Figure 1. Courtesty of Insects Limited

Black Carpet Beetle

Attagenus Unicolor spp.

Family Dermesidae

Identification/Description: “Adult black carpet beetles are oval and shiny-black with brownish legs. They vary in body length from 1/8 to 3/16 inch. Larvae, frequently staying hidden when feeding, are golden to dark brown and about 1/2-inch long. The body resembles an elongated carrot or cigar with a long brush of bristles at the tail end. Adult varied carpet beetles are about 1/10 to 1/8-inch long and nearly round. The top body surface is usually gray with a mixture of white, brown and yellow scales and irregular black crossbands. The bottom surface has long, gray-yellow scales. (These scales are 2-1/2 to 4 times as long they are broad.) Larvae are about 1/4-inch and light to dark brown. The body is wide and broader at the rear than the front. Adult common carpet beetles are about 1/10 to 1/8-inch long, nearly round, and gray to black. They have minute, whitish scales and a band of orange-red scales down the middle of the back and around the eyes. Larvae, frequently moving rapidly, are elongated, oval, reddish-brown, about 1/4-inch long and are covered with many brownish-black hairs. Adult furniture carpet beetles are about 1/16 to 1/8-inch long, nearly round and whitish checkered with black spots, each outlined with yellowish orange scales. These scales are broadly oval and two times or less long as broad. The legs have yellow scales. The bottom surface of the body is white. Color patterns vary. Larvae, frequently crawling rapidly, are about 1/4-inch, elongated, oval and covered thickly with brownish hair. A good quality hand lens or microscope is necessary to see these characters,” according to Ohio State University.

Length: They vary in body length from 1/8 to 3/16 inch” as per above.

Wing Span: about 1/2 inch

Immature Stages: Depending upon the species (i.e. varied, furniture or black), 40-90 eggs; 6-20 days to hatch; 70-630 days for larval stage; 8-17 days for pupation; and adult life: 2-8 weeks depending upon gender.

Life Cycle: “The female Black Carpet Beetle will lay 42 - 114 eggs near a possible food source. The larval stage is the destructive stage. The period from egg to adult will last about 1 year, possibly more depending on environment, according to Insects Limited. According to OSU, “All carpet beetles pass through the egg, larva, pupa and adult stages. Adults fly readily and during warm, sunny days feed outdoors on flower pollen of spirea, dogwood, crepe myrtle and buckwheat that have white or cream-colored flowers. Others feed on daisies, wild asters, etc. Adults are attracted by light, fly into homes and may be found on windows and screens. Depending on the species, each female can lay up to 100 white eggs or more that hatch in 8 to 15 days in warm weather. Eggs laid indoors occur in lint accumulations near the food source, in air ducts, under heavy furniture, underneath baseboards, etc. After hatching, larvae begin their destructive feeding, avoiding light, and molting several times as they develop. Sixty days to a year or more may be spent in the larval stage feeding, depending on food and temperature. Some life cycles are two to three years, depending on the species of carpet beetle. When rooms are warm indoors, the life cycle is shorter than in an unheated portion of the house during the winter. In the spring, the pupa stage is followed by new adults. Usually there are three to four generations per year except for the black or varied carpet beetle that may have one generation per year.”

Food: “Carpet beetle adults do not feed on fabrics but seek out pollen and nectar,” according to UC Davis. “Can survive up to five years without food,” according to Hogue.

Habitat: in dark, undisturbed places; isolated areas including insect collections; oriental carpets; tapestries and wood-based wall-to-wall carpets

Behavior: Evidence of fecal pellets and the shed skins of the larva. Small holes in the paper of old books may be due to the wood boring beetle (also commonly called wood worm and powder post beetle) which began chewing through the binding (i.e., the wooden boards).

Control/Prevention: Locate the source of infestation before treatment. Carpet beetle larvae prefer to feed in dark, undisturbed, protected places. Use a flashlight and nail file to check in such places as under baseboards, in and under upholstered furniture, piano felts, air ducts, stuffed animal trophies, stored cereals, bird nests under eaves, rodent nests, wasp nests in attics, dead birds or rodents in wall voids, woolens, clothes closets, furs, etc. Often the cast skins are more abundant than the larvae. Adult beetles flying around windows may help in locating the infestation,” according to OSU; “Good housekeeping is critical. Use a strong suction vacuum cleaner with proper attachments to remove lint, hair and dust from floors, shelves and drawers. Periodically brush, air outside, or dry-clean furs, woolens, blankets, etc. Clean rugs, carpets, draperies, furniture, baseboards, air vents, moldings and other hard-to-reach places regularly. Destroy untreated worthless animal skins or hides, valueless insect collections, old woolen rags and old clothing. Cedar-lined closets and chests help but are not 100 percent effective. Use one pound of naphthalene flakes or balls or paradichlorobenzene (PDB) crystals per 100 cubic feet of closet space for limited protection. Any tight box or bag that can be sealed is a good storage container. Place garments in and add PDB crystals or naphthalene flakes interspaced between sheets of paper. Use one ounce of crystals or flakes per two cubic feet of container space. Be sure that all cloth goods are dry-cleaned, washed, pressed with a hot iron, sunned or brushed prior to storage. Fur storage in cold vaults is effective. Remove and destroy abandoned bird and insect nests in attics, under eaves, etc

Number of Species: North American, 120

Citations: Hogue, p. 308-309, 410 and Kaufman, p. 210.

Updated: 19 January 2010