Tuesday, 8 January 2013

Spider House Rules

Another mild, dull day but, ever the optimist, I sallied forth to the pocket park. Over recent weeks I have generally been greeted by the chak-chak of Fieldfares but all was very quiet.

Again I noted leaves of bramble mined by the Glossy Bramble Pigmy Moth Stigmella splendidissimella, first recorded here about three weeks ago. This is a widespread and common 'micro-moth' although I cannot recall ever having found the adult insect.

Now, about those spiders...

Passing my net through some shrubs in the hope of catching insects I took instead a small (2 mm long) female Linyphiid spider. Commonly known as Money Spiders, there are about 270 species of Linyphiids in Britain and identification needs care. As it happens, although I made a dog's breakfast of dissecting the abdomen I manage to isolate the key structure, the epigyne, and was able to identify the spider as Erigone atra. This is an abundant species in many habitats and even occurs commonly on garden lawns.

Few spiders can by identified by the naked eye but an exception is Amaurobius similis; just before commencing my homeward journey I turned over a stone and revealed a specimen of this very common species. It is frequently found in stacks of house bricks and so on and is also abundant around houses where it spins a very sticky, lacy grey web around window frames. I was surprised to find that I hadn't recorded it previously in the Pocket Park and this brings the total number of arthropods (insects, spiders, woodlice, etc) for the site up to 434.  

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