The Harlequin Ladybird Beetle is a non native species in the UK. It originates from Japan.
It was used around the world by farmers and the agriculture industry to get rid of other pests!
From this they have escaped into the wild in countries all over the world.
Harlequin Ladybird Beetles were not introduced in this way in the UK, but it seems they got here by being accidentally introduced on food or plant imports back in the 1990's.
The Harlequin Beetles were first classed as established in the UK in 2004, since this time they have become very well established in all four corners of the UK.
One of the problems with these invaders is that they like to overwinter in your houses! They particularly like to form large groups in bedrooms, usually in the corners of a southern facing bedroom. They also like to invade loft spaces. Where they settle, to overwinter, they tend to leave a yellow residue (this is thought to be a pheromone signal to bring others of their species to cluster with them!) this can stain fabrics and even paintwork!
Another problem is that they seem to be outcompeting our native Ladybirds.
The Harlequin Ladybird species is starting to become of such concern that there are scientists wanting to know about sightings of them, such as, www.harlequin-survey.org
WHAT WE CAN DO
Firstly we can try to stop them getting into your house in the first place. We can do this by sealing any holes around window frames (although this is no precise science and quite time consuming.) We can also fit fine mesh air brick covers to the exterior of your house, this has the added benefit of stopping rats and mice gaining entry in the same manner as the Ladybirds.
We can also use a specialist insecticidal fog/smoke to kill any adult Harlequin Beetles inside your home.
We also use a residual insecticide (this keeps working for several months after application) around window frames and in the corners of rooms where they are likely to cluster.