Dermestid Beetle

Characteristics

Of the 500 species of dermestid beetles worldwide, 123 live in North America. They are sometimes called museum beetles, bow bugs, or carpet beetles, depending on where they are found and what they eat.

Species Specifics

This is the largest dermestid in California with a length of 9 to 14 mm. An adult has a slightly flattened elongated oval carapace. It is black with gray scales forming spots and a broad band across the base of the wing covers. The underside is mostly whitish. Larvae are elongated and reddish brown with a pale stripe down the back. They are covered with long reddish brown hairs.

Physical Characteristics

The hair of the larvae break off readily and cause irritation of tender skin (e.g. in a bird’s mouth), thus acting as a defense mechanism. Coleoptera means sheathed wing. Beetles have their forewings strengthened and hardened with a special material called chitin as protective covers for the operative under pair.

Ecology

Habitat

Low to middle elevations in North America.

Distribution

Diet

Dermestid beetles feed on decaying flesh but have expanded their diet to include human-made items. Beetles of the Dermestidae family feed on a great many things such as cereal products, grains, rugs and carpets, various stored foods, upholstery, fur coats, etc. and thus most are considered destructive pests. Some dermestids are harmful in museums since they may feed on mounted birds or mammals and specimens of plants and insects, while other dermestids are employed by museums to clean skeletons for exhibits.

Ecological Web

Dermestid beetles show up on carcasses when they start to dry-out. They break down and decompose decaying flesh which helps keep ecosystems clean and healthy. They will also eat fresh carcasses in captivity but in the wild they are pushed out by more aggressive maggots who need more moist food.

Activity and Behavior

Activity Pattern

Behavior

Social Behavior

Reproductive Behavior

Adult female insects emerge from the pupa with a full complement of eggs retained in the ovaries. Sperm introduced by the male is stored and released as the eggs pass out through the ovipositor. This beetle’s eggs are usually deposited in carrion.

Offspring

Beetles lay eggs which produce larvae quite different in form from the adult. When full-size, such larvae undergo a further change of form to become a pupa which is inert and does not feed. The pupa undergoes metamorphosis and emerges as the adult. Adult female insects emerge from the pupa with a full complement of eggs retained in the ovaries. Sperm introduced by the male is stored and released as the eggs pass out through the ovipositor. This beetle’s eggs are usually deposited in carrion.

Conservation

Status

Historical

It is thought dermestid beetles were introduced into California by hide traders in the early days.

Current Threats

Our Role

Oakland Zoo exhibits dermestid beetles in the Bug House and educates the public about their role in ecosystems. At Halloween time, we have a special exhibit at our event, Boo at the Zoo, where you can see many different carcasses being eaten by dermestid beetles.