June 23, 2005

Hobo spiders bum a ride

Every day I take the train to work over a bridge across the sound between Sweden and Denmark. Its not completely bridge though. A third of the distance is a normal high suspension bridge. A third of the distance is a tunnel. The 5 kilometers in between are spanned by an island made from sand scooped from the seabottom. The new island is next to an existing island named saltholm and has been named pepparholm. Biologists have been studying the island to record how it is colonized by new species. Already after 3 years there are an amazing variety of flowers and grasses, and even a few bushes. The seeds are brought to the island by wind, sea currents or birds (vehicles are not allowed to stop on the island). All this is very nice, but today I read that they have found a colony of two inch long poisonous spiders on the island that are native to the Pacific Northwest and unknown in Sweden. How did the Hobo spiders (Tegenaria agrestis) get there? Apparently they were carried by the wind from Denmark, where they were first seen two years ago. How did they get to Denmark?? I really don't know.

2 Comments:

At June 24, 2005 9:51 AM , Blogger Matt_J said...

There was an error in the article in the Swedish newspaper where I heard about the Hobo spider. Turns out the spiders are originally from Western Europe and were introduced to the Pacific NW in the 1930s, probably from european agricultural products-- see http://hobospider.org/.

 
At August 19, 2005 7:24 PM , Anonymous Andrea said...

Reminds me of the Chunnel - the British fear that it will bring the introduction of rabies to England

 

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