October 14, 2008

Imports Bring New Species Of Spiders To UK

Scientists say that certain exotic species of spiders are making their homes in the UK.

Due to the UK's increasingly mild climate, arachnids arriving in imports of food and plants are now able to survive and spread.

A species of false widow spider have been confirmed and some believe the deadly black widow could be the next to invade.

The conservation group Buglife wants import rules to be strengthened to stem the tide of alien species invasion.

"Other countries in the world take great care about what biological material they allow in, because it can contain pests that can damage our goods, our livelihoods, our health and our biodiversity," said Matt Shardlow, director of Buglife.

"Currently in the UK, we have a laissez-faire attitude - there is an open license for people to bring in dangerous pests."

But a new strategy was in place to "tackle the threat to the UK's native biodiversity from unwanted pest species which have 'hitchhiked' into the UK on plants", according to a spokesperson for the Department for Environment, Food and Rural Affairs (Defra).

John Partridge from the British Arachnological Society said his organization had had an increase in the number of enquiries about "strange spiders".

"We are certainly getting more spiders coming into the UK - and it seems that more are spreading around the country once they are in," he said.

The Steatoda paykulliana, a false widow spider that is native to Southern Europe, West Asia and North Africa is one of the new inhabitants. It is about 0.7-1.5cm (0.3-0.6in) in size and can bite.

Experts say the spider had been noted in the UK in the past, but it was thought that no colonies had established.

However, Stuart Hine, who runs the Insect Identification Service at the Natural History Museum, said this was no longer the case.

"Now we have found it in Plymouth. And it looks as if it is here to stay."

Hine said the arrival of exotic spiders and insects that had hitched a ride on various imports was not a new phenomenon.

"If there was a warm period they would be able to survive, but a cold snap would kill them off," he explained.

"But now, our increasingly warm climate is starting to suit many more spiders - and once they come in, they are able to stay put."

The warming has caused invasive species that once only existed within a few small pockets in the UK to spread.

That includes the Steatoda nobilis. This false widow is thought to have first arrived in the UK from the Mediterranean in the late 1800s.

For decades it remained in a small area within Devon, but about 15 years ago it began to spread and it can now be spotted all along the South Coast.

"It has a nasty bite - and some people can have a bad reaction to it," Hine said.

Also on the move, spreading from the South Coast much further north is the tube web spider (Segestria florentina), another non-native biter. It is a large spider, measuring between 1.5cm and 2.2cm (0.6-0.9in), with green iridescence on its jaws.

"In spider terms, it has to be said that this is an aggressive spider. If you approach it, it raises its legs and bares its fangs."

"Most spiders will back away - this one will jump at you and bite."

The black widow spider could be next on the list for the UK, Hine said.

"There is no great reason that they wouldn't survive here now - winters are now mild enough. It really is only a matter of time."

Although experts stress that not all new species have a negative impact, but they do warn that trade is a key factor in the number of new species that enter the country.

Defra is responsible for checking the products that enter the UK.

"The government and its agencies work with businesses, overseas authorities and the general public to minimize the risk of exotic animal and plant pests and diseases from entering the country and threatening public health, livestock, agriculture, horticulture and the environment," a Defra Spokesperson said.

"Disease can enter the country in many ways; that's why Defra undertakes international disease monitoring, while there are also strict controls on the movement of livestock and animals."

"We cannot just view moving biological material around like other trade products," said Shardlow from Buglife.

"You have to have a bit of environmental awareness, and I think we should be looking to import and export less biological material."


Image Caption: Steatoda nobilis, commonly known in England as the biting spider or the false black widow (though several other species are known by the latter name), is a common species of spider in the genus Steatoda. As one of this spider's common name indicates, the spider superficially resembles, and is frequently confused for, the black widow and other venomous spiders in the genus Latrodectus. The spider is native to the Canary Islands but arrived in England in around 1870 through bananas sent to Torquay. In England it has a reputation as one of the few local spider species which is capable of inflicting a painful bite to humans - although this is a comparatively rare occurrence. Courtesy Wikipedia


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