Occasional Invaders
Silverfish and Firebrats and House-Invading Crickets

          Silverfish and Firebrats
This insect has a scaly covering that helps it to escape from the grip of ants and spiders. Silverfish can survive without food for months.

• Silverfish and firebrats (also called bristletails) belong to the insect order Thysanura. Three species of silverfish, Lepisma saccharina, Ctenolepisma longicaudata and Ctenolepisma quadriseriata, and one species of firebrat, Thermobia domestica, are the important house-dwelling bristletails in North America (Figure 1). Some of the differences between these species are shown in Table 1. All bristletails are carrot-shaped, somewhat flattened, and covered with grayish scales. They have long, slender antennae and three slender appendages at the rear of the body. They are wingless and do not fly. However, they move quickly, often stopping for short intervals and then rapidly moving on.

• Species: Common silverfish
  Size: 1/2 inch
  Appearance: Color uniform; silvery sheen
  Preferences: Temp 70-80 degrees F Moisture high humidity
  Location in houses: Near moisture; basements, lower floors, crawl spaces, etc.
  
  
• Species: Gray silverfish
  Size: 3/4 inch Color
  Appearance: Color uniform; gray Markings none
  Preferences: Temp 80-85 degrees F Moisturewide humidity range
  Location in houses: Throughout; from basement to attic, closets, storage areas, kitchens, etc.
  
  
• Species: Four-lined silverfish
  Size: 1/2 inch
  Appearance: Color tannish-gray Markingsfour lines down back
  Preferences: Temp80-85 degrees F Moisturewide humidity range
  Location in houses: Throughout; from basement to attic, closets, storage areas, kitchens, etc.
  
  
• Species: Firebrat
  Size: 1/2 inch
  Appearance: Color mottled; gray Markingsdark patches on back
  Preferences: Temp100 degrees F Moisturemoderate humidity
  Location in houses: Warmer areas; boiler rooms, hot water heaters, ovens, attic, etc.
  
  

• Damage Silverfish and firebrats feed and cause damage to a variety of materials but seem to prefer materials of plant origin that are high in carbohydrates and protein. They feed on glue in bookbindings or behind wallpaper, and on paper, paper sizing, cereal grain products and dried meat. They may also damage silk and some synthetic fabrics, but they usually avoid woolens.
• Silverfish and firebrats prefer dark places and are most active at night. Most species are found outdoors in hidden locations, such as under tree bark and rocks, or in the nests of animals, but human dwellings provide a good environment for a few species. Inside the house, bristletails can be found almost anywhere, but they are most abundant in attics, basements, wall voids, hollow decorative beams, dark closets, bookshelves, and storage rooms. They are often found in sinks, lavatories and bathtubs because they have fallen in and become trapped while seeking moisture.
• Houses with wooden shingles seem to be particularly attractive to bristletails, which can enter the home from under these shingles. In addition, infestations can start when eggs, nymphs or adults are brought into a house on infested cardboard boxes, cartons, furniture or similar items.
• Life history Silverfish and firebrats are long-lived insects. Development time from egg to adult takes anywhere from three months to three years for silverfish, whereas firebrats complete development from egg to adult in about four months. Adult silverfish and firebrats may continue to live for up to three years. This equals a potential lifespan of approximately six years for silverfish and three to four years for firebrats. Adults continue to molt throughout the remainder of their lives.
• Adults lay eggs in cracks and crevices near food sources. Depending on species, adults lay 5-50 eggs per clutch. These eggs hatch into nymphs, which look like small adults. They molt several times during the nymph and adult stages and have been observed to shed their skins more than 30 times a year. Development time from egg to adult varies between the four house-dwelling species and is summarized in Table 1. All stages have a similar diet.
• Prevention Control Infestations usually start when infested materials are brought into the home. When possible, inspect and treat all boxes, furniture, cartons or other items that have been used or stored in infested areas. Caulking holes and cracks, which allow silverfish to enter from outside, will help prevent infestations. Reduce potential food sources by storing old books, papers, starched linens and cardboard boxes in sealed plastic containers.
• Lowering the humidity and temperature in a house will also help control silverfish, since they generally prefer high humidity and moderately high temperatures. Lowering the temperature in areas around hot water pipes, water heaters and boilers will reduce firebrat populations. Improved air circulation in these areas will usually lower temperatures slightly.
• Chemical control Chemical insecticide treatments are often necessary to eliminate established silverfish and firebrat infestations. The services of a professional, such as X-Terminators, are very helpful when encountering silverfish.

• Crickets belong to the insect order Orthoptera, which also includes grasshoppers and katydids. Crickets have chewing-type mouthparts and normally feed on living or decaying plant materials. The chirping sounds for which they are famous are made by the adult males rubbing their wings together to attract females. Like their grasshopper and katydid relatives, crickets have long hind legs fitted for jumping. In addition, adult females have long, swordlike ovipositors at the tip of their abdomens for laying eggs in the soil.
• Indoor control Because crickets are large, they are easily captured or killed indoors. Crickets should always be removed after killing them so they don't serve as a food source for other insects like ants or beetles. Vacuum cleaners work well for removing living and dead crickets indoors. Sticky traps have also been used successfully to capture and kill crickets, especially the camel cricket.
  Cricket baits are particularly effective when applied indoors. Other over-the-counter insecticides can also be used indoors if the label specifically allows. They should only be applied in cracks and crevices where crickets are suspected to be hiding. Spraying the air or applying insecticides to large, exposed surfaces is undesirable and mostly ineffective.
• Sanitation Understanding cricket behavior is important if you want to minimize the risk of household invasion. Remember that crickets prefer to live in dark, protected locations behind or under objects and in cracks or crevices. They generally prefer cool, damp and dark habitats. Large populations may become established around buildings where these conditions are present. Minimize cricket habitat near your home by eliminating rocks, stacked boards, firewood, overgrown vegetation, and other types of clutter.
  Most crickets are active at night. Field and house crickets are strongly attracted to lights, while mole crickets are less responsive. Limit the use of outdoor lighting to minimize the attractiveness of your home to these types of crickets. You can use yellow lights, which are less attractive to insects than are white, neon or mercury vapor lights. Camel crickets are not attracted to lights.
  Cracks and crevices in and around the foundation are common openings that crickets use to gain entry into homes. They also enter buildings through open or poorly fitting doors, windows and vents. Repairs that eliminate these small openings will greatly minimize the risk of cricket invasions.
  
  
• Field cricket
  Several species in the genus Gryllus are called field crickets They are usually black and vary in length from 0.5 to 1.25 inches. The brownish-colored rear wings project back beyond the front wings like pointed coat tails.
  
  Field crickets invade homes most often during the fall in response to cooler nighttime temperatures. They are also attracted to lights at night, and this often brings them into close proximity to buildings. Once inside, they may cause damage to items such as cotton, linen, wool, silk and fur. Materials soiled by perspiration or food are more likely to be damaged by crickets. They also consume dead or dying insects, including their own species. At times field crickets may also cause damage to field crops.
  
  
• House cricket
  The house cricket, Acheta domesticus, is light yellowish brown in color and has three darker brown bands across the head. The adult stage varies in length from 0.75 to 1 inch.
  During warm weather, house crickets can live outdoors and are especially fond of garbage dumps.
  Like the field cricket, house crickets are driven indoors by cool temperatures. All stages are able to live in buildings year-round. Adults are attracted to lights at night. Inside buildings, house crickets are normally found in warm, dark places. They may damage items such as cotton, linen, wool, silk and fur -- especially when these items are soiled by perspiration or food.
  
  
• Ground cricket
  The ground cricket, Nemobius fasciatus, and possibly other species of the genus, are very common in Missouri. They are dark reddish brown to black in color and vary in length from 0.3 to 0.5 inch as adults.
  Ground crickets normally are found outdoors, but lights and the warmth of buildings may cause large-scale indoor invasions. Because of their small size, they find it easier to gain entry than other crickets. They may do damage indoors similar to field crickets. The chirping sound of the male is more shrill and high-pitched than that of field crickets.
  
  
• Camel cricket
  Most species of camel crickets belong to the genus Ceuthophilus. This name describes their hump-backed appearance when viewed from the side. They have jumping hind legs and long antennae like other crickets but they are wingless and so are unable to chirp. Color varies by species, ranging from light tan to brown, often having dark brown bands on some segments. Adults range from 0.5 to 1.5 inches in length.
  Camel crickets are usually associated with cool, damp, dark habitats. Since they are often found in caves, they are also commonly called cave crickets. Outdoors, they may be found under stones and logs and in other cool, damp habitats with suitable amounts of organic matter, which they use for food.
  Like other crickets, camel crickets will invade buildings in the fall seeking suitable places to pass the winter. In these cases, they often remain in basements or crawl spaces and seldom damage items in the home. They are usually considered a nuisance only by virtue of their presence.