Alien invasion: Non-indigenous spiders thriving across Britain

Any arachnophobes should look away now. It has emerged that numerous species of non-indigenous spider, some venomous, are spreading across England at an alarming rate thanks to rising temperatures.

The problem has become so acute in some parts of the country that people are beginning inundate experts with worried calls about a host of frightening-looking species that have started turning up in their gardens and houses.

Until recently, most were limited to areas around ports in the South, where they would have come in on imported goods such as plants or building materials and then died off over winter. But, in recent years, scientists have noticed colonies surviving and spreading further afield.

One such species, Steatoda paykulliana, used only to be found on rare occasions in imported goods but has now created colonies in and around Plymouth. Part of the false widow spider family, it is distantly related to the black widow that, on occasion, can administer a fatal bite.

No one has ever died of a spider bite in the UK, but the spread of the paykulliana – a native of southern Europe, west Asia and North Africa – is causing alarm because its venom is more toxic than that of native species. Experts say a bite would be similar to a bee sting.

Stuart Hine, head of the Insect Identification Service at the Natural History Museum, has recently set up an online forum where people can post pictures of spiders that they do not recognise. "Many of these invasive species have been in Britain for a while but the difference is that the public are now coming across them," he said. "So far the species that have been introduced are not all that venomous but I don't see any reason why a black widow wouldn't be able to make a home here."

One of the species people are coming across most often is Segestria florentina, or the tube web spider. It used to be limited to east London's docks and ports on the South Coast but can now be found as far afield as the Midlands.

Unlike native spiders, it can become aggressive when cornered and, although not venomous, has been known to bite. "I received a call recently from a father whose 18-month-old child had picked one up," says Hine. "It gave him a hell of a fright."

"Fruit imports don't bring over that many foreign spiders," says Matt Shardlow, a director of Buglife, which wants stricter controls on imports that might contain non-native species. "The big problem is pot plants, as the soil they are in can harbour all sorts of species."

New species...

Steatoda nobilis

A less venomous member of the false widow family, which was probably introduced into Britain from the Canary Islands and Madeira. Can now be found across the South-west.

Argiope bruennichi

A native of southern Europe, Argiope bruennichi has been living happily in southern England for decades. Often called the wasp spider because of its yellow and black colouring, it is not venomous to humans.

Steatoda paykulliana

Frequently mistaken for the more dangerous black widow spider, Steatoda paykulliana is part of the false widow family and has created colonies in Plymouth. It is mildly venomous and can deliver a nasty bite, likened to a bee sting.

Segestria Florentina

A member of the funnel web family, the tube web is now one of Britain's largest spiders. They spin a tubular web, often in masonry cracks, and are known to bite. Can be found across the South and the Midlands.

Dicranopalpus ramosus

Not technically a spider, Dicranopalpus ramosus is a species of harvestman that was first spotted in Bournemouth in 1957 and can now be seen as far north as Tyneside. Harvestmen differ from spiders in that they only have one section of body as opposed to two.