A readers found this tiny creature in his bathroom:

He hopes we can provide some information about it. We recognize this creature as the larval form of the Phereoeca uterella moth. This species was once known by its nickname “plaster bagworm”, however its now called the “household casebearer.” Most don’t even see the larva when they spot this species, they simply notice the case or shell that surrounds it. In the photos our reader sent, you can just make out the head of the larva peeking out of the brown case. These larvae have dark brown heads, white bodies, and three pairs of well developed legs.

Larvae construct their cases during the first larval stage, which is known as the 1st instar.  The case is originally made of silk that the larva secretes. The inside of the case is completely lined with silk, and its shape provides a safe home that the larva can move around in. The outside of the case collects tiny particles of sand, dust, dirt, arthropod remains, and other fibers. During each successive larval stage, more particles attach to its case, and it grows with the larva. As the larva gets bigger, it drags the case behind it.  When it has reached its final larval stage and is ready to pupate, the larva walks up a vertical surface and attaches its case to the wall with secreted silk. The pupation occurs within the case, which the larva modifies for this process. After pupation, a moth emerges from the case!

Household casebearers can be household pests, but you can install an air conditioning unit to keep cool air flowing to keep these creatures at bay. In addition, clean to eliminate particles that contribute to the cases these larvae build.

To sum up, one of our readers sent us a photograph of a household casebearer. The larvae build mini homes for themselves until they are ready to mature into moths!

 

 

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