The Walnut Orb-Weaver Spider

I found this spider crawling around on the side of a shed last summer. With its dark, leathery, flattened body and disconcertingly slow movement, it seemed rather, well, sinister. It certainly appeared much meaner than most of the spiders to be found in the garden: a sneaky, dangerous-looking creature with something of the night about it. Concerned that it might be capable of a nasty bite, I left it well alone.

In fact, this little beastie is a perfectly ordinary, harmless garden spider. Despite being extremely common it is rarely seen as it is mostly active at night. During the day it squeezes its thin body into crevices, often under bark, hidden well out of sight of any predators. Then in the evening it emerges, cautiously, and spins its flat, circular web. Once it has finished this construction it will move to the web’s centre and stay there perfectly still, waiting for unwary flying insects to get trapped.

If the spider feels spooked during the night it will return to hide in its crevice, slowly following a guideline of silk. Before the sun rises it completely dismantles its web, leaving no trace that it was ever there. Given that the webs can reach 70 cm in diameter, this daily cycle of building and demolition seems like an extraordinary waste of effort. Maybe all this work just fills the time, or maybe the webs are actually a bit naff and so wouldn't last more than a night anyway.

If you spot one of these spiders it's likely to be a female. These are bigger, at up to 15 mm long, and are active all year. Males on the other hand only ever grow to 9 mm and are only out and about during the summer. Interestingly, if you pick up a male it may bite you, although however hard it chomps down it won't do you any real harm. The Walnut Orb-Weaver would seem therefore not to be the villain it appears. It does 'live in the shadows' as its Latin name Nuctenea umbractica implies, but this is simply because it is too cowardly to come out during the day.