Kuwana's Lady Beetle (Chilocorus kuwanae) — identification, habitat & look-alikes

Kuwana's lady beetle is a tiny, shiny black lady beetle from East Asia with one deep-red spot on each wing cover. It was brought to the United States to fight scale insects, mainly euonymus scale, a common pest of yard shrubs. It is now established across much of the eastern United States and in California.

Appearance

Appearance: About 1/8–1/5 in (3–5 mm) long, round, and glossy black. Each wing cover has one deep-red, somewhat rectangular spot near the middle, and the lower edges of the wing covers flare outward like a brim.

Look-alikes

Twice-stabbed lady beetleChilocorus stigma

The native twice-stabbed lady beetle has round, orange-yellow spots set toward the head end. Kuwana's spots are deep red, more rectangular, and sit near the middle of the wing covers.

Why they get mixed upBoth are small, round, black lady beetles with two red spots.

Ashy gray lady beetle (black form)Olla v-nigrum

The black form of the ashy gray lady beetle has pale gray or whitish patches on the head and thorax, which Kuwana's lacks. Its larvae are smooth, not spiny.

Why they get mixed upIts dark form is black with two red spots.

Where it lives

Typical habitats: Landscape shrubs and trees
Woodlands
Range: Native to East Asia, including Korea, Japan, and China. USDA imported beetles from China, Korea, and Pakistan several times between 1895 and the 1980s and released them in most states east of the Mississippi River, several central states, and California. It is now widespread from Alabama to southern New England and west to the Appalachians, and also established in California.
Preferred conditions: Lives on woody plants wherever s are thick, such as euonymus shrubs in yards.

Behavior

Diet: Mainly armored scale insects, especially euonymus scale; it also eats San Jose scale and oystershell scale. Adults also feed on nectar and pollen.
Activity: Adults wake up and start feeding when spring temperatures rise above about 50°F (10°C).
Overwintering: Adults spend the winter in leaf litter at the base of infested plants.

Life cycle

Breeding season: Usually three generations a year in the Midwest. Egg to adult takes about a month in warm conditions. Females lay bright orange eggs singly or in small groups under scale covers.
Larva: Brown to dark pinkish, covered in black branched spines. Each larva eats more than 100 scales.

Name and classification

About the name: A 2020 study comparing Asian and European specimens concluded that this beetle is the same species as the European kidney-spot ladybird (Chilocorus renipustulatus), which would make that the correct name. Not every checklist has adopted this yet.

Conservation

IUCN Red List: NENot EvaluatedNot yet assessed
Threats: Broad-spectrum pesticide sprays kill it along with the scales. Short-lived options like horticultural oil or insecticidal soap are much easier on the beetle.