Nature · Insects & other invertebrates

Harlequin ladybird

Established in Britain since 2004 · 6–8 mm

Harmonia axyridis — Coccinellidae; an invasive non-native species

An Asian ladybird introduced to Europe and North America as a biological control for aphids, which became established in Britain in 2004 and spread across the country faster than any other invasive insect on record. It is bigger than a seven-spot, hugely variable — red, orange or black, with anything from none to twenty-one spots — and it eats not only aphids but the eggs and larvae of native ladybirds. It is the "harlequin" for its costume-changing colour forms.

How to spot them

▸Larger and more domed than native ladybirds, typically 6–8 mm
▸Brown or reddish-brown legs (native seven-spot and two-spot have black legs)
▸Black-and-white pronotum usually carrying a white M- or W-shaped mark
▸Enormously variable: red or orange with up to 21 black spots, or black with two or four red or orange spots
▸Often a small keel or ridge across the rear of the wing cases; masses gather indoors to overwinter

How to know it

Brought to Europe and North America deliberately as an aphid-eating biological control, it became established in Britain in 2004

Harlequin ladybird — the fastest-spreading invasive insect recorded in Britain.

Its legs are brown, not black, and its white pronotum usually carries a black M- or W-shaped mark

Harlequin ladybird — the two features that settle it against native ladybirds.

Named for its costume-changing variability: red, orange or black, with anywhere from no spots to twenty-one

Harlequin ladybird; the succinea, spectabilis and conspicua forms look like different species.

Besides aphids it eats the eggs and larvae of native ladybirds, and has been implicated in the decline of the two-spot

Harlequin ladybird — intraguild predation is the reason it is a conservation problem.

Hundreds of them crowd into window frames and lofts to overwinter, staining paintwork when they bleed

Harlequin ladybird, the ladybird that turns up indoors in autumn in numbers.

Native to eastern Asia, its scientific name pairs 'harmony' with an ancient name for the Sea of Azov

Harlequin ladybird — Harmonia axyridis.

Quick-fire facts

•Harmonia axyridis, native to eastern Asia — Japan, China, Korea and eastern Russia
•The RHS records it as having become established in the UK in 2004 and now widespread
•It was introduced to continental Europe and North America as a biological control agent against aphids and scale insects
•It is polymorphic: forma succinea (orange-red with 0–21 spots), forma spectabilis (black with four red spots) and forma conspicua (black with two red spots) are the commonest
•It practises intraguild predation, eating the eggs, larvae and pupae of other ladybirds; its spread coincides with sharp declines in the two-spot ladybird
•The UK Ladybird Survey, run through the Biological Records Centre, tracks its spread with public records
•Sap-feeding in autumn means it damages soft fruit and taints wine; in North America it is a notorious household nuisance
•Distinguishing features from the seven-spot: brown legs, larger size, the pronotum M-mark, and a rear keel on the elytra

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Sources

Royal Horticultural Society — Harlequin ladybird
Biological Records Centre — UK Ladybird Survey