Booklouse (psocid), likely a barklouse

Humid indoor areas, especially window frames, curtains, books, cardboard, and wall crevices; also occurs beneath bark and leaf litter outdoors.

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

Tiny, soft-bodied insects that favor moisture and darkness; populations increase in damp conditions and decline when areas are dried and ventilated. They may disperse by walking or, in winged species, short flights.

Harmless to people, pets, clothing, and structures; they do not bite or transmit disease. They recycle organic material, but noticeable indoor numbers indicate excess humidity or mold risk.