Spiders in your house? Relax, they’re just looking for love

The arachnids invading your home at this time of year are fully grown males crawling towards the women of their dreams

Welcome home: a house spider (Tegenaria domestica). Photograph: Thinkstock
Welcome home: a house spider (Tegenaria domestica). Photograph: Thinkstock

Autumn is a great time of the year for fashionistas, as the autumn-winter collections hit the shelves, but it's not such a great time for arachnophobes, because it's around this time of year that your house seems to be overrun with creepy spiders.

It can’t have escaped your attention that, over the past couple of months, spiders have been treating your house like Airbnb (except without the payment). And some of them are big, hairy and very scary.

Their appearance is usually signalled by the blood-curdling scream of your spouse. Once you’ve established that there’s no axe murderer in the house (no, it’s far worse than that), there’s the panicked demand to “get rid of it now” followed by the entreaty “don’t kill it”.

A zebra jumping spider (Salticus scenicus). Photograph: Thinkstock
A zebra jumping spider (Salticus scenicus). Photograph: Thinkstock

Not that killing them will bring bad luck, but they are more use to us alive than dead, because they keep the insect population under control.

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Eight-legged invasion

So, what’s causing this eight-legged army invasion? Did they stow away on a banana boat en masse and land at every port? Are they exercising spider squatters’ rights? Or are they simply looking for a warm, snug place to get in out of the cold: your winter wardrobe perhaps? And how come they’re so bloody B-movie big?

The explanation is simple. These are fully grown, mature male spiders – hence the intimidating size – and, like any hot-blooded male, are in search of a mate.

They’re out on the prowl, hitting all the hot spots in the hope of pulling a nice lady spider and being invited back to her web. They’re seeking warmth all right, but it’s the glow of love they’re after rather than the glow of your hearth. Common places to spot them are in your bath, behind the toilet (shudder) or running out from under your sofa or bed (double shudder).

But they’re looking for love in all the wrong places, because, while they’re wandering about your house like a clueless stag-partygoer lost in Temple Bar, the females are waiting patiently in their webs for suitors to call, and wondering where all the good men have gone these days.

Female spiders are more likely to stay in the garden, or in your shed or under-stairs cupboard, where they won’t be disturbed.

When the male spider does finally locate his true love’s lair, he will move in with her for several weeks (typical bloke) and mate with her repeatedly. Some species “pluck” the strands of the female’s web to signal their intent – a method familiar to flamenco guitarists.

The male usually dies before winter sets in, while the female will bed in for the winter, so we can look forward to a spider-free season.

When spring comes, she builds up to 10 egg sacs, spherical structures that hang from her web, each one containing up to 70 eggs. When the spiderlings hatch, they’ll stay on the web for a few days, being cared for by the mother, then disperse before they possibly get eaten by their siblings.

During a warm, wet summer, spiders have more prey to feed on, and thus grow bigger than usual. The UK has had a particularly mild if damp summer, so householders across Britain have seen an increase in numbers and size of their house invaders.

Our summer hasn’t exactly been a scorcher, but it’s been mild (and wet) enough for the spider population to thrive, and the particularly temperate September and October hasn’t done them much harm either.

Inevitably, the arachnid invasion has brought its share of scare stories, mostly revolving around false widow spiders, whose venom can cause painful swelling and redness, and in some cases can trigger a severe allergic reaction. According to a recent British tabloid report, “millions of Brits could be at risk” while they sleep, as “Britain’s deadliest spider” comes into people’s bedrooms, usually via an open window. This is juicy stuff, guaranteed to give you bedtime shudders and have you sealing up your room.

The false widow spider certainly has a nasty bite, said to be similar to a bee sting, but unless you have an underlying medical condition, chances are you’ll survive.

Sightings of the species are still quite rare, and false widow bites are less common than the media reports would have you believe.

So, how do you tell if a spider is just a harmless house variety or a venomous threat? For some people, anything with eight legs is a clear and present danger, but if you can hold your nerve long enough to download the Spider in da House app from the Royal Society of Biology, you can learn how to identify some of the 660 species of spiders found in the UK and Ireland.

SPIDER-SPOTTING: FIVE COMMON SPECIES

  • House spider (Tegenaria domestica): The most common spider you'll spot in the home. The tegenaria usually lives in the shed, garage or wood pile, but will wander into the house in search of a mate. They make sheet webs with a funnel-shaped retreat.
  • Giant house spider (Eratigena atrica): These blighters are one of the biggest of the northern European spiders (although they are dwarfed by the giant Cardinal spider). They used to belong to the tegenaria genus, but now have their own classification, which is an anagram of tegenaria. They may be big, but the biggest threat they pose is to human eardrums due to screams of people who are scared of them.
  • Tube web spider (Segestria SPP): These spiders lurk in holes on outer walls, lining their lairs with a tubular web, then weaving tripwires around the entrance for their prey to stumble over. The smaller Segestria senoculata has an elongated abdomen with a series of dark diamond-shaped markings.
  • Money spider (Linyphiidae): Probably the most welcome residents of the home because (a) they're tiny, and (b) superstition has it that if one of these spiders lands on you, it will bring you financial good luck.
  • Zebra jumping spider (Salticus scenicus): The zebra, the most common of the jumping spiders, stalks its prey in a cat-like way before pouncing. They have excellent vision thanks to four pairs of large eyes (one pair particularly large). They will raise their head to look up at you, giving you the unnerving feeling they're about to jump on you.
Kevin Courtney

Kevin Courtney

Kevin Courtney is an Irish Times journalist