Beware Carpet Beetles

One of the most common and damaging heritage eaters in your building is likely the varied carpet beetle. Close regular inspections of your storage and exhibit areas will often yield these insects. Adult beetles often emerge from the darkness that the larvae prefer and move into lit areas. At a glance they are about the size and shape of a small mouse dropping. A closer look reveals a brown spotted pattern and a flattened underside. Although it may be a relief to find that the particle is an insect rather than rodent feces, carpet beetle lavae can destroy a variety of materials in your collection. Wool, leather, horn, and feathers are all attractive as larval feeding sites.

There are two primary techniques to protect your vulnerable collection items.

  1. Vacuum! This process dislodges all stages of beetles and their leavings.
  2. Block! It may be helpful to seal up your building’s cracks and crevices, but it is unrealistic to believe that you’ll be able to block tiny pests in this way. Storage containers are a much more reliable preventative measure. If insect damage has been a problem at your institution, consider polypropylene boxes to store proteinaceous materials. Of course, vacuum before sealing in a storage container.

Luckily, there is an expanding set of free resources on the internet to help you identify heritage eaters and strategize solutions to protect your collection. Several years ago Alaskan Conservator Ellen Carrlee posted an illustrated discussion of heritage eaters and helpful Integrated Pest Management guidelines for small museums. Additionally,  contains an image library that can be a great resource to help you identify the heritage eaters at your site. The site also includes fact sheets to give you specific information about each type of pest. Click here for more about the varied carpet beetle.  NC State University also has an especially strong arthropod identification program and entomology extension service.

In contrast to the collection dangers they present, carpet beetles have a helpful role to play within institutions that collect bone specimens. Natural history museums, medical museums, and some anthropology museums can use these critters to their benefit in preparing bones for storage. See page 3 of the National Park Service’s Conserve O Gram on vertebrate collections. By efficiently eating away all tissue remnants, the beetles leave bone specimens clean and ready for perpetual preservation.

What other heritage eaters plague your collection? Which integrated pest management techniques have proven the most effective for your site?

Carpet beetle image from


About collectionsconversations

This blog will contain posts from the C2C project staff on a variety of topics related to collections care and disaster preparedness. Enjoy the posts and let us know if you would like additional information or have a topic you would like for us to address.

Posted on August 10, 2012, in cleaning, collections care, collections management, storage and tagged , , , , . Bookmark the permalink. 2 Comments.

  1. Hello,
    I found numerous carpet beetles in their infant stage in the crevices of my bed mattress. I cleaned everything and sprayed pesticide throughout my room and vacuumed my bed. Where do these things come from? How do I prevent them from returning other that vacuuming several times a week? Any help out there I would so greatly appreciate it.

    Thank you,

    • Regular brushing and vacuuming is our recommended treatment for museum artifacts. The larvae love wool and will also eat linen, but should not be attracted to the synthetics that make up most modern mattresses. However, the human hair on and around your mattress may prove to be enough of a food source. You may want to contact an exterminator if your regular cleaning efforts are not controlling the problem. Adults are tiny and can get inside through closed windows or any other tiny cracks, so preventing their entry altogether is nearly impossible. Good luck!

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