Two spiders in the bath - only one came out alive

Cellar spiders Pholcus phalangioides look fragile, with those long, slender legs, but they are formidable hunters. This is what happened when a house spider climbed down into our bath, to drink from a dripping tap, and became trapped. The cellar spider climbed down after it, snared it with silk, bit and paralysed it, then wrapped up its prey in a silken shroud.

The cellar spider had little difficulty in climbing out, with its prey slung under its body, then spent the rest of the day clinging to the skirting board, guarding its meal from rival spiders.

These lanky, harmless arachnids need warmth and are confined to human dwellings in Britain. In 1958 the eminent arachnologist W.S. Bristowe, in his book The World of Spiders, described how he zig-zagged across England on his motorcycle, requesting to see hotel rooms on the pretext that he might rent them, so that he could check for the presence of Pholcus and map its distribution. He only found it along a narrow corridor in southern England.

Since then this synanthropic spider has moved north – perhaps in furniture removal lorries, because it seems to have a predilection for living behind settees and under tables – and has even reached the Shetland islands.

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.

Cellar spider catches a woodlouse (arachnophobes look away now)

 

The cellar spider Pholcus phalangioides is a welcome guest in our house. In summer it's a very effective fly killerand it also catches and eats much larger spiders, of the kind that sometimes turn up in the bath or race across the ceiling and floor when the cold weather brings them indoors, in autumn. A few cobwebs in corners of the ceilings are a small price to pay for these services.

Sometimes these spiders catch woodlice, which is what this one has trapped in its web, alongside a fly that has already been encased in silk. But this woodlouse was a prize catch, because its a female that was carrying baby woodlice, known as mancas, in its brood pouch, under those armoured plates. They are the tiny translucent woodlice, as yet with no hardened armour, that you can see in the photograph below.

Female woodlice carry their young in a brood pouch under their body, and at this stage the young only have six pairs of legs. After their first moult they develop an extra body segment and after the second moult they grow an additional pair of legs, so they are then classified as juveniles with the full adult complement of seven pairs of legs.

For a closer look at woodlice, check out my Beyond the Human Eye blog here.

Uninvited house guests

The rain might be lashing down outside but there's still plenty of wildlife to track down much closer to home. Unless your house is hermetically sealed and doused in deadly chemical cleaning agents, any or all of these could be lurking in the shadows.

If you settle down to read a good book and the punctuation seems to be moving around, then you could be looking at one of these tiny booklice. They are not much bigger that a full stop and feed on fungi that grow on damp paper, and also eat the glue that holds the pages together. Old damp paperbacks are prime habitat but they also like nothing better that feeding on wallpaper paste behind loose wallpaper. If your wallpaper makes clicking noises, it may be because they are headbutting it during their courtship.

Silverfish. You might have these most ancient of insects, that move like greased lightning, in a damp corner of a kitchen cupboard where they like to feed on starchy foods like flour.

Silverfish Lepisma saccharina are covered in tiny scales that rub-off easily, making it easier for them to wriggle out of the grip of a predator - which might go some way to explaining why they've been around for 400 million years.

This is the firebrat, the silverfish's larger and hairier cousin. It likes warmer conditions and used to be common in bakeries. Give yourself a pat on the back if you provide a home for these - they are not very common.

And finally, the daddy long-legs spider Pholcus phalangioides. Whatever you do, don't throw these out of the house as they can't survive anywhere else. They are humans' constant companions, only ever found inside our homes and outbuildings in our northern latitudes. They are useful to have around, preying on other household invertebrates - even on the fearsome house spider that comes into our homes during cold weather. This daddy long-legs spider is showing her maternal instincts by carrying her eggs around in her jaws.

Climbing the Walls

If you have an oldish house with some dark, damp corners - like ours - the chances are that you'll discover sooner or later that you are sharing it with daddy-long-legs spiders Pholcus phalanioides. This is a spider that is only found inside buildings in Britain. It comes from warmer climates and can't survive outside here.

I spotted this individual climbing the walls of our stair well at around midnight last night and noticed that it was carry something in its jaws.

Its cargo turned out to be its eggs, that looked like they might be close to hatching, which female Pholcus spiders carry around for safety. Even an arachnophobe would have to admire this high degree of maternal care. After dark, when we humans sleep, spiders emerge from behind bookcases, under settees and from inaccessible corners to conduct their nocturnal lives, and this one seemed to be moving home, perhaps to spin one of its untidy webs in a corner where it will catch enough prey to feed its spiderlings. If it doesn't, they'll eat each other. Pholcus is especially partial to catching and eating other spiders, including its own kind.

For more on the intriguing world of spiders take a look at the British Arachnological Society web site at http://wiki.britishspiders.org.uk/index.php5?title=Main_Page