(Lespisma saccharina) & (Thermobia
Silverfish (Lespisma saccharina) are shiny, silver or pearl gray,
and firebrats (Thermobia domestica) are shiny, mottled gray.
Adults of both are slender, wingless, soft-bodied insects 1/3 to
1/2 inch long. They have scaly bodies that taper gradually to the
rear with two slender antennae in front and three long, thin
appendages in back. The presence of scales around or under the
damage is a good indication that these pests are the culprits.
During the day, both silverfish and firebrats hide. If the object
they are hiding under is moved, they dart toward another hiding
place. They come out at night to seek food and water. Items on
their preferred menu are cereals, moist wheat flour, books, any
paper on which there is glue or paste, sizing in paper (including
wallpaper) and book bindings, and starch in clothing. They can
live for several months without food.
Silverfish live and develop in damp, cool places, particularly in
basements and laundry rooms. Firebrats thrive best in very warm,
moist places. They may be found around ovens, heating units,
fireplaces, hot water pipes, the attic in summer, and near the
furnace in winter. In apartments and homes, the insects crawl
along pipelines and through openings in the walls or floors from
basements to rooms above.
Silverfish and firebrats can be found in any part of the home.
Because they are seeking food, they choose bookcases, closets, and
places where books, clothing, starch, or sugar foods are
available. They hide in baseboards and around window and door
frames from which they seek out food sources. Sometimes they are
seen in the bathtub or sink. They do not crawl up through the
drain, but fall in and cannot climb up the slippery sides to
Large numbers of these insects may invade new homes from
surrounding wild areas, especially as these areas dry in summer.
They may be brought in on lumber, wallboard, or similar products.
Freshly laid cement and green lumber supply humidity, and
wallpaper paste provides them with food.
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