Quick answer: Orange beetles on the siding in October and Asian lady beetles in house windows in January are the same insect: the multicolored Asian lady beetle, not a native ladybug. Look for the black M or W behind the head. They do not breed indoors, but they can nip, stain and smell. Vacuum them, seal the sunny side of the house, and plan exterior treatment for early fall.
Key takeaways
- Native Oregon lady beetles do not overwinter indoors, so a lady beetle in the house in winter is almost always an Asian lady beetle, according to OSU Extension.
- The tell is a dark M or W on the whitish plate behind the head; body color runs from tan to deep red, and spots range from none to 19 or more.
- They gather on light-colored, sun-warmed south and west walls on the first warm afternoons after a cold snap, then settle into wall voids and attics.
- Indoors they can pinch skin, leak a yellow fluid that stains, and bother people with allergies, but they do not reproduce, feed or damage anything.
Are the orange beetles in my house ladybugs or Asian lady beetles?
Almost certainly Asian lady beetles. OSU Extension notes that Oregon’s native lady beetles do not overwinter inside buildings, so a lady beetle on your windowsill in December is the introduced species by default.
The multicolored Asian lady beetle (Harmonia axyridis) earns its name. Adults are about 1/4 inch long, a little larger than most natives, and range from pale tan through orange to deep red, with anywhere from zero to 19 or more black spots. The one consistent feature is the plate behind the head: it is whitish with a dark marking shaped like an M (or a W, depending on which way the beetle faces). Native species have their own fixed patterns and never show that M.
| Feature | Multicolored Asian lady beetle | Native lady beetles |
|---|---|---|
| Size | About 1/4 inch; slightly larger than most natives | Usually smaller |
| Color | Tan, orange or red; sometimes black with red spots | Typically red or orange, consistent within a species |
| Spots | None to 19 or more; faint or bold | A set pattern for each species |
| Behind the head | Whitish plate with a dark M or W | No M; markings vary by species |
| Fall behavior | Masses on sunny walls and moves into buildings by the hundreds | Overwinters outdoors, not in buildings |
| Indoors in winter | Common | Rare |
Why do Asian lady beetles gather on houses in fall?
Because a sun-warmed, light-colored wall on the first warm afternoon after a cold snap is exactly the signal they use to pick a winter shelter.
The University of Kentucky’s entomology department describes the pattern well: flights are heaviest on sunny afternoons following a period of cooler weather, once temperatures climb back to at least the mid-60s F, and the beetles congregate on the sunnier southwest sides of buildings lit by afternoon sun. Contrasting light and dark features, such as white siding with dark shutters or trim, draw them in. In the Willamette Valley that adds up to a few big flight days in October and early November, usually the same warm afternoons that bring boxelder bugs and stink bugs to the same walls.
Once on the wall, they follow the warmth into cracks under siding, behind soffits, around window and door frames and into the attic. Researchers at North Carolina State University note that chemical cues, possibly from the droppings or remains of beetles that overwintered there before, or an attractant pheromone, help explain why the same houses fill up year after year.
Asian lady beetles in house walls: what happens all winter
They sit still until a warm day. Beetles that entered in October rest in wall voids, attics and window frames, and each mild, sunny spell sends a few dozen crawling toward light: windows, ceiling fixtures, lampshades.
They do not reproduce indoors and they do not feed while overwintering. Every beetle you see in February entered the house as an adult last fall. Many die in the walls and on windowsills over the winter. The survivors leave in spring to find aphids and lay eggs outdoors.
Salem’s climate makes the winter phase more noticeable than it is in colder places. With long stretches between 35 and 50 F and frequent sunny breaks, valley homes get repeated indoor appearances from November through March, instead of one big emergence in spring.
Do Asian lady beetles bite?
Sometimes. They have chewing mouthparts built for eating aphids, and a beetle on bare skin will occasionally nip, but University of Kentucky entomologists describe the bite as feeling like a pinprick. It is a nuisance, not an injury.
The bigger nuisances are the fluid and the smell. When disturbed or crushed, the beetles release a yellowish defensive fluid from their legs that has an acrid odor and stains paint, fabric and drywall. That is the main reason we say vacuum, never swat. There is also a health note: studies cited by the University of Kentucky suggest infestations can trigger allergies in some people, from itchy eyes to asthma symptoms. If someone in the house reacts every winter, keeping the beetle numbers down matters more than it would for most nuisance pests.
If a dog eats a large number of beetles and is drooling or pawing at its mouth, call your veterinarian.
How to get rid of Asian lady beetles in the house right now
Vacuum them, do not crush them, and skip indoor sprays. In November the beetles are already in the walls, so this season is about removal; prevention is a late-summer job.
- Use the stocking trick. Push a knee-high nylon into the vacuum hose, fold the top over the end and hold it with a rubber band. The beetles collect in the stocking instead of the bag; tie it off and put it in the outside trash.
- Do not swat or crush. Every crushed beetle is a yellow stain on the wall or the curtain.
- Try a light trap in the attic. University of Kentucky notes light traps can be useful in dark, confined spaces such as attics, though they catch few beetles in living areas.
- Skip indoor insecticides. Sprays applied indoors for lady beetles tend to be ineffective, and they can stain or leave residue on walls and countertops. A vacuum is cleaner and works better.
- Seal what you can from inside. Caulk around window trim, add foam gaskets behind outlet and switch plates on exterior walls, and seal gaps where pipes come through.
- Mark the calendar. Exterior sealing belongs in late summer, before the flights begin. The same steps we lay out for boxelder bugs and stink bugs apply here, wall for wall.
Why Albany and the mid-valley see so many
Aphids and sunshine. Asian lady beetles spend summer wherever aphids are thick, and the mid-valley’s grass seed fields, hazelnut orchards and vegetable farms around Albany, Tangent and Lebanon give them a lot of summer habitat. When the weather turns, the beetles head for the nearest light-colored, sun-warmed buildings, and a farmhouse or shop building at a field edge often takes the heaviest flight.
In town, the ranch homes built from the 1950s through the 1980s have what the beetles want: lap siding with gaps, wide eaves, west-facing walls, and light paint.
Outdoors, leave them alone. Both larvae and adults eat large numbers of aphids and scale insects, and OSU notes that the bigger concern with this species is competition with native lady beetles, not damage to your garden.
When to call a professional
Call when beetles are reaching living space by the dozens, when the same walls fill every fall, or when someone in the house has asthma or allergies that flare whenever the beetles are active.
Our fall-invader inspection identifies which walls the beetles use, where they enter (soffits, siding joints, window frames, attic vents) and whether the attic is holding a large group. We vacuum out accessible clusters, walk you through the sealing that will make the biggest difference, and schedule an exterior treatment for the late-September window next year, applied to the sunny walls and entry points with EPA-registered products according to the label. We tell you exactly what to expect, including any re-entry times, and offer family- and pet-considerate options. The same visit covers boxelder bugs, cluster flies and stink bugs; see our stink bug service, and lady beetles fall under our general pest control services. AAA Pest Exterminators has been family-owned and operated in Salem since 1997, with no long-term contracts.
Frequently asked questions
Are Asian lady beetles bad for my garden?
No. Outdoors they are useful predators; both larvae and adults eat aphids and scale insects, doing the same work as native ladybugs on a rose or in a vegetable bed. The concern OSU Extension raises is competition with native species, not plant damage. Leave the ones outside alone and deal with the ones that come in.
Why do they come back to the same house every year?
Because the house smells right. Researchers at North Carolina State University report that chemical cues, possibly from the droppings or remains of beetles that overwintered there before, or an attractant pheromone, help guide new arrivals to the same spots. Sun exposure and light color do the rest. A thorough vacuuming of the attic and wall cavities you can reach, plus sealing, weakens the pull.
Do Asian lady beetles lay eggs in the house?
No. They do not reproduce indoors, and they do not feed while overwintering. Every beetle you see in January entered the house last fall as an adult. Once spring warms up, the survivors leave to find aphids and lay eggs on plants outside. Vacuuming the stragglers is removal, not a losing battle against a breeding population.
Is it too late to do anything in November?
Not for removal once they are inside, but yes for prevention. Once the beetles are in the walls, the winter job is vacuuming the ones that appear and sealing indoor gaps around windows and outlets on exterior walls. Put exterior sealing on the calendar for late summer and exterior treatment for late September, before next year’s flight.
Pests in the nest? Don’t stress. Call the best.
Family-owned and operated in Salem since 1997. No long-term contracts. Serving Salem, Keizer, Albany, Dallas, Woodburn and McMinnville.
Not sure what you’re looking at? Text us a photo and we’ll help identify it.
