The boxelder bug (Boisea trivittata) is a common North American insect known for its striking black and red coloration. While they are harmless to humans and do not cause significant structural damage to homes or trees, they are widely considered a major nuisance pest. Every autumn, thousands of these bugs congregate on the warm, sunny sides of buildings, desperately trying to find a way inside to survive the winter cold.
Quick Facts: Boxelder Bug Profile
| Category | Information |
|---|---|
| Scientific Name | Boisea trivittata |
| Common Name | Boxelder bug, maple bug |
| Kingdom / Phylum | Animalia / Arthropoda |
| Class / Order | Insecta / Hemiptera (True Bugs) |
| Family / Genus | Rhopalidae / Boisea |
| Diet Type | Herbivore (Sap-feeder) |
| Average Lifespan | Approximately 1 year |
| Conservation Status | Not Evaluated (Abundant) |
Physical Characteristics and Size
Boxelder bugs belong to the order of “true bugs” (Hemiptera), meaning they have specialized piercing-sucking mouthparts rather than chewing mandibles.
- Size & Length: Adult boxelder bugs are small, measuring about 0.5 inches (1.2 cm) in length.
- Shape: They have a flat, elongated, oval-shaped body.
- Coloration: Their bodies are dark brown or matte black, marked by three distinct, bright red or orange stripes behind their head. Their wings lay flat across their backs, creating a red “V” or “X” pattern.
- Nymphs (Babies): When boxelder bugs first hatch, they lack wings and are almost entirely bright red. As they molt and grow, they gradually develop their black wings and adult markings.
Geographic Range and Habitat
Boxelder bugs are native to North America and can be found across the United States and southern Canada. Their presence is directly tied to the location of their primary host plant: the boxelder tree (Acer negundo).
Preferred Habitats: During the spring and summer, boxelder bug habitat is strictly outdoors in deciduous forests, suburban neighborhoods, and parks. They live almost exclusively on:
- Female (seed-bearing) boxelder trees
- Silver maple and bigleaf maple trees
- Ash trees
Winter Habitat: In the fall, their habitat shifts drastically. As temperatures drop, they leave their host trees in massive swarms. They seek out the south- or west-facing walls of houses and buildings to soak up the sun. Eventually, they crawl into cracks in the foundation, gaps in siding, or under roof eaves to overwinter inside wall voids.
Diet: What Does a Boxelder Bug Eat?
Despite invading homes by the thousands, boxelder bugs do not eat human food, wood, or clothing. They are strict herbivores that feed entirely on plant juices.
What they eat:
- Primary Diet: The juices inside the seeds of female boxelder trees.
- Secondary Diet: They will also feed on the leaves, stems, and newly developing twigs of maple and ash trees.
- Feeding Method: They use a straw-like proboscis to pierce the plant tissue, inject a digestive enzyme, and suck out the liquefied sap. Their feeding rarely causes any actual harm to the host tree.
How to Get Rid of Boxelder Bugs
Because they do not sting, bite, transmit diseases, or chew on wood like termites, boxelder bugs are purely a nuisance. However, if crushed, they release a foul-smelling odor and their bodily fluids can permanently stain curtains, carpets, and walls.
The Best Removal Methods:
- Seal the House: The most effective control is prevention. In late summer, use silicone caulk to seal cracks around windows, doors, pipes, and foundations. Repair any holes in window screens.
- Soapy Water Spray: You do not need harsh pesticides. A mixture of water and liquid dish soap sprayed directly on the bugs will break down their protective outer shell and kill them almost instantly.
- Vacuuming: If they are already inside your house, do not crush them. Use a vacuum cleaner with a hose attachment to suck them up, then immediately empty the canister into a sealed bag outdoors.
Frequently Asked Questions (FAQ)
The best way to get rid of boxelder bugs is to spray them directly with a mixture of dish soap and water, which kills them on contact. If they are already inside your home, vacuum them up instead of crushing them to avoid foul odors and stains. Prevent future invasions by caulking cracks around windows and doors in late summer.
A boxelder bug eats the sap and juices from the seeds, leaves, and stems of female boxelder trees, as well as maple and ash trees. They do not eat human food, wood, or fabric, meaning they will not damage your pantry or home structure if they get inside.
During the spring and summer, their habitat consists of boxelder, maple, and ash trees across the United States and southern Canada. In the fall and winter, their habitat shifts to the warm, sun-facing walls of houses and buildings, eventually moving inside wall voids to survive the cold.
Adult boxelder bugs are approximately 0.5 inches (1.2 cm) long. They have a flat, oval-shaped body that is black with distinct red or orange lines on their back.
No, boxelder bugs do not bite or sting humans or pets. Their mouthparts are designed strictly for piercing plant seeds and sucking out sap. They are harmless, though they can release a bad odor if crushed.