Sunday, November 2, 2014

Black Carpet Beetles, Attagenus spp.

Among the more common household pests you are likely to encounter are the Black Carpet Beetles in the genus Attagenus, family Dermestidae. They are slightly larger, more oval, and jet black compared to the usually more abundant Anthrenus carpet beetles, but they share similar feeding habits.

Adult Black Carpet Beetle

There are nine species of Attagenus known from north of Mexico. Most are about 3-5 millimeters in length as adults. The larvae are distinctive in being tapered from front to back, with a bundle of long hairs extending from the rear end. At maturity the larva is about 9.5-12.7 millimeters, excluding the "tail" of hairs.

Larva of Black Carpet Beetle

As is the case with other carpet beetle larvae, the hairs can cause dermatitis in some people. The patient may frequently interpret the symptoms as insect "bites," resulting in misdiagnosis by physicians. It usually takes years of exposure to carpet beetle infestations to begin exhibiting reactions, but in rare instances, inflammation of the respiratory tract and eyes can also occur.

While the larvae feed mostly on dried animal products such as shed hair and skin cells from people and pets, wool garments and blankets, silks, furs, animal hides, and dead insects that collect in spider webs, light fixtures, and along window sills, they also consume dried plant matter on occasion, especially cereals and grains. So, they can be a pantry pest as well as a clothes closet pest.

Adult Attagenus feed on flower pollen

Control and prevention of a Black Carpet Beetle infestation is best achieved by thorough cleaning of one's domicile, through vacuuming up accumulated pet hair, and dust (most of which is flakes of dead skin from people and pets). Discard any infested items. Outdoors, remove abandoned mammal, bird, and wasp nests. Understand that despite all your efforts, it is next to impossible to become immune to the occasional infestation.

Insects are incredibly adept at exploiting human behavior and household ecosystems. Few are as efficient as Black Carpet Beetles when it comes to scavenging our food and clothing. They are to be despised, no doubt, but also admired for their adaptability.

Sources: Evans, Arthur V. 2014. Beetles of Eastern North America. Princeton, NJ: Princeton University Press. 560 pp.
Gahlhoff, Jerry G., Jr. 2013. "Black Carpet Beetle," Featured Creatures. Entomology and Nematology, University of Florida/Institute of Food and Agricultural Sciences. Publication Number EENY-18. Note the image of the adult beetle depicts a Dermestes species, not Attagenus.
Jacobs, Steve. 2010. "Carpet Beetle Dermatitis," Insect Advice from Extension. College of Agricultural Sciences, Pennsylvania State University.
White, Richard E. 1983. A Field Guide to the Beetles of North America (Peterson Field Guides). Boston: Houghton Mifflin Company. 368 pp.

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