There are about 50 species of carpet beetles (family Dermestidae) that infest stored food or feed on wool, silk, leather, furs, skins, museum specimens, and carrion. Several species were common pests of household carpeting when it was made primarily of wool fiber. The name carpet beetle is now generally applied to this group of beetles, although their feeding habits extend beyond carpeting. The larvae are capable of digesting keratin, which is the protein in wool and other animal products. The adult beetles fly very well; they visit flowers outdoors to feed on pollen and move indoors to lay eggs on the material that the larvae will infest. Adults of the common carpet beetle are attracted to lights and often are found dead in receptacles of household ceiling lights. The larvae of these beetles often are noticed as they crawl slowly up walls or in kitchen cabinets, dresser drawers, or closet shelves.
Development. The life cycle can be extended through 6 to 20 larval stages. The accumulation of larval cast skins can give the impression of a large infestation, however accumulated cast skins can be from only a few larvae. Larvae are identified by the dense rows of setae that ring the body and the long setae that extend from the sides and the posterior. Setae on larvae are easily detached and can produce allergic reactions, such as rhinitis and respiratory asthma. When there are large infestations, and cast skins of carpet beetles accumulate, setae can become detached and cause irritation.
Habits. Carpet beetle infestations can originate from various organic sources, both indoors and outdoors. In attics and wall voids, these sources include abandoned bird nests, old umbrella wasp and yellowjacket nests, dead mice and birds, and dry pet food cached by a deer mouse infestation. Rat and mouse nests usually contain food scraps and rodent feces, and these provide a food source for carpet beetle larvae. Larder beetle is a species of Dermestid. Larvae of these beetles are not specific in their feeding habits; they can be found attacking animal skins and bee hives remaining in wall voids. In these materials, carpet beetles feed on dead bees and the comb wax. Black carpet beetle infestations often are centered on stored food, and the adults and larvae rarely move away from this site. The varied carpet beetle is responsible for most of the damage to wool, silk, and furs; these larvae are small and easily overlooked. Larvae of the Anthrenus species, such as the common carpet beetle and furniture carpet beetle, can survive nearly one year without feeding. This increases the opportunity for infestations to persist while household material is in storage or transit.