The Multicolored Asian Ladybug
An Invasive Species
Scientific Name: Harmonia axyridis
Common Names: Multicolored Asian beetle, Asian ladybug, Harlequin ladybug, Halloween ladybug
The multicolored Asian ladybug is a predator that feasts on aphids, scale insects, eggs and larvae of butterflies, and other ladybugs. They are pollinators who also consume pollen, nectar, fruit juices and honeydew. Their bright colors serve as a warning to predators that they taste bad. Each female Asian ladybug can produce around 1,000 to 2,000 eggs in its lifetime, usually laying them in batches of about 10 to 30 per day. The adult Asian ladybug usually lives for about a year, and is active in reproduction for around three months of its lifetime. Unlike many other ladybug species, which require a period of winter dormancy before they can breed and have only one generation each year, the multicolored ladybug often has two generations in a year.
Native Range Map
Harmonia axyridis is native to eastern Asia from central Siberia, Kazakhstan, and Uzbekistan in the west, Russia south of the Himalayas and east of the Pacific coast, and Japan including Korea, Mongolia, China, and Taiwan.
Invasive Range Map
Harmonia axyridis is now established in the United States, Canada, Argentina, Brazil, Italy, the United Kingdom, Denmark, the Netherlands, Belgium, Luxembourg, France, Germany, the Czech Republic, Hungary, Croatia, Poland, and South Africa.
- Has an unpleasant odor and stain left by bodily fluid when frightened (known as reflex blood) or squashed
- Spends the winter indoors
- Tendency to bite humans
- Voracious appetite enabling it to out compete and even eat other ladybugs
- Highly resistant to diseases that affect other ladybug species
- Carries microsporidian parasite, immune but can infect and kill other species
- Native ladybug species have experienced dramatic population declines in areas of invasion
- Contaminates crops of tender fruits and grapes in Iowa, Ohio, New York State, and Ontario
Can Humans Reduce Impact?
Methods for controlling the species include insecticides, trapping, and mechanically preventing entry to buildings. Methods under development involve the investigation of natural parasites and pathogens. Traps are available that contain the pheromones used by the beetles to attract each other into large gatherings. The best methods for dealing with them in private homes involve sealing openings they may enter.
Prognosis and Human Influence
Harmonia axyridis has been artificially introduced to North America and Europe to control aphids and scale insects. The multicolored Asian ladybug secretes a number of defensive compounds that counteract pathogens. They will be around for a long time.