07 February 2008

Britain's most invasive insect

The harlequin ladybird ,Harmonia axyridis, is a very recent British resident. Originally from Asia it was first spotted in 2004 in a pub garden in Sible Hedingham, Essex. In just four years it has spread across England and made inroads into Scotland and Wales. By comparison it took the grey squirrel a century to do the same.

The Ladybird’s has been tracked by the Harlequin Ladybird Survey, an online survey overseen by the Centre for Ecology and Hydrology. Peter Brown, of the centre, said: “It’s the most invasive species in Britain. It is perhaps equalled by the horse chestnut leaf-miner* but nothing else comes close.”

Last month the species was reported in Orkney. So serious is the problem that the ladybird is the subject of a special issue of the journal BioControl. More than 50 scientists from Europe and North America contributed to the journal to share knowledge about its impact.

Because it eats so many aphids, its staple diet, as well as other ladybirds, it has threatened the number of native ladybirds and species, such as lacewings, which also eat aphids. It also threatens aphid numbers. The two-spot and seven-spot ladybirds are particularly threatened. The harlequin ladybird’s voracious appetite for aphids attracted interest in its use as a biological pest control but after it was released in several European countries in the 1980s and 1990s it rapidly became established and spread widely.

*The horse chestnut leaf-miner is an insect first seen in southwest London in 2002. It has spread rapidly and now infests about 20 per cent of horse chestnut trees, causing leaf loss.


Anonymous said...

'Ordinary' ladybirds are one of my favourites. You would think that people would have a little foresight!

jams o donnell said...

Well may you ask Maddy! It's something we've done time and tiem again. I'm sure it'll happen again too

Dragonstar said...

I read about this yesterday, and it was mentioned that the Harlequin also eats other ladybirds - don't know if this is the case, though, It's also made it into Northern Ireland, so it's just a matter of (short) time before it turns up in my garden!

jams o donnell said...

This summer I would imagine Dragonstar. THey have moved with such rapidity

beakerkin said...

Actually I am amazed at the amount of invasive species problems in the UK.
You have the dreaded Satanic Canada Goose, red eared sliders (turtles), gray squirels and probably the dreaded American Crayfish on the way.

However your side dropped House Sparrows and Starlings in the US.

I am trying to picture what would happen if Armadillos somehow ended up in the UK.

elasticwaistbandlady said...

I love ladybugs!

It's considered a good luck charm here to catch them and make a wish.....before they leave ladybug droppings in your palm.

jams o donnell said...

We do indeed, Beakerkin - also crayfish. Then again it's not all bad - rabbits were not indigineous here. In Ireland and the SW fuchsias grow wild. I'm sure armadillos would thrive. Wallabies did for years.

If you're a gardner they generally are good luck. THis one I think bites though, Ewbl!

Andree said...

strange that I ran across this post this week. Another US blog had photo of some ladybug and all the commenters were vigorously if it was a ladybug, potato bug or asian ladybug. And I have wanted a photo of my ladybugs in my house, the kind that bite (and taste bad because cats won't eat them), so that I could compare. so this is informative and helpful.

jams o donnell said...

Glad to be of service Andree!