February 7, 2012
Alien Ladybug In Europe Dropping Native Species Population
An alien predator in Europe is leading to a rapid decline of a native ladybugs in Britain, Belgium and Switzerland.
Scientists have found that Harlequin ladybugs are overwhelming native ladybugs through predation and competition.
The native ladybug, most known for the 2-spots on its back, have declined by 30 percent in Belgium and 44 percent in Britain over the past five years after the Harlequin species arrived in 2001.
"This study provides strong evidence of a link between the arrival of the Harlequin ladybird and declines in other species of ladybird, a result that would not have been possible without the participation of so many members of the public gathering ladybird records across Britain, Belgium and Switzerland," Lead author Dr Helen Roy of the UK's Centre for Ecology & Hydrology said in a press release.
Invasive alien species are internationally recognized as one of five major causes of biodiversity loss.
The large 7-spot ladybug, another common species, has been able to retain a stable population and abundance across Europe.
The researchers said the Harlequin ladybug's population increase has coincided with the declines of the native 2-spot species.
"Within the insect world ladybirds are as iconic as panda bears and they provide an incredibly useful ecological function by keeping aphids in check," Co-author Tim Adriaens from the Research Institute for Nature and Forest (INBO) in Belgium, said in a press release.
"At the continental scale the arrival of the Harlequin could impact on the resilience of ecosystems and severely diminish the vital services that ladybirds deliver."
Dr Marc Kenis from CABI Europe-Switzerland, who is leading studies on the Harlequin in Switzerland, said the work of the researchers is essential for scientists to determine whether the decline will continue, or if other species are at risk of local extinction.
"Furthermore, we need to find specific methods to better investigate the potential decline of rarer species, which were hardly noticed in our general surveys before the arrival of the invasive species," Kenis said in a press release.
The study was published in the scientific journal Diversity and Distributions.
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