  to grab the next couple of stones with its strong front legs,  and then with the rest of its body pull its twig-decorated shelter behind it.

Saunders Case Moths (Metura elongatus) for that is their real name, spend most of their lives in these cleverly constructed cocoons.  Even mating takes place (with difficulty) inside the cocoon.

The caterpillars can 'extend' their homes as they grow bigger themselves, by adding twigs woven in with their own silk, an onerous task. They move around by using three pairs of legs to pull themselves and their cocoon along.  It's a very slow process. When they are ready to pupate, they attach themselves to a handy tree or post  by silk threads, as shown in my first photo.

The female,  who lives all her life in her cocoon ( no emancipation in this species) lays many eggs and dies within the case. She doesn’t develop wings.

The male moths, however, emerge from their cocoons in orange and black suits complete with wings, ready to search for a mate and begin the cycle all over again.

Until recently, a metal power pole on a roundabout in our town hosted scores of these case moths or bagworms.  It seems they were very appreciative of the plants growing below, which rapidly showed signs of ill-health thanks to the caterpillars’ ministrations. After the moths departed, the cases hung and swayed in the breezes, slowly disintegrating over time, their occupants long gone.


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Because I know so little about these creatures, I resorted to an information sheet from the Queensland Government to fill in some of the details.

32 Comments Add yours

  1. Very interesting. So glad we don’t have that variety here.

    1. Jane says:

      It’s harmless, Cindy and quite fascinating in that the cocoons are quite different depending on which sticks are used!

  2. Great story and photos. Pity the female never gets to see much of the world. Some insects the female eats the male after mating which at least gives some balance.

    1. Jane says:

      Thanks, Gerard. I found them very interesting too.

  3. fascinating. cadis fly lavea cover themselves in debris in a similar way , but I have never heard of a caterpillar doing the same.

    1. Jane says:

      Caddisflies are interesting too. I’ve never seen one of their cocoons, though I believe we have them in Australia.

  4. Tracy says:

    That’s a new one on me, Jane. Fascinating.

    1. Jane says:

      Thanks, Tracy.

  5. I have often seen these funny moving stick things but didn’t know what they were … so thanks for that. Not much of a life for the female!

    1. Jane says:

      Indeed, Gerrie. I feel much more benevolent now that I know a bit more about them.

  6. Nate says:

    Wow! That’s a bit like the caddisfly that builds little homes out of whatever is available. I used to see their little floating “houses” in our pond.

    1. Jane says:

      I had to look caddisfly up. I think their cocoons are even more interesting, with their jewel-like attachments.

  7. Kris P says:

    I’d heard of them but I’ve never seen a photo. Their story is fascinating, although I can’t say I’m sorry there aren’t any here. The photos made me think of caterpillars wearing Halloween costumes – scary!

    1. Jane says:

      Luckily they don’t cause any damage in my garden, Kris, although they may do in large numbers. The only time I’ve ever seen a lot of them is on that power pole.

  8. That is so interesting! It must have been fascinating seeing so many of them on the power pole!

    1. Jane says:

      They made quite a headline locally, Kristah.

  9. Liz H says:

    Quite the most elaborate camouflage project. We have here too and i count myself lucky to find them as they blend so well into their surrounds.

    1. Jane says:

      Yes, they have very interesting arrangements of sticks on their cocoons, and every one is different.

  10. Pauline says:

    How fascinating, never heard of these before.

    1. Jane says:

      They could well be in your garden, Pauline as they’re quite common all along the East coast.

  11. Lis says:

    My goodness, what an incredible creature – such camouflage! I take it they are not a threat to your brassica crop? I used to love looking for caddisfly larvae in streams with our children when they were little but I think your bagworm would have trumped the lot, much bigger and so fascinating.

    1. Jane says:

      Hi Lis, I don’t really know what they eat, but nothing has eaten my broccoli. I suppose if there were enough of them they might be a problem, but I’ve only seen the two I’ve photographed in my garden.

  12. bonnie groves poppe says:

    Surely this qualifies as another weird creepy australian thingy ……
    Bonnie the american living in provence

    1. Jane says:

      Strange, Bonnie, but not so creepy. It’s quite harmless, and as I’ve only seen a couple in the garden, not injurious to plant life. Yet.

  13. Vicki says:

    Fascinating stuff, Jane.

    Those cocoons sure do look heavy 🙂

  14. Something entirely new for me. Took me ages to figure out that the long bundle on the tree trunk was the animal you were writing about! Thank you for introducing me.

    1. Jane says:

      Oh, perhaps I should have been more specific. Or does that mean excellent camouflage? I found it quite a fascinating creature.

  15. Fascinating, took me a while to realise the long baggy thing on the tree was the animal you were talking about!

  16. Hi Jane

    I am in Australia with Andy and 2 friends and we are in Tamworth now, Thurs 11 Oct 1140, it would be lovely to say hello in person if you are around this afternoon….we would be near Mudgee at around about 1500 today…just a longshot but you never know! Contact mobile number is 0481354693….

    Very best

    1. Jane says:

      What a shame we couldn’t quite make that connection Alison, but at least we had a quick chat! Enjoy the rest of your Aussie holiday!

  17. Lonnie Miller says:

    GREAT POST! I don’t have a problem with these critters now, but many years ago they would get on grandpas Junipers. Thanks for sharing.

    1. Jane says:

      Hi Lonnie, I think the plants that the bag worms on the metal pole munched were a kind of conifer. Perhaps that’s their favourite. Thanks for the follow btw.

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