Recent swarming of the Harlequin Ladybird, Harmonia axyridis (Pallas), on the Yorkshire coast.
D. E. Whittaker
The Harlequin ladybird, a recent introduction to the British fauna, is the most variably coloured and patterned ladybird to be found in the British Isles. Otherwise known as the Multicoloured Asiatic ladybird, it was introduced into Europe as a biological control agent, spreading rapidly through western Europe, then to the British Isles, where it was first found in southern England in the summer of 2004. By the late summer of 2007 it had reached east Yorkshire and has since been recorded to the north of Scotland.
As a voracious predator in both its adult and larval stages, there are fears that it could have a detrimental effect not just on our native ladybirds, but on other insect species as well. Some scientists have predicted that it will seriously effect probably several hundred of our native British species, and so the insect fauna throughout Britain is being monitored closely to see what effect, if any, the Harlequin ladybird explosion has through the next few years.
The Yorkshire coast now appears to be thoroughly populated by this ladybird. In the path of strong southerly air flows along the country in October 2009, large numbers of the beetle swept through the Yorkshire area. In late October, further warm southerly winds from the Sahara induced the beetles to flight and on one morning near Scarborough, thousands were seen on the wing and alighting on herbage. The swarm penetrated at least to Cleveland. With torrential rain the following week, masses of the beetle were seen among flood refuse in the Tees at Stockton. More observant members of the public had found them in their houses, while one lady at Scarborough was surprised to find 25 sheltering under her dustbin lid.
With such a large population of the beetle now present in the Scarborough district and throughout the area, where many of the recent swarm will doubtless hibernate successfully over the winter, a noticable explosion of Harmonia larvae may be expected along the North East coast in 2010.