A reader discovered a worm-like creature on her bathroom wall and wrote to us curious about any information we could provide. She included a photo and the following description, “it has what it seems to live in (like a cocoon) or hatched from what is seems to drag around with it. It can retreat inside turn around and poke it’s head out the other end and crawl around also, still dragging it around”. Based on the photo and the description, we are confident that she has discovered casebearers!

These creatures are technically moths, not worms. The scientific name for them is Phereoeca uterella, but they are commonly called household casebearers. Casebearers create their shells, or “cases” during the earliest larval stage. They construct their camouflaging cases with small particles of sand, soil, and other fibers, and bind it together using secreted silk. The inside of their shell is lined with silk, and is home to the larva. Once the larva grows, it will emerge from the case and drag it behind them. Eventually, a moth will exit the case and leave it behind.

Household casebearers eat spiders and spider webs, but might also resort to eating wool carpets or clothing. If she found them in her bathroom, perhaps the reader has some wool carpets or towels in there. The reader didn’t sound too concerned with getting rid of these little creatures, but if she wants to see them go she should clean her home often, specifically removing any spider web and cobwebs.

In sum, our reader found some curious creatures in her home. We determined these to be household casebearers.

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