Every spring, I see a few small beetles in one bathroom off of my kitchen. There seems to be two types, and they disappear after a few weeks. One is small, rounder, and has brown, yellow and white patterns. The other is longer, black with a brown section in the middle. Should I be concerned?

SC, Webster, MA

It sounds like you are seeing a couple of different dermestid beetles. Dermestid beetles, also known as Skin Beetles, are a family of beetles who vary in their behavior, but are commonly considered to be scavengers. These beetles feed on dead vegetable and animal matter, often infesting hides of animals and beneficially removing the material. What you are describing sounds like two different Dermestid Beetles, the Varied Carpet Beetle and the Larder Beetle.

The Varied Carpet Beetle

Adult and Larva of carpet beetles

Anthrenus verbasci, the Varied Carpet Beetle is a common insect found in and around homes. These insects are known to infest items inside the home, especially natural fibers such as wool sweaters, rugs, and clothing. These beetles also feed on dead insects and their nests, often found in abandoned wasp nests and can significantly damage insect collections at natural history museums.

See Could Carpet Beetles Eat My Shirts? and Carpet Beetles Are on the Move!

The Larder Beetle

Adult and Larva of Dermestes lardarius,  larder beetle

Dermestes lardaris, the Larder Beetle is also found in and around homes. The sources for this beetle are often found in dried pet food, animal hides, feathers, and furs. It has been known to damage cured meats among other things. When considering sources inside the home, the larder beetle will often be a secondary pest to another insect which has died within a wall void. For example, if a mouse expires within a wall, flies feed on the carrion, and the larder beetle feeds on the mouse hide as well as the fly pupae and larvae.

See Larder Beetles Infest Meats and Yikes! Beetle Larvae in Your Holiday Ham!

Should you be Concerned?

Although both of these specific Dermestid beetles can result t in significant damage to your home’s clothing, rugs, and other fibers, as well as infest dog and food and treats, seeing a few of these beetles in the spring is not uncommon, and not necessarily concerning. Many Dermestid beetles are also pollinators, and when everything is starting to bloom and pollen is plentiful, you can rest assured that a few of these in the spring are probably occasional invaders rather than infesting pests.

To prevent them from infesting, you can do a few simple things. You can make sure that any pet food or treats are kept in tightly sealing containers and are not stored past their expiry date. Some dermestid (especially larder beetle) eggs may have been shipped with the food, and will eventually hatch if given the time to develop. Additionally, make sure that your winter clothing and wool blankets are cleaned and then stored in areas not likely to be exposed to occasional invaders. Finally, do not allow for dust and household debris to build up inside your home. This is especially important for room with wool rugs underneath furniture. If your spring cleaning is thorough, your winter-to-summer clothing switch is effective, and your dog food game is on point, you likely don’t need to worry about a few spring beetle.

For an assessment and prevention and control plan, please call 800-525-8084 and we’ll be happy to help!