Family Dermestidae and Dermestid Beetles

The family Dermestidae includes skin or hide beetles, carpet beetles, and larder beetles, some of which can be serious pests of closets and pantries. The name dermestid comes from the Latin derma, for skin, and este, meaning to consume.

Description

Museum curators know dermestid beetles all too well. These scavengers have a reputation for devouring museum specimens. Dermestid beetles' protein-eating habits make them equally valuable in museum settings, however, as colonies of dermestids can be used to clean the flesh and hair from bones and skulls. Many entomology students have encountered dermestids as pests, too, as they're known for their rather bad habit of feeding on preserved insect specimens.

Forensic entomologists look for dermestid beetles at crimes scenes when trying to determine the time of the death of a cadaver. Dermestids typically appear late in the decomposition process, when the corpse begins to dry out.

Dermestid adults are quite small, ranging from just 2 mm to 12 mm in length. Their bodies are oval and convex in shape, and sometimes elongated. Dermestid beetles are covered in hair or scales, and bear clubbed antennae. Dermestids have chewing mouthparts.

Dermestid beetle larvae are worm-like, and range in color from pale yellowish brown to light chestnut. Like the adult dermestids, the larvae are hairy, most noticeably near the hind end. The larvae of some species are oval, while others are tapered.

Classification

• Kingdom – Animalia
• Phylum – Arthropoda
• Class – Insecta
• Order – Coleoptera
• Family - Dermestidae

Diet

Dermestid larvae can digest keratin, the structural proteins in the skin, hair, and other animal and human remains.

Most feed on animal products, including leather, fur, hair, skin, wool, and even dairy products Some dermestid larvae prefer plant proteins and feed instead on nuts and seeds, or even silk and cotton. Most adult dermestid beetles feed on pollen.

Because they can digest wool and silk, as well as plant products like cotton, dermestids can be a real nuisance in the home, where they may chew holes in sweaters and blankets.

Life Cycle

Like all beetles, dermestids undergo complete metamorphosis with four life stages: egg, larva, pupa, and adult. Dermestids vary greatly in the length of their life cycles, with some species going from egg to adult in 6 weeks, and others taking as long as a year or more to complete development.

Females usually lay eggs in a dark crevice or other well-hidden location. Larvae molt through as many as 16 instars, feeding throughout the larval stage. After pupation, the adults emerge, ready to mate.

Range and Distribution

The cosmopolitan dermestid beetles live in varied habitats, provided there's a carcass or other food source available. Worldwide, scientists have described 1,000 species, with just over 120 known in North America.

Sources:

• Borror and DeLong's Introduction to the Study of Insects, 7th Edition, by Charles A. Triplehown and Norman F. Johnson
• Kaufman Field Guide to Insects of North America, by Eric R. Eaton and Kenn Kaufman
• Family Dermestidae, Bugguide.net, accessed November 25, 2011
• Dermestid Beetle, Texas A&M AgriLife Extension, accessed November 25, 2011
• Dermestids, Utah State University Extension fact sheet