More than 350,000 beetle species have been documented worldwide, making the number of beetle species far greater than the number of plant species in the world. Also, the actual number of beetle species worldwide likely exceeds 1 million, with the possible exception of wasps, this makes beetles the most species-rich animal group in the world. While the vast majority of beetles are not classified as “pests,” there exists several types of beetle pests that often infest homes and buildings. These beetles include wood-boring beetles, beetle pests of stored foods, beetles that damage fabrics and paper, beetles that are attracted to artificial light, and beetles that overwinter within homes, many of which are invasive.
Beetles are abundant on turf grass and gardens located in residential yards, but these commonly seen beetles are not considered pests. In fact, any gardener will claim that beetles are beneficial in gardens due to their habit of preying on plant-damaging insects. Common garden beetles may be considered pests under certain circumstances, such as when certain beetles cause unpleasant skin conditions, when certain beetles bite humans, and when beetles inadvertently wind up in homes. For example, dermestids or blister beetles cause skin irritation that sometimes requires medical intervention, as blister beetles secrete a defensive chemical that acts as a blistering agent when it makes contact with human skin. Also, many garden beetles, such as the Hercules beetle, possess unusually large mandibles that they very rarely use to inflict bites to humans.
The most common beetle pests in the US are adult beetles that belong to species that overwinter within homes. Overwintering beetles are in the habit of invading homes in massive numbers during the fall and winter season in order to secure warm shelter until the arrival of spring. Overwintering beetle pests invade homes only as adults, and the most common species include invasive Asian lady beetles, elm leaf beetles, black vine weevils, and strawberry root weevils. Fabric beetles are also common indoor pests due to their taste for fabrics that contain animal based materials or animal byproducts.
Carpet beetles, varied carpet beetles and furniture beetles prefer to feed on indoor fabrics and other materials that contain an animal protein known as “keratin.” Leather, wool and items containing feathers all contain keratin, which makes these materials particularly appetizing to fabric beetles. Fabric beetles will also consume any soft material that contains perspiration, dead skin and hair, including clothing, furniture upholstery, bedding and carpeting. Unlike overwinter beetle pests, however, only beetle larvae inflict damage to fabrics.
Have you ever suspected a fabric beetle infestation after finding damaged clothing?