April Showers Bring May Flowers… and Carpet Beetles
By James Feston, BCE, Director of Product Research and Development at Insects Limited, Inc.
As a native of the Pacific Northwest, coming to Indiana 12 years ago was a real shock in a few ways.
Aside from the prolific quantities of cornfields and the ability to see a flat horizon from any direction, there are the seasons. Indiana has hot summers and cold winters.
So here in Indiana, as we are just coming out of another cold winter and into a new spring, I am starting to see (and receive phone calls about) one of our more pesky pest insects, the carpet beetle.
Carpet beetles don't just eat wool carpets! Check out this photo of feather arrow fletching and the damage that carpet beetles can do to items in long term storage. These arrows were stored in a closet for 5 years. During that time, they ate all the fletching completely off of one arrow, and damaged several others!
Carpet beetles are a member of diverse family of beetles called Dermestidae. There are over 1700 species of dermestid beetles worldwide (Háva & Herrnmann, 2021) with a variety of feeding habits and behaviors. However, feeding on dry plant (seeds, pollen) and animal (hair, skin) matter is common in this group. These insects live in abundance outdoors and can easily enter structures looking for something good to eat. Many homeowners will run across the varied carpet beetle (Anthrenus verbasci) at some time or another but Spring is often when we see the adults for the first time after a long winter. Adult carpet beetles are small, about the size of the head of a pin.
This time of year, the adults are out feeding on pollen from flowering plants (Spirea is one of their favorites). If only these gentle pollen feeders could just stay out there doing their thing, we could all get along! But, because they are flying around in such great numbers, it’s only a matter of time before they find their way into our homes through gaps in windows, doors, or through damaged screens. The adult beetles don’t do any damage directly. Once inside, they are adept at seeking out food sources for their future offspring.
While you may not have a cockroach this big in your home (pictured above), it is best not to let even small dead insects accumulate in your home (windows and baseboards are great places to check) because carpet beetles will happily feast on their fellow insects!
What Do Carpet Beetles Eat?
Their prime targets are food items like dog food, pasta, and cereal. What’s worse, is that they don’t just eat conventional food items. These insects will feed on wool, fur, feather, taxidermy, and other dead insects. The other bad news about carpet beetles is that it’s not just homeowners that have to worry.
Museums often contain a diversity of objects that can serve as a food source for carpet beetle larvae. Any irreplaceable museum object made of natural fibers like hair, wool, fur or feathers can be at risk. The other problem in a museum setting is that the larvae are inconspicuous and only feed on small amounts of the materials at a time.
Diapause
When stressed, they can also extend their larval development period by undergoing a process known as diapause (think hibernation for insects). During this diapause, they can survive for months and years while only occasionally feeding.
Diapause is a strategy that some insects use to cope with stress. They can slow their metabolism and try to ride out stressful conditions such as extreme temperatures, lack of food, and physical disturbance.
The warehouse beetle, a close relative of the carpet beetle, has been living in this vial on the same small amount of food for the last 4 years!
Hastisetae
Another unfortunate aspect of carpet beetle biology is their hair. Some dermestid beetle larvae are covered in a fuzzy outer coating of hairs called hastisetae.
Hastisetae are a little different than the normal setae (hairs) on other insects because they have a barbed or “arrowhead” structure on the end of each one.
Hastiseatae can cause contact dermatitis and allergic reactions in many people and pets. These hairs typically serve a defensive purpose for the larvae to protect it from other arthropod predators as well as discourage other insects that might be competing for the same food resources.
Many dermestids are covered in hairs called hastisetea. These barbed hairs can cause allergic reactions in some people and pets. Small children and the elderly can be at higher risk for complications due to these irritating hairs
So now that we know that carpet beetles are gearing up for the season, what can we do?
Carpet Beetle Reduction Springtime Checklist
- Check window screens for tears and other damage
- Fix gaps and cracks around window frames and doors
- Install sturdy door sweeps on exterior doors to eliminate gaps
- Vacuum regularly while paying special attention to baseboards, windowsills, behind appliances (where you dropped those spaghetti noodles between the counter and the stove 5 years ago)
- Deploy carpet beetle and dermestid traps on feathers, dry food items)
While it is nearly impossible to be 100% carpet beetle-proof, by following the steps from the Carpet beetle prevention checklist, you can help reduce the number of beetles joining you in your home this Spring.
References:
Háva, J. and Herrmann, A., 2021. Checklist of Dermestidae (Insecta: Coleoptera: Bostrichoidea) of the United States.
Insects Limited, an Insect Pheromone Company
Insects Limited, Inc. researches, tests, develops, manufactures and distributes pheromones and trapping systems for insects in a global marketplace. The highly qualified staff also can assist with consultation, areas of expert witness, training presentations and grant writing.
Insects Limited, Inc. specializes in a unique niche of pest control that provides mainstream products and services to protect stored food, grain, museum collections, tobacco, timber and fiber worldwide. Please take some time to view these products and services in our web store.
