Biology of Carpet Beetles

Carpet beetles are small insects belonging to the family Dermestidae. Although the adult beetles are often seen near windows and light sources, it is the larval stage that causes damage inside homes and commercial buildings.

Carpet beetles undergo complete metamorphosis, meaning they pass through four life stages: egg, larva, pupa, and adult.

1. Egg Stage

Female carpet beetles lay their eggs in hidden, undisturbed areas where food is available. Common egg-laying sites include:

Carpet edges and baseboards
Closets and storage bins
Upholstered furniture
Cracks, crevices, and under appliances

Eggs are tiny, white to cream-colored, and hatch within 7 to 21 days, depending on temperature and humidity.

2. Larval Stage (Damaging Stage)

The larva is the destructive phase of the carpet beetle’s life cycle. Larvae are small, brown, oval-shaped, and covered with fine hairs.

They feed on:

Wool, silk, fur, leather
Carpets and rugs
Upholstered furniture
Pet hair, lint, and food debris

The larval stage can last several months to over a year, depending on food availability and environmental conditions. During this time, larvae molt multiple times, leaving behind shed skins.

3. Pupal Stage

When fully grown, the larva forms a pupa. This non-feeding stage lasts 1 to 3 weeks. During pupation, the insect transforms into an adult beetle.

4. Adult Stage

Adult carpet beetles are small (2–5 mm), oval, and often patterned in black, brown, yellow, or white scales. Adults do not damage fabrics; instead, they feed on pollen and nectar outdoors.

However, once inside a building, they:

Lay eggs near food sources
Restart the infestation cycle

Adults typically live for 2 to 6 weeks.

Why Biology Matters in Control

Because carpet beetles have a long larval stage and hidden nesting areas, infestations often go unnoticed until damage is severe. Effective control requires: