Bad Ladybird

Before I bore you with the bad ladybird stuff, a bit of late news from yesterday. It's unusual for me to actually be up to date with blips. So having blipped early yesterday, Mrs L wasn't entirely chuffed that she didn't get credit for mending our Panasonic TZ8 camera. Well it wasn't actually broke, but there were so many intrusive dust spots on it we'd retired it and gone back to our TZ7 which we'd retired because it had a scratch on the lens that showed up quite badly in certain light conditions.

Anyhow yesterday, Mrs L armed with mini screwdrivers, cotton buds & an instructional video on youtube disassembled the TZ8, cleaned it, put it back together, there were no bits left over, there is one screw that's a little bit proud of the surface, but most importantly there are absolutely no dust spots anywhere - Well done Mrs L.

Now for the boring bad ladybird bit:

Here we have a harlequin ladybird, Harmonia axyridis, the most invasive ladybird on Earth. It is a native of eastern Asia, occurring from central Siberia, Kazakhstan and Tashkent eastwards through Russia to the Pacific coast, Korea and Japan and south to Mongolia, China, and Taiwan and into the Himalayas. It was introduced to North America in 1988 as a biological control agent against aphid and scale infestations in greenhouses, crops and gardens. It is now the most widespread ladybird species on the continent. It has already invaded much of northwestern Europe.

The harlequin ladybird arrived in Britain in 2004 probably by a variety of routes. Some have probably flown across the channel, others have been found on flowers imported from Europe, and in packing cases from Canada. The high numbers found in Battersea, Clapham and Chelsea suggest that some could have arrived via Eurostar or with vegetables and flowers destined for Covent Garden.

Why should we be concerned about the arrival of the harlequin ladybird?

Threat to wildlife -

Harlequin ladybirds can seriously affect native ladybird species

Harlequin ladybirds are very effective aphid predators and have a wider food range and habitat than most other aphid predators (such as the 7-spot ladybird) and so easily out-compete them.

Harlequin ladybirds do not have a requirement for a dormant period before they can reproduce, as some ladybirds have (e.g. 7-spot and eyed ladybirds), and so have a longer reproductive period than most other species. In 2004 in London, harlequin ladybird larvae were found still feeding in late October, long after all the native species had sought overwintering sites.

When aphids are scarce, harlequin ladybirds consume other prey including ladybird eggs, larvae and pupae, butterfly and moth eggs and caterpillars.

Harlequin ladybirds can disperse rapidly over long distances and so have the potential for rapid geographic expansion.

Problem to humans -

Harlequin ladybirds have a tendency to aggregate in buildings in large numbers during autumn and winter.

Many people find harlequin ladybirds a nuisance in the house, and do not wish to share their home with a few tens of thousands of harlequins.

As a defence mechanism many ladybird species exude a yellow fluid (called reflex blood) which has an unpleasant acrid smell, and which can stain soft furnishings.

When hungry, harlequin ladybirds will bite humans in their search for something edible. Ladybirds in houses, woken from dormancy by central heating, may bite people as there is no food available. The bites usually produce a small bump and sting slightly. There are a few documented cases of people having a severe allergic reaction to harlequin ladybirds.

Harlequin ladybirds damage soft fruit

In late summer, when harlequin ladybirds are feeding up for the winter, they will seek ripe fruit and suck the juice from it to gain sugar. They thereby cause blemishes on late summer ripening fruits, such as pears, and reduce the value of the crop.

Harlequin ladybirds are also particularly fond of grapes, and wineries are finding large numbers in the grape harvest. These are difficult to separate from the grapes before pressing, and the defensive chemicals (reflex blood) produced by the ladybirds taint the wine.

What can we do?

Probably not a lot - perhaps one day it'll dawn on us that we ain't that good at doing the job "Mother Nature" does naturally!