If items on your bookshelf have chewed-on pages and bindings, suspect the look–alike household pests silverfish and firebrats.
Both insects have enzymes in their gut that digest cellulose, and they choose book–cases, closets, and places where books, clothing, starch, or dry foods are available.
Silverfish and firebrats are nocturnal and hide during the day. If the object they are hiding beneath is moved, they will dart toward another secluded place. They come out at night to seek food and water. Both insects prefer dry food such as cereals, flour, pasta, and pet food; paper with glue or paste; sizing in paper including wasllpaper; book bindings; and starch in clothing. Household dust and debris, dead insects, and certain fungi also are important sources of food.
However, they can live for several months without nourishment.
Large numbers of these insects can invade new homes from surrounding wild areas, especially as these areas dry out during the summer. They also can come in on lumber, wallboard, and similar products. Freshly laid concrete and green lumber supply humidity, while wallpaper paste provides food.
Silverfish are medically harmless and are noted simply to damage goods and contaminate food in your home.
Infestations of silverfish can easily go unnoticed, since these insects travel and reproduce quickly, and are active at night. Since juvenile silverfish grow faster in humidity, the best way to prevent them is to control your home's humidity levels with a dehumidifier.
Although do-it-yourself treatments work to kill the occasional silverfish, it is best to hire a pest control professional for infestations.