Beetle Facts, Identification and Control
Scientific Order: Coleoptera
Size: Varies widely based on species. The largest species can be over six inches long while the smallest species can be less than a millimeter long. The most common beetles in New York are the black carpet beetle, which are 2.8 to 5 mm long, and the confused flour beetle, which are about 3.5 mm long.
Color: Different species of beetle may be vibrant, bright colors, or simple blacks or browns. Regardless of species, beetles tend to be shiny because of their hardened, thick forewings and shell-like wing covers. Common beetles in New York tend to be black, dark brown, or reddish-brown.
Signs of Infestation
There are three different kinds of pest beetle in New York: food consuming, fabric consuming, and wood consuming beetles. Each type of beetle damages the products they consume. Look for signs of tampering or damage on food boxes, fabrics like clothing and carpeting, and wood, including wooden furniture.
Food consuming beetles often chew through cardboard packaging to feed on dry stored products. They may also leave behind crumbs or droppings. Fabric consuming beetles create small holes in fabric as they bite through it. Wood consuming beetles bore small, circular holes into wood to deposit eggs.
Treatment and Prevention
The best way to prevent beetle infestations in your home or business is to deprive them of the things that attract them. Beetles require food, water and shelter. If you can make sure they can’t get these, you’ll go a long way toward preventing any infestations.
Keep at-risk food such as grains and dry good in sealed, hard plastic containers. Take the garbage out every day. Launder all clothing and uniforms regularly. Wash any linens and fabrics after a couple of weeks, even if you didn't use them. Make sure all wooden furniture is treated and stained. Dispose of old or damaged wood.
Behavior and Diet
Beetles demonstrate a wide variety of adaptations to their environments, so specific beetle behavior depends largely on individual species. Some beetles burrow or tunnel through dirt or even hard materials like wood easily; others can't burrow at all. Some beetles are eusocial; others are mostly solitary.
Most beetles are poor fliers and prefer to search for food and shelter from the ground. You'll often find them in dark, secluded areas of your building such as basements, warehouses, and crawl spaces. Different kinds of beetles can feed on virtually anything, including fabric, wood, plants, other insects, and garbage.
Reproduction and Life Cycle
Beetles undergo a four-stage life cycle: egg, larva, pupa, and adult. The entire life cycle takes around 21 to 27 days, though it may take longer in winter. Different species of beetles reproduce in different ways. Female beetles can lay anywhere between 63 to 228 egg cases, which may have 3 or more eggs inside of them.
Eggs typically hatch after 4 to 6 days. Beetle larvae usually burrow into their food source and feed continuously. Larvae must molt their skin multiple times as they grow. When larvae get big enough they enter the pupal stage, which usually lasts four days. Beetles emerge from the pupal stage as fully-grown adults.
The beetle order’s scientific name, Coleoptera, means “folded wing” in Latin. It refers to the beetle's defining characteristic, which is that all beetles have a hardened and thickened pair of forewings, or wing covers, called elytra.
The elytra cover and protect beetle’s fragile flying wings. The elytra resemble a shell or pair of shells and cover most beetle’s entire back abdomen, with an opening in the middle where the two separate wing covers meet. When beetles take flight, their elytra lift and allow their wings beneath to unfold outward.
Beetles always have chewing, biting mouthparts, with sharp mandibles or “pincers.” Beetles use their chewing mandibles to breakdown and eat their meals of shrubs, trees, fabrics, or other woods.
Cornell University Insect Diagnostic Laboratory (several fact sheets about specific beetle species, including the ones covered here)
Penn State College of Agricultural Studies, Department of Entomology insect fact sheets (includes several common beetle species)
Identification of Beetles, a step-by-step guide by the Virginia Tech College of Agriculture and Life Sciences