Giant bug looks spot on to wreak ecological havoc in killing spree

LAST Monday I mentioned that I thought cuckoos were more plentiful this year than they have been in recent years and asked if any readers had noticed the same thing.

I got a big response – and the emails are still coming in. Every one of them agrees there are more cuckoos around than usual and they report them in counties Limerick, Waterford, Cork, Kerry, Clare and Kilkenny.

Another creature that seems to have declined in numbers in recent years is the ladybird. Like cuckoos, ladybirds tend to be well-liked and we all know they eat greenfly and other garden pests, so if they are declining they’ll be missed.

There are, in fact, 18 different species of ladybird that have been recorded here – though three of them haven’t been seen for a long time and may be no longer with us.

Most of the remaining 15 are named after the number of spots on their backs.

Our commonest species is the seven-spot, though we also have the 11-spot, 13-spot, 14-spot, 18-spot and 22-spot. The three doubtful ones are the 12-spot, the 24-spot and the water-ladybird – if you see one of those the Natural History Museum would like to know.

They would also like to know if you see a harlequin ladybird. This is a large and voracious species from the Far East that has become a pest in North America and over much of Europe, including Britain.

Harlequin ladybirds were first imported into America and Europe to control aphids and other pests in greenhouses and tunnels. They escaped and because they have no natural predators and they breed more frequently than native species, they were soon present in the wild in huge numbers.

This caused a number of problems. When they ran out of aphids they started to eat other things, including the smaller native ladybirds. They also developed a taste for soft fruit and when they descended on vineyards they tainted the wine.

Then, when the weather got cooler, they started to seek shelter in houses for the winter.

Householders retaliated with vacuum cleaners and discovered two things: firstly harlequins can bite people. Apparently it’s not a particularly painful bite but some people have an allergy to it, and this can be quite serious. Their second form of defence is to squirt out a foul-smelling liquid which also leaves a stain that’s hard to remove.

Harlequins were never deliberately imported into Britain or Ireland but in 2004 they appeared in south-eastern England. They spread so rapidly that four years later they were recorded on the Orkney Islands off the north coast of Scotland.

Then, on November 6, 2007, a harlequin was found in a Tesco shop in Lisburn in Co Antrim. It was hiding in a head of celery brought in from Cambridgeshire in England. It was killed and I know of no other Irish sightings, but given the speed of their spread across Europe it’s probably only a matter of time. They can fly.

Unfortunately, it’s not easy to describe harlequin ladybirds because they come in an astonishing variety of colours and patterns. You can check out the variations on the internet. They are large, about a third larger than our largest native species, and they have a noticeably high, domed back. Also all the variants recorded from Europe have a pale, white or off-white head with a distinctive black ‘W’ mark on – M if you happen to be holding the ladybird upside down.

* dick.warner@examiner.ie

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