Are Asian Lady Beetles Invasive?

Yes — Asian lady beetles (Harmonia axyridis) are considered an invasive species in North America. They were originally introduced from Asia in the early 1900s and again in the 1980s as a form of biological control to manage agricultural pests like aphids and scale insects. However, their population spread rapidly beyond intended areas, and they have since become a nuisance for homeowners and a threat to native ladybug species. Here’s why Asian lady beetles are classified as invasive:

Competition with Native Species: Asian lady beetles outcompete native ladybugs for food and habitat, leading to a decline in native populations.
Rapid Reproduction and Adaptability: They reproduce quickly, adapt to various climates, and can survive winters by invading homes and buildings to overwinter.
Nuisance to Humans: When they gather indoors, they release a foul-smelling yellow fluid that can stain walls and cause allergic reactions in some people.
Agricultural and Ecological Impact: Although they eat harmful pests, their dominance disrupts natural ecosystems and reduces biodiversity among beneficial insects.

While they were introduced with good intentions, Asian lady beetles have become a problematic invasive species across much of the U.S. and Canada.