The Harlequin ladybird is found naturally in the Far East, including Japan and Korea. It was introduced into several European countries as a predator of pest insects such as aphids, in greenhouses. However it was soon found living ‘wild’ in Belgium in 2001, in Germany in 2003, and in the UK in 2005. Within the UK, it was first reported in the London area, but is now rapidly spreading north and west. At present it appears likely that the Harlequin ladybird will become widely established in the UK.
Numbers of large ladybirds active on the outside of buildings, and sometimes entering buildings, may cause concern to residents. The peak of this autumn activity is restricted to a few weeks only, but once inside wandering ladybirds may occur on mild days throughout the winter. When disturbed, the beetles produce a foul smelling liquid, which may also stain fabrics etc. They do no damage to the building itself.
Being more vigorous than our native ladybird species, there are concerns that it may have a negative impact on their numbers.
Remedy: For properties that have regular problems with ladybirds entering the building, proofing of entry points will reduce future problems.
Ladybirds within buildings may be removed with a vacuum cleaner.
Residual insecticides labelled for ‘beetles’ or ‘crawling insects’ and applied into crevices and entry points around buildings are likely to kill Harlequin ladybirds, but beware; native ladybird species may also be present in the same hibernation sites within buildings.