Case Bearing Moth Larva

Subject: What is this?
Location: Rancho Bernardo, San Diego, CA
January 31, 2016 12:39 pm
I have found a few of these in my home.
What are they.
Signature: Dave Douthett

Case Bearing Moth Larva
Case Bearing Moth Larva

Dear Dave,
This is a Household Casebearer,
Phereoeca uterella, a common household pest.  According to BugGuide:  “The larval case is silk-lined inside and open at both ends. The case is constructed by the earliest larval stage (1st instar) before it hatches, and is enlarged by each successive instar. In constructing the case, the larva secretes silk to build an arch attached at both ends to the substrate. Very small particles of sand, soil, iron rust, insect droppings, arthropod remains, hairs and other fibers are added on the outside. The inside of the arch is lined exclusively by silk, and is gradually extended to form a tunnel, while the larva stays inside. The tunnel is closed beneath by the larva to form a tube free from the substrate, and open at both ends. After the first case is completed, the larva starts moving around, pulling its case behind. With each molt, the larva enlarges its case. Later cases are flattened and widest in the middle, allowing the larva to turn around inside.”

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