The Canadian Encyclopedia — neutral, cited, updated
July 27, 2026Sources cited
Canadianwire.
Canada’s encyclopedia & explainer
Home›Science & Nature›Entomology›Asian lady beetle
Science & Nature • Entomology

Asian lady beetle

The Asian lady beetle is a lady beetle species, *Harmonia axyridis*, native to Asia and introduced in North America as a biological control agent for aphids and other soft-bodied pests.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

The Asian lady beetle is a lady beetle species, *Harmonia axyridis*, native to Asia and introduced in North America as a biological control agent for aphids and other soft-bodied pests. It is now widespread across much of the United States and parts of Canada, where it is beneficial outdoors but can become a nuisance in homes.

Taxonomy and naming

*Harmonia axyridis* is a beetle in the family Coccinellidae. It is widely known as the Asian lady beetle, multicolored Asian lady beetle, or harlequin ladybird.

Distribution and introduction

The species is native to Asia and was introduced to North America for biological control of crop pests. It is now established across much of the United States and parts of Canada.

Biology and appearance

Adults vary widely in colour and spot number, and many have an M-shaped mark behind the head. The larvae are predatory and feed on aphids and scale insects alongside adults.

Human interactions

Outdoors, the beetle is generally beneficial, but indoors it can be a nuisance when large numbers gather to overwinter. It can bite occasionally, may emit a defensive fluid, and may trigger allergies in some people.

Key facts

  • The species is native to eastern Asia and has been introduced to North America for pest control.
  • Adults and larvae feed on aphids and scale insects, making them useful in gardens and agriculture.
  • The beetle is common in homes in autumn because it seeks warm sheltered places to overwinter.
  • It does not attack wood, food, or clothing, and is generally not dangerous to humans or pets.
  • Some people may experience allergic reactions, and the beetles can leave a yellowish stain or odour when disturbed.
🍁
Canadian context

The species is established in parts of Canada and is commonly encountered by Canadian homeowners as a fall nuisance indoors, while remaining beneficial in gardens and agricultural settings by preying on pests.[5][6][8]

Frequently asked questions

What is the Asian lady beetle?
It is a lady beetle species, *Harmonia axyridis*, native to Asia and introduced elsewhere for biological pest control.
Is the Asian lady beetle harmful to people?
It is generally not dangerous to people or pets, though it can bite, cause nuisance infestations, and may trigger allergies in some individuals.
Why do Asian lady beetles come indoors?
They often enter buildings in autumn to seek warm sheltered places for overwintering.
What do Asian lady beetles eat?
They prey on aphids, scale insects, and other soft-bodied insects, especially on plants and trees.
How can you identify an Asian lady beetle?
They have highly variable colours and spot counts, and many show an M-shaped mark on the pronotum behind the head.
Are Asian lady beetles native to Canada?
No. They are native to Asia and are established in parts of Canada after introduction and spread from North America.

References

  1. University of Kentucky Entomology — https://entomology.mgcafe.uky.edu/ef416
    Supports: Native range, introduction, spread in North America, nuisance indoors, dietary habits, and allergy notes.
  2. University of Connecticut — https://homegarden.cahnr.uconn.edu/factsheets/asian-lady-beetle/
    Supports: Scientific name, common names, family, and colour/spot variation.
  3. WebMD — https://www.webmd.com/a-to-z-guides/asian-lady-beetle-what-to-know
    Supports: Human safety, bites, and disease transmission.
  4. Orkin Canada — https://www.orkincanada.ca/pests/beetles/asian-lady-beetles/
    Supports: Canadian nuisance status, diet, lifespan, and general behaviour.
  5. USDA Agricultural Research Service — https://www.ars.usda.gov/oc/br/lbeetle/index/
    Supports: Native range, introduction history, and use in biological control.
  6. Vermont Atlas of Life — https://val.vtecostudies.org/projects/lady-beetle-atlas/asian-lady-beetle/
    Supports: Appearance, spot count range, and distribution in North America.
  7. University of Maryland Extension — https://extension.umd.edu/resource/multicolored-asian-lady-beetle
    Supports: Identification, life stage details, diet, habitat, and development timing.
  8. Missouri Department of Conservation — https://mdc.mo.gov/discover-nature/field-guide/asian-lady-beetle
    Supports: Non-dangerous status and lack of disease transmission.