The shiny spider beetle, Gibbium psylloides (Czemp.), is a small insect. The adult is usually less than 1/8″ long. It is often dark reddish-brown, but it can be almost black.
Many people confuse this beetle with the American spider beetle. The shiny spider beetle is completely reddish brown. The American spider beetle has light-colored head, antennae, and legs.
Spider beetles are members of the beetle family Ptinidae. Like many other Ptinid beetles, the shiny spider beetle has a round body and very long legs. The head is hidden when the beetle is viewed from above. This appearance is the reason for the name “spider beetle”.
The shiny spider beetle is a scavenger. It is attracted to damp areas. It deposits its eggs in or near moldy or decaying material.
The larvae can feed on hair, fur feathers, wool, paper, and a variety of food products. The larvae have been found feeding on rodent droppings and even on rodent carcasses. Infestations have also been started in bird nests on buildings. When the beetle population grew, they migrated into the building.
Shiny spider beetles are not common, but if they are left undisturbed, an infestation can become large. The larvae spin silken webbing and they make cocoons. The webbing is often the homeowner's first clue that there is a problem.
Spider beetles usually avoid light. In lighted places, they are usually active at night. They can thrive in basements, storage sheds, and other places where stored items can become damp and moldy.
Controlling shiny spider beetles starts with a thorough inspection. It is very important to find the source of the infestation. Since the beetle populations are often small, removing the infested material may solve the immediate problem.
Solving the mold and moisture problem is important for preventing future infestations. Inside of homes, plumbing leaks are often the causes of dampness and mildew. Bath traps are often damp, so they should have an access door for inspection. Crawl space vents should be open and free from blockage. In basements, it is sometimes necessary to use a dehumidifier.
The source of the dampness and mold must be corrected in order to prevent shiny spider beetles. Since these insects are often in dark places, many people prefer to have a pest control professional make the inspection and find the material that the larvae are eating. The pest control professional can help identify moisture issues that should be addressed.
In many cases it is necessary to apply insecticide to get complete control of shiny spider beetles. Liquid insecticide can be effective in the areas where the adults wander. Aerosol insecticide can be used in cracks and crevices where the beetles hide. Insecticidal dust is often useful inside of walls and other void spaces. The pest control professional will have the products and the equipment to make these applications.