Household Casebearer or Plaster Bagworm

Natural Habitat

Typically found indoors, especially in damp, dark, and undisturbed areas like closets, attics, bathrooms, garages, and under furniture. They can also be found outdoors in sheltered locations.

Diet & Feeding

The larvae are scavengers, feeding on a wide variety of materials including spiderwebs, insect remains (especially dead spiders), lint, shed hair, wool, silk, felt, dried animal products, and sometimes fungi or mildew. They prefer materials of animal origin. They are also known to feed on keratinized materials like hair and feathers.

Behavior Patterns

The most distinctive behavior is the larvae's construction and carrying of a flattened, silk and debris case (resembling a pumpkin seed or a small piece of lint). They enlarge this case as they grow, moving around inside it with their head and legs protruding from one end. They retreat entirely into the case when disturbed. The adult moths are small, dark, and typically weak fliers, often found resting on walls or ceilings.

Risks & Benefits

Potential risks: Primarily considered a minor household pest if infestations are large, as their feeding can cause damage to natural fibers (wool, silk, fur) and stored animal products. They are not known to bite or sting and do not pose direct health risks to humans. Benefits: In small numbers, they can be beneficial as detritivores, helping to clean up dead insects, spiderwebs, and other organic debris.

Identified on: 10/30/2025