The varied carpet beetle probably gets its common name because there is great variation in the color pattern on its dorsal surface. This species is known to cause dermatitis in humans. It is worldwide in distribution and is found throughout the United States.

Adults are about 1/16-1/8" (1.8-3.2 mm) long. The body is black, with pattern of yellow and white scales on the pronotum and elytra (wing covers), 2 transverse zigzag bands of white scales bordered by yellow scales on the elytra; scales are elongate, 2-3 times as long as broad; the lower/underside of body is covered with grayish yellow scales. The antennae are short, with a 3-segmented, compact club on each. The posterior end of the elytra are evenly rounded. The abdominal 5th sternite broadly and are deeply emarginate (notched) epically. In addition, the body is oval, the head more or less concealed from above, with a median ocellus, and tarsi 5-5-5. The larval length is up to 1/4" (4-5 mm). It is stout and widest posteriorly. It is colored dark brown to black. It is covered with brown hairs with tufts of spear-headed hairs (hastisetae) arising from membranous areas on the sides of abdominal segments 5-6-7 pointing towards the rear and converging towards the center, and heads of spear-headed hairs of the hind tufts equal in length to a combined length of 7-8 preceding segments. The antennae with segment 2 is less than 2.5 times as long as broad. The abdominal sternites are entirely membranous.

Fabrics typically have much surface damage and holes here and there, but larvae can cause large irregular holes in material. Furs and brushes have mostly the tips of hairs damaged, leaving uneven areas. With museum insect specimens, the accumulation of fine powder/frass beneath the specimen is often the only indication of these beetle's presence. Larval caste/molt skins are often present. Frass/droppings are minute, irregular in form, often the color of the material being damaged. The larvae may burrow through packaging materials when seeking food.

Females do not always lay their eggs on larval food material. The eggs hatch in 17-18 days. The larval period ranges from 222-323 days but may last up to 623 days under adverse conditions of temperature, humidity, and food, and requires an average of 7-8 molts (range 5-16). The larva pupates in the last larval skin and pupation lasts 10-13 days. Developmental time (egg to adult) usually requires 249-354 days at room temperature, but may take as long as 2-3 years depending on temperature and food. Adult males live 13-28 days whereas, females live 14-44 days.

Varied carpet beetle larvae feed on a wide variety of animal and plant products. Animal-origin materials include woolens, carpets, furs, hides, feathers, horns, bones, hair, silk, fish meal, insect pupae, and dead insects. Plant-origin materials include rye meal, corn, red pepper, cacao, cereals, etc. Their favored foods are insects and spiders which makes them a major pest of museum collections and buildings with cluster fly, boxelder bug, and other similar problems.

On fabrics, larvae tend to surface graze but are quite capable of making small or large irregular holes. On furs and bristles, they damage mostly the tips leaving uneven areas. On dead insects, they typically feed from within and the accumulation of fine powder/frass beneath the specimen is usually the only indication of their presence. The larvae may burrow through packaging materials to get to the contained food.

Adults are found outside during warm weather. They are often found on flowers, particularly in the spring and especially on Spirea spp., where they often eat the pollen. Females seek out the nests of bees, wasps, and spiders as oviposition sites, as well as bird nests.

Inside, adults are often found at windows during the spring. The primary breeding areas are quite diverse and may include obscure or unusual places such as wall/ceiling voids where yellow jackets, honey bees, and the like nest; where cluster flies, boxelder bugs, and other creatures have over wintered; rodent bait left in attics, crawl spaces, or basements; wasp and hornet nests in attics, under eaves, around windows, etc.; dead insects and spiders in the attic or in light fixtures; behind and under baseboards where lint and hair accumulate; animal trophies or rugs; insulation which contains animal hair; dead animals in the chimney flue; etc. In such places, the larvae feed on the animal and/or plant material present.

The larvae tend to wander about and can be found far from the primary infestation. When disturbed, the larva erect their hair tufts and spread the bristles and hairs, forming a ball.

Adults hatching from indoor pupae avoid or shun light until egg laying is mostly complete, and then become attracted to light. Most outdoor adults show an attraction to light.

Information compiled from the National Pest Management Association, Inc. (NPMA)