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Aphid Predator (Coleoptera: Coccinellidae)Harmonia axyridisHarlequin ladybirdOn this page: Identification Biological control & DistributionIdentificationHarmonia axyridis is a relatively large species, around 6-8 mm long. Harlequin ladybirds are highly variable both in terms of colour and pattern. The commonest forms of Harmonia axyridis (at least in Europe) are shown below. Form succinea (see three pictures below) has red or orange elytra with 0 - 21 (usually 15-21) black spots. The pronotum is white or cream, with a thick black M marking which may be broken into black spots.
Harmonia axyridis form spectabilis (see first picture below) has black elytra with 4 red spots, and a white or cream pronotum with a solid black trapezoid central portion. Form conspicua (see second picture below) has black elytra with 2 red spots which each have a black spot within them, and a white or cream pronotum with a solid black trapezoid central portion. The elytra usually have a wide keel at the back and the legs and underside are almost always brown.
The fourth-instar larva of Harmonia axyridis (see third picture above) is black with conspicuous orange markings. The bases and spines of the lateral tubercles on abdominal segments I-V are yellow-orange, as is the pair of dorsal tubercles on abdominal segment, making an orange L-shape on each side. The pairs of dorsal tubercles on abdominal segment IV and V bear a total of four orange spines (cf. the larva of Harmonia quadripunctata which has only two of orange spines towards the rear). Biological control & DistributionHarmonia axyridis is most commonly found on deciduous trees and on low growing vegetation. The harlequin ladybird is a voracious predator of aphids and scale insects. It also eats the eggs and larvae of other insects, including other ladybird species. The adults and larvae are also cannabilistic, consuming the eggs and smaller larvae of their own species. An immense amount has been written about the harlequin ladybird, much of which is covered in the review by Koch (2003). The Harlequin ladybird is native to eastern Asia, but has been introduced for biological control purposes to various European countries, the United States and South Africa. Harmonia axyridis has since proved to be highly invasive - in Britain it took Harmonia axyridis just two years to spread from East Anglia to Devon (Brown et al., 2008) - and now has a cosmopolitan distribution.
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