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Wednesday, 27 March 2019

Invader

Harlequin Ladybird (Harmonia axyridis)
It was there, lurking under the shoe rack, when I went out to the porch to put my trainers on. An invader. A wolf in sheep's clothing. Yet another example of humans just not leaving well enough alone. This is a Harlequin Ladybird (Harmonia axyridis) and it's one species I wish we didn't have in our garden. It's an Asian species that was brought to Europe (and the United States) as a biological agent: a supposedly "biologically friendly" way to control unwanted insect species. Except that it turns out to be very biologically UNfriendly. This large and voracious species has been munching its way across Europe and North America for decades now, outcompeting local ladybird species (and other insects as well) for food. And unlike our native ladybirds, it will happily switch to the eggs and larvae of butterflies, moths, and local ladybirds if aphid prey is scarce. It's a reproduction machine, churning out young from spring right through autumn, which allows it to expand its populations very quickly. Since arriving on the islands in 2004 (when it made its own way across the English Channel), the Harlequin Ladybird has spread across much of the country and is now considered a serious threat to some UK insect populations. Did we squash it after taking its picture? No we didn't. But we probably should have.

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