The Harlequin Ladybird (Harmonia axyridis) is also known as the Asian Lady Beetle and the Halloween Lady Beetle. It gets its latter name from its tendency to enter homes in October in preparation for hibernation. The harlequin ladybird first came to Britain in the summer of 2004, unfortunately due to its large size and voracious appetite, the harlequin ladybird may now pose a threat to our native species.
HABITAT AND DISTRIBUTION
The harlequin ladybird can be found in many habitats from gardens and woodlands, to fields, meadows and parks. It is an inhabitant of hedgerows, low-lying vegetation. Originating in Asia, the harlequin ladybird is now thriving in the UK, Europe and the USA. Reports have also come from sightings in Argentina, Brazil, Egypt, Turkey and south Africa. Most of the harlequins photographed here were found near nettles and deciduous trees.
The adult (imago) is generally red on the elytra with multiple black spots, although over 100 variations have been recorded for this species. The pronotum is white with a black 'w' marking and the legs and antennae are a light reddish-brown. Other colour forms can be found listed below. The elytra are very rounded and are unfused, they protect the soft wings which the harlequin ladybird uses for flight. The harlequin grows to a maximum size of 6 - 8mm
The larvae of this species is generally thin and uniform black. The legs are short and very dark. The whole of the back and sides are covered in small black spikes, although some of the dorsal spines are orange.
The pupae, normally found stuck to the leaves of trees, is round and bulbous with a serrated edge and spiky protrusions near the base of one end.
DIET, BEHAVIOUR AND REPRODUCTION
The primary diet of the harlequin ladybird is aphids, although it will eat other ladybird eggs and larvae, butterfly eggs, small insects, pollen and nectar if food is scarce. During the winter, the harlequin goes in to a form of hibernation where it lays dormant in cracks and crevices and awaits the warmer weather. On hot sunny days swarms of harlequins have been known to form, communicating with other harlequins using semiochemicals. When threatened it may produce a liquid known as isopropyl methoxy pyrazine. This liquid is present in its internal fluids (hemolymph) and it secretes it through its legs. Not only is the liquid foul tasting, but it also has a strong and foul odour. It is also capable of delivering a small bite as a last resort. The average lifespan of the harlequin ladybird is around 3 years.
The harlequin ladybird is polymorphic (having many different colour forms). Some of the more common colour forms include f.succinea (standard), f.spectabilis (black with 2 large and 2 small red spots), f.conspicua (black with 2 red or yellow spots, sometimes incomplete), f.axyridis (black with multiple red spots).
THREATS AND STATUS
The harlequin ladybird was introduced to Europe and North America as a way to control aphids. Unfortunately they have adapted so well that they now pose a threat to the native species that live there.
OTHER NOTABLE INFORMATION
There are a few similar species to the harlequin ladybird in the UK. First is the Eyed Ladybird (Anatis ocellata), which is a similar size but its spots are ringed with yellow. Some of the harlequins forms match the 2-Spot Ladybird (Adalia bipunctata), but the harlequin is larger in size. The other 2 species are the Pine Ladybird (Exochomus quadripustulatus) and the Kidney-Spot Ladybird (Chilocorus renipustulatus) but both of these are smaller and generally have all black pronota.
Have you seen an harlequin ladybird? If so please help track its spread by filling in the survey at www.harlequin-survey.org.