Seven out of eight UK ladybird species have declined over five years following the arrival of larger alien 'harlequin' ladybirds in 2004.
Harlequins out-compete with other ladybirds for prey and habitat, and even eat their native cousins, the researchers said.
The two-spot ladybird appears to be particularly threatened - overall numbers have fallen by 44 per cent, according to a study led by the Centre for Ecology and Hydrology.
The researchers said the two-spot was now hard to find in some areas where it had once been common.
The harlequin is slightly bigger and better protected from predation by other ladybirds than some of the UK’s native species, spread to the UK after being imported from East Asia to Europe for commercial pest control of crops.
The study, published in the journal Diversity and Distributions, used thousands of records from 'citizen science”' projects dating back to 1971 to help provide 'strong evidence' of the link between the arrival of the harlequin and declines in other species. Read More