30 October 2012

Spinning spider


Eigg is one of the few locations in Scotland where the Daddy-Longlegs Spider, Pholcus phalanginoides, has been found.

In Britain this spider is quite common in the south, but is only found indoors, though it may be found in caves on the continent. It has an unusual defence mechanism; if disturbed, it rotates its body at great speed so that it becomes blurred.

We found these spiders in the house on Eigg where we were staying last year, and again this year. This year I managed to make a couple of videos of them using this defence behaviour in response to my hitting the wall close to their webs:




By slowing down the videos, I was able to discover that the spider in the first video rotated about 8 times per second and the second at about 5 times a second.

It is sometimes stated that these spiders are one of the most poisonous spiders in the world, but their fangs are too short to penetrate human skin. Fortunately this is a myth. For more information see
http://spiders.ucr.edu/daddylonglegs.html

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