Saturday, July 5, 2008

The threat of the harlequin

A meeting with Steve Cornish (Friends of the RDW) and Rebeka Clark (TRUE) last week was something of a revelation to me - I came away with a notebook full of my vile scrawl and a head spinning with new information and knowledge. Thanks guys - it was great to meet up with you both.

One of the things that Rebeka told me is that the harlequin has been spotted in Stave Hill Ecological Park and the Russia Dock Woodland. I had never heard of it and when I first saw a photograph it looked to me like just another one of many forms of ladybird that I've seen over the road. But the harlequin ladybird (Harmonia axyridi) turns out to be a very different matter - instead of keeping down the wretched greenfly like the "ordinary" ladybirds, it actually predates on the ladybirds themselves, which has a knock-on effect on the good job that the ladybirds do. Sadly I didn't have any knowledge of the differences when I took the above photograph so I don't know if I've snapped the angel or the devil.

The Harlequin Ladybird Survey is a project which seeks to highlight the dangers of this insect. Here's what the website's introduction says:

A new ladybird has arrived in Britain. But not just any ladybird: this is the harlequin ladybird, Harmonia axyridis, the most invasive ladybird on Earth.

The harlequin ladybird was introduced to North America in 1988, where it is now the most widespread ladybird species on the continent. It has already invaded much of northwestern Europe, and arrived in Britain in summer 2004.

The distribution map on the left or the annnual spread maps show that it has spread rapidly north and west from the southeast of England since its first sighting.

There are 46 species of ladybird (Coccinellidae) resident in Britain and the recent arrival of the harlequin ladybird has the potential to jeopardise many of these. The Harlequin Ladybird Survey will monitor its spread across Britain and assess its impact on native ladybirds.

Monitoring ladybirds across the country has never been more important. We want YOU to get involved! Please record your harlequin ladybird sightings

Unfortunately I don't have any photographs of harlequins my own, but there's a useful page on the above website which helps you to spot the difference. As you can see from one of the photographs copied from their page (left). You can download their full Ladybird Identification Sheet from that page or go straight to the Identification Sheet, in PDF format by clicking here.

I hesitate to extend the advice for dealing with them because it scarecly seems species-friendly, but apart from helping the Survey to keep a record of their distribution the only way to fix the harlequin is to eliminate it. The harlequin is to the ladybird what the grey squirrel turned out to be to the red squirrel.

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