The harlequin ladybird is one of about 40 species of ladybird found in Britain and Ireland. Like many other ladybirds it is predatory. It has a preference to feed on aphids but will feed on other insects.
The harlequin ladybird originates from Japan and has been introduced as a biological control agent around the world to control aphids. It was not deliberately introduced to Britain or Ireland, but it become established in 2004. Since then it has become widespread in England and is spreading in Wales, Scotland and Ireland.
Harlequin ladybird and other ladybird sightings can be reported to the UK ladybird survey.
Adult harlequin ladybirds are 8-10mm in length, and very variable in colour and markings. The two most common forms are black with two red spots or orange with 18 black spots. There are more than 40 species of ladybird native to the UK several of which also have many colour forms. Some of these native ladybirds can appear similar to those of the harlequin ladybird and it is often not easy to determine which species you have. For example, the native two-spot ladybird and ten-spot ladybirds have many colour forms but can be distinguished by size; the two-and ten-spot ladybirds are small at 4-5mm in length.
Harlequin ladybird larvae are black and orange reaching up to about 1cm (½in) in length. They also feed on aphids and other insects. Ladybird larvae all generally have the same elongate body shape and most are black or dark grey. Some have yellow or orange markings and some have hairs or spikes. The harlequin larvae is characterised by having two orange stripes and being spikey.
Harlequin ladybird pupa like other ladybird pupa is immobile and can often be found attached to plants. It is rotund and about 8mm in diameter. The pupae are dark in colour with some orange/red markings.
Harlequin ladybird eggs are yellow/orange and laid in groups on leaves, they are approximately 1-2mm in length and not readily distinguished from the eggs of other ladybirds.