Silverfish

Silverfish  (Lepisma saccharina)

Habitat

Silverfish are typically seen in moist, humid areas in the home; such as bathrooms, basements and attics. They tend to hide their presence from humans, which means any damage they have caused could go unnoticed for some time.

Food

Silverfish consume matter that contains polysaccharides, such as starches and dextrin in adhesives. These include book bindings, carpet, clothing, coffee, dandruff, glue, hair, some paints, paper, photos, plaster, and sugar. They will damage wallpaper in order to consume the paste. Other substances they may eat include cotton, dead insects, linen, silk, or even their own exuvia (moulted exoskeleton). During famine, a silverfish may even attack leatherware and synthetic fabrics. Silverfish can live for a year or more without eating if water is available

Biology

Silverfish have no wings, but are able to run very fast. Adult silverfish have a body length of about ½-3/4” (12-19 mm) not including the tail. They have a flattened body and their shape is often compared to a teardrop, carrot or fish, tapering from head to rear and generally covered with scales. Silverfish are typically silvery or gun metal in color and have long, threadlike antennas. In addition, they have small compound eyes that are widely separated. . The female lays groups of fewer than 60 eggs at once, deposited in small crevices. The eggs are oval-shaped, whitish, about 0.8 mm (0.031 in) long, and take between two weeks and two months to hatch. A silverfish usually lays fewer than 100 eggs in her lifetime. When the nymphs hatch, they are whitish in color, and look like smaller adults. As they molt, young silverfish develop a grayish appearance and a metallic shine, eventually becoming adults after three months to three years. They may go through 17 to 66 molts in their lifetimes, sometimes 30 in a single year—many more than most insects. Silverfish are among the few types of insect that continue to molt after reaching adulthood.

Threat

Silverfish are considered household pests, due to their consumption and destruction of property. They also contaminate food products. 

Detection

Keep an eye out for feeding marks, although they may be irregular whether they are holes, notches along an edge, or surface etchings. Yellow stains, scales and/or feces (tiny black pepper-like pellets) may also be seen on infested materials.

Prevention

Anything stored against or near the house’s exterior must be moved or removed since silverfish can easily climb up walls and find entrance around window and door frames, utility pipes and vents. Shake roofs should also be cleaned and sealed every other year. Also, consider a dehumidifier for your home, repair leaky pipes and drains and eliminate or repair any moldy or wet wood. Don’t keep old books and magazines in areas where silverfish are usually found like basements, attics and garages. It’s also important to keep food items such as flour and sugar in tight containers.