Sunday, 20 July 2008

The Harlequin Ladybird

Another Asian coloniser destroying Our Country

The most invasive ladybird on Earth has arrived in Scotland. Harmonia axyridis originally from eastern Asia spread rapidly across north-western Europe and was first spotted in the south east of England Sept. 2004. It may have hitched a ride up here with tourists or come in with imported plants and flowers both are plausible vectors. It was only a matter of time before this alien predator turned up elsewhere in the UK, and they are now in Perthshire and Orkney. The assault on Scotland has begun.

Harlequin ladybirds have a rapacious appetite and are fond of aphids but having consumed all they can find will soon turn to other things. These include the young of our own native species of ladybird, (of which there are about 43), and the eggs and caterpillars of moths and butterflies.

When the Harlequin was first reported in England specialists warned that some of our more unusual species of ladybird could disappear within ten years, but it’s not only the rarer species now under threat, all are endangered. Harlequins tend to aggregate in winter and hibernate in dwellings, tens of thousands have been found in people’s homes waiting for favourable conditions to breed and hence go forth to make possible their conquest.

If the inexorable advancement of the Harlequin is not contained it could decimate our butterfly and moth population, it also bites humans and damages soft fruit, in short it’s an unfriendly pest. Organisation Buglife Scotland a conservation trust is intensely concerned about the situation and has called for government action to eradicate the ladybird. Their aims are threefold.

1. If at all possible, to exterminate the Harlequin ladybird.

2. To join American research efforts to find a long-term solution to the problem.

3. To work in the EU to secure better bio-security for the continent.

The case of the Harlequin ladybird, however, is not a unique occurrence. Many examples abound where the introduction of a new or alien species, accidental or deliberate, has been ecologically devastating to the native residents.

Everyone must be familiar with news relating to the expanding numbers of grey squirrels (Sciurus carolinensis) throughout the UK. Directly because of this increase the native red squirrel (Sciurus vulgaris) is in drastic decline. Greys compete with reds for food and shelter, and also spread the squirrel- poxvirus. Greys are immune to this disease, but it kills the reds. Attempts have been made to produce and establish a sort of immuno-contraceptive into the grey squirrel population, supposedly to attack their reproductive systems, alas it failed, and an effective vaccine according to Defra is at least ten years away. Meanwhile the reds have fled to the extremities of the country. There are a few in Northumberland and a few more in Scotland. Another disturbing detail is that it’s not possible to reintroduce the red squirrel into a grey squirrel region since they are easily out-competed or else become infected and die.

Plant life also has its foreign aggressors. Non-native invasive plants are the second most significant threat to our native plants after habitat destruction. Noteworthy is the Spanish Bluebell (Hyacinthoides hispanica). It hybridises with our native bluebell (Hyacinthoides non-scripta) causing a loss of genetic distinctiveness. The Spanish variety is not as delicately beautiful as our own bluebell and has no perfume. Surveys reveal one out of six woodland sites to be infected.

Another problem plant is New Zealand Pigmy Weed (Crassula helmsii), which is semi-aquatic. Just a minute fragment of this virulent species can regrow and multiply into a dense mat of vegetation. When introduced to a site it becomes the dominant species within three to five years destroying bio-diversity and choking up ponds and waterways. The cost of removing Crassula from ponds in the New Forest in 2002 was a staggering £110.000. Its sale in Scotland is banned in fact the Conservation (Scotland) Act 2004 has banned the sale of quite a number of plants which pose a danger to the environment and is presently engaged in lobbying the government with the intension to include legislation for England and Wales. Well done Scotland, we never did take kindly to being invaded.

Could there be a correspondence emerging here? Often within the science of Ecology in general and Population Dynamics in particular there is a remarkable tendency to leave mankind out of the picture. The examples above illustrate what inevitably occurs when there is competition for resources and territory, yet our theories and hypotheses are seldom directed towards ourselves. We evolved through natural selection just like ladybirds, squirrels and bluebells and therefore cannot be left out of the equation. We are subject to the same forces and behavioural predispositions. What is happening all around us all the time in the ‘animal and plant kingdom’ is happening to us too. We, the native population, are under threat from dwindling resources, lack of space, disease and dilution of the gene pool. Whilst remedial action is undertaken to some extent on behalf of other species there appears to be no such assistance for our native variety of Homo sapiens. We must mobilise before it’s too late… join the BNP now to battle trespassers, invaders and embryonic dominant species.



Anonymous said...

An interesting article, Elizabeth! Your analogies are compelling.

Infidel K9 said...

At least we can be thankful

Grey squirrels dont explode on trains