Booklouse (psocid), likely a barklouse

Humid indoor areas, especially near stored paper, cardboard, books, cupboards, and mold; also occurs under bark and in leaf litter.

Feeds mainly on mold, fungal spores, algae, and microscopic organic debris rather than fabric or wood.

Wingless, soft-bodied, and slow-moving; populations increase in damp conditions and decline when humidity is reduced. They may occur in clusters around moldy materials.

Harmless to people and pets and do not bite or transmit disease. Large numbers indicate excess moisture or mold and can contaminate stored foods or paper, but they also help recycle organic matter.