Asian Multicolored Lady Beetle, Harmonia axyridis

Habits and Traits of Asian Multicolored Lady Beetle

The Asian multicolored lady beetle is an exotic, invasive species in North America.
The Asian multicolored lady beetle, Harmonia axyridis, is easy to identify from its false "eyes"-- twin white football-shaped markings behind the head. Scott Bauer, USDA Agricultural Research Service

The Asian multicolored lady beetle, a native of Asia, came to North America through several accidental and intentional releases. By the mid-1990's, Harmonia axyridis was well-established from coast to coast in the U.S. and Canada. If you look for lady beetles in your backyard garden, and there's a good chance you'll find one or more Asian multicolored lady beetles (often called Japanese lady beetles).

Description:

The adult Asian multicolored lady beetle comes in many color variations, from yellow to black. Many have the familiar red back with black spots that we associate with lady beetles. The number of spots varies as much as the color, but the most common form has ten spots on each elytra. To identify a lady beetle as Harmonia axyridis, look at the thorax, on the dorsal (upper) side just behind the head. Japanese lady beetles have several black dots which merge together to form an M-shaped marking. On some individuals, you will also notice two football-shaped white patches, one on each side of the thorax.

Larvae of the Asian multicolored lady beetle look like tiny alligators at first glance, with flattened bodies and tiny flexible spines along their backs. Japanese lady beetles deposit their yellow, oval eggs in clusters of up to twenty, on the undersides of leaves. 

Classification:

Kingdom - Animalia
Phylum - Arthropoda
Class - Insecta
Order - Coleoptera
Family - Coccinellidae
Genus - Harmonia
Species - axyridis

Diet:

Both adults and larvae of Asian multicolored lady beetles feed voraciously on aphids, mites, scale, and other soft-bodied insects. They also eat eggs of moths and butterflies.

Life Cycle:

Like all beetles, Asian multicolored lady beetles undergo complete metamorphosis with four stages: egg, larva, pupa, and adult.

Egg - Eggs usually hatch in 3-5 days.
Larva - The larvae feed and molt for approximately two weeks.
Pupa - The pupal stage lasts just 5-6 days before the adult emerges.
Adult - In an optimal environment, adults can live as long as three years.

Special Behaviors and Defenses:

Like many other insects, Asian multicolored lady beetles produce a foul smelling chemical to deter predators. When threatened, the beetle "reflex bleeds," releasing hemolymph with this repulsive smell through the leg joints. The orange fluid stains, making this tendency a nuisance when the beetles invade your home. And invade they do! In their native Asia, the beetles overwinter in large groups along cliffs. North American populations have adapted to their new habitats by moving indoors for winter, spending the cold days in walls and window casements.

Habitat:

In their native Asia, Harmonia axyridis lives in forests and mountains. In North America, Asian multicolored lady beetles inhabit places where aphids and other soft-bodied insects are plentiful: gardens, home landscapes, orchards, fields, and forests.

Range:

Asia (except China), North America, and Europe.

Other Common Names:

Halloween lady beetle, Japanese lady beetle, harlequin ladybird

 

Sources:

  • Multicolored Asian Lady Beetle, Ohio State University Extension Service
  • Asian Lady Beetle Fact Sheet, University of Connecticut IPM
  • Biological Control: A Guide to Natural Enemies in North America, by Catherine R. Weeden, Anthony M. Shelton, and Michael P. Hoffman.