Dear Readers, at this time of year many people become terrified of the spiders that suddenly seem to ‘appear’ in their gardens, sheds and, worst of all, their houses. I have every sympathy with arachnophobes, but I wanted to add in a few facts that might help those of us with a milder antipathy towards these fascinating animals to enjoy their autumns a bit more. These are fascinating animals with extraordinary life histories, and it’s possible to cohabit with them quite happily, as I know.
I recommend ‘Charlotte’s Web’ as a way of rehabilitating small children who are starting to develop a fear of spiders. It really works as a way of inspiring empathy and curiosity, surely great attributes for life.
Firstly, as far as the garden and shed goes, the spiders have been there all along, as spiderlings or eggs. We only start to notice them when they get big enough to see, and when they start flinging their webs at head-height across our paths. In the garden, the vast majority are Garden Cross Spiders (Araneus diadematus), easily identifiable by the ‘cross’ on their abdomen. Many of them are females, who will lay their eggs in the autumn and then die – they can grow up to 15mm long, but the pregnant ones will also look extremely fat.
What seems to cause people the most trepidation, however, is the sudden sight of a house spider creeping along the skirting board. There are two species that you’re likely to see in the autumn: the large house spider (Tegenaria gigantea) and the common house spider (Tegenaria domestica). Both have very long legs, which is probably one reason why they give so many people the willies, but then the males in particular have to do a lot of running around, as we’ll see. The common house spider is similar to its ‘large’ relative, but is naturally a bit smaller, and according to my book ‘Britain’s Spiders – A Field Guide’, it tends to be paler, sometimes without those impressive tiger stripes on the abdomen. The common house spider is known as the barn funnel weaver in North America.
The female is bigger than the male in both species. However, you are unlikely to see her (unless, like me, you tend to leave cobwebs in corners) – she makes a tube-like retreat which spreads out into a sheet, and there she waits for gentleman callers. In fact, if not wafted away with a feather duster, a web may be inhabited by several generations of house spiders, like an ancestral mansion out in the shires.
The males are looking specifically for a female who has not already been mated: they can tell if she’s receptive to their advances by pheromones that she secretes into her web. But life is extremely tough for a male house spider (you can tell that it’s a male by the ‘boxing gloves’ or pedipalps that are attached to their ‘jaws’, as in the photo above). They might get into fights with other males. They won’t eat, because they only have one thing on their minds. But they do get thirsty, and our homes are very dry environments – one reason why you often find the poor souls in the shower or bath tub.
When they find a female, they tug the web with their feet and fangs and dance up and down, to make sure the female knows that they are male and the right species. If they mess this up, they could be dinner. If all goes well they will move in with the female for a while, and it’s not unusual to find a pair snuggled up together in the web. The male is waiting for the female’s final moult, when she will be ready to reproduce: those palps act like hypodermic syringes to inject her with sperm. Then the male may stay with her, guarding her against other males and mating with her frequently. Sometime in the winter, though, the male dies, leaving the female alone.
The female doesn’t lay her eggs until the following spring, and the young take 30-50 days to hatch. Right from the start they are formidable hunters, eating tiny fruit-flies to begin with but soon graduating to houseflies, bluebottles and house moths. Spiders don’t have to eat often, but they have a feast or famine approach, storing up the sad little corpses when there are lots of flying insects about so that they have enough for a rainy day. However, the availability of food when young does impact on the size of the adult spider, and being big both helps with the number of eggs that can be produced (in females) and in the ability to protect your mate from other males. This might be one reason why we sometimes see ‘monster’ spiders of a whacking 10 cms to 14 cms long, though I imagine my readers from other parts of the world are having a good old chuckle at this moment, especially anyone in South Africa or Australia, where the arachnids are decidedly more substantial.
So, the poor old house spider doesn’t have an easy life of it, and all it wants to do, as it scuttles out from behind the sofa, is to find a mate, reproduce and die. Incidentally, although escorting the spider outside is undoubtedly a better option than dropping a hot water bottle on the animal from a great height like my grandmother used to, it still isn’t very helpful for the spider. Male spiders only want to find a female of the same species, and these are usually living in your house or shed, so if he can find a way back in, I’m sure he will. Otherwise, if at night you hear the sound of a tiny guitar being plucked by one of 8 hairy legs as a lady spider is serenaded from outside your house, I hope you feel very, very guilty.