Boxelder Bug Life Cycle

- Larvae feed on maple tree leaves -

Summary: Boxelder bugs have only one generation per year in most regions. The bugs develops on maple trees during summer months then migrate in the fall to find protected places to spend the winter. Unfortunately, sometimes this protected place is our homes.

Jack DeAngelis, PhD

OSU Ext. Entomologist (ret.)

For some unfortunate homeowners boxelder bugs are a yearly ordeal (see What are Boxelder Bugs?) when these fairly large bugs congregate on their homes each fall. Once settling on the home's siding they may even find ways to get indoors. The good news is they pose no real threat to you or your home and don't breed indoors. The bad news is they may be back year after year, and they can be a real nuisance. If they do get indoors they can soil interior furnishings with their droppings and may be a nuisance all winter.

Unfortunately we don't have any permanent solutions to offer but there are a few things that will help. First, caulk openings and cracks around doors and windows and repair window and soffit (roof vent) screens to block entry. If bugs get in, in large numbers, it may be necessary to treat wall voids and attic spaces with insecticide. See our DIY Boxelder Bug Control article for suggestions for treating siding and wall voids.

Boxelder bug (about 1/2 inch long). Note the red markings around the dark grey wings.

Why are certain houses selected by boxelder bugs?

The natural habitat of overwintering boxelder bugs is the deep furrows in the bark of large trees. These furrows provide boxelder bugs with protection from winter weather. While it is not entirely clear why some houses are selected instead, boxelder bugs seem to be attracted to those that share certain characteristics. Tall buildings, two-story or higher, get more attention from these critters. Also, houses that are sited high relative to their surroundings such as those built on a hill.

The migrating adult bugs also seem favor houses with large trees immediately adjacent, especially if these trees are on the side that gets afternoon sun. These large trees apparently act as beacons when the adult bugs are on the move. During sunny afternoons bugs that are resting in the trees fly onto the warm house siding.

Boxelder bug life cycle

FALL - adult bugs leave maple trees and search for protected place to spend winter months, this is when they are the biggest nuisance.

WINTER - adult bugs inactive, unless in warm indoor living spaces.

SPRING - adult bugs leave winter sites, fly to maple trees and lay eggs for next generation.

SUMMER - eggs hatch, young bugs feed on maple leaves and complete development. There is only 1 generation per year.

Remember, as much of a nuisance as they are, boxelder bugs will only be active outdoors until the weather gets cold so the best solution may be to just ignore the bugs until they go away. A final caution: In some areas yearly boxelder bug invasions have become a discloseable condition, like a leaky roof, when selling real estate. Discuss this with your real estate agent.

Soaps, dusts and other supplies for boxelder bug control are available here (DoMyOwn.com), our affiliate.

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