Habitats: Harlequin ladybirds are noted for being habitat generalists. Like the 2-spot ladybird, the species is considered to be arboreal, and many records are from urban areas where deciduous trees are abundant. This species can be readily found on mature lime or sycamore trees, for example in churchyards and parks. However, harlequin ladybirds also occupy mature woodlands (both deciduous and coniferous), scrub, grassland, marshland and reed beds. Crops and orchards are common habitats for harlequin ladybirds. Harlequin ladybirds overlap with a number of other species of ladybird including 2-spot, 7-spot, 10-spot, 14-spot and pine ladybirds.
Host plants: The host plant list for the harlequin is diverse and extensive; however, it undoubtedly has a preference for lime and sycamore trees. It is also commonly associated with herbaceous plants such as nettle, thistles, cow parsley, rosebay willowherb and fat-hen. Harlequin ladybirds are common in gardens where they can be found on many ornamental plants.
Food: aphids, coccids, coccinellids.