Watch out – the spiders are coming

Warm damp summer means arachnid numbers are set to soar. You have been warned, says Michael McCarthy

Good news for naturalists; bad news for arachnophobes. Reports of sightings from around the country suggest this is an absolutely bumper year for spiders. In gardens and garages, in houses and hedges, in town and countryside both, spiders are unusually prominent this autumn, spinning their shimmering webs in such numbers that the conservation charity Buglife is asking people to go on a spider hunt this weekend and next.

Buglife – officially the Invertebrate Conservation Trust – wants to get a proper idea of just how numerous this year's spider crop really is, and also try to counter some people's arachnophobia, as fear of spiders is technically known (from the fact that spiders and scorpions are not insects but arachnids, with eight legs as opposed to six).

"Spiders get a very bad press generally and we want people to reappraise them, and see how they are important to the local environment," said Matt Shardlow, Buglife's director. "Britain is very bad for spider phobia – it's worse here than in countries where they do have venomous species. I don't think we're genetically hard-wired for it. I think it has a social origin – people react to other people's fear."

In fact, Mr Shardlow points out, none of Britain's 650 spider species can deliver a fatal bite and only one uncommon species, the noble false widow, can even give a bite that will cause discomfort. The rest, including all the spiders you are likely to meet in your house and garden, are entirely harmless.

Right now, many are very visible as the generally warm and damp summer has provided ideal breeding conditions after the two washout summers of 2007 and 2008; and they are not only numerous, but not a few seem larger than normal as there has been abundant insect food for them (and some of the females are heavily pregnant).

"It's been an absolutely fantastic year for spiders," said Dante Munns, a naturalist and spider enthusiast who runs the Dorset nature reserves of the Royal Society for the Protection of Birds. "It's one of the best autumns I've ever seen for them. On misty mornings the webs seem to be glistening everywhere, and the countryside is full of them."

Spiders Mr Munns has been noticing and enjoying on his nature reserves recently include wasp spiders, whose females are brightly striped in yellow and black, and raft spiders, palm-sized beasts which do not spin a web but float on the surface of the water and feel the vibration if an insect falls in (which they then scurry over to capture.)

More familiar spiders Mr Shardlow has been watching include the garden cross spider, the common house spider and the daddy-long-legs spider, all of which you are more likely to see around your home, and all of which might seem to some people surprisingly large, although they present no threat whatsoever.

Buglife is asking people to poke around in their houses, garages, gardens and sheds to see if they can spot and identify 10 spider species over this weekend and the first weekend in October – and send in their results using the Buglife website at www.buglife.org.uk.

Five spiders to spot this weekend

*Garden cross spider

Araneus diadematus

The commonest garden spider, with a white cross on its back that looks like a crucifix; spins an orb-like web.

*Common house spider

Tegeneria domestica

Spins a sheet web instead of an orb web, usually in the corner of a room, which is why cobwebs seem to collect in corners.

*Wasp spider (female)

Argiope bruennichi

First seen in the 1920s, but has now spread throughout much of southern England. The female's wasp-like coloration is thought to be mimicry which serves as a defence against predators such as birds.

*Daddy-long-legs spider

Pholcus phalangioides

Common in house cellars, this has a long thin body and even longer, thinner legs. It will eat other spiders, if they blunder into its almost invisible webs in dark corners.

*Raft spider

Dolomedes fimbriatus

This spider has worked out that water can have the same properties as a spider's web: it can trap insects, and convey the vibrations caused by their struggles to the spider waiting on the surface.