Living With Booklice

Booklice are tiny insects that feed on molds and mildews. The name booklice comes from some of the species that are found in libraries. However, most species of booklice live outdoors, under bark and other moist habitats. Only a handful of the 150 species of booklice found in the United States occur indoors or become pests. Booklice can infest stored grains. However, booklice are most commonly feeding on molds that are growing on wet grain. The grain is probably bad because of the mold and booklice are only adding insult to already injured grain.

In climates and buildings where humidity is high, booklice can establish and damage books and other paper products. Libraries fight booklice and other insect pests by maintaining low humidity and preventing books from getting wet or humid. This is one reason why most libraries have a “No food and drink” policy. Why do bookstores allow patrons to eat and drink or even sell beverages? Bookstores sell books, they don’t store them for decades or centuries as do libraries.

Some parts of the world have more significant booklice infestations than the US. This is in part due to differences in building design, heating and cooling and decorative materials. In Japan, “tatami” mats, used as floor coverings can harbor booklice. Booklice are the most common insect found in dust samples from Japanese homes. Booklice are among the known agents responsible for allergies. A recent study published in the journal, Allergy and Immunology, investigated allergies to the most common booklice, Liposcelis bostrichophila. Two hundred Japanese patients with allergies were tested for reaction to booklice proteins and 22 percent had allergies to Liposcelis bostrichophila. The primary allergen was identified as a protein that is unique to booklice. Thus, allergies to booklice are not likely to cause cross reactivity to other allergens.

I recently posted about cockroach allergies which are the most common insect allergies in the United States. People who develop allergies to insects must make changes in their habits and habitat to reduce their exposure. Cockroach exposure can be reduced by good building repair and maintenance and good sanitation. Reducing populations of booklice that are harbored in a common home feature (tatami mats) may require more creative solutions.

Liposcelis bostrichophila, a globally distributed booklice
Photo: Jarmo Holopainen,

About jjneal

Jonathan Neal is a retired Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in Environment, Health, News, Pest Management. Bookmark the permalink.

4 Responses to Living With Booklice

  1. Pingback: Living “Green” With Insects | Living With Insects Blog

  2. Sophie. says:

    Thank you for your useful information!
    I have found a few booklice in my studio apartment, some in the bathroom and others in corners around the studio room. My main concern is ; HOW do they spread?? will they travel in suitcases, clothes and belongings when I go on holiday? Will they travel in duvets, pillows etc when I move?? I have looked everywhere and found no answer to this! Please help me out!

    • Sophie. says:

      edit; of course this will be after I’ve dry cleaned all bedding and washed all clothes. Will they still be there. And are they in general in every house, am I overreacting to the situation?
      I look forward to your answer.

      • jjneal says:

        Book Lice are associated with high humidity and require moldy moist environments. Sometimes they are in potted plants, or can be in wallpaper if it has received water damage. Drying out the house can help. If the infestation is severe, a pest control specialist might be able to determine the source of the population. A substantial infestation suggests a structural problem such as a leak.

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