Asian Lady Beetles

Asian lady beetles look like native ladybugs but aggregate on homes in fall and push indoors to overwinter. They can bite lightly and stain surfaces with a yellow fluid, making them a bigger nuisance than their harmless appearance suggests.

How to identify Asian lady beetles

About 1/4 inch, orange to red with variable black spots and a distinctive black-and-white M-shaped mark behind the head. Color and spotting vary widely.

Behavior & season on Whidbey & Fidalgo

After feeding on aphids all season, they mass on sun-warmed walls in fall and enter through gaps to overwinter in voids, re-emerging on warm days and in spring, often at windows.

Why Asian lady beetles are a problem

They can nip skin, and when disturbed they exude a foul-smelling yellow fluid that stains walls and fabrics. Large indoor aggregations are a recurring seasonal nuisance.

Signs of Asian lady beetles activity

• Orange beetles with an M-mark clustering on walls in fall
• Beetles at windows on warm winter days
• Yellow staining where they gather or are crushed
• Aggregations near attic vents and eaves

How Salty Dog treats Asian lady beetles

We treat exterior aggregation sites and harborage in fall and seal the gaps they use, reducing indoor numbers without staining surfaces. Learn more about our Outdoor Pest Control service, or browse the full Pest Library.

Frequently asked questions

How is this different from a regular ladybug?

Asian lady beetles have an M-shaped mark behind the head, aggregate on homes to overwinter, can bite, and stain — native ladybugs do none of that indoors.

What is the yellow stain they leave?

A defensive fluid they release when disturbed. It smells and stains, so vacuuming rather than crushing is best.

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