Multicolored Asian Lady Beetles
Why Multicolored Asian Lady Beetles Show Up Around Maine Homes
Multicolored Asian lady beetles (Harmonia axyridis) are common throughout Maine and are usually beneficial outdoors, where they feed on aphids and other plant pests. Problems begin in the fall, when large numbers of adult beetles gather on homes and other buildings in search of protected places to spend the winter.
These beetles are sometimes called Halloween lady beetles because their movement toward buildings becomes especially noticeable around October. While they don't typically cause damage to homes, they can become a nuisance when large numbers find their way indoors.
What Do Multicolored Asian Lady Beetles Look Like?
The name “multicolored” is appropriate because these beetles can vary considerably in appearance.
Adults are generally about ¼ inch long with a rounded, dome-shaped body.
Identification features may include:
Yellow, orange, or red wing covers
Zero to 19 black spots
Rounded, dome-shaped body
Reddish-brown legs
Pale area directly behind the head
Distinct dark marking behind the head that often resembles an “M” or “W”
Spot count alone is not a reliable way to identify this species because individual beetles can look quite different from one another.
Are Asian Lady Beetles the Same as Ladybugs?
“Ladybug” is a general term people use for many species of lady beetles. Multicolored Asian lady beetles are one particular nonnative species within that larger group.
Maine is home to other lady beetles, including native species that may look similar at first glance. That means finding a ladybug on your property doesn't necessarily mean you're looking at a multicolored Asian lady beetle.
When Are Multicolored Asian Lady Beetles Most Noticeable in Maine?
Spring
Beetles that spent the winter inside protected areas of a building begin to emerge as temperatures rise. Once outdoors, adults feed, mate, and lay eggs near aphid and other soft-bodied insect populations.
Summer
During summer, multicolored Asian lady beetles generally remain outdoors, where both adults and larvae prey on aphids, scales, mites, and other small insects.
At this time of year, they are usually beneficial rather than a household pest.
Fall
Fall is when multicolored Asian lady beetles become most noticeable around homes in Maine. As temperatures cool, adults begin gathering on buildings in search of protected overwintering sites.
Activity can be especially noticeable on sunny fall afternoons when beetles collect around exterior walls, windows, doors, and rooflines.
Winter
Most beetles remain hidden during winter, but warmth from the home or sunlight on exterior walls can cause some to become active.
That is why homeowners sometimes find lady beetles crawling around windows or flying through rooms in the middle of winter.
Where Do Asian Lady Beetles Overwinter?
Multicolored Asian lady beetles naturally seek protected spaces to avoid winter weather.
Around homes, they may shelter:
Behind siding
Inside wall voids
Around window and door frames
Beneath rooflines
In attics
Around soffits and fascia
Inside cracks and crevices on the exterior
Around utility penetrations
Unlike household pests that establish breeding populations indoors, these beetles are using the building as a temporary winter shelter. They do not normally reproduce, feed, or build nests inside the home.
Why Do So Many Gather on the Same House?
Multicolored Asian lady beetles tend to gather together when searching for winter shelter, and certain buildings can attract especially large numbers.
Warm, sun-exposed exterior surfaces may become gathering points on cool fall days. Once a suitable shelter is found, aggregation behavior can result in dozens, hundreds, or sometimes even larger numbers of beetles collecting around the same structure.
This does not mean the home is dirty or has an indoor food problem. The beetles are simply looking for protection from winter weather.
Do Multicolored Asian Lady Beetles Damage Homes?
No. Multicolored Asian lady beetles do not eat wood, fabrics, stored food, or other building materials. Their main concern is nuisance activity.
When disturbed or crushed, they can release a yellowish-orange defensive fluid with a noticeable odor that may stain light-colored walls, curtains, furniture, or fabrics.
Large numbers of insects indoors can be frustrating, particularly when beetles gather around windows, walls, and ceilings.
Do Asian Lady Beetles Bite?
They can occasionally pinch or bite exposed skin, although they do not feed on people and do not sting.
These incidents are usually minor and occur when beetles land on or are handled by a person. Multicolored Asian lady beetles are not known to transmit diseases to people.
Why Prevention Matters Before Fall Beetles Move Indoors
Exterior gaps around windows, doors, siding, rooflines, utility penetrations, and similar areas can provide access to protected spaces inside a home.
Sealing accessible openings before fall migration begins can help reduce the number of beetles that make it indoors. Homeowners should also check for worn weatherstripping, damaged screens, and gaps around window and door frames.
These preventive steps are most helpful before beetles begin gathering on buildings for the winter.
What Should You Do With Asian Lady Beetles Already Indoors?
If you find Asian lady beetles inside your home, avoid crushing them against walls, windows, or furniture.
Small numbers can often be removed with a vacuum. Empty the vacuum contents afterward to prevent collected beetles from escaping or producing odors.
If you're finding large numbers indoors, professional pest control can help you evaluate the problem and plan for future seasonal activity.
Multicolored Asian Lady Beetle Control in Maine
Timing matters when addressing multicolored Asian lady beetles. Exterior treatment is generally most useful before large numbers have settled into inaccessible areas of a home for the winter.
Advanced Pest Solutions can provide treatment for multicolored Asian lady beetles for an additional fee. These beetles are not typically included in our standard residential pest control plans, so homeowners who have experienced large fall aggregations or recurring overwintering problems should contact us to discuss treatment options.
Our team can evaluate where beetles are gathering and identify areas around the exterior that may be contributing to indoor activity.
If multicolored Asian lady beetles gather on your Maine home every fall or continue showing up inside during winter, contact Advanced Pest Solutions to learn more about available treatment options.
Multicolored Asian Lady Beetle FAQs
Does the number of spots tell you how old an Asian lady beetle is?
No. Spot number does not indicate age. Multicolored Asian lady beetles naturally vary in color and can have anywhere from 0 to 19 visible spots.
Are Asian lady beetles attracted to certain house colors?
Yes. Multicolored Asian lady beetles are often attracted to light-colored homes, particularly those with white, cream, or pale yellow exteriors. Contrasting features, such as dark shutters against light siding, may also attract beetles. However, homes of any color can experience problems.
Can multicolored Asian lady beetles cause allergies?
Yes, although most people are not affected. Exposure to large numbers of Asian lady beetles indoors can trigger allergic reactions in sensitive individuals. Symptoms may include sneezing, irritated eyes, or other respiratory symptoms, particularly with repeated exposure.