Booklouse or Barklouse
Scientific Name: Not identifiable to a specific scientific name from the image alone, as there are many species of booklice/barklice. Examples include Liposcelis spp. (common indoor booklice) or Psocus spp. (common outdoor barklice).
Order & Family: Psocoptera (formerly Corrodentia), various families (e.g., Liposcelididae, Psocidae)
Size: Typically 1-2 mm, though some species can be up to 10 mm. Indoor species are usually quite small, often less than 2 mm.
Natural Habitat
Outdoors, they are found on bark, under rocks, in leaf litter. Indoors, they prefer damp, dark, and undisturbed areas with high humidity, such as bathrooms, basements, kitchens, and areas with water leaks or condensation. They are often found in stored food products or old books.
Diet & Feeding
Fungi, molds, algae, lichen, grains, starch, paper, glue, organic detritus. Indoors, they commonly feed on microscopic mold spores that grow in damp conditions, and on starchy materials like book bindings, wallpaper paste, and food items.
Behavior Patterns
Psocids are mostly scavenging insects, feeding on fungi, algae, lichen, and organic detritus. Some species can live outdoors on trees, under bark, or in leaf litter, while others are found indoors, often in damp, undisturbed areas. They are typically nocturnal and prefer high humidity. They are not known to bite humans or animals. Most species are parthenogenic, meaning females can reproduce without males. Their life cycle involves incomplete metamorphosis (egg, nymph, adult).
Risks & Benefits
Risks: Booklice can be a nuisance pest indoors. While they don't directly harm humans or pets, their presence in large numbers can indicate high humidity and potential mold issues, which can be detrimental to human health (allergies, respiratory issues). They can damage paper products (books, documents), food items, and other organic materials by feeding on mold or the materials themselves. Benefits: Outdoors, they play a minor role in decomposition of organic matter.
Identified on: 8/29/2025