Shiny Spider Beetle

The shiny spider beetle, Gibbium psylloides (Czemp.), is a pest of stored food products. It gets its name from the fact that the adult beetle resembles a small spider. The wing covers give it a “humped” appearance. It is a small insect. Adults range in size from 1/16” to 1/8”.  It does not fly and it is not attracted to light.

The shiny spider beetle is solid colored. The color varies from dark red to black.

This beetle is often confused with the American spider beetle, which has cream-colored head and legs.  There are several other species of spider beetles, including the Australian, the golden, and the whitemarked.

The shiny spider beetle feeds on moldy food and food products. It also feeds on products that have been stored a very long time and are out of condition for use by people. Shiny spider beetles have infested houses, hotels, warehouses, and bakeries.  They feed on cereal, pet food, stored seeds, woolens, animal droppings, and paper.

Shiny spider beetles have also been found in bird nests and rat nests. When the nests are in attics or crawl spaces, the beetles can easily move into the living space

The female beetle deposits eggs on the food material. When the eggs hatch, the larvae feed and grow. While they are feeding, the larvae spin silken webbing.  When they are ready to change into adult beetles, the larvae spin silken cocoons. The adults sometimes stay in the cocoons for a few days before coming out to find a mate.

Shiny spider beetles can complete the entire life cycle, from egg to reproducing adult, in as few as 22 weeks or as many as 42 weeks. The length of time depends on the temperature and the amount of food that is available.

Shiny spider beetles ruin more food with their webbing and their droppings than they actually eat. Webbing on food and holes in packages is a sign that shiny spider beetles may be active.

Inspection and cleaning are the key steps in eliminating shiny spider beetles. It is important to find everything that they have infested. Empty pantry and cabinet shelves. Inspect every package and throw away any that are infested.  Vacuum the empty shelves. This will remove any food residue. Store new food products in sealed glass or plastic containers.

Insecticide application is the final step. Apply it into the cracks and crevices at the back and sides of the shelves. Treat cracks and crevices in any other areas where the beetles have been active. The object is to eliminate any insects that might be hiding. To avoid misapplication, it is often preferable to call the local pest control professional.