Beetles

Beetles are a diverse group of insects that can be found all around the world. While some species of beetles are harmless, others can cause significant damage to food, wooden structures, and other materials.

Shiny Spider Beetle

Gibbium aequinoctiale

Spider beetles resemble small spiders due to their long legs and rounded abdomens.

These pests prefer dark places with lots of moisture, such as damp basements and crawl spaces. At night they scavenge for food, which includes wool, hair, animal droppings, and other debris.

If they get into pantries and food containers, spider beetles may contaminate stored food products with their eggs, larvae, silk (produced by the larvae), and droppings.

Shiny Spider Beetle

Size: 1/16–1/8 inch long (1.5–3.5 mm); smaller than the thickness of a phone charging cable

Color: Dark reddish brown or black

Shape: Round, bulb-like body with a small head, a hard shell, long antennae, and 6 spider-like legs

Legs: 6 spider-like legs with pale yellow hairs

Antennae: Long, thin antennae

Head: Head and thorax are small and oriented downwards

Body: Round, bulb-like body with a dark reddish-brown or black abdomen that appears and smooth and shiny

American Spider Beetle

Mezium americanum

Similar to Shiny Spider Beetles.

American Spider Beetle

Size: 1/16–1/8 inch long (1.5–3.5 mm); smaller than the thickness of a phone charging cable

Color: Reddish-black and yellowish-gray

Shape: Round, bulb-like body with a furry head and thorax, a hard shell, long antennae, and 6 spider-like legs

Legs: 6 spider-like legs with yellowish-gray hairs

Antennae: Long, thin antennae covered in yellowish-gray hairs

Head: Well-developed head and thorax covered in a dense coating of short yellowish-gray hairs

Body: Round, bulb-like body with a dark reddish-brown or black abdomen that appears and smooth and shiny

Cigarette Beetle

Lasioderma serricorne

Cigarette beetles are named for their attraction to stored tobacco (cigarettes, cigars, dried tobacco leaves, etc.), although they may also be found in a wide range of stored foods.

Adult beetles are nocturnal. They are good fliers and can occasionally be seen around doors and windowsills as they try to fly outside.

Aside from contaminating food, cigarette beetles are otherwise harmless and don’t carry any diseases.

Cigarette Beetle

Size: 1/12–1/8 inch long (2–3 mm); about the length of a small sesame seed

Color: Brown or reddish-brown

Shape: Rounded, oval-shaped body with a hard shell, serrated antennae, 6 legs, and 2 pairs of wings

Legs: 6 legs

Antennae: Look for serrated antennae with 11 tiny segments resembling the teeth on a saw

Body: Rounded, oval-shaped body covered in a hard shell that is divided into 3 sections: 1 pronotum (thorax) and 2 elytra (forewings); head is angled downwards and concealed by the pronotum when viewed from above

Wings: Look for its brown elytra covered in fine hairs; capable of flight

Drugstore Beetle

Stegobium paniceum

Drugstore beetles can infest almost any type of stored food, including grains, seeds, spices, cereals, flour, nuts, beans, dried fruits, dried fish, and leather.

They have also been known to feed on prescription drugs, hence their name.

They are similar in appearance and behavior to Cigarette Beetles. Adult beetles are nocturnal and are particularly attracted to light at night. The main concern with drugstore beetles is food contamination.

Drugstore Beetle

Size: 1/10–1/8 inch long (2.25–3.5 mm); about the length of a large sesame seed

Color: Brown or reddish-brown

Shape: Rounded, oval-shaped body with a hard shell, clubbed antennae, 6 legs, and 2 pairs of wings

Legs: 6 legs

Antennae: Look for a thick, 3-segmented club at the end of each antenna

Body: Covered in a hard shell that is divided into 3 sections: 1 pronotum (thorax) and 2 elytra (forewings); head is angled downwards and concealed by the pronotum when viewed from above

Wings: Look for rows of small grooves running longitudinally down the back of its brown elytra; capable of flight

Sawtoothed Grain Beetle

Oryzaephilus surinamensis

Sawtoothed grain beetles are widespread pests in the food industry as well as in home pantries. They can infest a wide range of stored foods, especially stored grains, seeds, and pet food.

They don’t bite, but their jaws are capable of chewing through cardboard and plastic- or foil-wrapped packaging. Once inside, these pests contaminate the food they feed on and cause moisture to build up, which may lead to mold problems.

Sawtoothed Grain Beetle

Size: 1/10–1/8 inch long (2.5–3 mm); about the length of a sesame seed

Color: Reddish-brown

Shape: Narrow, flattened body with saw-like ridges, clubbed antennae, 6 legs, and 2 pairs of wings

Legs: 6 legs

Antennae: Beady antennae with a 3-segment club

Body: Narrow, flattened body with 3 distinct segments (head, thorax, and abdomen) covered in a hard, bumpy shell; look for saw-like ridges on its thorax (6 projections on each side and 3 longitudinal ridges on the top)

Wings: Long, narrow elytra with many longitudinal grooves; cannot fly

Powderpost Beetles

Multiple Species (Lyctinae spp.)

Powderpost beetles are wood boring insects that are second only to termites when it comes to the damage they cause. They get their name from the fine powder-like sawdust they leave behind.

The adult beetles lay their eggs in cracks or pores in hard wood. After hatching, the larvae bore tunnels inside the wood as they feed and develop.

New adult beetles emerge from the infested wood, leaving behind tiny, round exit holes (called “shot holes”) about the size of a pencil lead.

Powderpost Beetle

Size: 1/12–1/4 inch long (2–6 mm); about the length of a flax seed

Color: Reddish-brown to black

Shape: Narrow, cylindrical-shaped body with a hard shell, short antennae, 6 legs, and 2 pairs of wings

Legs: 6 legs

Antennae: Short antennae with a 2-segment club

Body: Narrow, cylindrical-shaped body covered in a hard shell divided into 3 sections: 1 pronotum (thorax) and 2 elytra (forewings); head is prominent and not covered by the pronotum

Wings: Long, narrow elytra with many longitudinal striations (grooves); capable of flight

Rice Weevil

Sitophilus oryzae

Rice weevils are serious pests of stored grain and seeds, as well as hard processed foods like dry pasta and dry pet food.

They are “internal” feeders, meaning they deposit eggs inside whole grains and seeds. Their tiny, grub-like larvae feed from the inside while developing and eventually pupating within the hollowed-out husk.

Adult rice weevils can fly, which distinguishes them from a similar-looking species, wheat weevils. Neither species of weevils bite nor carry diseases.

Rice Weevil

Size: 1/8–1/6 inch long (3–4.5 mm); about the length of a peppercorn

Color: Reddish-brown

Shape: Oval-shaped body with a narrow and elongated snout, short and elbowed antennae, and 6 legs

Legs: 6 legs

Antennae: Short, elbowed antennae that stick about half way down its snout

Head: Elongated head with a long, narrow snout (rostrum)

Body: Stout, bumpy-looking thorax and abdomen covered in many large, round pits

Wings: 2 pairs of fully-developed wings that are capable of flight; look for 4 large, pale orange spots on its elytra (hardened forewings) arranged in a ‘X’ shape (2 on each side)

Black Vine Weevil

Otiorhynchus sulcatus

Black vine weevils are garden pests that feed on a variety of ornamental plants.

The adult weevils feed on foliage, leaving behind notched chewing marks on the edges of leaves. The larvae are more problematic—they feed on roots, which can injure or stunt the growth of the host plants.

Black vine weevils are not as commonly seen indoors, but they can occasionally wander in through an open window or hitch a ride in newly-bought houseplants.

Black Vine Weevil

Size: 1/4–3/8 inch long (8–10 mm); about the length of an apple seed

Color: Slate gray to black

Shape: Oval-shaped body with a short and thick snout, long and elbowed antennae, and 6 legs

Legs: 6 legs

Antennae: Thin, elbowed antennae that are about half the length of its body

Head: Elongated head with a downward-curved snout (rostrum)

Body: Large, bumpy thorax and abdomen speckled with many small pits and patches of short, pale-colored hairs; its elytra (hardened forewings) are fused together and cannot fly