Boxelder bugs, those black insects with distinctive reddish markings, are likely showing up around your home for specific reasons. These half-inch pests can detect temperature differences of just one degree, which is why you’ll spot them congregating in large numbers on warm, sunny surfaces, particularly during fall when they’re searching for winter shelter. If you’ve noticed these unwelcome visitors, the proximity of boxelder, maple, or ash trees might be the primary culprit.
Your home becomes especially attractive to boxelder bugs when temperatures drop. As these sap-sucking insects seek warmth, they target sunny sides of buildings and eventually find their way inside through small gaps and crevices. While they don’t cause significant damage to your home or plants, they can leave reddish stains when crushed—creating a frustrating nuisance. Understanding what attracts boxelder bugs to your house is the first step toward effectively preventing an infestation and keeping these seasonal invaders at bay.
What Attracts Boxelder Bugs to Your Home
Ever wondered why these red-and-black insects seem to target your home specifically? Understanding what attracts boxelder bugs is the first step toward keeping them at bay.
Warm surfaces and sunny walls
Boxelder bugs are heat-seekers by nature. They’re remarkably sensitive to temperature changes and can detect differences as small as one degree. These insects absolutely love basking on warm, sunny surfaces—specifically walls that face south or west.
Buildings that stand taller than surrounding structures or stand alone on flat ground tend to attract larger numbers of these pests [1]. You’ll notice them congregating in significant numbers on brick or stucco facades that receive abundant sunlight [2]. In fact, dark-colored exteriors attract them even more readily because these surfaces absorb and retain heat better [3].
As autumn approaches and temperatures fluctuate, boxelder bugs become increasingly desperate for warmth. When temperatures drop below 40 degrees and then climb back to 65 degrees, they begin their search for winter shelter [3]. This temperature-driven behavior explains why you’ll often see them clustered together—they’re literally huddling for warmth.
Nearby boxelder, maple, or ash trees
The primary attraction for these insects is in their name—boxelder trees. Female boxelder trees (a type of maple also known as Acer negundo) produce seeds that serve as the bugs’ favorite food source [4][5].
These insects feed primarily on:
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Seeds from boxelder trees
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Seeds from other maple varieties
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Occasionally ash tree seeds
In spring, they consume juice from ungerminated seeds that have fallen from trees. As summer progresses, they feed on newly developing seeds [6]. Having any of these trees on or near your property significantly increases your chances of encountering boxelder bugs [7].
Cracks, crevices, and cozy hiding spots
As temperatures cool in autumn, boxelder bugs actively search for protected spaces to overwinter. Your home provides ideal shelter with its many small openings and warm interior.
These insects are remarkably adept at finding entry points around:
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Window frames and door casings
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Gaps in siding or under eaves
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Cracks in foundations or exterior walls
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Vents and utility penetrations
Once inside, they seek undisturbed areas like attics, wall voids, basements, and storage spaces [8]. They remain largely inactive during winter months but may become visible on warmer days when they mistakenly believe spring has arrived [1].
Remember that boxelder bugs aren’t searching for food inside your home—just shelter from freezing temperatures. This distinction helps explain their seasonal appearance and disappearance.
How Boxelder Bugs Get Inside
Those pesky boxelder bugs don’t just appear inside your home by magic. Understanding exactly how they infiltrate your living space can help you stop them before they become unwelcome houseguests.
Common entry points around windows and doors
Boxelder bugs are surprisingly skilled at finding their way into your home through the smallest openings. They commonly enter through:
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Cracks around window frames and door casings
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Gaps under exterior doors without proper sweeps
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Openings around utility lines, cables, pipes, and faucets
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Pulley openings in older homes with double-hung windows
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Tears in window and door screens
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Gaps in siding, especially in older homes with vinyl siding
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Cracks where different materials meet (like brick and wood siding)
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Vents, soffits, and unsealed attic openings
Even openings as small as 1/8 inch provide ample space for these determined insects to squeeze through. Newer homes often have better protection with house wrap beneath siding, creating fewer entry opportunities.
What attracts boxelder bugs in the fall
As summer transitions to fall, boxelder bugs begin a predictable migration pattern. Several environmental factors trigger this behavior:
First, the changing daylight hours signal it’s time to find winter shelter. As temperatures fluctuate—warm days followed by cold nights—boxelder bugs instinctively seek protected spaces where they can hibernate safely.
These insects aren’t randomly wandering—they’re following specific environmental cues. They’re searching for temperatures between 40-50°F, which is ideal for hibernation without depleting their stored energy reserves.
Rather impressively, adult boxelder bugs can fly up to two miles to find suitable winter quarters. This explains why removing nearby host trees doesn’t always solve the problem.
You’ll notice them congregating most heavily on south and west-facing walls where afternoon sun creates warmth. From these gathering spots, they methodically explore your home’s exterior, probing for any potential entry point. Once inside, they typically remain inactive until warmth brings them out—either from a sunny winter day or your home’s heating system.
How to Prevent a Boxelder Bug Infestation
Image Source: The Spruce
Preventing a boxelder bug invasion requires a proactive approach. With a few straightforward strategies, you can significantly reduce your chances of finding these red-shouldered insects overwintering in your home.
Seal gaps and install door sweeps
The most effective prevention method is creating a physical barrier. Thoroughly inspect your home’s exterior for potential entry points, paying close attention to:
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Cracks around window frames and door casings
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Gaps in siding and foundation (seal any openings 1/8 inch or larger)
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Areas where cables, pipes, and utility lines enter your home
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Weep holes in brick structures (cover with wire mesh)
Use silicone caulk for smaller gaps and expandable foam for larger spaces. Install door sweeps on all exterior doors and add rubber seals along the bottom of garage doors. For older homes with vinyl siding, this task may be challenging since there are typically more gaps than in newer construction with house wrap underneath.
Use soapy water to break up boxelder bug clusters
A simple mixture of dish soap and water works wonders against boxelder bugs. Add about a tablespoon of dish soap to a spray bottle filled with water and shake gently. This solution kills boxelder bugs by breaking down their protective outer shell, causing them to dehydrate.
Spray this mixture directly on bug clusters gathering on your home’s exterior. Additionally, this helps remove the pheromones they leave behind that attract more bugs to the same spot.
Trim or manage host trees near your home
Since boxelder bugs primarily feed on seeds from boxelder trees (and occasionally other maples and ash), managing these trees is crucial. Consider these approaches:
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Remove female (seed-producing) boxelder trees if practical
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Regularly trim branches, especially those extending toward your house
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Promptly rake up fallen seeds and pods, particularly in spring and early summer
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Create a 6-10 foot debris-free zone around your foundation
Remember that adult boxelder bugs can fly several blocks, so removing trees won’t completely eliminate the problem but will reduce numbers substantially.
Clean surfaces to remove boxelder bug-attracting scents
Boxelder bugs leave behind aggregation pheromones that attract others to the same location. Regular cleaning of heat-reflective surfaces (windows, siding, doors) helps disrupt this chemical invitation. Focus mainly on:
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South and west-facing walls where bugs typically congregate
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Dark-colored exterior surfaces that retain heat
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Areas with previous boxelder bug activity
Use scented cleaning solutions to mask any remaining pheromones and make these surfaces less appealing.
FAQs About Boxelder Bugs
Got questions about those red and black bugs showing up around your home? These common concerns will help you better understand your uninvited guests.
Do boxelder bugs bite or sting?
Rest easy—boxelder bugs rarely bite humans or pets. Although they have piercing-sucking mouthparts to feed on plant material, they almost never use them on people. In the extremely rare case of a defensive bite, you might notice a small red mark similar to a mosquito bite with mild irritation that typically resolves quickly without treatment. Furthermore, boxelder bugs don’t sting and don’t transmit diseases, making them primarily a nuisance rather than a health concern.
Can they damage my home or plants?
Boxelder bugs cause minimal damage overall. Inside your home, their primary issue is staining. Their fecal matter can leave yellowish, brown, or gray discoloration on light-colored surfaces, curtains, upholstery, and clothing. Outside, they typically don’t harm vegetation significantly. Nonetheless, they might occasionally feed on fruit trees like peaches, plums, and grapes, causing minor cosmetic damage such as roughed-up pits and skin dimpling—an issue mainly for commercial orchards concerned with appearance.
Are they the same as stink bugs?
Although sometimes confused, boxelder bugs and stink bugs are different insects:
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Boxelder bugs have flat, elongated bodies with distinctive red markings on black backgrounds
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Stink bugs have shield-shaped bodies that are typically green to brown
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Both emit odors when crushed, though stink bugs produce a stronger smell
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Stink bugs generally cause more crop damage than boxelder bugs
When should I call a pest control pro?
Consider professional help if:
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You’ve tried sealing entry points and using DIY methods without success
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You’re seeing large numbers of boxelder bugs inside despite prevention efforts
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You have a recurring seasonal infestation that gets worse each year
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The infestation is causing significant staining or nuisance issues
Professional pest control might be particularly helpful for addressing large gatherings on exterior walls before they make their way inside during fall.
Conclusion: Knowing What Attracts Boxelder Bugs is Half the Battle
Understanding what attracts boxelder bugs is undeniably your best defense against these seasonal invaders. After all, prevention remains far more effective than trying to eliminate an established infestation. Boxelder bugs might be persistent, but they’re largely predictable—seeking warmth, shelter, and proximity to their favorite trees.
Your most powerful strategy combines several approaches simultaneously. First, seal all potential entry points around your home, particularly before fall when migration begins. Additionally, regular cleaning of sunny exterior walls disrupts the pheromone trails that lead others to your home. The simple combination of dish soap and water serves as both a deterrent and solution for existing clusters.
While these insects might seem determined to make your home their winter headquarters, remember they cause minimal damage and pose virtually no health risks. The occasional stain from crushed bugs represents their biggest threat to your household. Most boxelder bug problems can be managed through diligent home maintenance and basic preventive measures without professional intervention.
Lastly, patience plays a key role in dealing with these seasonal visitors. Though you might never completely eliminate boxelder bugs if their host trees remain nearby, you can significantly reduce their numbers through consistent prevention efforts. Armed with this knowledge, you can now confidently tackle your boxelder bug challenges and enjoy a more pest-free home throughout the changing seasons.
References
[1] – https://extension.umn.edu/nuisance-insects/boxelder-bugs
[2] – https://www.terro.com/articles/boxelder-bug-questions-answered?srsltid=AfmBOop1PHjskXqdD5p1m3dDWr_Ivni-WilLYaM_fBGB7qICJpZpviS6
[3] – https://structuretech.com/boxelder-bugs/
[4] – https://ask2.extension.org/kb/faq.php?id=443650
[5] – https://ucanr.edu/blog/spill-beans/article/boxelder-infestation
[6] – https://www.terro.com/articles/boxelder-bug-questions-answered?srsltid=AfmBOopK8OC3df27xcZEf7bXyLfvYtV9h2KCJZQDVJfFpk3FnQySW0pk
[7] – https://www.ecoguardpestmanagement.com/pest-resources/what-attracts-boxelder-bugs
[8] – https://www.domyown.com/boxelder-bug-inspection-guide-a-718.html?srsltid=AfmBOor9nK2_fOP4MYhR4Ya-EQfnU0DHt4ShuO7zzEfIthZJFSKJqv2e
