A species of ladybird called the 'most invasive on earth' has been found to prefer urban environments in Britain.
The harlequin ladybird, or Harmonia axyridis, first arrived in the UK in 2004 and has rapidly become established across the country, especially in cities and urban areas. It now outcompetes native ladybird species, which have suffered from a deterioration of their natural habitats as well as competition from the alien harlequin.
Scientists have been studying the new species to understand its rapid dispersal. A new paper published in the Journal of Biogeography on Monday 13th October has shown that the harlequin has a marked preference for urban areas, spending the winter inside buildings, which may be the key to the invasion. Scientists from the Centre for Ecology and Hydrology and the Universities of Edinburgh, Anglia Ruskin and Reading used around 23,000 records of sighting submitted by citizen scientists to the UK Ladybird Survey to study the species.
Lead author Dr Bethan Purse from the Centre for Ecology & Hydrology said, “Our new study indicates that environmental factors, particularly habitat, have made some areas of Britain such as cities more vulnerable to rapid invasion of the harlequin ladybird than other areas.”
The results indicated that climate change could be a factor in the harlequin's invasion, and also showed that the new species struggles to live into coniferous woodland. A number of native ladybird species are largely confined to coniferous woodland and it appears that such habitats are more resistant to invasion by the harlequin ladybird.
The study was funded by the Natural Environment Research Council and the Joint Nature Conservation Committee.