Harlequin ladybirdsANDREAS VILCINSKASAsian harlequin ladybirds, introduced to Europe and other parts of the globe as an environmentally-friendly means of pest control, are causing their own ecological problems—they’re wiping out native ladybird species. And one reason for the harlequin’s global dominance could be its use of a biological weapon, according to a report published online today (May 16) in Science. The study reveals that harlequins carry a fungal parasite to which they are immune, but which kills other ladybird species.
“[We] should have seen this coming, because we knew all about it from human history,” said Stuart Reynolds, emeritus professor of biology and biochemistry from the University of Bath in the U.K., who was not involved in the work. “When the Spanish conquistadores invaded Central and South America, there were tiny numbers of them and yet they managed to invade extremely successfully because they carried smallpox and diphtheria and measles.” The harlequin ladybirds are successful invaders for essentially the same reason, he said.
Harlequin ladybirds (Harmonia axyridis) are good eaters, with each beetle consuming roughly 200 aphids per day. It is for this reason, that they were considered a great way to fight aphid infestations on agricultural crops, explained Andreas Vilcinskas, a professor of phytopathology ...
