Spiders in the Amaurobiidae (lace web) family

Amaurobiidae (lace web) overview

There are just 5 British species in the Amaurobiidae family. All have eight eyes (see the drawings below showing the eye arrangement) and are medium to large, fairly chunky looking spiders. They are called the lace webs as the web is made of a wooly silk which has a blueish tinge when fresh. Later, and when the spider adds to the web each night the silk turns white and can be very messy with bits of debris, dust and the remains of past meals attached to it. Often the web is built around a hole or a crevice or even dense vegetation where the spider can retreat.

Amaurobiidae head, front and top view

Males mature in the late summer and autumn. Males and females are very similar except that the males are slimmer and have longer legs. The male seeks out a prospective mate, and when he finds one he strums the threads of her web to find out if she is interested. The eggs are laid in a sac in the retreat, and the spiderlings often eat their mother before dispersing.

Amaurobius similis

Amaurobius similis

Amaurobius similis is above. I believe she is A. similis and not A fenestris because of her size. They tend to be found on structures, window frames being a favourite. They usually construct a silken tube in crack and crevices. This one was found inside the bathroom during a particularly bad spell of weather. She already had one of her third legs damaged. I kept her overnight to photograph her, then let her out in the morning when the weather was better. They are common throughout most of the U. K. Male body length is 6 - 8 mm, and female is 9 - 12 mm.

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