Booklouse (psocid)

Warm, humid indoor areas such as window frames, closets, stored books, and cardboard; often associated with mold or high humidity.

Feed mainly on microscopic mold, fungi, spores, starches, and organic debris rather than blood or living tissue.

Wingless, soft-bodied insects that crawl slowly and favor darkness and moisture. They reproduce rapidly under humid conditions but decline when areas are dried.

Harmless to people and pets and do not bite or transmit disease. Large numbers indicate excess moisture and may contaminate stored food or damage paper products slightly; reducing humidity controls them.