Carpet beetles belong to the family of beetles known as dermestids. These insects are pests in warehouses, homes, museums, and other locations where suitable food exists. In California, three species of carpet beetles cause serious damage to fabrics, carpets, furs, stored foods, and preserved specimens.
Identification And Life Cycle
All three carpet beetle species have a similar life history. Adults lay eggs on the larval food source, such as furs and woolen fabric or carpets. Eggs hatch in about 2 weeks and the larvae feed for varying periods, depending upon species and environmental conditions. They prefer dark, secluded places. When ready to pupate, the larvae may burrow further into the food or wander and burrow elsewhere. They may also pupate within the last larval skin if no other shelter is available. Larvae do not make webs as clothes moths do, but their shed skins and fecal pellets, which are about the size of a grain of salt, make it obvious where they have been feeding.
Carpet beetle adults do not feed on fabrics but seek out pollen and nectar. They are attracted to sunlight and are commonly found feeding on the flowers of crape myrtle, spiraea, buckwheat, and other plants that produce abundant pollen. Be careful not to bring these pests into the home on cut flowers—with their rounded bodies and short antennae, carpet beetles somewhat resemble lady beetles in shape.
| Varied Carpet Beetle | Furniture Carpet Beetle | Black Carpet Beetle | |
|---|---|---|---|
| number eggs laid |
40 |
60 |
90 |
| number days to hatch |
10-20 |
9-16 |
6-16 |
| number days for larval stage |
220-630 |
70-94 |
166-330 |
| number days for pupation |
10-13 |
14-17 |
8-14 |
| adult life (weeks) |
female 2-6; male 2-4 |
4-8 |
4-8 |
Varied Carpet Beetle
The varied carpet beetle, Anthrenus verbasci, is common in California. The adult is about 1/10 inch long and black with an irregular pattern of white, brown, and dark yellow scales on its elytra (wing covers). In older adults the scales that form this pattern wear off so the beetles appear solid brown or black. Outdoors, female beetles search out spider webs and nests of bees, wasps, and birds in which to lay their eggs. The nests contain dead insects, beeswax, pollen, feathers, or other debris that can serve as larval food. Indoors, beetles deposit eggs on or near wool carpets and rugs, woolen goods, animal skins, furs, stuffed animals, leather book bindings, feathers, animal horns, whalebone, hair, silk, dried plant products, and other materials that can serve as larval food.
Mature larvae are about the same length as adults and are covered with dense tufts of hair that they extend upright to form a round plume if disturbed. They have alternating light and dark brown transverse stripes and are distinguishable from other carpet beetle larvae because they are broader in the rear and narrower in front. Adults usually appear in spring or early summer; indoors, they are often seen near windows.
Furniture Carpet Beetles
When viewed from above, adults of the furniture carpet beetle, Anthrenus flavipes, are slightly larger and rounder than the varied carpet beetle adult. Coloration and markings of the adult are highly variable, but they generally have a mottled appearance due to white and dark yellow to orange scales interspersed with black spots on their elytra; if these scales have been worn off, they may appear solid black. Their undersides are white.
Larvae are white at first but darken to dark red or chestnut brown as they mature. In contrast to larvae of the varied carpet beetle, these larvae are broader in front and narrower at the rear. Larvae of the furniture carpet beetle feed on the same types of items as larvae of the varied carpet beetle.
Black Carpet Beetle
Larvae and adults of the black carpet beetle, Attagenus megatoma, are distinctly different from the carpet beetles described above. Adult black carpet beetles range from 1/8 to 3/16 inch in length. They are shiny black and dark brown with brownish legs. Full-sized larvae may be as long as 5/16 inch. They range in color from light brown to almost black. Larvae are shiny, smooth, hard, and are covered with short, stiff hairs. Their body tapers toward the rear and ends in a tuft of long hairs.
In California and other arid areas, the black carpet beetle is a more serious stored-product pest than a fabric pest.
DAMAGE
Damage is caused by the larval stage of dermestid beetles. Larvae feed in dark, undisturbed locations on a variety of dead animals and animal products, such as wool, silk, leather, fur, hair brushes with natural bristles, pet hair, and feathers; occasionally they feed on stored products such as certain spices and grains. They do not feed on synthetic fibers.
It is not always possible to tell from the damage whether it was caused by clothes moths or carpet beetles, but in general, the beetles are more likely to damage a large area on one portion of a garment or carpet while moth damage more often appears as scattered holes. Also, carpet beetle larvae leave brown, shell-like, bristly looking cast skins when they molt. These skins and the lack of webbing are usually good clues that the culprits are carpet beetles.
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