During the past ten years the Asian Lady Beetle (Harmonia axyridis) has been increasing in numbers to the point that they are now classed as a major pest. The beetle is sometimes called the Harlequin ladybird and was originally native to China and Japan. The beetle was once introduced for biological pest control. In the 1990s the beetle was introduced into large-scale production greenhouses in order to keep aphid populations in check. However, they soon left the greenhouses and their number rose. The Asian Lady Beetle is now so well established that it is classed as a “neozoon”, that is a biological term for a species which is invading new habitats and ecosystems. 

 Until now scientists have been unsure why the beetle numbers have been increasing, often at times when native beetle populations have been decreasing. However, researchers believe that they have a reason: fungus. 

 The Asian Lady Beetle appears to be resistant to a microscopic fungus called micro sporidia. For most native beetles, the parasitic fungus is deadly. This explains why so many native beetle species within Europe and the U.S. have been falling and yet numbers of the Asian Lady Beetle have been rising. 

 This finding may help to reverse the rise of Asian Lady Beetle numbers. It could also lead to other scientific research into the biochemistry of the beetle, to find out why it is resistant to a fungus that is itself lethal to most other beetles. 

 Adapted from http://www.digitaljournal.com/article/350411#ixzz2TnCbTeaf