The spider season

 There are some fascinating spiders around at this time of the year. This little beauty is a zebra spider, that lives in my greenhouse. It doesn't make a web, it leaps on its prey. The forward-facing pair of its eight eyes are especially large, giving it binocular forward vision and the ability to judge distance accurately.

The garden spider below has spun its web in my greenhouse, across the doorway: I have to duck under it to get in and out. I watched as it caught this wasp and wrapped it in a silken shroud in less that 20 seconds. In the second picture you can see the prey's jaws protruding through the silk, as it tried to bite its way out - unsuccessfully.

This house spider, below, had fallen into our bath - probably entering the bathroom through an open window after climbing up the outside wall. It most likely fell in when it tried to drink from the dripping tap. It's now re-housed in the greenhouse.

House spiders look fearsome but they are easy prey for cellar spiders that trap them in their silken threads, using their long legs to drape the thread around their prey, then paralysing it with venom. They guard their captured prey, usually taking a couple of days to eat them, leaving only a few pieces of its exoskeleton. 

Both cellar spiders and crane flies are commonly known as daddy-long-legs but when the two meet (below) the outcome is never in doubt. Most crane flies that find their way into our house end up in a cellar spider's web.

Must Remember not to hit F10....

This little zebra spider always appears mid-morning while I'm working on my computer, lowering itself down from the desk lamp and making lively jumps across the keyboard. All the time that it sticks to the dusty keys that I don't use much, like F10, it'll be safe. I presume it's the same one that I photographed on the window ledge back in January, although it has certainly grown a bit since then.

The Spider who was Determined to be on the Web.

There's quite a varied spider fauna on the window ledge in the room where I work (examples here and here) and this very small zebra spider put in an appearance at the beginning of the week, exploring my desk and even my computer keyboard. Since it seemed so eager to get itself on the web, I thought I'd oblige. The pictures are not very good because it really is tiny - just a few millimetres long - and these are small sections of the whole frame.

Zebra spiders don't actually spin a web to capture their prey. Instead they stalk it then leap onto it from a distance. They can do this with remarkable accuracy, thanks to the two large forward facing eyes that are somewhat akin to a pair of binoculars.

There are two further pairs of smaller eyes on either side of the central pair, so this arachnid has almost 360 degree vision. I find it hard to imagine how its relatively simple brain can process, prioritise and respond to all that visual information. It must be like watching six TV screens at once.

As you can see from this angle, its difficult to creep up on a zebra spider from behind - there's a rearward facing eye watching both flanks.

Although zebra spiders don't spin a capture web they do anchor themselves with a thread of silk, ready for instant escape ....... which is what my specimen did when I got too close with the camera ..... it bungee-jumped from the window ledge then climbed back up its escape thread when it thought the coast was clear. The other role of this escape thread is as an emergency safety line, in case the fly that it leaps on carries it aloft before the spider can subdue its victim.