If you have recently noticed in colder months you have an infestation of ladybirds in your home/office etc. mainly around your windows, you probably have an infestation of Harlequin ladybirds. Harlequin ladybirds are not native to the UK. They originate from eastern Asia and are commonly known as the Asian lady beetle outside of the UK. The Harlequin ladybird did not reach Britain until 2004 and has had a detrimental effect on the UK’s native species.
These beetles can be hard to identify because of variations in colour. The two most common are black with big red dots and light red with small black dots.
Harlequin ladybirds are becoming a nuisance pest due to their tendency to overwinter indoors and the unpleasant odour and stain left by their bodily fluids. Sometimes the beetles will bite people.
Harlequin ladybirds can get into houses through the tiniest holes even if windows are closed. There are numerous methods of control that can be used. The best way to control the entry of any beetles is to seal any holes and gaps
found. Pesticides and traps can be used. But I have found the best method of control is to seal any gaps and to use a desiccant dust (a non-toxic silicon based dust) around the seals and hoover up any that may be left. It is the most affective and safest way of solving the problem.