Along came a million spiders (looking for love)

Don’t be alarmed if your garden looks like a world wide web of arachnids. It’s mating season!

IT’S THE time of year when spiders seem to be everywhere – big ones, fat ones, hairy ones. Surely there are more than have ever been seen before? But no, it’s perfectly normal, because September is the month when spiders look for partners and mate so as to ensure the survival of this most essential group of creatures.

There are, broadly speaking, two sorts of spiders in Ireland. There are the web-spinning spiders which spin webs to catch food, and the hunting spiders, which chase after their food. These can make webs too for nests, but they don’t catch food in them.

We are all well up enough on spiders to know that they are not insects – they have eight legs, not six as insects do, and thus are termed arachnids. But did you know that they have eight eyes too, arranged in a circle on the top of their heads? A sensible place to have eyes if you are watching out for attack from above from hungry birds.

There are many species of webspinning spiders, distinguished by the shape and complexity of the web they spin. One particularly common one is the garden spider which has a white cross on its back making it easy to identify. It often spins its web on the outside of the kitchen window. This is an invisible, sticky, flexible curtain, constructed on a highway that is hopefully frequented by lots of flies. The anchor lines are dropped first. These are lines of good strong spider silk, so that the whole edifice has a firm foundation.

THEN the spider spins the thin sticky strands, which are actually the trap, from the centre out and sits at the side attached to the last silken strand. Then he waits for a fly to blunder in. And when one does, it is the vibrations on the end of the strand attached to the spider that alerts it to the presence of food.

Out it charges at once, across the web to the struggling victim who is now stuck fast. A quick bite with a dash of venom to the hapless fly and he is no more. He can be eaten on the spot by sucking out all the juicy insides, or, if the spider is a trifle full, the fly can be embalmed in lots of new silk and hung up in the spider’s larder for leaner times. The fly didn’t have a chance once it touched the web; the sticky silk quickly entrapped it.

But did you ever wonder how spiders themselves don’t get caught in their own webs? There are two reasons, actually. The main anchor stays of the web, substantial threads of silk, are not sticky and the spider knows to move along these highways. But what about when it gets to the struggling fly in the sticky bit? Well, the spider has oily feet which don’t stick to the sticky strands so it doesn’t look like an eejit getting caught in its own web.

This means that spiders don’t get stuck in each other’s webs either, but why would you want to go calling anyway if your neighbour is a savage cannibal? Spiders – particularly females – have no problem eating other spiders that come their way. So, if a dashing young spider’s thoughts turn to love, how can he win the lady without becoming her dinner? Well, like any good suitor he must bring a gift when he comes calling. A nice juicy fly, particularly well wrapped in sticky web, fits the bill, and no courting spider would set off without this.

Mating in most species normally involves an extremely close intimate encounter, but our hero really doesn’t want to get too close. So, in matters amorous, his interesting body design comes into its own. Male spiders can transfer their sperm to the ends of their palps – two antennae-like appendages on their heads – which gives them literally breathing space during a mating encounter.

A spider out for a night on the town arms himself with a juicy present, arranges his personal toilette, and comes calling on the neighbouring web. He indicates to herself that he has arrived by vibrating the sticky silk in the web. She thinks that dinner has landed and rushes out to polish off the intruder. Our hero quickly thrusts the gift-wrapped fly at his ladylove and while she is distracted unwrapping the present, mates gingerly with her from as far away as possible, keeping her literally at palp’s length. If he hasn’t wrapped the present enough, or lingers too long in the love department, herself has no compunction gobbling him up. The adrenalin rush must be mighty.

ACTUALLY, it makes no difference to the survival of the species if the female eats the male after mating. In fact the extra protein will come in handy for the ensuing egg-laying – because the vital sperm and male genes have already been transferred.

That’s the web-spinning spiders. Then there are the big black spiders you find under loose floorboards or at the back of the garden shed. These are the hunters.

These spiders come out at night and chase their prey – earwigs, beetles, woodlice, anything that will provide a meal – around the garden. And they hunt over the whole garden and the walls of the house, anywhere they can find food. They come in and out of the house through open windows with impunity. They do, that is, until they unfortunately enter the room in the house with the spider trap and, indeed, the room most likely to have the window open – the bathroom. They race around this room too, until they have the bad luck to fall into the bath. Then they are trapped. They cannot climb up the slippery sheer sides. And of course, it is always a huge spider that gets trapped in the bath. The small ones seem to be light enough to scramble out.

What should you do about the situation when you are finished screaming? The clever thing to do is to put the plug into the plughole. End of problem. This is not because it stops them coming up the plughole – they’d want to be equipped with sub-aqua gear to get through the water trap in the S bend. No, it quite simply provides them with a ladder – if a spider falls in, it can climb up the chain attached to the plug and escape. A towel casually thrown over the edge would do the trick as well. Simple, really.

Most of the spiders in this country do us no harm at all. Their jaws are not strong enough to bite us, and they haven’t enough venom to kill us. They are tiny, really, in the world order of spiders. Our biggest spider would have a body size at most of about 20mm and its legs might be this length again; the whole thing, legs and all, would easily fit in the palm of your hand – a far cry from your average tropical tarantula.

We have just over a thousand species of spiders in Ireland – a very small proportion of the 35,000 species in the world. New species get here from time to time. A recent addition is the false widow spider. This mostly lives outdoors and so this is where we usually encounter it. Although it doesn’t seek us out to attack, it can bite us if caught up in our clothing, and although normally no worse than a wasp sting, the bite can cause a reaction in more allergic people.

But we have no seriously dangerous spiders here – Australia is the country for those. Ours are just an essential part of our biodiversity. We should leave them in peace.