Sunday 22 February 2015

I-Spi

I became interested in spiders last summer, and attended a workshop at Preston Montford, which was part of the Invertebrate Challenge programme. Over the winter I have not spent much time looking at them, but a spider with distinctive markings on the abdomen, found climbing up the curtains in our bedroom, made me curious.

I dusted off one of my favourite, and least expensive, pieces of kit - my Spi-pot. This was given to me by Richard Burkmar at the aforementioned spider day. It is essentially a couple of inches of pipe covered with clingfilm at one end, with a foam plunger inserted into the other. The idea is that you pop the spider into the chamber and push the foam plunger until the spider is pressed immobile against the clingfilm. This allows you to examine and photograph it without causing any damage.

Spi-pot

By doing this and looking closely at the spider I was able to narrow the choice down to a female of one of the Lace-weaver Spiders. The combination of glossy carapace and velvety abdomen, with the distinctive cream markings, was helping with the identification.

Amaurobius similis (Lace-weaver Spider)

There are two very similar spiders in this genus, Amaurobius similis and A. fenetsralis. Of the two, A. similis is found in and around buildings, whilst A. fenestralis is found in and around bark, logs and leaf litter. This means that A. similis is overwhelmingly more likely to be present in the house, but I wanted to see if I could be certain. One of the benefits of the Spi-pot is that you can look at the underside of a spider without damaging it. Using a lens I could make out the distinctive dark markings on the epigyne, which identifies this as Amaurobius similis. It is difficult to capture the details with my compact camera, but hopefully this gives an idea.

Amaurobius similis (Lace-weaver Spider)

Also yesterday, whilst walking along Batch Valley, I found a snail on a grassy bank. This is one of the plain forms of Cepaea hortensis (White-lipped Snail) - a species I have already recorded this year, but a form I have not previously looked at closely.

Cepaea hortensis (White-lipped Snail)

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