A predatory Asian ladybird, the harlequin ladybird (Harmonia axyridis) has caused dramatic declines of various native ladybirds in Europe and North America.
Photo: Charles J. Sharp | CC BY-SA 4.0
Adults are described first, followed by the larvae.
The harlequin ladybird, also called the multicoloured Asian ladybird, is a challenge to identify because of extreme variation in its appearance. It can be orange or red with few or many spots, or (far less often) black with orange or red blotches or swirls. The rarer black forms are less likely to engender confusion with other ladybird species. The plate below shows most of the variation that exists. If you find a beetle that can’t be matched to one of these it is probably not a harlequin ladybird. The goal of this guide is not to identify this species definitively, but to rule out enough alternatives that an approach to authorities is justified.
This species is larger than many ladybirds, and its length of 5-8 millimetres distinguishes it from most ladybirds that look similar. Some of these can reach 5 millimetres but they are never longer than that.
There is some orange or red on the body.
The head and pronotum (the section between the head and the wing cases) have black and white (or cream) markings and lack orange and brown.
The pronotum usually has the black markings forming an M against a whitish background. The M is sometimes broken into spots or replaced by a black patch. Beetles that are mainly black lack an M.
The centre of the head usually has a white patch, most often in the shape of a triangle.
The legs and feet are reddish-brown, at least in part.
The underside is black in the centre and reddish-brown along the sides of the abdomen.
Undersides can be mostly black or mostly brown but both colours are present.
More images showing the variations can be found on the Interesting Insects & other Invertebrates website.
Harlequin ladybird variations. Photo copyright entomart | Wikimedia Commons
Harlequin ladybird larvae are distinctive when they approach maximum size. They occur on leaves and stems, especially where there are aphids.
They are black with an orange or yellow-orange patch along each side.
They have many soft projections (scoli) on their abdomens, some of which branch like a tree into three spines and others into two.
The front of the body has many small unbranched spines.
The lower side of the body has a series of white dots forming a broken line.
When they are very small they are all black.
Harlequin ladybird larva. Photo: Gilles San Martin | CC BY-SA 2.0
The beetles are 5–8 millimetres long. Larvae reach about 12 millimetres in length.
Behaviour and location
Harlequin ladybirds can be found in gardens, parks and farmland on the foliage of trees, shrubs and smaller plants, especially on young leaves with aphids.
On cold autumn days they may aggregate on warm sunlit walls and tree trunks, then enter houses to hibernate for winter in crevices such as gaps along window ledges.
Harlequin ladybirds have wide climatic tolerances so they could show up anywhere in Australia except the tropical north.
The ladybirds that bear resemblance to the harlequin are mainly Northern Hemisphere species that have entered Australia with plant imports or other cargo. The black and white patterns on their head and pronotum are different, and they have other differences.
The two-spot ladybird (Adalia bipunctata) is a Northern Hemisphere species that is slightly smaller, with entirely black legs and feet, and only one large spot on each wing shield. It usually, though not always, has two white spots on the head.
Two-spot ladybird (Adalia bipunctata). Photo: Entomart
The eleven-spot ladybird (Coccinella undecimpunctata) is another introduced species that is smaller with entirely black legs and feet, and the underside is black. It usually has two white spots on the head.
Eleven-spot ladybird. Photo: Gilles San Martin | CC BY-SA 2.0
The spotted amber ladybird (Hippodamia variegata), also called the Adonis ladybird, is also smaller (4-5 millimetres long), with legs that are partly black. The black pattern on the pronotum is different. It is yet another Northern Hemisphere species, having appeared in Australia in 2000.
Spotted amber ladybird (Hippodamia variegata). Photo: Francisco Welter-Schultes | CC0 1.0
The six-spotted zigzag ladybird (Cheilomenes sexmaculata) is a native species, with a black stripe running down the back, and very different pronotum patterns.
Six-spotted zigzag ladybird (Cheilomenes sexmaculata). Photo: Aarian Suresh | CC BY-SA 2
The larva of the spotted amber ladybird (Hippodamia variegata) has many differences from the harlequin ladybird larva, including a different colour pattern and a lack of branching spines.
Spotted amber ladybird. Photo: Gilles San Martin | CC BY-SA 2.0
The two-spot ladybird (Adalia bipunctata) has very different larvae.
Two-spot ladybird. Photo: Whitney Cranshaw | CC BY 3.0 US
A ladybird can be photographed in the wild or after being scooped into a bottle and killed in the freezer.
These ladybirds sometimes nip people and a small number of people have developed an allergic rhinoconjunctivitis from contact.
Who to tell
Think you’ve found harlequin ladybirds?
If you find them phone 1800 900 090 and ask for the office of Australia’s Chief Environmental Biosecurity Officer. If you do not receive a satisfactory response within a week email us via our contact form. Do not contact ISC in the first instance.
This little beetle has been described by biologists as ‘perhaps the most infamous of invasive insects in the twenty-first century’. In many parts of North America and Western Europe it is now the dominant ladybird, after it was introduced to control aphids on crops. The adults and larvae are voracious predators – typically eating 15 to 65 aphids a day – and they compete with and prey on other aphid predators, especially native ladybirds. The large larvae are particularly aggressive predators.
In Britain, seven native ladybird species (out of eight assessed) have declined since the arrival of harlequin ladybirds in 2003. The formerly common two-spot ladybird (Adalia bipunctata) declined by 44% within five years and ladybird communities on lime trees went from of 99.8% native species to 30.7% in 11 years. In a central European study, harlequin ladybirds were found to be the dominant ladybirds on trees, the abundance of native ladybirds on all plants having declined by 50–70% since the 1980s. Harlequins are only partly to blame for this, because the native ladybirds had been declining before they arrived. A decline from harlequin ladybirds has also been noted in Chile.
Other prey species for the ladybirds include scale insects, psyllids, mites, leaf beetles, weevils and butterflies, as well as other aphid predators, including lacewings, midges and hoverflies. Predation on eggs and larvae of monarch butterflies (Danaus plexippus) is concerning. The harlequins also eat nectar, pollen, fruit and young plant tissues, which has caused economic losses.
The harlequin ladybird can carry spores of a parasitic microsporidia benign to them but lethal to other ladybird species which, it has been proposed, ‘may function like a biological weapon’. Harlequin ladybirds have a high reproductive potential, producing (under laboratory conditions) up to 3800 eggs at a rate of 25 a day. Because they kill other ladybird species they are not associated with a decline in aphids and other crop pests.
In the United States and Canada, harlequin ladybirds have caused millions of dollars of losses in the wine industry. They feed on grapes at harvest time, and even small numbers taint wine, producing an aroma compared to burnt peanut butter. They are considered a threat to the wine industry in New Zealand after being accidentally introduced there in 2016, the first record for Oceania. The harlequin ladybird can also damage fruit crops, including grapes, stone fruit, apples, pumpkins and berries.
Harlequin ladybirds are a nuisance to humans when they form large overwintering aggregations in buildings, staining carpets and furnishings if they are crushed. A 2006 report from the Isle of Wight described ‘clouds’ of ladybirds ‘smothering vegetation’, ‘covering outside walls and window frames’ and ‘clogging up footpaths’. In houses they can trigger allergic reactions.
Harlequin ladybirds have spread rapidly around the world, reaching New Zealand in 2016, where they are now plentiful. Each year they are intercepted at Australian ports. Australians should be on high alert for them.
- Interesting Insects & Other Invertebrates: Harlequin ladybird.
- Invasive Species Council: England’s killer ladybird a warning for Australia.
- Invasive Species Council: Invasion watch profile.
- The Guardian: Britain is stalked by cannibal invaders.