Last October I wittered on about an invasion of harlequin ladybirds crawling up our outside walls. For the last two or three months a steady trickle of them has found its way back down from the attics into the house. On average I destroy about half a dozen of the little bastards a day, but I am fighting a losing battle; there may be thousands up there (in one Kentish barn a mass of up to half a million was found). Before last autumn I had never noticed a Harlequin; now we are overwhelmed by them.
Introduced into the States in 1988, its numbers have been soaring in France, Belgium and Holland, where bio-control companies were still marketing it long after its invasive character was recognised. It is now spreading rapidly through the UK and may soon wipe out our 46 native species. There is currently no effective method of control specific to Harlequins.
When disturbed Harlequins release volatile, noxious compounds which smell like rotten potatoes. The redder the ladybird, the smellier. They have been known to destroy batches of wine and even entire vinyards.
Harlequins stain walls and furniture and have a penchant for nesting in computers, causing them to crash. In the US some people now tape up their doors and windows to stop ladybirds getting in during the autumn mating season (ladybirds can be very disturbing when you're mating). I can see us having to do that this year. I mean tape up doors and windows.
The Harlequin Ladybird Survey (http://www.harlequin-survey.org) has pretty much given up on the South East, but is inviting reports of sightings from elsewhere. The chart shows what they look like.