Attagenus unicolor (Brahm, 1791)

Black carpet beetle

Bigger, darker, and hungrier than its mottled cousins, the larvae can feed for nearly two years on a single wool rug.

Order: Coleoptera
Family: Dermestidae
Group: Fabric & structural beetles
Ontario status: Established, widespread in Ontario; the most destructive dermestid of homes and museums

Why it matters

The most damaging carpet beetle in North American homes and museums, larger larvae, longer feeding, tougher diet than Anthrenus species.

Origin

Likely Eurasian; now worldwide in homes and museums.

Behavior

Larvae avoid light and feed for many months, growing to about 8 mm, the largest of the home dermestid larvae. Adults are strong fliers found on windowsills in spring.

Living conditions

Larvae in the same dark places as other carpet beetles, but this species' larvae feed longer and on tougher material, including leather and heavy woolens. Adults also visit flowers.

Signs of presence

Long (up to 8 mm) carrot-shaped hairy larvae with a tail tuft, in closets or under rugs
Elongated dark beetles (3-5 mm) on windowsills
Clean-edged damage to woolens, often in hidden areas (under collars, cuffs, rug edges)

Weaknesses

Long larval stage means a long window for detection, shed skins accumulate
Same keratin dependence; no keratin, no beetles
Adults must exit to flowers; exclusion reduces breeding

Myths and facts

Myth Black carpet beetles bite people.
Reality Neither larvae nor adults bite. The itchy rash some people blame on them is usually irritation from the larval hairs (hastisetae) or an unrelated allergy.

Research notes

Morphology

Adult 3-5 mm, elongate-oval, uniformly dark brown to black, sparsely hairy (no colorful scales). Larva up to 8 mm, carrot-shaped, golden-brown hairs with a distinctive tuft of long hairs at the tail end.

Diagnostics

Uniform dark elongate adult + large carrot-shaped larva with tail tuft = black carpet beetle. The larval tail tuft is the field character.

Easily confused with

Varied carpet beetle, Anthrenus verbasci Varied carpet beetle adults are smaller, oval, and mottled with scales; black carpet beetle adults are larger, elongate, and uniformly dark.

Life cycle

Adult: 2-4 weeks; pollen-feeding, mating, dispersal
Egg: Laid in lint, wool, or carcasses; hatch in ~2 weeks
Egg to adult: Often 1-2 years in temperate conditions
Generations per year: 1 per year, sometimes less
Nymph or larva: Larvae feed 6-24 months, exceptionally long; the tail-tufted final instars are the most damaging

Development

Complete metamorphosis; larvae pass through 6+ instars over many months.

Reproduction

Females lay ~50-100 eggs.

Distribution

Global: Cosmopolitan
Native range: Eurasia (probable)
Ontario: Established and widespread; homes, museums, warehouses

Ecology

Scavenger of high-protein animal matter, wool, fur, feathers, leather, dead insects. The long larval stage is an adaptation to patchy, low-quality food.

Resistance

Unknown, no significant documented resistance.

IPM implications

The long larval stage is both the damage and the opportunity: shed skins and frass accumulate, making infestations findable, and the slow cycle means a single thorough cleanout plus reservoir removal (attic nests, dead insects in voids) has lasting effect. In museums, quarantine and freezing of incoming materials.

Chemical ecology

Larval hastisetae (detachable barbed hairs) are a mechanical defense; adult floral visitation mediated by pollen volatiles.

Genetics and DNA

No reference genome published as of 2026.

Taxonomy

Order Coleoptera, family Dermestidae. Genus Attagenus; unicolor = 'one-colored,' for the uniform dark adult.

Open questions

What regulates the extreme plasticity of larval development time (6 months vs. 2 years).

References

Hinton, H.E. (1945). A Monograph of the Beetles Associated with Stored Products, Vol. 1. British Museum (Natural History).